OpenCv 006---LUT的作用与用法

1 所用到的OpenCv API：

/** @brief Applies a GNU Octave/MATLAB equivalent colormap on a given image.

@param src The source image, grayscale or colored of type CV_8UC1 or CV_8UC3.
@param dst The result is the colormapped source image. Note: Mat::create is called on dst.
@param colormap The colormap to apply, see #ColormapTypes
*/

CV_EXPORTS_W void applyColorMap(InputArray src, OutputArray dst, int colormap);

 #ColormapTypes

COLORMAP_AUTUMN = 0, //!< 

COLORMAP_BONE = 1, //!< 

COLORMAP_JET = 2, //!< ![jet](pics/colormaps/colorscale_jet.jpg）

COLORMAP_WINTER = 3, //!< 

COLORMAP_RAINBOW = 4, //!< 

COLORMAP_OCEAN = 5, //!< 

COLORMAP_SUMMER = 6, //!< 

COLORMAP_SPRING = 7, //!< 

COLORMAP_COOL = 8, //!< 

COLORMAP_HSV = 9, //!< 

COLORMAP_PINK = 10, //!< 

COLORMAP_HOT = 11, //!< 

COLORMAP_PARULA = 12 //!< 

2 测试代码

#include "opencv2opencv.hpp"
#include <iostream>

using namespace std;
using namespace cv;

void myColorMap(Mat &grayImg);

int main(int argc, char**argv)
{
    Mat src = imread("G:\CVworkstudy\program_wwx\研习社140课时\ZhaiZhigang140\Blender_Suzanne1.jpg");
    if (src.empty())
    {
        printf("Could not load image...
");
        return -1;
    }
    imshow("sourceImg", src);
    Mat grayLutDemo, dst;
    // 使用LUT
    applyColorMap(src, dst, COLORMAP_HSV);
    // 显示结果
    imshow("ColorMap", dst);

    cvtColor(src, grayLutDemo, COLOR_BGR2GRAY);
    myColorMap(grayLutDemo);
    imshow("GrayLutDemo", grayLutDemo);
    waitKey(0);
    return 0;
}

void myColorMap(Mat &grayImg)
{
    int lut[256];
    //这个for循环中可以进行其他的操作 使相应的像素值 改变为 指定的像素值
    //这里相当于对单通道图像的像素进行二值化处理
    for (int i = 0; i < 256; i++) {
        if (i < 127) {
            lut[i] = 0;
        }
        else
            lut[i] = 255;
    }

    int hight = grayImg.rows;
    int width = grayImg.cols;
    for (int row = 0; row < hight; row++) {
        for (int col = 0; col < width; col++) {
            uchar pv = grayImg.at<uchar>(row, col);
            grayImg.at<uchar>(row, col) = lut[pv];
        }
    }
}

3 代码运行结果