伽马校正公式：。^（gamma）或。^（1 / gamma）？ [英] gamma correction formula : .^(gamma) or .^(1/gamma)?

问题描述

我正在为灰度图像寻找一个简单的伽马校正公式，其值介于0到255之间。

I'm looking for a simple gamma correction formula for grayscale images with values between 0 and 255.

假设屏幕的灰度为2.2（它是一个液晶显示屏，所以我可能需要用更复杂的程序估算它，但让我们假设我的屏幕表现得很好。）

Let's say that the gamma of my screen is 2.2 (it's a LCD screen so i would probably need to estimate it with a more complicated procedure, but let's assume my screen is behaving nicely).

以下哪个公式是正确的一个？

Which one of the following formulas would be the correct one ?

（1）更正= 255 *（图像/ 255）。^ 2.2

(1) Corrected = 255 * (Image/255).^2.2

或

（2）更正= 255 *（图像/ 255）。^（1 / 2.2）

(2) Corrected = 255 * (Image/255).^(1/2.2)

（那些注定是matlab代码，但我希望即使对非matlab人也是可以理解的）

(those are destined to be matlab codes but i hope they are understandable even to non-matlab people)

我一直在互联网上环顾四周但发现这两个公式都在。我怀疑（2）是正确的，我的困惑是由于倾向于将伽玛值称为实际伽马值的倒数，但我真的很感激那些知道他们在谈论什么的人的一些反馈。 。

I've been looking around on the internet but found both formulas going around. I suspect (2) is the right one, and my confusion is due to the tendency to call "gamma value" the inverse of the actual gamma value, but i would really appreciate some feedback by people who know what they are talking about...

谢谢： - ）

推荐答案

Gamma校正控制图像的整体亮度。未经校正的图像可能看起来漂白或太暗。假设计算机显示器具有 2.2 功率函数作为强度到电压响应曲线。这只是意味着如果您向监视器发送一条消息，某个像素的强度应该等于 x ，它实际上会显示一个强度等于的像素x ^2.2 因为发送到监视器的电压范围在 0 和 1 ，这意味着显示的强度值将小于您想要的强度值。据说这样的显示器的伽马值 2.2 。

Gamma correction controls the overall brightness of an image. Images which are not corrected can look either bleached out or too dark. Suppose a computer monitor has 2.2 power function as an intensity to voltage response curve. This just means that if you send a message to the monitor that a certain pixel should have intensity equal to x, it will actually display a pixel which has intensity equal to x^2.2 Because the range of voltages sent to the monitor is between 0 and 1, this means that the intensity value displayed will be less than what you wanted it to be. Such a monitor is said to have a gamma of 2.2.

所以在你的情况下，

Corrected = 255 * (Image/255)^(1/2.2).

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