一幅图像的动态范围一般是指亮度的最大值和最小值的比值。人眼对物体的分辨率是非常高的，它亮度的动态范围可达到1000000000:1，而一般的成像设备的范围比人眼看到的要小得多，达不到人眼亮度动态范围的千万分之一。如果要让设备上的显示能尽可能地接近人眼，显示出更多的信息，因此需要进行动态范围压缩处理。-The dynamic range of an image generally refers to the ratio of the maximum and minimum brightness. The human eye is a very high resolution of the object, and it luminance dynamic range of up to 1 billion: 1, and the scope of the general imaging apparatus than the human eye can see much smaller, less than the dynamic range of the human eye brightness thousand million. If you want to display on the device can be as close as possible to the human eye, showing more information, hence the need for dynamic range compression.