1. An object information acquiring apparatus, comprising:a plurality of conversion elements which receive acoustic waves emitted from an object and convert the acoustic waves into electrical signals;
a correlation calculator which calculates correlation data by using the plurality of electrical signals output from said plurality of conversion elements;
an average correlation calculator which calculates an average correlation matrix by extracting a plurality of submatrices from the correlation data and averaging the submatrices; and
an adaptive signal processor which generates power distribution by performing adaptive signal processing by using the average correlation matrix and calculating the power of each target position,
wherein said correlation calculator calculates the correlation data by obtaining the correlation of input signals that are separated by at least one input signal among the input signals input to said correlation calculator and without obtaining the correlation of input signals that are not separated by at least one input signal among the input signals input to said correlation calculator, and
wherein the correlation data calculated with said correlation calculator contains only elements of diagonal components of the correlation matrix, and elements at positions that are separated at intervals of one or more columns from the elements of the diagonal components.