In order to extract all the surface contours of the reconstructed object as much as possible, according to the poor quality of veterinary B-ultrasound images, the outlined contours should be as accurate as possible when manually outlining. For some organs with complex shapes, only experienced veterinarians can outline the contours with accurate positions. To overcome this shortcoming, the edges detected by the edge differential operator have the characteristics of accurate positions. The contours are not manually outlined on the original veterinary B-ultrasound image, but are erased on this basis to erase the uninteresting areas and then fill the reconstructed object to extract the complete closed contour of the reconstructed object. The process is similar to the eraser in the brush under the WINDOWS operating system, which is very convenient.

Extract a veterinary B-ultrasound contour image of the kidney, which includes both the contours of the reconstructed kidney of interest and the contours of the surrounding or internal tissues of the kidney. For the redundant contours that are useless for the reconstruction of veterinary B-ultrasound images, it is necessary to extract the edges of the objects of interest for reconstruction. However, there is currently no completely effective algorithm for this pattern recognition. Most of them are to manually outline the areas of interest and then perform edge extraction.

To perform 3D reconstruction, it is necessary to extract the contours of nearly a hundred images. If each veterinary B-ultrasound image is manually intervened, the workload is too large and the time is too long, which will lose the convenient and practical clinical significance of the 3D reconstruction system. Therefore, manual intervention should be minimized, and only a few typical images are selected from all the serial cross-sectional veterinary B-ultrasound images for manual intervention, and their contours are extracted, which will be used as a reference for contour extraction of other serial images.