Image detection device for detecting shadow or light based on detected edges

An image detection system comprising:

• an imaging apparatus that acquires an input image, the imaging apparatus being installed at an optional position;
• and
• an imaging processing apparatus that
• extracts first edges each representing a boundary line between areas with different features, from the input image;
• compares second edges preliminarily extracted from a background image with the first edges to extract specific edges including at least remaining edges present in the input image and the background image;
• extracts candidate areas to be detected from the input image;
• and
• determines a candidate area in which an amount of the at least remaining edges is larger than a preset threshold value inside the candidate area except for a contour of the candidate area, as an area to be detected, based on the specific edges.