The Application And Research Of X-ray Nondestructive Detective Technology In Food Detection

The common detective methods for foreign bodies in food include visible light, near-infrared, magnetic resonance, ultrasonic wave imaging and x-ray imaging six kinds of detective methods. As it has a wide range of application in detection, we choose the x-ray imaging technology as the detective method for the foreign bodies detection in food. It can be used in the detection for foreign bodies in Packing food, Shrimp&Scallop and bulk food which mixed with stone, metal, glass, rubber and other types of foreign bodies. The x-ray imaging detective methods has obvious advantage than other detective methods in practicality and real-time online detectionwe choose the bagged sunflower seeds as the object of our study. We can detect and distinguish the invisible foreign bodies that exist in bags by using the x-ray digital detection technology.Three common foreign bodies are mixed with the bagged sunflower seeds for simulating scene that foreign bodies are mixed in the seeds when processing in factory. We use the portable x-ray instrument to get the x-ray digital image by the USB image acquisition card for further processing.The image preprocessing of foreign bodies is the basis of subsequent image processing. In this thesis we analyzes the source of the image noise that exist in the x-ray image and take the appropriate algorithm to undo noise; Image enhancement for low contrast of x-ray foreign bodies image is also need, we can get more accurate information from the images after denoising and enhancement processing.In the feature extraction process of x-ray foreign body image, image edge extraction is an effective method for foreign body identification, in this paper we analyze several classical edge detection methods, as well as the edge detection method based on morphological gradient. For the foreign body which has greater density than sunflower seeds, we adopt the line gamma curves feature extraction method. According to the significant differences of gray value on the same line where the foreign body lies in image containing foreign bodies and the one doesn’t have, we can judge the presence of the foreign body in the seeds. If the density of the foreign bodies is similar to the seeds’, we can choose the image subtraction method. The adaptive median filter and adaptive morphology method are chosen for simulating the background of the image. Subtract of the original image and the background image, we can get the target image of the foreign bodies. Compare the target images of the foreign bodies obtained by this two methods, we can get a satisfactory experiment result when we choose the adaptive morphology method in simulating the background of image.Apply the x-ray detection technology in the detection of foreign bodies of the bags of seeds, we can identify the foreign bodies in the seeds successfully. It has an important guiding significance for the similar food production enterprises in the detection of d foreign bodies.