LASER RANGE IMAGING FOR ON-LINE MAPPING OF 3D IMAGES TO PSEUDO-X-RAY IMAGES FOR POULTRY BONE FRAGMENT DETECTION

Abstract

A laser ranging image system was developed for on-line high-resolution 3D shape recovery of poultry fillets. The range imaging system in conjunction with X-ray imaging was used to provide synergistic imaging detection of bone fragments in poultry fillets. In this research, two 5 mW diode lasers coupled with two CCD cameras were used to produce 3D information based on structured lights and triangulation. A laser scattering phenomenon on meat tissues was studied when calculating the object thickness. To obtain the accurate 3D information, the cameras were calibrated to correct for camera distortions. For pixel registrations of the X-ray and laser 3D images, the range imaging system was calibrated, and noises and signal variations in the X-ray and laser 3D images were analyzed. Furthermore, the relationship between the X-ray absorption and 3D thickness of fillets was obtained, and a mapping function based on this relationship was applied to convert the fillet 3D images into the pseudo-X-ray images. For the on-line system implementation, the imaging hardware and software engineering issues, including the data flow optimization and the operating system task scheduling, were also studied. Based on the experimental on-line test, the range imaging system developed was able to scan poultry fillets at a speed of 0.2 m/sec at a resolution of 0.8(X) x 0.7(Y) x 0.7(Z) mm3. The results of this study have shown great potential for non-invasive detection of hazardous materials in boneless poultry meat with uneven thickness.