1. A method for producing a program for a numeric controller (NC) of a machine tool for inspecting a workpiece, the method
comprising in any suitable order the steps of:
i) providing a path for a cutter of the machine tool; and
ii) selecting, from a computer aided manufacture (CAM) program containing data relating to a plurality of geometric features
of a workpiece, one of the plurality of geometric features of the workpiece that is to be inspected and generating a measurement
probe path based on the selected geometric feature; and then

iii) creating an integrated program containing both the machine tool cutter path and the generated measurement probe path
for use with a motion control of the machine tool to control the measurement probe path.

1. A frequency tuneable laser device comprising:
a laser cavity formed from a plurality of optical components, the plurality of optical components comprising:
a laser source that generates a beam of light,
a spectral tuning element, and
one or more further optical components that directs the beam of light on to the spectral tuning element,
wherein at least one of the plurality of optical components is a moveable optical component configured to move in a first
degree of freedom, the movement of said at least one moveable optical component in the first degree of freedom simultaneously
altering an effective optical path length of the laser cavity and a tuning frequency of the spectral tuning element, thereby
providing frequency tuning in which mode hopping is suppressed,

wherein the effective optical path length and the tuning frequency are substantially insensitive to any movement of said at
least one moveable optical component in degrees of freedom other than the first degree of freedom, and

wherein the movement of the at least one moveable optical component keeps the beam of light directed on to the spectral tuning
element.

1. A vision machine apparatus, comprising;
an imaging sensor arranged to image an object,
a radiation source arranged to generate radiation having a first property, and
an object supporting base comprising (1) a radiation converter arranged to convert radiation having the first property into
radiation having a second property, and (2) a member that is substantially transparent to radiation having the first property,
is substantially transparent to radiation having the second property, comprises a glass member comprising two layers of glass
and a light diffusing layer sandwiched between the two layers of glass, and has a lower surface to which the radiation converter
is adjacent, wherein:

the radiation source is arranged to project radiation having the first property through the member and onto the radiation
converter, the radiation converter thereby producing radiation having the second property,

the radiation converter is arranged to illuminate, with radiation having the second property, an object to be imaged by the
imaging sensor that is separate from the vision machine apparatus,

the object to be imaged is releasably locatable on an upper surface of the glass member arranged to support the object to
be imaged, between the radiation converter and the imaging sensor, so as to be spaced from the radiation converter by the
member, the object thus being back-lit by radiation having the second property produced by the radiation converter, and

the radiation source is arranged to project radiation having the first property onto the object to be imaged and onto the
radiation converter.

1. A method for producing a passive encoder scale, the method comprising the steps of:(a) mechanically working a scale substrate to form a magnetic scale substrate, wherein the scale substrate is cooled prior to the mechanical working step, wherein the mechanical working step is performed on a substrate that has been cooled to a temperature below room temperature, and
(b) using a laser to locally heat the magnetic scale substrate to form non-magnetic markings therein that define the passive encoder scale in which the non-magnetic markings have a different magnetic permeability than the magnetic scale substrate, wherein the passive encoder scale does not generate a magnetic field.

1. A measurement scale device comprising:at least one scale marking, wherein:
the or each scale marking comprises at least one periodic nanostructure that (i) represents scale device information and (ii) comprises a Laser Induced Periodic Surface Structure (LIPSS), and
the measurement scale device is for determining relative position of two objects.

6. An additive manufacturing apparatus comprising a processing chamber, a plurality of lasers for generating a plurality of
laser beams and an optical module comprising a housing containing a plurality of optical trains for delivering the plurality
of laser beams into the processing chamber simultaneously.

1. A method for measuring a feature of an object, the method comprising:
using a surface sensing measurement probe mounted on a coordinate positioning apparatus to measure at least the feature of
the object and thereby acquire, based on feedback from the measurement probe, a representation of at least the feature that
comprises multiple data points;

fitting, by an analysis device, a model of at least the feature of the object to the representation, the model comprising
parameters defining at least two independently alterable portions that each replicate a different region on the surface of
the object and that are linked along a common edge so that a certain alteration of at least one of the at least two independently
alterable portions causes a consequential alteration of another of the at least two independently alterable portions, the
fitting comprising changing the form of the model by altering at least one of the at least two independently alterable portions;

obtaining information regarding at least the feature from the fitted model;
analyzing the information to determine deviations of at least the feature from a nominal feature; and
providing an output based thereon.

1. Magnetic encoder apparatus comprising:
a plurality of magnetic sensor elements for reading an associated magnetic scale that produces a periodically repeating magnetic
pattern, the plurality of magnetic sensor elements producing a plurality of sensor signals;

an analyser for analyzing the plurality of sensor signals to provide a measure of the position of the magnetic sensor elements
relative to the associated magnetic scale;

the analyser being arranged to use the plurality of sensor signals to assess the period of the periodically repeating magnetic
pattern sensed by the plurality of magnetic sensor elements; and

the magnetic scale having a series of alternating firs magnetized regions and second magnetized regions, wherein:
the first magnetized regions are of the opposite magnetic pole to the second magnetized regions,
centers of the first magnetized regions are spaced apart from one another by a fixed interval such that a distance between
neighboring centers of each of the first magnetized regions is the same, and

each first magnetized region has a first width or a second different width and thereby encodes a data bit, the data bit taking
a first value if the first magnetized region has the first width and a different second value if the first magnetized region
has the second width.

