I have set of images taken from right side of object like image1. I need to rotate it about vertical axis and change it tobe like image2.
Is that affine transformation useful to convert image1 to image2 ? I used affine transform and played with it, but didn't get desired results. What should I do? I used this part of code for image transformation.
cv::Mat shearedImage;
cv::Point2f srcPoints[3] = {cv::Point2f(0, 0), cv::Point2f(resizedImage.cols, 0), cv::Point2f(0, resizedImage.rows)};
cv::Point2f dstPoints[3] = {cv::Point2f(0, 0), cv::Point2f(resizedImage.cols, 0), cv::Point2f(0, resizedImage.rows)};
cv::Mat transformMatrix = cv::getAffineTransform(srcPoints, dstPoints);
cv::warpAffine(resizedImage, shearedImage, transformMatrix, resizedImage.size());
Here is the complete code in Qt
#include "mainwindow.h"
#include <QApplication>
#include <opencv2/opencv.hpp>
#include <QDebug>
#include <QLabel>
int main(int argc, char* argv[])
{
QApplication a(argc, argv);
// Load the original image
cv::Mat originalImage = cv::imread("Pic1.jpg");
// Crop the image
cv::Rect roi(200, 300, 1350, 850);
cv::Mat croppedImage = originalImage(roi);
// Resize the cropped image
cv::Mat resizedImage;
cv::resize(croppedImage, resizedImage, cv::Size(), 0.4, 0.4);
// Shear the resized image
cv::Mat shearedImage;
cv::Point2f srcPoints[3] = {cv::Point2f(0, 0), cv::Point2f(resizedImage.cols, 0), cv::Point2f(0, resizedImage.rows)};
cv::Point2f dstPoints[3] = {cv::Point2f(0, 0), cv::Point2f(resizedImage.cols, 0), cv::Point2f(0, resizedImage.rows)};
cv::Mat transformMatrix = cv::getAffineTransform(srcPoints, dstPoints);
cv::warpAffine(resizedImage, shearedImage, transformMatrix, resizedImage.size());
// Display the shear image
cv::namedWindow("Transformed Image");
cv::imshow("Transformed Image", shearedImage);
MainWindow w;
w.show();
return a.exec();
}
I searched more and found more details, based on this Question, I should use cv::warpPerspective
instead of affine transform to change the image perspective.
#include "mainwindow.h"
#include <QApplication>
#include <opencv2/opencv.hpp>
#include <QDebug>
#include <QLabel>
cv::Point2f srcPoints[4];
int pointCounter = 0;
/*using mouseCallback function to selecting 4 points by left click for changing image perspective.*/
void mouseCallback(int event, int x, int y, int flags, void* userdata)
{
if (event == cv::EVENT_LBUTTONDOWN && pointCounter < 4)
{
srcPoints[pointCounter] = cv::Point2f(x, y);
pointCounter++;
qDebug() << "Selected point: (" << x << ", " << y << ")";
}
}
int main(int argc, char* argv[])
{
QApplication a(argc, argv);
// Load the original image
cv::Mat Image = cv::imread("image1.jpg");
if (Image.empty())
{
qDebug() << "Failed to load image";
return -1;
}
// Resize the cropped image
cv::Mat originalImage;
cv::resize(Image, originalImage, cv::Size(), 0.9, 0.9);
// Create a window to display the image
cv::namedWindow("Original Image");
cv::imshow("Original Image", originalImage);
// Set mouse callback
cv::setMouseCallback("Original Image", mouseCallback);
// Display instructions to the user
// cv::putText(originalImage, "Select points from left to right and clockwise", cv::Point(10, 30),
// cv::FONT_HERSHEY_SIMPLEX, 1, cv::Scalar(0, 0, 255), 2);
cv::imshow("Original Image", originalImage);
// Wait until 4 points are selected
while (pointCounter < 4)
{
char key = cv::waitKey(10);
if (key == 27) // Esc key
{
qDebug() << "Selection aborted";
return 0;
}
}
cv::destroyWindow("Original Image");
// Generate the perspective transform matrix
cv::Point2f dstPoints[4] = {cv::Point2f(0, 0), cv::Point2f(originalImage.cols, 0), cv::Point2f(originalImage.cols, originalImage.rows), cv::Point2f(0, originalImage.rows)};
cv::Mat perspectiveMatrix = cv::getPerspectiveTransform(srcPoints, dstPoints);
// Apply the perspective transform
cv::Mat transformedImage;
cv::warpPerspective(originalImage, transformedImage, perspectiveMatrix, originalImage.size());
// Display the transformed image
cv::namedWindow("Transformed Image");
cv::imshow("Transformed Image", transformedImage);
MainWindow w;
w.show();
return a.exec();
}