The laser speckle stereo camera and the line laser stereo camera are used complementarily in different scenarios, effectively resolving the problem of barcode obstruction when the distance between the measured objects is small. The laser speckle stereo camera captures the lateral displacement of speckles in the image to reflect the height difference between the measured object and the conveyor belt. It only captures a narrow area during image acquisition, improving the frame rate of image acquisition, reducing the processing time of the image algorithm, and enabling high-frequency measurement.