The modified gradient edge detection method for the color filter array image of the CMOS image sensor

•This method sorts the adjacent pixels with the same color from large to small.•This method calculates the absolute differences of the sorted pixels.•This method designs the arithmetic operators to estimate the accurate edge.

The modified gradient edge detection method applied in demosaicing the color filter array image is proposed in this paper. Firstly, the adjacent pixels are ranged from large to small. Then, the absolute differences of sorted pixels are calculated to analyze the distribution of the possible edge. Finally, the arithmetic operators being along the possible edge and that being across the possible edge are designed to estimate the accurate edge information. The experimental results verify that the proposed method gives better performance than the traditional gradient edge detection methods, and can discriminate the accurate edge, even where the gradients in different direction are close.