Inconsistency response correction method for scintillator array in flash radiography
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摘要: 阵列屏采用大量独立晶柱组合而成限制了可见光在转换屏内的扩散，能够在提高X光转换效率的同时保证照相系统有较高的空间分辨能力，是高能闪光照相系统中的重要器件。阵列屏由于各晶柱之间的转换系数不同而导致接收图像中存在非一致响应现象，必须将其校正才能对图像进行有效判读。研究了中阵列屏接收图像中非一致响应现象的校正方法，首先使用平板照相获得空场图像，然后对实验图像和空场图像扣除暗电流本底和消除脉冲噪声，最后将实验图像与空场图像进行像素相除运算。针对强振动环境下空场图像与实验图像不匹配问题，提出对空场图像进行位移的方法以实现空场图像与实验图像的重新匹配，采用校正后图像的标准差数据来判断两者的匹配性。实验结果表明位移后的空场图像能够校正强振动环境下阵列屏图像的非一致性响应。Abstract: Scintillator array is composed of a large number of independent crystal columns, which limit the diffusion of visible light in the conversion screen, can improve the X-ray conversion efficiency while ensuring the radiography system to have higher spatial resolution, thus it is an important device in high-energy flash radiography system. There are inconsistency response in the received image due to the different conversion coefficients among the crystal columns of the scintillator array. Only by correcting the inconsistency response can the image be interpreted effectively. In this paper, the correction method of inconsistency response in experimental images is studied. Firstly, the empty field image is obtained by flat plate radiography, then the dark current background and impulse noise are deducted from the experimental image and the empty field image, and finally the pixel division operation is carried out between the experimental image and the empty field image. Aiming at the mismatch between the empty field image and the experimental image in strong vibration environment, a method of shifting the empty field image is proposed to realize the re-matching between the empty field image and the experimental image, and the standard deviation data of the corrected image is used to judge the matching between the two images. Experimental results show that the shifted empty field image can correct the inconsistency response of array screen image in strong vibration environment.
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Key words:
- flash radiography /
- scintillator array /
- image process /
- inconsistency response /
- correction
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图 1 阵列屏的结构示意图及其原理示意图
Figure 1. Structure diagram and principle diagram of scintillator array
图 2 实验图像、空场图像与暗电流图像示例
Figure 2. Examples of experiment image, empty field image and dark current image
图 4 含阵列屏伪影的实验图像及其校正结果
Figure 4. Experimental image with scintillator array artifacts and the image after correction
图 3 实验前采集的空场图像、消除脉冲噪声后的空场图像与暗电流图像示例
Figure 3. Examples of empty field images and dark current image collected before the experiment
图 5 强振动环境下校正图像的非匹配伪影
Figure 5. Artifact of corrected image in high vibration environment
图 7 空场图像不同位移条件下的校正结果
Figure 7. Corrected images using empty field images with different displacements
图 8 校正图像标准差数据与空场图像位移量之间的关系曲线
Figure 8. Relationship curve between standard deviation data of corrected image and displacement amount of empty field image
图 9 空场图像不同移位后对实验图像的校正结果对比
Figure 9. Comparison of corrected images after different displacement of empty field image
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