OpenCV学习记录6

一 学习内容

1 获取图像坐标处的像素值，并修改图对比度

二 代码

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

using namespace std;
using namespace cv;

int main(int argc, char** argv) {
	Mat src2, dst;
	src2 = imread("e:/2 opencv_projects_zl/desk4.jpg");

	if (!src2.data) {
		cout << "Load Image Desk2 Error...\n" << endl;
		return -1;
	}
	char Figure_name[] = "Figure1";
	namedWindow(Figure_name, CV_WINDOW_AUTOSIZE);
	imshow(Figure_name, src2);

	// 学习新内容
	//1. 调整图像亮度和对比度
	int height = src2.rows;
	int width = src2.cols;
	double alpha = 1.2;
	double beta = 10;
	dst = Mat::zeros(src2.size(),src2.type());
	for (int row = 0; row < height; row++) {
		for (int col = 0; col < width; col++)
		{
			if (src2.channels() == 3) {
				float b = src2.at<Vec3b>(row,col)[0];
				float g = src2.at<Vec3b>(row, col)[1];
				float r = src2.at<Vec3b>(row, col)[2];
				// 修改像素值
				dst.at<Vec3b>(row, col)[0] = saturate_cast<uchar>(b*alpha + beta);
				dst.at<Vec3b>(row, col)[1] = saturate_cast<uchar>(g*alpha + beta);
				dst.at<Vec3b>(row, col)[2] = saturate_cast<uchar>(r*alpha + beta);
			}
			else if (src2.channels() == 1) {
				float value = src2.at<uchar>(row, col);
				dst.at<uchar>(row, col) = saturate_cast<uchar>(value*alpha + beta);
			}
		}
	
	}
	char Figure_name2[] = "Figure2";
	namedWindow(Figure_name2, CV_WINDOW_AUTOSIZE);
	imshow(Figure_name2, dst);

	//2. 将原图像转化为Vec3f型，并从中读取数据
	Mat dst2;
	src2.convertTo(dst2,CV_32F);
    height = src2.rows;
	width = src2.cols;
	alpha = 1.2;
	beta = 10;
	dst = Mat::zeros(src2.size(), src2.type());
	for (int row = 0; row < height; row++) {
		for (int col = 0; col < width; col++)
		{
			if (src2.channels() == 3) {
				float b = dst2.at<Vec3f>(row, col)[0];
				float g = dst2.at<Vec3f>(row, col)[1];
				float r = dst2.at<Vec3f>(row, col)[2];
				// 修改像素值
				dst.at<Vec3b>(row, col)[0] = saturate_cast<uchar>(b*alpha + beta);
				dst.at<Vec3b>(row, col)[1] = saturate_cast<uchar>(g*alpha + beta);
				dst.at<Vec3b>(row, col)[2] = saturate_cast<uchar>(r*alpha + beta);
			}
			else if (src2.channels() == 1) {
				float value = dst2.at<uchar>(row, col);
				dst.at<uchar>(row, col) = saturate_cast<uchar>(value*alpha + beta);
			}
		}

	}
	char Figure_name3[] = "Figur3";
	namedWindow(Figure_name3, CV_WINDOW_AUTOSIZE);
	imshow(Figure_name3, dst);

	//3. 将原图像直接转化为灰度图像，再执行一遍
	cvtColor(src2,src2,CV_BGR2GRAY);
	height = src2.rows;
	width = src2.cols;
	alpha = 1.2;
	beta = 10;
	dst = Mat::zeros(src2.size(), src2.type());
	for (int row = 0; row < height; row++) {
		for (int col = 0; col < width; col++)
		{
			if (src2.channels() == 3) {
				float b = src2.at<Vec3b>(row, col)[0];
				float g = src2.at<Vec3b>(row, col)[1];
				float r = src2.at<Vec3b>(row, col)[2];
				// 修改像素值
				dst.at<Vec3b>(row, col)[0] = saturate_cast<uchar>(b*alpha + beta);
				dst.at<Vec3b>(row, col)[1] = saturate_cast<uchar>(g*alpha + beta);
				dst.at<Vec3b>(row, col)[2] = saturate_cast<uchar>(r*alpha + beta);
			}
			else if (src2.channels() == 1) {
				float value = src2.at<uchar>(row, col);
				dst.at<uchar>(row, col) = saturate_cast<uchar>(value*alpha + beta);
			}
		}

	}
	char Figure_name4[] = "Figure4";
	namedWindow(Figure_name4, CV_WINDOW_AUTOSIZE);
	imshow(Figure_name4, dst);

	waitKey(0);
	return 0;
}

三、调试结果