Method of and apparatus for image processing using a variable focal spot size

Abstract

A method of and apparatus for the non-destructive inspection and/or evaluation of materials by the computer processing of images produced on/by an image conversion screen/device is disclosed in which the images are produced by placing the object to be inspected and/or evaluated between the screen/device and a source of x-rays from an x-ray machine having the capability of varying its focal spot area size. Two images, one created with a large focal spot size and one created with a small focal spot size are processed and then combined in such a manner so as to accentuate the fine structure detail in the resulting image.

What is claimed is: 
     
       1. A method for the processing of converted images of an object in order to accentuate the fine structure detail of the object, comprising the steps of: placing the object between an x-ray tube and an image conversion screen/device;   generating a mask image of said object using a large focal spot size of said x-ray tube;   generating a second image of said object using a small focal spot size of said x-ray tube;   decreasing the image noise and increasing the image signal-to-noise ratios for each of said mask and second images of said object;   subtracting said second image of said object from said mask image of said object to generate an image having accentuated fine structure detail, and   amplifying the gray levels of said image having accentuated fine structure detail thereby increasing the contrast of said image having accentuated fine structure detail.   
     
     
       2. The method of claim 1, wherein the steps of decreasing the image noise and increasing the image signal-to-noise ratio for each of said mask and second images of said object prior to performing said step of subtracting are performed by a programmed computer. 
     
     
       3. The method of claim 1, including the further step of amplifying the gray levels of said image having accentuated fine structure detail to increase image contrast. 
     
     
       4. The method of claim 3, wherein the step of amplifying said gray levels is performed by a programmed computer.