Introduction of gamma correction

gamma correction is a method of editing the gamma curve of an image and editing the image in a nonlinear tone, so as to detect the dark part and the light part in the image signal and increase the ratio of the two parts, thereby improving the contrast effect of the image.

what is gamma correction? .

This concept of gamma correction is of little use

In the real world, the photoelectric conversion characteristics of almost all CRT display devices, photographic films and many electronic cameras are nonlinear. The relationship between the output and input of these nonlinear components (for example, the relationship between the output voltage of an electronic camera and the light intensity in the scene, and the relationship between the light intensity emitted by a CRT and the input voltage) can be expressed by a power function. Its general form is: output = (input) γ. γ (gamma) in the formula is the exponent of the power function, which is used to measure the conversion characteristics of nonlinear components. This characteristic is called power-law conversion characteristic. Traditionally, both "input" and "output" are scaled to ~ 1. Where represents the black level and 1 represents the highest level of the color component. For a specific component, people can measure the functional relationship between its input and output, so as to find out the γ value. The actual image system is composed of multiple components, and there may be several nonlinear components in these components. If all components have the transformation characteristics of power function, then the transfer function of the whole system is a power function, and its exponent γ is equal to the product of g of all individual components. If the whole gamma of the image system is 1, the output and input are linear. This means that the ratio of the intensity of any two image regions in the reconstructed image is the same as that of the two regions of the original scene, which seems to be the goal pursued by the image system: to truly reproduce the original scene. But the actual situation is not entirely like this. When this regenerated image is viewed in a "bright environment", that is, when the brightness of other white objects is almost the same as that of the white part of the image, the system of γ =1 can really make the image look like the "original scene". However, some images sometimes get better results when viewed in a "dark environment", such as showing movies and projecting slides. In this case, the value of γ is not equal to 1, but it is generally considered that G? 1.5, the scene seen by the human perspective system is like the "original scene". According to this view, the gamma value of the projection slide is designed to be about 1.5, not 1. There is also an environment called "dim environment" in the middle environment, which can be seen just like other things in the room, but is darker than the brightness of the white part of the image. The environment of watching TV and the environment of computer room belong to this situation. In this case, it is generally considered that γ? 1.25 to look like the "original scene".

how to use gamma correction in vray?

the gamma value can be adjusted in many places.

1 in the customization in the menu bar above, select the preference, and then select "GAMMA and LUT" in the open dialog box to see the Gamma value, which is called gamma in English.

2 if you have a VRAY renderer, you can also find the gamma value in the color mapping in the renderer.

what does gamma correction mean? 3 points

to correct brightness.

mathematical function of gamma correction

according to the characteristics of traditional CRT(Cathode Ray Tube) screen, the curve is usually a power function, where Y=(X+e)γ, where y is brightness, x is output voltage, e is compensation coefficient, and the power value (γ) is gamma value, and the size of the power value (γ) is changed. The typical Gamma value is .45, which makes the image brightness of CRT linear. Display screens such as televisions using CRT are not linear functions, but exponential functions, so they need to be corrected.

What do you mean by gamma correction in the picture setting of Need for Speed 18? How many pictures should I adjust to 5%? I'll show you 97

Gamma correction? Turn it up to see if the brightness is high. Sometimes these strange options come from the egg-aching Chinese group

What does it mean to check the gamma value

The gamma value of the display

is the physical property of the display, which is fixed, unchangeable and uncorrectable. Display gamma has different meanings in different contexts, one meaning refers to the distortion of the output image of the display to the input signal, and the other meaning refers to the specific value of this distortion. Because the monitor gamma and file gamma are fixed, the gamma correction process is to correct the system gamma of the computer! , so that the superposition of the three transformations of display gamma, system gamma and file gamma is 1., so that the image of the final display is the same as the original scene without distortion.

This is like password communication. File gamma is an encryption process, while system gamma and monitor gamma are a reaction of file gamma, which is a decryption process. The final result is the same as the original information.

What is gamma correction?

The so-called gamma correction is a method of editing the gamma curve of an image to perform nonlinear tone editing on the image, so as to detect the dark part and the light part in the image signal and increase the ratio of the two parts, thereby improving the contrast effect of the image. In the field of computer graphics, the conversion curve between the screen output voltage and the corresponding brightness is usually called Gamma Curve. According to the characteristics of traditional CRT(Cathode Ray Tube) screen, the curve is usually a power function, Y=(X+e)γ, where y is brightness, x is output voltage, e is compensation coefficient, and the power value (γ) is gamma value. Changing the power value (γ) can change the gamma curve of CRT. The typical Gamma value is .45, which makes the image brightness of CRT linear. Display screens such as televisions using CRT are not linear functions, but exponential functions, so they need to be corrected.

what does gamma mean when the display adjusts the light?

Gamma is transliterated as "gamma" in Chinese.

every pixel in a digital image has a certain brightness, that is, from black () to white (1). These pixel values are the information input into the electric display. However, due to technical limitations, flat panel (CRT) displays can only output these values in a nonlinear way, that is, output = input x gamma.

without adjustment, most CRT monitors have a gamma value of 2.5, which means that if the brightness of a pixel is .5, the brightness of the light it outputs on the display is only .18(.5X2.5) without the intervention of color management applications. For liquid crystal display (LCD), especially the LCD of laptop computer, its output curve is even more irregular. Some calibration software or hardware can make the display screen output images according to a certain gamma curve. For example, the gamma value commonly used in Windows is 2.2, which is almost the opposite of human vision. The colors of sRGB and Adobe RGB are also based on the gamma value of 2.2.