Template Matching Processing Apparatus and Method, Hologram Reproducing Apparatus and Method, and Computer Program

A hologram reproducing apparatus for reproducing record information from a holographic recording medium on which an interference pattern is recorded, the interference pattern being formed from reference light and object light corresponding to the record information,

• said hologram reproducing apparatus comprising:
• an image obtaining device for obtaining a detection image including the record information, on the basis of detection light generated by irradiation of the reference light;
• a first calculating device for calculating a plurality of correlation values, each of which indicates a correlation between the detection image and a predetermined template image, by a pixel unit while shifting the template image by the pixel unit with respect to the detection image;
• a second calculating device for subtracting a predetermined reference value from each of the plurality of correlation values and then calculating a coordinate position of the detection image on the basis of a coordinate position of a center of gravity of the plurality of correlation values from each of which the reference value is subtracted;
• a correcting device for correcting at least one of a distortion and a position-shift of the detection image on the basis of the coordinate position of the detection image, which is calculated by said second calculating device;
• and
• a reproducing device for reproducing the record information included in the detection image in which at least one of the distortion and the position-shift is corrected.

A hologram reproducing method of reproducing record information from a holographic recording medium on which an interference pattern is recorded, the interference pattern being formed from reference light and object light corresponding to the record information,

• said hologram reproducing method comprising:
• an image obtaining process of obtaining a detection image including the record information, on the basis of detection light generated by irradiation of the reference light;
• a first calculating process of calculating a plurality of correlation values, each of which indicates a correlation between the detection image and a predetermined template image, by a pixel unit while shifting the template image by the pixel unit with respect to the detection image;
• a second calculating process of subtracting a predetermined reference value from each of the plurality of correlation values and then calculating a coordinate position of the detection image on the basis of a coordinate position of a center of gravity of the plurality of correlation values from each of which the reference value is subtracted;
• a correcting process of correcting at least one of a distortion and a position-shift of the detection image on the basis of the coordinate position of the detection image, which is calculated by said second calculating process;
• and
• a reproducing process of reproducing the record information included in the detection image in which at least one of the distortion and the position-shift is corrected.

A computer program product in a computer-readable medium for tangibly embodying a program of instructions executable by a computer provided in a template matching processing apparatus, the computer program making the computer function as at least one portion of a first calculating device and a second calculating device,

• said template matching processing apparatus comprising:
• said first calculating device for calculating a plurality of correlation values, each of which indicates a correlation between an inputted detection image and a predetermined template image, by a pixel unit while shifting the template image by the pixel unit with respect to the detection image;
• and
• said second calculating device for subtracting a predetermined reference value from each of the plurality of correlation values and then calculating a coordinate position of the detection image on the basis of a coordinate position of a center of gravity of the plurality of correlation values from each of which the reference value is subtracted.

A computer program product in a computer-readable medium for tangibly embodying a program of instructions executable by a computer provided in a hologram reproducing apparatus, the computer program making the computer function as at least one portion of an image obtaining device, a first calculating device, a second calculating device, a correcting device, and a reproducing device,

• said hologram reproducing apparatus for reproducing record information from a holographic recording medium on which an interference pattern is recorded, the interference pattern being formed from reference light and object light corresponding to the record information,
• said hologram reproducing apparatus comprising:
• said image obtaining device for obtaining a detection image including the record information, on the basis of detection light generated by irradiation of the reference light;
• said first calculating device for calculating a plurality of correlation values, each of which indicates a correlation between the detection image and a predetermined template image, by a pixel unit while shifting the template image by the pixel unit with respect to the detection image;
• said second calculating device for subtracting a predetermined reference value from each of the plurality of correlation values and then calculating a coordinate position of the detection image on the basis of a coordinate position of a center of gravity of the plurality of correlation values from each of which the reference value is subtracted;
• said correcting device for correcting at least one of a distortion and a position-shift of the detection image on the basis of the coordinate position of the detection image, which is calculated by said second calculating device;
• and
• a reproducing device for reproducing the record information included in the detection image in which at least one of the distortion and the position-shift is corrected.