Image processing device, image forming apparatus, image processing method, and non-transitory computer-readable medium

An image processing method comprising:

• controlling a scanner to capture image data of a detection object overlapping a background member;
• sequentially selecting a target pixel one by one from multiple pixels of the image data;
• calculating an edge amount for the target pixel selected, the edge amount indicating a change in pixel value between the target pixel selected and peripheral pixels adjacent to and surrounding the target pixel selected, in a shadow region in the image data, between:
• an object region corresponding to the detection object;
• and
• a background region corresponding to the background member;
• determining whether the target pixel selected corresponds to an edge, based on the edge amount calculated;
• determining whether the edge is a part of a continuous edge, based on the edge amount calculated for the target pixel selected, in response to a determination that the target pixel corresponds to the edge;
• counting an edge continuity number for the target pixel selected, the edge continuity number for the target pixel selected representing a number of target pixels, each corresponding to the edge of the part of the continuous edge;
• counting an edge continuity number for a previous target pixel selected immediately before the target pixel selected and determine whether the edge continuity number for the previous target pixel is greater than a preset number in response to a determination that the target pixel selected does not correspond to the edge;
• and
• detecting a boundary position between the detection object and the background member, based on the edge amount of each of the target pixels forming the continuous edge up to the previous target pixel, in response to a determination that the edge continuity number for the previous target pixel is greater than the preset number.

A non-transitory computer-readable medium storing a program which, when executed by a processor, causes the processor to perform a method including:

• controlling a scanner to capture image data of a detection object overlapping a background member;
• sequentially selecting a target pixel one by one from multiple pixels of the image data;
• calculating an edge amount for the target pixel selected, the edge amount indicating a change in pixel value between the target pixel selected and peripheral pixels adjacent to and surrounding the target pixel selected, in a shadow region in the image data, between:
• an object region corresponding to the detection object;
• and
• a background region corresponding to the background member;
• determining whether the target pixel selected corresponds to an edge, based on the edge amount calculated;
• determining whether the edge is a part of a continuous edge, based on the edge amount calculated for the target pixel selected, in response to a determination that the target pixel corresponds to the edge;
• counting an edge continuity number for the target pixel selected, the edge continuity number for the target pixel selected representing a number of target pixels, each corresponding to the edge of the part of the continuous edge;
• counting an edge continuity number for a previous target pixel selected immediately before the target pixel selected and determine whether the edge continuity number for the previous target pixel is greater than a preset number in response to a determination that the target pixel selected does not correspond to the edge;
• and
• detecting a boundary position between the detection object and the background member, based on the edge amount of each of the target pixels forming the continuous edge up to the previous target pixel, in response to a determination that the edge continuity number for the previous target pixel is greater than the preset number.