1. A method of locating a feature of an object comprising:
bringing a stylus of a contact probe mounted on a positioning apparatus into contact with the object to obtain at least first
and second measurements of the object, each of which gives rise to a range of possible points of contact between the object
and a part of the stylus along its length and therefore inherently containing uncertainty in the location of the object along
said length, and

using the at least first and second measurements to at least reduce the extent of said uncertainty comprising using known
stylus orientation related information associated with the at least first and second measurements.

1. A method of applying one or more markings onto a metrological scale, comprising:
locating one or more markings with respect to the scale substrate in a provisional state in which the one or more markings
can be removed;

checking whether the one or more markings located with respect to the scale substrate are acceptable; and
finalizing the one or markings which are acceptable so as to transform the one or more markings into a permanent state in
which the one or more markings are less readily removable than in the provisional state.

1. A metrology apparatus, comprising:
a first structure rotatably connected to a second structure by a bearing arrangement, the bearing arrangement including at
least a first friction bearing comprising parts in sliding contact during rotation of the first structure relative to the
second structure;

at least one magnet that relieves the load on the first friction bearing; and
at least one mechanical stop,
wherein the parts of the first friction bearing that are in sliding contact are arranged to disengage when subjected to a
mechanical shock, the amount of displacement permitted during such disengagement being limited by the at least one mechanical
stop.

1. A method of finding an object using an analogue probe mounted on a machine tool, the method comprising causing the analogue
probe and/or object to follow a course of motion which is configured such that the analogue probe is initially sufficiently
far away from the object such that the analogue probe is not in a position sensing relationship with anything and the course
of motion is configured to cause the analogue probe's surface sensing region to traverse past the object to be found a plurality
of times whilst approaching the object over successive traverses so as to ultimately arrive in a position sensing relationship
with the object so as to collect scanned measurement data about the object along at least part of a traverse.

1. An analogue probe for a machine tool apparatus, comprising:
a probe body;
a stylus member movably secured to the probe body in a suspended rest position via a suspension mechanism;
a sensor that measures an extent of displacement of the stylus member relative to the probe body from a rest position;
a first compliant sealing member extending between the probe body and the stylus member such that the sensor is contained
within a chamber sealed from external contaminants; and

a suppressor that suppresses movement of the stylus member away from its suspended rest position induced by a change in pressure
difference between the sealed chamber and the analogue probe's operating environment.

1. A metrology apparatus comprising:
a body and a member mounted to the body by mechanical bearing assemblies such that the member is rotatable relative to the
body about an axis of rotation;

a motor for actuating rotation of the member relative to the body about the axis of rotation;
wherein a surface sensing device is attachable to the member such that the surface sensing device rotates with the rotation
of the member, relative to the body;

wherein the motor comprises a magnet and at least one metal coil spaced apart along the axis and mounted such that the magnet
and the at least one metal coil are moveable relative to one another; and

wherein the motor is arranged such that when it actuates rotation of the member relative to the body, substantially no radial
forces from the motor act on the mechanical bearing assemblies such that the location of the axis remains substantially fixed.

1. A measurement probe, comprising;
a stylus holder deflectably mounted to a probe housing,
one or more sensors for sensing deflection of the stylus holder relative to the probe housing,
a processor for producing a trigger signal when the deflection sensed by the one or more sensors meets a trigger condition,
and

an accelerometer for measuring acceleration of the measurement probe,
wherein the trigger signal produced by the processor is only output by the measurement probe when the acceleration measured
by the accelerometer is below an acceleration threshold.

1. A method of building up a measurement data set for a surface of an object, the method comprising:
using an analogue measurement probe mounted on a machine tool apparatus to obtain scanned measurement data of the surface
over a plurality of offset traverses,

in which a subsequent traverse is offset from a previous traverse such that, over a series of traverses, a surface detecting
region of the analogue probe progresses i) laterally across the object, and/or ii) away from or towards the object, and

in which the course of relative motion for at least one subsequent traverse is generated and/or updated based on data obtained
during at least one previous traverse.

1. A selective laser solidification apparatus, comprising:
a build carrier for supporting a powder bed onto which a powder layer can be deposited;
a gas flow unit for passing a flow of gas over the powder bed along a gas flow direction;
a laser scanner for scanning a laser beam over the powder layer to selectively solidify at least part of the powder layer
to form one or more objects; and

a processor for selecting a scanning sequence of the laser beam based on the gas flow direction.

