Abstract: In order to improve the quality and accuracy of residual oil edge detection, a method of residual oil edge detection with improved multi-direction Sobel operator is proposed. The improved bilateral filtering method is used to remove the image noise of the microscopic residual oil distribution, so as to achieve the purpose of edge preserving and denoising. Combined with Otsu algorithm, the optimal threshold of the residual oil image can be obtained adaptively. The amplitude and direction of the gradient of the remaining oil image are calculated by using the Sobel operator with the amplitude of 3×3 in the four improved directions. Non-maximum suppression algorithm is used to filter out the pseudo-edge pixels to obtain the final remaining oil edge detection image. The experimental results show that the proposed method can accurately detect the information of residual oil edge in the microscopic residual oil distribution image while removing the noise of the image.

Key words: residual oil, edge detection, bilateral filtering, Otsu algorithm, Sobel operator