灰度图转伪彩色图

来源：互联网发布：qq视频变声软件编辑：程序博客网时间：2024/04/19 05:17

前言

人类能够观察到的光的波长范围是有限的，并且人类视觉有一个特点，只能分辨出二十几种灰度，也就是说即使采集到的灰度图像分辨率超级高，有上百个灰度级，但是很遗憾，人们只能看出二十几个，也就是说信息损失了五十倍。但人类视觉对彩色的分辨能力相当强，能够分辨出几千种色度。

代码

#include <opencv2/opencv.hpp>using namespace cv;using namespace std;Mat scaleGray(const Mat& inputGray){    Mat outputGray(inputGray.size(), CV_8U);    unsigned char grayValue, maxValue = 1;    for (int y = 0; y < inputGray.rows; y++)        for (int x = 0; x < inputGray.cols; x ++)        {            grayValue = inputGray.at<uchar>(y, x);            maxValue = max(maxValue, grayValue);        }             float scale = 255.0 / maxValue;       for (int y = 0; y < inputGray.rows; y++)        for (int x = 0; x < inputGray.cols; x ++)        {            outputGray.at<uchar>(y, x) = static_cast<unsigned char>(inputGray.at<uchar>(y, x) * scale + 0.5);        }    return outputGray;}Mat gray2pseudocolor(const Mat& scaledGray){    Mat outputPseudocolor(scaledGray.size(), CV_8UC3);    unsigned char grayValue;    for (int y = 0; y < scaledGray.rows; y++)        for (int x = 0; x < scaledGray.cols; x++)        {            grayValue = scaledGray.at<uchar>(y, x);            Vec3b& pixel = outputPseudocolor.at<Vec3b>(y, x);            pixel[0] = abs(255 - grayValue);            pixel[1] = abs(127 - grayValue);            pixel[2] = abs(0 - grayValue);        }    return outputPseudocolor;}/* * color    R   G   B   gray * red      255 0   0   255 * orange   255 127 0   204 * yellow   255 255 0   153 * green    0   255 0   102 * cyan     0   255 255 51 * blue     0   0   255 0 **/Mat gray2rainbow(const Mat& scaledGray){    Mat outputRainbow(scaledGray.size(), CV_8UC3);    unsigned char grayValue;    for (int y = 0; y < scaledGray.rows; y++)        for (int x = 0; x < scaledGray.cols; x++)        {            grayValue = scaledGray.at<uchar>(y, x);            Vec3b& pixel = outputRainbow.at<Vec3b>(y, x);            if (grayValue <= 51)            {                pixel[0] = 255;                pixel[1] = grayValue * 5;                pixel[2] = 0;            }            else if (grayValue <= 102)            {                grayValue -= 51;                pixel[0] = 255 - grayValue * 5;                pixel[1] = 255;                pixel[2] = 0;            }            else if (grayValue <= 153)            {                grayValue -= 102;                pixel[0] = 0;                pixel[1] = 255;                pixel[2] = grayValue * 5;            }            else if (grayValue <= 204)            {                grayValue -= 153;                pixel[0] = 0;                pixel[1] = 255 - static_cast<unsigned char>(grayValue * 128.0 / 51 + 0.5);                pixel[2] = 255;            }            else if (grayValue <= 255)            {                grayValue -= 204;                pixel[0] = 0;                pixel[1] = 127 - static_cast<unsigned char>(grayValue * 127.0 / 51 + 0.5);                pixel[2] = 255;            }        }    return outputRainbow;}int main(int argc, char* argv[]){    if (argc < 5)    {        cout << "Usage: ./gray2rgb inputGray scaledGray pseudocolor rainbow" << endl;        return 0;    }    Mat inputGray = imread(argv[1], 0);        Mat scaledGray = scaleGray(inputGray);    Mat pseudocolor = gray2pseudocolor(scaledGray);    Mat rainbow = gray2rainbow(scaledGray);    imwrite(argv[2], scaledGray);    imwrite(argv[3], pseudocolor);    imwrite(argv[4], rainbow);    return 0;}

结果

0 0