1. An implantable percutaneous fluid delivery device comprising:
a subcutaneous base portion comprising one or more ports for supplying fluid to one or more implanted catheter devices; and
a percutaneous portion comprising an extracorporeal surface, the one or more ports of the subcutaneous base portion being
accessible from the extracorporeal surface of the percutaneous portion,

wherein the subcutaneous base portion is at least partially insertable into a complementary recess formed in a bone and comprises
one or more anchoring features for directly anchoring the subcutaneous base portion to the bone,

the one or more anchoring features comprise at least one radially protruding wing extending from the subcutaneous base portion,
the at least one radially protruding wing has a proximal end adjacent the subcutaneous base portion, the proximal end of the
at least one radially protruding wing being configured to lie within the complementary recess formed within the bone, and

the at least one radially protruding win has a lower surface that curves upwardly towards an outer surface of the bone as
it extends outwardly from the subcutaneous base portion.

1. A non-contact method of inspecting the topography of an area of an object via analysis of the phase of a pattern projected
on the object, comprising:
i) taking a first image of the object, obtained from a first perspective, on which an optical pattern is projected;
ii) taking a second image of the object, obtained from a second perspective, on which an optical pattern is projected but
in which the optical pattern, as it falls on the object, in the second image differs to that in the first image; and

iii) determining data describing the topography of at least a region of the object based on phase data relating to the phase
of at least a region of the optical pattern as imaged in the first image in which phase data obtained from a corresponding
region of the object as imaged in the second image is used to resolve any ambiguity in the phase or topography data obtained
from the first image,

wherein the region of the optical pattern as imaged in the first image and the corresponding region of the object as imaged
in the second image each comprise a plurality of mutually adjacent pixels that define areas extending substantially in two
dimensions.

10. A transmission system for a measurement device for a coordinate positioning apparatus, the transmission system comprising:
a first station for mounting with one of the measurement device and the coordinate positioning apparatus; and
a second station for mounting with the other of the measurement device and the coordinate positioning apparatus;
wherein the first station and the second station communicate with one another using a spread spectrum radio link,
the first station can be placed in a normal mode or in a power saving mode that consumes less power than the normal mode,
the first station transmits a plurality of request signals at intervals throughout a duration of the power saving mode, each
request signal asking if the first station should change to the normal mode,

the first station changes mode to the normal mode in response to receipt at the first station of an affirmative response to
one of the request signals from the second station,

the spread spectrum radio link is a frequency hopping spread spectrum link,
the first station hops between frequency channels, and
frequency hopping occurs at a slower rate when in the power saving mode while in rough synchronisation than when in the normal
mode.

1. A method for automatically estimating background in spectral data, the method comprising:
receiving spectral data captured by a Raman spectroscopy apparatus, the spectral data comprising a Raman spectrum together
with a background signal;

carrying out an iterative process comprised of an initial iteration and a subsequent iteration, the initial iteration comprising
(i) fitting an analytical curve to initial reference data based upon the received spectral data, (ii) determining an allowable
deviation of the initial reference data from the analytical curve, and (iii) removing data points of the initial reference
data or the spectral data that are more than the allowable deviation above the analytical curve to provide subsequent reference
data, and each subsequent iteration comprising (i) fitting an analytical curve to the subsequent reference data, (ii) determining
an allowable deviation of the subsequent reference data from the analytical curve, and (iii) removing data points of the subsequent
reference data or the spectral data that are more than the allowable deviation above the analytical curve to provide reference
data, wherein the reference data is used as the subsequent reference data in a next subsequent iteration of the iterative
process unless termination criterion is met; and

outputting an estimate of the background signal in the spectral data based upon the reference data or the analytical curve
refined by the iterative process.

1. A laser scanning apparatus for detecting and describing an object or topography in three dimensions, the apparatus comprising
a housing that includes at least one laser, the apparatus being configured to emit at least a first laser beam and a second
laser beam from the housing and to rotate the first laser beam and the second laser beam about a common axis of rotation,
wherein:
a path of the first laser beam forms a shape of a first cone when the first laser beam rotates about the common axis of rotation,
a path of the second laser beam forms a shape of a second cone when the second laser beam rotates about the common axis of
rotation, and

the first cone and the second cone face in opposite directions.

1. An error correction method for a coordinate positioning apparatus, the method comprising the steps of:
(i) taking a first data set comprising one or more first data values derived from measurement of a first object by a first
coordinate positioning apparatus, each first data value describing a position on the surface of the first object;

(ii) taking a second data set comprising one or more second data values derived from measurement of the first object by a
second coordinate positioning apparatus, each second data value describing a position on the surface of the first object;

(iii) calculating an error map comprising one or more error values, each error value describing a positional difference between
the surface of the first object as described by the first data set and the surface as described by the second data set,

the surface normal of the first object being known at each position described by each first data value and each error value
being calculated by determining the positional difference substantially in the direction of the known surface normal; and

(iv) using the second coordinate positioning apparatus to perform a processing or measurement operation on the first object,
or an object nominally identical to the first object, in which positions on the surface thereof are corrected using the error
map calculated in step (iii).

1. A joint part comprising a porous portion, the porous portion having:
a multiplicity of solid regions where material is present, locations of at least most of the multiplicity of solid regions
being defined by one or more mathematical functions; and

a remaining multiplicity of pore regions where material is absent,
wherein the one or more mathematical functions define the solid region locations so that the locations of the remaining multiplicity
of pore regions are nonrandom, and

wherein the one or more mathematical functions include at least one term that defines a porosity gradient such that porosity
of at least part of the porous portion changes continuously and without any discontinuity.

