Patent ID: 8660349

Claim:
A screen area detection method comprising: a step of capturing an image including a screen area; a step of obtaining plural candidate boundaries of the screen area based on variation of brightness values of respective pixels in the captured image; a step of converting the obtained candidate boundaries into straight lines by using a Hough transform; a step of carrying out binary image processing with regard to the captured image, wherein, the captured image is divided into one or more target areas and one or more non-target areas; a step of obtaining boundary pixels of a maximum target area in the target areas, and letting the boundary pixels serve as an outline of the maximum target area; a step of selecting straight lines located on the outline from the converted straight lines based on minimum distances between the boundary pixels and the respective converted straight lines as well as directions of the respective converted straight lines; a step of dividing the selected straight lines into an upper boundary straight line class, a bottom boundary straight line class, a left boundary straight line class, and a right boundary straight line class based on positional relationships of the selected straight lines; and a step of obtaining final straight lines by carrying out straight line fitting with regard to plural straight lines in the respective classes so as to obtain four boundaries of the screen area.