Image processing apparatus, image processing method, and computer-readable recording medium

An image processing method comprising:

• calculating a gradient strength of a pixel value of each pixel based on an intraluminal image that is a captured image of an intralumen;
• setting an initial shape of a closed region, the closed region satisfying conditions that the pixel of which gradient strength is a predetermined value or more is not included in the closed region and a boundary of the closed region does not bend with a predetermined curvature or higher toward an inner side of the closed region;
• extracting the closed region from the intraluminal image;
• and
• detecting an abnormal portion inside the closed region, wherein
• the extracting includes
• calculating values of a plurality of types of energy including at least energy determined by an outer shape of the closed region and energy determined by the gradient strength in the closed region;
• calculating a weighted sum of the plurality of types of energy;
• determining an update range in which the shape of the closed region is updated based on any one of the values of the plurality of types of energy;
• and
• updating the shape of the closed region within the update range based on the weighted sum.

A non-transitory computer-readable recording medium with an executable program stored thereon, wherein the program instructs a processor to perform:

• calculating a gradient strength of a pixel value of each pixel based on an intraluminal image that is a captured image of an intralumen;
• setting an initial shape of a closed region, the closed region satisfying conditions that the pixel of which gradient strength is a predetermined value or more is not included in the closed region and a boundary of the closed region does not bend with a predetermined curvature or higher toward an inner side of the closed region;
• extracting the closed region from the intraluminal image;
• and
• detecting an abnormal portion inside the closed region, wherein
• the extracting includes
• calculating values of a plurality of types of energy including at least energy determined by an outer shape of the closed region and energy determined by the gradient strength in the closed region;
• calculating a weighted sum of the plurality of types of energy;
• determining an update range in which the shape of the closed region is updated based on any one of the values of the plurality of types of energy;
• and
• updating the shape of the closed region within the update range based on the weighted sum.