1. A method of treating a movement disorder using deep brain stimulation, the method comprising:inserting at least one lead into the brain of a subject along a trajectory from the occipito-temporal or occipito-parietal regions, passing laterally to the posterior horn of the lateral ventricle to contact a target area of the brain, the lead comprising at least one electrode; and
electrically stimulating the target area of the brain through the electrode,
wherein the target area of the brain is selected from the group consisting of the subthalamic nucleus, the zona incerta and the globus pallidus.

1. A method of finding an object using an analogue probe mounted on a machine tool, the method comprising causing the analogue probe and/or object to follow a course of motion which is configured such that the analogue probe is initially sufficiently far away from the object such that the analogue probe is not in a position sensing relationship with anything and the course of motion is configured to cause the analogue probe's surface sensing region to traverse across the object to be found a plurality of times and approaching the object over successive traverses so as to ultimately arrive in a position sensing relationship with the object so as to collect scanned measurement data about the object along at least part of a traverse.

1. An apparatus for mounting a coordinate positioning apparatus accessory to a workpiece mounting surface of a coordinate
positioning apparatus, the workpiece mounting surface having a slot formed therein, the apparatus comprising:
an insert comprising means for fixing the insert within the slot; and
a mount attachable to the coordinate positioning apparatus accessory, the mount comprising at least one protruding member
for engaging the insert when contained within the slot, thereby fixing the mount to the workpiece mounting surface of a coordinate
positioning apparatus, wherein

the means for fixing the insert within the slot is configured to retain the insert fixed within the slot with the insert lying
flush or sub-flush with the workpiece mounting surface, when the mount is detached from the insert.

1. A method of calibrating a contact probe having a contact element, the method comprising:
measuring with the contact probe a first geometric property of a calibrated artefact and a second geometric property of the
or a further calibrated artefact, the first and second geometric properties being such that a deviation between a measured
value and the expected value, resulting from a difference between an effective diameter of the contact element and an assumed
diameter used for determining the measured value, has the opposite sign for each of the first and second geometric properties;

identifying a difference in the effective diameter of the contact element from the assumed diameter comprising comparing deviations
of the measured value to the expected value for each of the first and second geometric properties to determine whether there
is a difference in the deviations; and

determining an effective diameter of the contact probe from the measurements of the first and second geometric property.

1. A readhead arranged to read an absolute scale encoding a series of data bits, the readhead comprising:
a plurality of sensors that are each arranged to produce a sensor signal indicative of measured magnetic field strength;
a plurality of signal combiners, each signal combiner being arranged to receive at least two of the sensor signals produced
by the plurality of sensors and to produce therefrom a combined sensor signal, the plurality of signal combiners thereby generating
a plurality of combined sensor signals;

a plurality of data bit extractors for generating absolute position data and arranged to receive the plurality of combined
sensor signals, each data bit extractor being arranged to receive at least two of the combined sensor signals and to determine
the value of a data bit encoded in an associated absolute scale; and

an incremental signal generator arranged to receive at least two of the plurality of combined sensor signals also received
by the data bit extractors and to generate at least one incremental signal from the at least two combined sensor signals.

1. An analogue probe for a machine tool apparatus, comprising:
a probe body;
a stylus member movably secured to the probe body;
a sensor that measures an extent of displacement of the stylus member relative to the probe body, in which the sensor is contained
within a chamber in the probe body; and

a vent between the chamber and the outside of the probe body, configured such that when the vent is open the pressure within
the chamber can equalise with the ambient pressure outside the probe body, and further configured such that an opening of
the vent to the outside of the probe body can be closed so as to seal the chamber and therefore the sensor from external contaminants
during operation of the analogue probe.

1. A method of controlling a coordinate positioning machine to separate a retaining module from a releasably coupled task
module, the retaining module being provided on a movable part of the machine, and the method comprising:
moving the retaining module to place the task module into engagement with a storage port for holding the task module; and
moving and simultaneously rotating the retaining module to separate the retaining module from the task module with a tilting
action of the retaining module.

1. A method for measuring an object using a coordinate positioning apparatus comprising a platform, a measurement probe having
a replaceable stylus, and a probe head for reorienting the measurement probe relative to the platform, the method comprising
the steps of:
(i) taking a first calibration data set for the coordinate positioning apparatus that comprises datum data for a plurality
of orientations of the measurement probe, the first calibration data set defining a calibration of the coordinate positioning
apparatus when the measurement probe comprises a first stylus, and the datum data including first datum data for a first nominal
orientation of the measurement probe;

(ii) replacing the first stylus of the measurement probe with a second stylus that is nominally identical to the first stylus;
(iii) updating the first calibration data set to generate a second calibration data set that defines the calibration of the
coordinate positioning apparatus when the measurement probe comprises the second stylus, the step (iii) comprising the steps
of:

(a) using the coordinate positioning apparatus to acquire one or more position measurements,
(b) calculating a first correction from the one or more position measurements, the first correction describing any change
in the first datum data following the replacement of the first stylus with the second stylus, and

(c) updating the datum data for a plurality of different orientations of the measurement probe using the first correction
to thereby generate the second calibration data set; and

(iv) using the coordinate positioning apparatus, with the second calibration data set, to measure an object.

