The Study Of X-ray Image Real-time Processing Based On High-resolution Digital Camera

With the cost of high-resolution, high-performance digital video camera coming down, the group comprised an x-ray imaging system based on high-resolution digital camera and the new generation of image intensifier, which have the advantages of high spatial resolution and better anti-interference, compared with the system consisting of traditional image intensifier and ordinary analog video CCD camera. The paper is mainly to develop detection software, which contains image acquisition and the basic functions of the image processing, it can realize the calculation of characteristic parameters, but also be able to assist evaluation staff to determine the level of defects.First of all, the paper introduced the hardware structure of imaging system. After being familiar with the CCD digital camera and acquisition card, compiled the camera control and image acquisition software, then according to the request of x-ray detection and the actual needs of auto aluminum wheels detection, developed a set of software. In the image pre-processing part, according to the character of image noise, used a multi-frame superimposed average and median filtering method for processing; by improving the median filtering, it got a good effect. For the low contrast, using the linear and the logarithm transformation, the image contrast was enhanced; for the boundaries fuzzy image, it is helpful to use gradient peaking based on the judgment of threshold. Then aiming at the characteristics of x-ray aluminum wheels image, applied a new image enhancement method, which is based on the contourlet transform,to deal with the images, then the contrast and the quality of the original images were improved , and the better visual effects of the minutia area was achieved. In the image segmentation stage, the software used the iterative method to realize threshold division, and got a nice result. But some noises appeared, so chose the appropriate method of morphology noise reduction. After analyzing the traditional operation, this paper showed a kind of edge detection based on SUSAN operation, and it got the desired results. Finally, on the basis of the testing requirement and casting defects level standard, it chose perimeter, area, circular and center of gravity as the characteristic parameters of defects, and the defect level is determined. So it is very helpful for the people to do the aluminum-rims detection and the flaw evaluation.