The present technique relates to an image processing device, an image processing system, an image processing method, and a program that enable simple and accurate detection of regions showing a detection object such as a body hair in images. A body hair region detection unit includes: a projective transform unit that generates a projected image by projectively transforming a first image generated by photographing a body hair into the coordinate system of a second image generated by photographing the body hair from a different direction from the first image； a difference image generation unit that generates a difference image between the second image and the projected image； and a region detection unit that detects a candidate region formed with pixels having difference values equal to or larger than a predetermined threshold value in the difference image, and divides the region corresponding to the candidate region in the second image into a body hair region showing the body hair and a non-body-hair region outside the body hair region. The present technique can be applied to devices that analyze skin conditions, for example.