1. A method for calculating an optimum stand-off distance for surface position measurements to be acquired by a coordinate
positioning apparatus comprising a measurement probe and at least one moveable portion for moving the measurement probe relative
to an object to be measured, the method comprising:
measuring at least one acceleration characteristic of the coordinate positioning apparatus, the at least one measured acceleration
characteristics comprising at least one of a measured acceleration and a measured deceleration of the at least one movable
portion;

calculating the optimum stand-off distance using the at least one measured acceleration characteristic of the coordinate positioning
apparatus using a processor, the optimum stand-off distance being optimum distance off a surface of the object from which
to initiate each surface position measurement;

moving the measurement probe to the calculated optimum stand-off distance; and
taking one or more surface position measurements of the object to be measured using the optimum stand-off distance; and
wherein the step of measuring the at least one acceleration characteristic of the coordinate positioning apparatus comprises
the steps of;

measuring a first time interval corresponding to the time taken for a moveable portion of the coordinate positioning apparatus
to move between two points of known separation at a commanded speed, wherein the move between the two points comprises acceleration
of the moveable portion, and

comparing said first time interval to a second time interval corresponding to the time that would be taken to move between
the two points of known separation at a substantially constant speed equal to the commanded speed.

1. A measurement scale device comprising:
at least one scale marking, wherein:
the or each scale marking comprises at least one periodic nanostructure that (i) represents scale device information and (ii)
comprises a Laser Induced Periodic Surface Structure (LIPSS), and

the measurement scale device is for determining relative position of two objects.

1. A camera inspection probe for a coordinate measuring apparatus including a housing having an exterior window, the housing
comprising:
an imaging assembly of the camera inspection probe that is configured to capture an image of an object at an object plane
of the imaging assembly; and

an illumination assembly of the camera inspection probe that is configured to produce a light beam directed toward the object
to illuminate the object, the light beam being directed toward the object plane,

wherein the light beam converges to a focal point at a first focal plane outside the housing, the focal point being between
the exterior window and the object plane so as to be prior to intersection of the light beam with the object plane, and

wherein the imaging assembly is configured to obtain a focused image of a region of the object from reflected light of the
light beam produced by the illumination assembly, at a point subsequent to the focal point of the light beam.

1. A method of manufacturing an article, comprising:
taking an article formed in an initial state via an additive manufacturing process; and
performing a second manufacturing process to transform the article into a second state, which second manufacturing process
comprises:

(a) mounting the article in a holding device of a machine for operating on the article, and, with the article so mounted in
the holding device, processing at least one first feature on the article and processing at least one mounting feature on the
article, the position of the at least one mounting feature being constrained in a known manner with respect to the at least
one first feature, and

(b) re-mounting the article in the holding device of the machine via the at least one mounting feature, and, with the article
so re-mounted in the holding device, processing at least one second feature on the article, the position of the at least one
second feature being controlled with respect to the at least one first feature using knowledge of the position of the at least
one mounting feature with respect to the at least one first feature

wherein the article comprises a medical implant.

1. A method of building up a measurement data set for a surface of an object, the method comprising:
using an analogue measurement probe mounted on a machine tool apparatus to obtain scanned measurement data of the surface
over a plurality of offset traverses,

in which a subsequent traverse is offset from a previous traverse such that, over a series of traverses, a surface detecting
region of the analogue probe progresses i) laterally across the object, and/or ii) away from or towards the object, and

in which the course of relative motion for at least one subsequent traverse is generated and/or updated based on data obtained
during at least one previous traverse.

1. A method for delivering a therapeutic transgene to a cerebral cortex or to the cerebral cortex and spinal cord, comprising
administering a viral vector that comprises the therapeutic transgene into white matter of a brain in order to deliver the
therapeutic transgene to the cerebral cortex or to the cerebral cortex and spinal cord,
wherein the viral vector is administered by convection enhanced diffusion (CED) below a motor cortex, visual cortex, or auditory
cortex at a junction of cortical gray matter and underlying white matter.

1. A method of building up a measurement data set for a surface of an object, the method comprising:
using an analogue measurement probe mounted on a machine tool apparatus to obtain scanned measurement data of the surface
over a plurality of offset traverses,

in which a subsequent traverse is offset from a previous traverse such that, over a series of traverses, a surface detecting
region of the analogue probe progresses i) laterally across the object, and/or ii) away from or towards the object, and

in which the course of relative motion for at least one subsequent traverse is generated and/or updated based on data obtained
during at least one previous traverse.

1. A selective laser solidification apparatus, comprising:
a build carrier for supporting a powder bed onto which a powder layer can be deposited;
a gas flow unit for passing a flow of gas over the powder bed along a gas flow direction;
a laser scanner for scanning a laser beam over the powder layer to selectively solidify at least part of the powder layer
to form one or more objects; and

a processor for selecting a scanning sequence of the laser beam based on the gas flow direction.

