Patent ID: 7684624

Claim:
A system for capturing an image of a target area on which information is recorded comprising: at least one imaging device capturing an image of said target area; and a processor in communication with said at least one imaging device, said processor receiving image data from said at least one imaging device and processing said image data to detect the presence of obstacles in the captured image, wherein during said processing said processor: compares the captured image with a reference image and computes a negative difference image by calculating, for corresponding pixels in said reference and captured images the pixel value: (255 −|R ij −C ij |) where: R ij is the binary form of the pixel at the i th row and j th column in the reference image; and C ij is the binary form of the pixel at the i th row and j th column in the captured image; and counts the number of pixels of the difference image having values suggestive of an obstacle and compares the number with a threshold value to detect the presence of an obstacle.