What is the principle of X-ray photography?

X-ray photography (CR) refers to the interaction between X-rays and the human body, and displays the information of the internal organ structure, density and tissue composition of the human body through a camera. It is an imaging technology that uses the penetration of X-rays to project the three-dimensional anatomical structure of human body into a two-dimensional plane image.

The physical characteristics of X-rays include penetration, ionization, fluorescence, heat and interference, diffraction, reflection and refraction. X-ray photography is mainly suitable for x-ray penetration. Because of the short wave length and high energy, when X-rays irradiate the matter, only a part of them are absorbed by the matter, and most of them pass through the atomic gap, showing strong penetration ability. The ability of X-rays to penetrate matter is related to the energy of X-ray photons. The shorter the wavelength of X-ray, the greater the photon energy and the stronger the penetrating power. The penetrating power of X-rays is also related to the density of substances, and substances with different densities can be distinguished by using the property of differential absorption.

CR is a device that records the image information taken by X-rays on an image board (IP), reads it through a reading device, then converts it into a digital signal and inputs it into a computer, and finally displays a gray image on the display screen through image processing. IP board is crystallized from fluoride containing trace elements. This substance can record the signal initially stimulated by light, and when stimulated by light again, it will release a signal similar to that initially stimulated by light. The reader uses high-precision laser scanning to convert the read fluorescence signal into digital signal and send it to the computer workstation, which can process the image according to different requirements and change the image characteristics freely in a large range.

Generally speaking, CR information processing can be divided into three parts: harmonic processing, spatial frequency processing and subtraction processing. ? Coordination processing involves image contrast, spatial frequency processing adjusts the corresponding frequency response, and silhouette can be divided into angiographic images and non-angiographic images. Like other digital images, CR system can also realize digital storage and networking.