1. A method of measuring a part with a contact probe mounted on a coordinate positioning machine, the method comprising measuring a plurality of points on the part when both the part and contact probe are moving continuously between different positions within the coordinate positioning machine, the probe moving to measure a plurality of sets of substantially coincident points on the part such that the substantially coincident points of each set are measured at spaced apart positions in the coordinate positioning machine and at spaced apart positions along a scan path, defined in a reference frame of the part,wherein, for each set, between measuring the substantially coincident points of the set, the contact probe measures at least one point that is non-coincident therewith.

1. A method of inspecting an artefact on a machine tool comprising:scanning a probe mounted on the machine tool along a surface of the artefact to be inspected; and
supplying a flow of fluid at least at the point of interaction between the probe and the artefact while scanning the probe along the surface of the artefact.

1. An encoder apparatus for determining movement between two relatively moveable parts of an apparatus, the encoder apparatus comprising:a detector; and
at least one optical element comprising at least one series of consecutive diffraction features for diffracting electromagnetic radiation from a source into diffraction orders and which are for contributing to the production at the detector of a signal varying with movement between the two parts,
wherein the diffraction features in said at least one series are shifted from a nominally regular spacing such that the spacing between the centres of adjacent diffraction features selectively varies irregularly from one pair of adjacent diffraction features to the next, each feature being shifted by a selected predetermined amount so as to substantially eliminate at least one nth diffraction order whilst maintaining the existence of the 1st and at least one selected mth diffraction order, such that said 1st and selected mth diffraction orders contribute to the production at the detector of the signal varying with movement between the two parts.

1. A calibrated gauge artefact for checking a coordinate positioning machine used in a gauging method to measure a set of
nominally identical parts, the calibrated gauge artefact comprising:
a base for mounting on a table of the coordinate positioning machine; and
a platform comprising at least two portions having a like but non-identical geometric property, the platform being locatable
relative to the base in at least two positions such that each of the at least two portions can be presented at a common location
relative to the base, wherein:

a difference between the like but non-identical geometric property of each of the at least two portions when presented at
the common location is known, and

the difference between the like but non-identical geometric property is of an order of an expected deviation in the set of
nominally identical parts to be measured by the coordinate positioning machine.

1. A method of measurement on measuring apparatus, comprising:
providing a master artefact in the form of a reference workpiece which is one of a series of nominally identical workpieces
to be measured, the master artefact having dimensions which are known from a source which is external to said measuring apparatus,

measuring the master artefact on said apparatus at two or more temperatures, and producing two or more corresponding sets
of measured dimensional values of the master artefact at the respective temperatures,

measuring said temperatures at which the master artefact was measured,
generating one or more error maps or look-up tables or functions which relate the measured dimensional values of the master
artefact to the known dimensions of the master artefact, the or each error map, look-up table or function being dependent
on said respective temperatures at which the master artefact was measured.

1. A method of finding an object using an analogue probe mounted on a machine tool, the method comprising causing the analogue
probe and/or object to follow a course of motion which is configured such that the analogue probe is initially sufficiently
far away from the object such that the analogue probe is not in a position sensing relationship with anything and the course
of motion is configured to cause the analogue probe's surface sensing region to traverse past the object to be found a plurality
of times whilst approaching the object over successive traverses so as to ultimately arrive in a position sensing relationship
with the object so as to collect scanned measurement data about the object along at least part of a traverse.

1. A spectroscopy system comprising: a light source; a focusing lens configured to receive light from the light source and focus it to a spot or line on a sample; a spectroscopic analyzer configured to receive and spectrally analyze light from the spot or line on the sample; a focus detection system including a detector, the focus detection system being configured to receive light from the spot or line on the sample and to direct it to the detector; the focus detection system having an optical axis and further comprising at least one pupil located eccentrically with respect to the optical axis, thereby producing on the detector an image of the spot or line on the sample, the image being displaced on the detector by an amount depending on distance between the focusing lens and the sample; and a control system configured to adjust the focus of the focusing lens on the sample in accordance with the displacement of the image of the spot or line on the detector.

1. An apparatus for applying a marking to a scale substrate, comprising:
a scale locator for positioning the apparatus in a defined position relative to the scale substrate in one dimension;
an applicator for locating one or more markings on the scale substrate in a provisional state in which the one or more marking
can be removed;

a detector for checking the markings in the provisional state; and
a finalizer for finalizing the one or more markings which are acceptable after the detector checks the markings in the provisional
state so as to transform the one or more markings into a permanent state in which the one or more markings are less readily
removable than in the provisional state.

1. A method of treating a movement disorder using deep brain stimulation, the method comprising:inserting at least one lead into the brain of a subject along a trajectory from the occipito-temporal or occipito-parietal regions, passing laterally to the posterior horn of the lateral ventricle to contact a target area of the brain, the lead comprising at least one electrode; and
electrically stimulating the target area of the brain through the electrode,
wherein the target area of the brain is selected from the group consisting of the subthalamic nucleus, the zona incerta and the globus pallidus.

