Image processing method, image processing system, image processing device, and computer program product

An image processing system including an imaging device which generates an image and an image processing device which detects a specific detecting object from the image including a plurality of two-dimensionally arranged pixels, characterized in that the image processing device comprises:

• a setting part which sets a plurality of candidate elliptical areas, each defined by using a center and lengths in both a first direction and a second direction orthogonal to each other, that become areas of a detecting object in the image;
• a comparing part which compares luminance of the pixels inside the candidate areas with the luminance of the pixels outside the candidate areas, for each of the set candidate areas;
• a detecting part which detects an area suitable to the detecting object out of a plurality of the set candidate areas on the basis of the comparison result;
• a part which sets as a circumscribed rectangle a rectangle that circumscribes an area suitable to the detecting object detected by the detecting part and has one side parallel to the first direction;
• a part which sets a reference luminance based on distribution of luminance of pixels which are included in the circumscribed rectangle;
• a part which calculates a central moment around a center of the distribution of the pixels with higher luminance than the reference luminance in the circumscribed rectangle;
• and
• a part which detects an inclination of the detecting object in the first direction in the image.

An image processing device which detects a specific detecting object from an image including a plurality of two-dimensionally arranged pixels, comprising:

• a part which sets a plurality of candidate elliptical areas, each defined by using a center and lengths in both a first direction and a second direction orthogonal to each other, that become areas of the detecting object in the image;
• a part which compares luminance of the pixels inside the candidate areas with the luminance of the pixels outside the candidate areas, for each of the set candidate areas;
• a part which detects an area suitable to the detecting object out of a plurality of the set candidate areas, based on the comparison result;
• a part which sets, as a circumscribed rectangle, a rectangle that circumscribes an area suitable to the detecting object detected by the detecting method has one side parallel to the first direction;
• a part which sets a reference luminance based on distribution of luminance of pixels which are included in the circumscribed rectangle;
• a part which calculates a central moment around a center of the distribution of the pixels with higher luminance than the reference luminance in the circumscribed rectangle;
• and
• a part which detects an inclination of the detecting object in the first direction in the image.

A computer program product stored on a non-transitory computer-readable medium for controlling a computer that detects a specific detecting object from image data showing an image including a plurality of two-dimensionally arranged pixels, comprising:

• setting a plurality of candidate elliptical areas, each defined by using a center and lengths in both a first direction and a second direction orthogonal to each other, that become candidates of areas of a detecting object in the image shown by the image data;
• comparing luminance of the pixels inside the candidate areas with the luminance of the pixels outside the candidate areas, for each of the set candidate areas;
• detecting an area suitable to the detecting object out of a plurality of the set candidate areas, based on the comparison result;
• setting, as a circumscribed rectangle, a rectangle that circumscribes the area suitable to the detecting object and has one side parallel to the first direction;
• setting a reference luminance based on distribution of luminance of pixels which are included in the circumscribed rectangle;
• calculating a central moment around a center of the distribution of the pixels with higher luminance than the reference luminance in the circumscribed rectangle;
• and
• detecting an inclination of the detecting object in the first direction in the image.