Process and apparatus for the acquisition and processing of screen images

Process for the detection of faults and defects in material used in the formation of a mechanical part comprising the following stages:

• a. X-ray irradiating the part at least twice under identical conditions and in accordance with the same view of the part;
• b. obtaining at least two X-ray screen images for each view of the part to be inspected;
• c. conversion of these screen images into digital video images coded on several grey levels;
• d. processing each image, said processing involving the following substages i. to iv. including:
• i. correction by digital filtering of each image compared with itself;
• ii. correction of the filtered images by comparison with a reference image;
• iii. binarization of the images by the comparison of each image with a threshold in order to only retain the image points which are equal to or higher than said threshold and which are liable to correspond to a fault in the part;
• and
• iv. superimposing the images in order to determine the image points which correspond to faults thus detecting the faults in the part.