1. A frequency tuneable laser device comprising a laser cavity defining a plurality of cavity modes at which the laser device is capable of lasing, each cavity mode having a different respective mode frequency, with the laser cavity comprising:a cavity mode selector having a frequency response with a selection feature that is alignable in frequency with a cavity mode of the plurality to encourage that cavity mode, denoted as the selected cavity mode, to lase in preference to others, with a frequency of the selection feature being selectively adjustable by a predetermined movement of the cavity mode selector; and
a cavity tuning arrangement for adjusting the effective optical path length of the laser cavity to move the cavity modes in frequency, with a frequency of the selected cavity mode being selectively adjustable by a predetermined movement of the cavity tuning arrangement, wherein the cavity tuning arrangement comprises a plurality of reflective elements arranged in optical series;
and the laser device further comprising:
an actuator configured to make the cavity mode selector and the cavity tuning arrangement perform a simultaneous coordinated movement, with respective frequencies of the selection feature and the selected cavity mode varying as a result with substantially the same dependence on a parameter characterising the simultaneous coordinated movement, at least over a predetermined range of the parameter,
wherein the frequency response of the cavity mode selector has a plurality of such selection features, each of which could potentially encourage a cavity mode to lase in preference to others, and only one of which selection features is aligned in frequency with the selected cavity mode, wherein the laser device further comprises a filter element which has a frequency response that (a) has a filter feature that is alignable in frequency with the selection feature of the cavity mode selector that is aligned with the selected cavity mode and (b) combines with the frequency response of the cavity mode selector to produce a combined frequency response that encourages the selected cavity mode to lase in preference to others, wherein the actuator is configured to make the filter element, the cavity mode selector and the cavity tuning arrangement perform a simultaneous coordinated movement, with respective frequencies of the aligned selection feature, the filter feature and the selected cavity mode varying with substantially the same dependence on the parameter characterising the simultaneous coordinated movement, at least over the predetermined range of the parameter.

1. A method of scanning an object, using a contact analogue probe that comprises a deflectable stylus for contacting the object and that is mounted on a machine tool, to collect scanned measurement data along a nominal measurement line on a surface of the object, the analogue probe having a preferred measuring range, the method comprising:controlling the contact analogue probe and/or the object to perform a scanning operation in accordance with a course of relative motion, the course of relative motion being configured such that, based on assumed properties of the surface of the object, the contact analogue probe will be caused to obtain data within the preferred measuring range and caused to go outside the preferred measuring range, along the nominal measurement line on the surface of the object.

1. Additive manufacturing apparatus for building objects by layerwise consolidation of material, the apparatus comprising:a build chamber containing a working area,
a high energy beam configured to consolidate material deposited in the working area in layers, and
a flow device configured to generate a gas flow across at least a part of the working area from a gas inlet to a gas outlet, the gas inlet and gas outlet arranged to be movable within the build chamber, wherein
the gas inlet and gas outlet are movable such that a position of the gas inlet relative to the gas outlet can be varied.

1. A method of measuring a series of substantially or nominally identical workpieces, in which each workpiece of the series is received from a manufacturing process and placed on a measuring apparatus that has an ambient temperature, comprising:(a) measuring one of said workpieces, or an artefact having a plurality of features the size and shape of which approximate said workpieces, on said measuring apparatus as a reference workpiece, to produce measured dimensional values of the reference workpiece;
(b) obtaining calibrated values of said dimensional values from a source external to said measuring apparatus; and
(c) generating an error map or look-up table or error function which relates measured dimensional values of the reference workpiece to the corresponding calibrated values,
wherein:
the reference workpiece is measured at a non-ambient temperature that is different from the ambient temperature, and
the generated error map or look-up table or error function relates to the measured dimensional values at the non-ambient temperature.

1. A kit comprising: a cranial drill system comprising:at least one surgical drill element configured to drill into a skull and to form an opening in the skull, the opening having a narrower diameter portion and a wider diameter portion; and
a spike configured to penetrate a dura, the spike dimensioned to be a close fit in the narrower diameter portion of the opening such that lateral translational movement of a section of the spike is limited when the section of the spike is located in the narrower diameter portion of the opening; and an implantable instrument configured to locate within the opening formed using the cranial drill system, the implantable instrument comprising a port, wherein the cranial drill system is arranged to form the opening having a profile corresponding to a profile of the port.

1. A rotation detection apparatus comprising:a beam source for emitting a beam of polarised light;
a decohering arrangement for eliminating or at least reducing the degree of coherence between first and second independent polarisation components of the beam of polarised light to produce a decohered beam of polarised light;
a detector for outputting a signal in dependence on the intensity of light which is incident thereupon, the detector being arranged so that the decohered beam of polarised light is incident upon it;
a polariser located in the path of the decohered beam of polarised light such that rotation of the polariser relative to the decohered beam of polarised light results in a variation of the intensity of light incident upon the detector from the beam source and a corresponding variation in the signal output from the detector; and
a processor for detecting the relative rotation based on the variation of the signal output from the detector.

