Image processing device, image processing method, and computer readable medium

An image processing device is provided, the image processing device comprising: an image input unit configured to be input with a frame image of an imaging area imaged by a camera; an image processing unit configured to process the frame image input to the image input unit, and detect an object imaged in the frame image; and an operation frequency determination unit configured to determine a frequency of an operation clock of the image processing unit according to the number of objects detected by the image processing unit, wherein the operation frequency determination unit lowers the frequency of the operation clock of the image processing unit as the number of objects detected by the image processing unit becomes smaller.