A combined X-ray and laser 3D imaging system for food safety inspection, which uses a 3D laser subsystem to get accurate depth information, which is further combined with an x-ray image to achieve accurate physical contamination detection in poultry and other meat products. A unique calibration model is used to calibrate the x-ray and laser 3D imaging systems at the same time. And a nested multi-thread software structure is implemented to prevent data conflict and ensure fully use of system resources during the physical contamination detection of the poultry and other meat products.