Apparatus and method for image processing, image processing program and image processor

An image processing method comprising the steps of:

• computing, based on image data representing a number N of images, n sets of initial corresponding points across the N images, where N and n are both integers, N≧4 and n≧4;
• selecting s sets of initial corresponding points from the n sets of initial corresponding points, where s is an integer and 4≦s≦n;
• making M groups of reference corresponding point candidates such that each of the M groups is made up of s sets of initial corresponding points, where M is an integer and M≧2;
• calculating a photometric coefficient as a coefficient for a photometric constraint equation such that in each of the M groups of reference corresponding point candidates, luminance values of respective points on the images satisfy the photometric constraint equation;
• generating multiple sets of aimed corresponding point candidates, each said set being comprised of new corresponding points that are associated with each other between the images, such that each of the M groups of reference corresponding point candidates satisfies a geometric constraint equation that is defined for that group between the images;
• estimating, based on the luminance values of the respective points on the images and the photometric coefficient calculated, how much those sets of aimed corresponding point candidates satisfy the photometric constraint equation;
• selecting a single set of aimed corresponding point candidates based on a result of the estimation and outputting the set as aimed corresponding points;
• evaluating the M groups of reference corresponding point candidates based on the result of the estimation, and selecting a single set of reference corresponding point candidates from the M groups based on a result of the evaluation;
• and
• outputting the selected single set of reference corresponding point candidates and aimed corresponding points associated with the selected candidates as corresponding points across the N images.

A storage medium on which a computer program is stored, the computer program being defined so as to make a computer perform the steps of:

• computing, based on image data representing a number N of images, n sets of initial corresponding points across the N images, where N and n are both integers, N≧4 and n≧4;
• making M groups of reference corresponding point candidates such that each of the M groups is made up of s sets of initial corresponding points across the N images, where M and s are both integers, M≧2 and 4≦s≦n;
• calculating coefficient as a coefficient for a photometric constraint equation such that in each of the M groups of reference corresponding point candidates, luminance values of respective points on the images satisfy the photometric constraint equation;
• generating multiple sets of aimed corresponding point candidates, each said set being comprised of new corresponding points that are associated with each other between the images, such that each of the M groups of reference corresponding point candidates satisfies a geometric constraint equation that is defined for that group between the images;
• estimating, based on the luminance values of the respective points on the images and the photometric coefficient calculated, how much those sets of aimed corresponding point candidates satisfy the photometric constraint equation;
• selecting a single set of aimed corresponding point candidates based on a result of the estimation and outputting the set as aimed corresponding points;
• evaluating the M groups of reference corresponding point candidates based on the result of the estimation, and selecting a single set of reference corresponding point candidates from the M groups based on a result of the evaluation;
• and
• outputting the selected single set of reference corresponding point candidates and aimed corresponding points associated with the selected candidates as corresponding points across the N images.

A processor having the ability to execute a computer program, wherein by executing an image processing program, the processor performs the steps of:

• computing, based on image data representing a number N of images, n sets of initial corresponding points across the N images, where N and n are both integers, N≧4 and n≧4;
• making M groups of reference corresponding point candidates such that each of the M groups is made up of s sets of initial corresponding points across the N images, where M is an integer and M≧2;
• calculating a photometric coefficient as a coefficient for a photometric constraint equation such that in each of the M groups of reference corresponding point candidates, luminance values of respective points on the images, which are associated with each other between the images, satisfy the photometric constraint equation;
• generating multiple sets of aimed corresponding point candidates, each said set being comprised of new corresponding points that are associated with each other between the images, such that each of the M groups of reference corresponding point candidates satisfies a geometric constraint equation that is defined for that group between the images;
• estimating, based on the luminance values of the respective points on the images, which are associated with each other between the images, and the photometric coefficient calculated, how much those sets of aimed corresponding point candidates satisfy the photometric constraint equation;
• selecting a single set of aimed corresponding point candidates based on a result of the estimation and outputting the set as aimed corresponding points;
• evaluating the M groups of reference corresponding point candidates based on the result of the estimation, and selecting a single set of reference corresponding point candidates from the M groups based on a result of the evaluation;
• and
• outputting the selected single set of reference corresponding point candidates and aimed corresponding points associated with the selected candidates as corresponding points across the N images.