#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <iostream>
using namespace cv;
// 基于等间隔提取图像缩放
cv::Mat imageReduction1(cv::Mat &srcImage, float kx, float ky)
{
// 获取输出图像分辨率
int nRows = cvRound(srcImage.rows * kx);
int nCols = cvRound(srcImage.cols * ky);
cv::Mat resultImage(nRows, nCols, srcImage.type());
for (int i = 0; i < nRows; ++i)
{
for (int j = 0; j < nCols; ++j)
{
// 根据水平因子计算坐标
int y = static_cast<int>((i + 1) / kx + 0.5) - 1;
// 根据垂直因子计算坐标
int x = static_cast<int>((j + 1) / ky + 0.5) - 1;
resultImage.at<cv::Vec3b>(i, j) =
srcImage.at<cv::Vec3b>(y, x);
}
}
return resultImage;
}
cv::Vec3b areaAverage(const cv::Mat &srcImage,
Point_<int> leftPoint, Point_<int> rightPoint)
{
int temp1 = 0, temp2 = 0, temp3 = 0;
// 计算区域子块像素点个数
int nPix = (rightPoint.x - leftPoint.x + 1)*
(rightPoint.y - leftPoint.y + 1);
// 区域子块各个通道对像素值求和
for (int j = leftPoint.y; j <= rightPoint.y; j++){
for (int i = leftPoint.x; i <= rightPoint.x; i++){
temp1 += srcImage.at<cv::Vec3b>(j, i)[0];
temp2 += srcImage.at<cv::Vec3b>(j, i)[1];
temp3 += srcImage.at<cv::Vec3b>(j, i)[2];
}
}
// 对每个通道求均值
Vec3b vecTemp;
vecTemp[0] = temp1 / nPix;
vecTemp[1] = temp2 / nPix;
vecTemp[2] = temp3 / nPix;
return vecTemp;
}
cv::Mat imageReduction2(const Mat &srcImage, double kx,
double ky)
{
// 获取输出图像分辨率
int nRows = cvRound(srcImage.rows * kx);
int nCols = cvRound(srcImage.cols * ky);
cv::Mat resultImage(nRows, nCols, srcImage.type());
// 区域子块的左上角行列坐标
int leftRowCoordinate = 0;
int leftColCoordinate = 0;
for (int i = 0; i < nRows; ++i)//行数-y
{
// 根据水平因子计算坐标
int y = static_cast<int>((i + 1) / kx + 0.5) - 1;
for (int j = 0; j < nCols; ++j) {//列数-x
// 根据垂直因子计算坐标
int x = static_cast<int>((j + 1) / ky + 0.5) - 1;
// 求解区域子块的均值
resultImage.at<Vec3b>(i, j) =
areaAverage(srcImage,
Point_<int>(leftColCoordinate,
leftRowCoordinate), Point_<int>(x, y));//!!
// 更新下子块左上角的列坐标，行坐标不变
leftColCoordinate = x + 1;
}
leftColCoordinate = 0;
// 更新下子块左上角的行坐标
leftRowCoordinate = y + 1;
}
return resultImage;
}
int main()
{
cv::Mat srcImage = cv::imread("F:\\processImage\\BaboonRGB.bmp");
if (!srcImage.data)
return -1;
cv::imshow("srcImage", srcImage);
cv::Mat resultImage1 =
imageReduction1(srcImage, 0.5, 0.5);
cv::imshow("res1", resultImage1);
cv::Mat resultImage2 =
imageReduction2(srcImage, 0.5, 0.5);
cv::imshow("res2", resultImage2);
cv::waitKey(0);
return 0;
}