1. Apparatus for generating geometric data for use in an additive manufacturing process, the apparatus comprising a processing unit, the processing unit programmed to:receive data defining surface geometry of a plurality of objects to be built together in an additive manufacturing process;
provide a user interface that allows a user to define a location of each object within a common build volume;
identify at least one selected object from a user selection of at least one of the plurality of objects located in the common build volume;
carry out a slicing operation on the at least one selected object located in the common build volume independently from at least one unselected object of the plurality of objects located in the common build volume such that sections of the at least one selected object are determined without carrying out a slicing operation on the at least one unselected object; and
output control data based upon the determined sections for controlling an additive manufacturing apparatus to build the plurality of objects,
wherein the user interface comprises a display and a user input device,
the user can select through the user input device the at least one selected object, and
the processing unit is programmed to at least one of determine and re-determine the sections of the at least one selected object whilst sections of the at least one unselected object remain at least one of undefined and previously defined, the processing unit causing the display to display the at least one selected object for which sections have been at least one of determined and re-determined together with the at least one unselected object such that relative positions of the objects can be observed by the user on the display.

1. A method of forming a diffractive optical device, the method comprising:applying a laser beam to a plurality of target areas located at different positions on a surface of a substrate so as to selectively melt material of the surface; and
controlling at least one of atmospheric conditions at the surface and composition of the surface such that the application of the laser beam causes a melt pool at each of the plurality of target areas to exhibit a surface tension gradient, with higher temperature areas of the melt pool having a higher surface tension than lower temperature areas of the melt pool, that results in a transfer of molten material to build up profiles on the surface, the profiles forming a diffractive structure of the diffractive optical device.

1. An absolute position encoder apparatus, comprising:a scale comprising features that encode along the length of the scale a series of unique position data pieces defining absolute position information; and
a readhead comprising a sensor configured to read the features via a process for capturing a single snapshot, the process being automatically adaptable so as to change, dependent on the relative speed between the scale and the readhead, at least one of:
(i) the feature capture duration of the readhead during the process, and
(ii) the duration that electromagnetic radiation (“EMR”) is emitted by at least one electromagnetic radiation (“EMR”) source during the process,
wherein the absolute position encoder apparatus is further configured to use the captured snapshot to fine-tune a determined absolute position between the readhead and the scale by determining a relative offset between the features of the scale and the sensor.

1. A method for delivering a fluid to a brain of a subject, the method comprising delivering the fluid to the brain by inserting at least one intraparenchymal catheter into a target volume of the brain using a posterior to anterior approach along an insertion axis that is substantially aligned with a long axis of the target volume,wherein the target volume is at least one of the putamen, globus pallidus and the head of the caudate nucleus, and
the catheter is inserted along a trajectory through an occipitoparietal region, the trajectory substantially parallel to an anterior commissure-posterior commissure plane.

1. A selective laser solidification apparatus, comprising:a build platform for supporting a powder bed onto which powder layers can be deposited;
at least one laser module for generating a plurality of laser beams for solidifying powder material deposited onto the powder bed;
a laser scanner for individually steering each laser beam to solidify separate areas in each powder layer, a scanning zone for each laser beam being defined by the locations on the powder bed to which the laser beam can be steered by the laser scanner, and the laser scanner being arranged such that each scanning zone is less than the total area of the powder bed and at least two of the scanning zones overlap; and
a processing unit arranged to select, for at least one of the powder layers, which one of the laser beams to use to solidify an area of the powder layer located within a region in which the scanning zones overlap based on a total length of time each laser beam is used for solidifying areas in the powder layer.

1. An encoder apparatus comprising:an amplitude scale comprising scale features in at least one track which define a series of incremental scale marks and at least one reference mark;
a readhead comprising a light source, a diffraction grating, an incremental photo detector and a reference photodetector comprising at least two detector channels, the features defining the at least one reference mark being configured such that each of the at least two detector channels resolve the at least one reference mark as a single feature, wherein:
the encoder apparatus is configured such that light from the source interacts with the incremental scale marks and the diffraction grating to produce diffraction orders which combine to produce at the incremental photodetector a resultant field which varies with relative movement of the scale and readhead, and
the optical arrangement of the encoder is configured such that a non-imaged representation of at least the track in which the at least one reference mark is contained falls onto the reference photodetector.

1. A method of treating a central nervous system (CNS) disorder, the method comprising administering an effective amount of a water-soluble histone deactylase inhibitor directly into a brain of a subject having the CNS disorder via convection enhanced delivery.

1. A method of measuring an object with a camera probe for capturing an image of an object, the camera probe and object being movable relative to each other by a measurement apparatus comprising a coordinate positioning machine, at least a part of the camera probe being rotatable about at least one axis, the method comprising:a) the measurement apparatus moving the camera probe and the object relative to each other; and
b) for at least one period during said relative movement turning at least a part of the camera probe about the at least one axis thereby slowing the passage of a feature of interest to be measured on the object across the camera probe's field of view, and capturing at least one image of the feature of interest during at least a portion of said turning.