09 OpenCV自带颜色表操作

09 OpenCV自带颜色表操作

opencv知识点：

• opencv4的颜色表
• 应用图像映射 - applyColorMap()

本科所解决的问题：

• 如何使用OpenCV中的颜色表？
• 如何循环转换各种颜色风格？

1.Opencv4的[颜色表

opencv提供22种颜色风格的查找表映射，官方文档查阅ColormapTypes即可

2.颜色表的使用

在使用的时候要用到applyColorMap，传入对应colormap，就可以进行颜色风格的转换

applyColorMap
	应用颜色图
		共3个参数 
			第1个参数 输入
			第2个参数 输出
			第3个参数 颜色图（查阅官方文档可知）

如我们传入COLORMAP_DEEPGREEN，就会有如下效果

重点程序部分

void QuickDemo::color_style_demo(Mat& image) {

	Mat dst;

	applyColorMap(image, dst, COLORMAP_DEEPGREEN);
	imshow("COLORMAP_DEEPGREEN", dst);
}

完整程序

main.cpp

#include "opencv2/opencv.hpp"
#include "quickopencv.h"
#include <iostream>

using namespace cv;
using namespace std;

int main(int argc, char** argv) {
	Mat src = imread("C:/Users/LZQ/Desktop/lena.png"); //  B, G, R
	if (src.empty()) {
		printf("could not load image....\n");
		return -1;
	}

	imshow("输入窗口", src);
	QuickDemo qd;
	qd.color_style_demo(src);

	waitKey(0);
	destroyAllWindows();
	return 0;
}

quickdemo.cpp

#include "quickopencv.h"
#include <opencv2/dnn.hpp>

using namespace cv;
using namespace std;

void QuickDemo::color_style_demo(Mat& image) {

	Mat dst;

	applyColorMap(image, dst, COLORMAP_DEEPGREEN);
	imshow("COLORMAP_DEEPGREEN", dst);
}

quickopencv.h

#pragma once
#include <opencv2/opencv.hpp>
using namespace cv;

class QuickDemo {            //快速的演示文件 class类
public:

	void color_style_demo(Mat& image);  //09

};

3.循环转换颜色风格

我们首先把颜色表做成一个枚举数组

int colormap[]= {
     COLORMAP_AUTUMN,
     COLORMAP_BONE,
     COLORMAP_JET,
     COLORMAP_WINTER,
     COLORMAP_RAINBOW,
     COLORMAP_OCEAN,
     COLORMAP_SUMMER,
     COLORMAP_SPRING,
     COLORMAP_COOL,
     COLORMAP_HSV,//10
	 COLORMAP_PINK,
	 COLORMAP_HOT,
     COLORMAP_PARULA,
     COLORMAP_MAGMA,
     COLORMAP_INFERNO,
     COLORMAP_PLASMA,
     COLORMAP_VIRIDIS,
     COLORMAP_CIVIDIS,
     COLORMAP_TWILIGHT,
     COLORMAP_TWILIGHT_SHIFTED,//20
     COLORMAP_TURBO,
     COLORMAP_DEEPGREEN
};

通过applyColorMap以及1个while循环，我们便可以实现颜色风格的循环转换

void QuickDemo::color_style_demo(Mat& image) {

	int colormap[] = {
	 COLORMAP_AUTUMN,
	 COLORMAP_BONE,
	 COLORMAP_JET,
	 COLORMAP_WINTER,
	 COLORMAP_RAINBOW,
	 COLORMAP_OCEAN,
	 COLORMAP_SUMMER,
	 COLORMAP_SPRING,
	 COLORMAP_COOL,
	 COLORMAP_HSV,//10
	 COLORMAP_PINK,
	 COLORMAP_HOT,
	 COLORMAP_PARULA,
	 COLORMAP_MAGMA,
	 COLORMAP_INFERNO,
	 COLORMAP_PLASMA,
	 COLORMAP_VIRIDIS,
	 COLORMAP_CIVIDIS,
	 COLORMAP_TWILIGHT,
	 COLORMAP_TWILIGHT_SHIFTED,//20
	 COLORMAP_TURBO,
	 COLORMAP_DEEPGREEN
	};

	Mat dst;
	int index = 0;
	while (true) {

		int c = waitKey(500);

		if (c == 27) {//退出
			break;
		}
		applyColorMap(image, dst, colormap[index % 22]);

		index++;
		imshow("22种颜色风格",dst);
	}
}

完整的22种图片程序

main.cpp

#include "opencv2/opencv.hpp"
#include "quickopencv.h"
#include <iostream>

using namespace cv;
using namespace std;

int main(int argc, char** argv) {
	Mat src = imread("C:/Users/LZQ/Desktop/lena.png"); //  B, G, R
	if (src.empty()) {
		printf("could not load image....\n");
		return -1;
	}

	imshow("输入窗口", src);

	QuickDemo qd;

	qd.color_style_demo(src);

	waitKey(0);
	destroyAllWindows();
	return 0;
}

quickdemo.cpp

#include "quickopencv.h"
#include <opencv2/dnn.hpp>

using namespace cv;
using namespace std;

void QuickDemo::color_style_demo(Mat& image) {
	int colormap[] = {
		COLORMAP_AUTUMN,
		COLORMAP_BONE,
		COLORMAP_JET,
		COLORMAP_WINTER,
		COLORMAP_RAINBOW,
		COLORMAP_OCEAN,
		COLORMAP_SUMMER,
		COLORMAP_SPRING,
		COLORMAP_COOL,
		COLORMAP_PINK,
		COLORMAP_HOT,
		COLORMAP_PARULA,
		COLORMAP_MAGMA,
		COLORMAP_INFERNO,
		COLORMAP_PLASMA,
		COLORMAP_VIRIDIS,
		COLORMAP_CIVIDIS,
		COLORMAP_TWILIGHT,
		COLORMAP_TWILIGHT_SHIFTED
	};

	Mat dst;
	int index = 0;
	while (true) {
		int c = waitKey(500);
		if (c == 27) { // 退出
			break;
		}
		applyColorMap(image, dst, colormap[index % 19]);
		index++;
		imshow("颜色风格", dst);
	}
}

quickopencv.h

#pragma once
#include <opencv2/opencv.hpp>
using namespace cv;

class QuickDemo {            //快速的演示文件 class类
public:

	void color_style_demo(Mat& image);  //09

};

22种颜色风格动图结果：

<video id="video" controls=""src="https://live.csdn.net/v/269702?spm=1001.2014.3001.5501" preload="none">

<video id="video" controls=""src="live.csdn.net/v/269702?spm=1001.2014.3001.5501" preload="none">

live.csdn.net/v/269702?spm=1001.2014.3001.5501

本课所用API查阅

OpenCV 4.6.0 官方文档

applyColorMap()

ColormapTypes