Region determining device, monitoring system, region determining method, and recording medium

A region determining method comprising:

• by at least one processor,
• calculating a likelihood of wetness of a pixel in an image including a plurality of frames;
• measuring the number of non-water pixels in which the likelihood falls within a first non-water range in any one of determination regions to be determined in the respective frames;
• measuring the number of boundary pixels in which the likelihood falls within a first water range in any one of the determination regions and the likelihood falls within a second non-water range in any one of the determination regions;
• and
• determining whether the determination region satisfies a predetermined determination condition based on the number of non-water pixels and the number of boundary pixels.

A non-transitory recording medium for recording a program for causing a computer to execute:

• calculating a likelihood of wetness of a pixel in an image including a plurality of frames;
• measuring the number of non-water pixels in which the likelihood falls within a first non-water range in any one of determination regions to be determined in the respective frames;
• measuring the number of boundary pixels in which the likelihood falls within a first water range in any one of the determination regions and the likelihood falls within a second non-water range in any one of the determination regions;
• and
• determining whether the determination region satisfies a predetermined determination condition based on the number of non-water pixels and the number of boundary pixels.