[X-ray radiographic imaging technique with high dynamic range].

In conventional X-ray radiographic imaging system with a fixed energy parameter, the acquired X-ray images are usually overexposed and have no useful information available. It is due to some constraints, like special structure of component, different attenuation coefficients of materials and dynamic range of optoelectronic devices. When maximum of transmitted X-ray luminous exceed capacity limitation of X-ray radiographic imaging system in one scene, the device up to saturate. Also when minimum of transmitted X-ray luminous is below the thermal noise level of imaging system, no useful information is available for imaging. To solve the problem of difficulties in acquiring transmitted X-ray luminous in a wide dynamic range by conventional X-ray radiographic imaging system, we put forward a new X-ray radiographic imaging technique with high dynamic range based on adjusting tube voltage. In the article, the influence by charge capacity of X-ray radiographic imaging system on effective irradiating thickness is analyzed. Through experiments of some standard samples, we gained the relationship between voltage range of X-ray tube and materials or structure of component for best testing sensitivity. Then we put forward an adjusting strategy of tube voltage and effective subgraphs extraction method from acquired raw X-ray images. By the mentioned method, we carried out X-ray radiographic imaging experiments with high dynamic range for components with thickness from 0 to 20 mm. The results show that X-ray radiographic imaging technique with high dynamic range is effective to realize imaging for some components with different thickness. It is available for us to find more detailed projection information from fusion images.