boolean checkPositionPatternAppearance ( Polygon2D_F64 square , float grayThreshold ) { return ( checkLine ( square , grayThreshold , 0 ) || checkLine ( square , grayThreshold , 1 ) ) ; }
Determines if the found polygon looks like a position pattern . A horizontal and vertical line are sampled . At each sample point it is marked if it is above or below the binary threshold for this square . Location of sample points is found by removing perspective distortion .