如何在MATLAB中将灰度矩阵转换为RGB矩阵？ [英] How to convert a grayscale matrix to an RGB matrix in MATLAB?

问题描述

rgbImage = grayImage / max(max(grayImage));

或

rgbImage = grayImage / 255;

以上哪项是正确的，还有原因？

Which of the above is right,and reason?

推荐答案

转换灰度图像到 RGB图像，您必须解决两个问题：

To convert a grayscale image to an RGB image, there are two issues you have to address:

• 灰度图像是2-D，而 RGB图像是三维，所以你必须复制灰度图像数据三次，并沿三维连接三个副本。


• 图像数据可以存储在许多不同的数据类型，因此您必须相应地转换它们。存储为 double 数据类型，图像像素值应为0到1范围内的浮点数。存储为 uint8 数据类型，图像像素值应为0到255范围内的整数。您可以查看图像矩阵的数据类型使用 class 。

• Grayscale images are 2-D, while RGB images are 3-D, so you have to replicate the grayscale image data three times and concatenate the three copies along a third dimension.
• Image data can be stored in many different data types, so you have to convert them accordingly. When stored as a double data type, the image pixel values should be floating point numbers in the range of 0 to 1. When stored as a uint8 data type, the image pixel values should be integers in the range of 0 to 255. You can check the data type of an image matrix using the function class.

以下是您可能遇到的3种典型情况：

Here are 3 typical conditions you might encounter:

• 要转换 uint8 或 double 灰度图像到 th的RGB图像相同的数据类型，您可以使用 repmat 或 cat ：

• To convert a uint8 or double grayscale image to an RGB image of the same data type, you can use the functions repmat or cat:

rgbImage = repmat(grayImage,[1 1 3]);
rgbImage = cat(3,grayImage,grayImage,grayImage);

转换 uint8 灰度图像到 double RGB图像，你应该转换为 double 乘以255：

To convert a uint8 grayscale image to a double RGB image, you should convert to double first, then scale by 255:

rgbImage = repmat(double(grayImage)./255,[1 1 3]);

转换 double 灰度图像到 uint8 RGB图像，你应先缩放255，然后再转换为 uint8 ：

rgbImage = repmat(uint8(255.*grayImage),[1 1 3]);

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