US Patent No. 9,769,442

INFORMATION DISPLAY APPARATUS


Patent No. 9,769,442
Issue Date September 19, 2017
Title Information Display Apparatus
Inventorship Akihiko Shirai, Kanagawa (JP)
Kazuhisa Yanaka, Kanagawa (JP)
Takeru Utsugi, Kanagawa (JP)
Assignee NEC DISPLAY SOLUTIONS, LTD., Tokyo (JP)

Claim of US Patent No. 9,769,442

1. A method for displaying information comprising a main image and a sub-image (A), comprising:
modifying tone values to compress the tone of the main image according to a formula (1);
wherein b? and b are the luminance values of each pixel the main image after and before compression, respectively, and amin is an offset value to be used when a sub-image (A) tone value is modified and U is a parameter for correcting the luminance
levels of projectors;
projecting by a first projector the main image compressed with tones through a first polarization component;
modifying tone values of the sub-image (A) for correcting tones of the sub-image according to a formula (2);
wherein a? and a are the luminance values of each of pixel of each of a modified sub-image (A?) and the original sub-image
(A), respectively and T is a parameter for correcting the luminance levels of projectors;
generating a correction image according to a formula (3);
wherein c is the luminance value of each pixel of the correction image and ? is the ? value of a projector for projecting
a correction image; and
projecting by a second projector the correction image with a second polarization component different from the first polarization
component over the main image with compressed tone projected by the first projector such that the main image is buried by
an overlapped projection of the main image and the correction image generated by using the sub-image and the offset value
to provide the sub-image to a viewer with a naked eye and to provide the main image to another viewer with a polarizer.