OpenCV 自带颜色表实现各种滤镜

一、知识点
1、void applyColorMap(InputArray src, OutputArray dst, int colormap);

(1)、通过给定的颜色映射表，将灰度图像或伪彩色图像转换为全彩色图像。

(2)、参数说明:

src: 源图像，灰度或彩色，类型为CV_8UC1或CV_8UC3。如果是CV_8UC3，则使用cv::COLOR_BGR2GRAY在内部生成CV_8UC1图像。

dst: 给源图像做颜色映射后的结果图像。

colormap: 颜色映射需要的enum类型，具体见(3)。

(3)、

enum ColormapTypes

{

COLORMAP_AUTUMN = 0, //!< ! $autumn$ (pics/colormaps/colorscale_autumn.jpg)

COLORMAP_BONE = 1, //!< ! $bone$ (pics/colormaps/colorscale_bone.jpg)

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

COLORMAP_WINTER = 3, //!< ! $winter$ (pics/colormaps/colorscale_winter.jpg)

COLORMAP_RAINBOW = 4, //!< ! $rainbow$ (pics/colormaps/colorscale_rainbow.jpg)

COLORMAP_OCEAN = 5, //!< ! $ocean$ (pics/colormaps/colorscale_ocean.jpg)

COLORMAP_SUMMER = 6, //!< ! $summer$ (pics/colormaps/colorscale_summer.jpg)

COLORMAP_SPRING = 7, //!< ! $spring$ (pics/colormaps/colorscale_spring.jpg)

COLORMAP_COOL = 8, //!< ! $cool$ (pics/colormaps/colorscale_cool.jpg)

COLORMAP_HSV = 9, //!< ! $HSV$ (pics/colormaps/colorscale_hsv.jpg)

COLORMAP_PINK = 10, //!< ! $pink$ (pics/colormaps/colorscale_pink.jpg)

COLORMAP_HOT = 11, //!< ! $hot$ (pics/colormaps/colorscale_hot.jpg)

COLORMAP_PARULA = 12, //!< ! $parula$ (pics/colormaps/colorscale_parula.jpg)

COLORMAP_MAGMA = 13, //!< ! $magma$ (pics/colormaps/colorscale_magma.jpg)

COLORMAP_INFERNO = 14, //!< ! $inferno$ (pics/colormaps/colorscale_inferno.jpg)

COLORMAP_PLASMA = 15, //!< ! $plasma$ (pics/colormaps/colorscale_plasma.jpg)

COLORMAP_VIRIDIS = 16, //!< ! $viridis$ (pics/colormaps/colorscale_viridis.jpg)

COLORMAP_CIVIDIS = 17, //!< ! $cividis$ (pics/colormaps/colorscale_cividis.jpg)

COLORMAP_TWILIGHT = 18, //!< ! $twilight$ (pics/colormaps/colorscale_twilight.jpg)

COLORMAP_TWILIGHT_SHIFTED = 19, //!< ! $twilight shifted$ (pics/colormaps/colorscale_twilight_shifted.jpg)

COLORMAP_TURBO = 20, //!< ! $turbo$ (pics/colormaps/colorscale_turbo.jpg)

COLORMAP_DEEPGREEN = 21 //!< ! $deepgreen$ (pics/colormaps/colorscale_deepgreen.jpg)

};

(4)、此功能通常用于增强图像的可视化效果，特别是在处理诸如热图(heatmaps)等数据可视化时非常有用。

二、示例代码: 循环切换各种滤镜

cpp 复制代码

#include <iostream>
#include <opencv2/opencv.hpp>


void TestColorMap(cv::Mat & src)
{
    int i_color_map[] = {
        cv::COLORMAP_AUTUMN,
        cv::COLORMAP_BONE,
        cv::COLORMAP_JET,
        cv::COLORMAP_WINTER,
        cv::COLORMAP_RAINBOW,
        cv::COLORMAP_OCEAN,
        cv::COLORMAP_SUMMER,
        cv::COLORMAP_SPRING,
        cv::COLORMAP_COOL,
        cv::COLORMAP_HSV,
        cv::COLORMAP_PINK,
        cv::COLORMAP_HOT,
        cv::COLORMAP_PARULA,
        cv::COLORMAP_MAGMA,
        cv::COLORMAP_INFERNO,
        cv::COLORMAP_PLASMA,
        cv::COLORMAP_VIRIDIS,
        cv::COLORMAP_CIVIDIS,
        cv::COLORMAP_TWILIGHT,
        cv::COLORMAP_TWILIGHT_SHIFTED,
        cv::COLORMAP_TURBO,
        cv::COLORMAP_DEEPGREEN
    };
    
    cv::Mat dst;
    int index = 0;

    while (true)
    {
        int c = cv::waitKey(1000);
        if (c == 27)
        {
            break;
        }

        cv::applyColorMap(src, dst, i_color_map[index % 22]);
        cv::imshow("颜色风格", dst);

        index++;
    }
}


int main()
{
    cv::Mat src = cv::imread("../images/8.png");
    if (src.empty())
    {
        std::cout << "load src image error..." << std::endl;
        return -1;
    }
    cv::imshow("原始图像", src);

    TestColorMap(src);
    
    return 0;
}