我将Mat对象推入std::vector。

但是,当我尝试在此之后访问元素(Mat)时,它并没有为我提供之前放入的图像,具体取决于frameOrientation。

例如,在下面的情况下,我得到的“after_push_rotated2.jpg”与“before_push_rotated3.jpg”相同,不应如此。

如果将frameOrientation设置为所有“2s”或“4s”,则“after_push_rotated1 / 2 / 3.jpg”都相同,并且等于“before_push_rotated3.jpg”。

怎么了

#include <cv.h>
#include <cxcore.h>
#include <highgui.h>
#include <iostream>
#include <vector>

using namespace cv;
using namespace std;

vector<Mat> checkOrientationAndRotate()
{
    Mat frame1 = imread("1.jpg" );
    Mat frame2 = imread("2.jpg" );
    Mat frame3 = imread("3.jpg" );



    vector<Mat> frameList;
    vector<Mat> frameList_rotated;

    frameList.push_back(frame1);
    frameList.push_back(frame2);
    frameList.push_back(frame3);

    Mat transposedFrame;
    Mat rotatedFrame;

    int i=0;
    for (vector<Mat>::iterator iter = frameList.begin(); iter != frameList.end(); iter++)
    {
        //Check for orientation of that frame
        int frameOrientation;
        if (i==0) frameOrientation = 1;
        if (i==1) frameOrientation = 2;
        if (i==2) frameOrientation = 4;

        switch (frameOrientation)
        {
        case 1: //1 - no rotate
            rotatedFrame = *iter;
            break;

        case 2: //2 - rotate it ACW 90 deg
            transpose(*iter, transposedFrame);
            flip(transposedFrame, rotatedFrame, 0);
            break;

        case 3: //3 - rotate it 180deg
            flip(*iter, rotatedFrame, -1);
            break;

        case 4: //4 - rotate it CW 90 deg
            transpose(*iter, transposedFrame);
            flip(transposedFrame, rotatedFrame, 1);
            break;
        default:
            break;
        }

        //Check frame before pushing into vector
        if (i==0) imwrite("before_push_rotated1.jpg",rotatedFrame);
        if (i==1) imwrite("before_push_rotated2.jpg",rotatedFrame);
        if (i==2) imwrite("before_push_rotated3.jpg",rotatedFrame);

        frameList_rotated.push_back(rotatedFrame);


        //Check frame after pushing into vector.
        //Depending on the frameorientation, the frames are not the frames pushed in earlier!
        int n=0;
        for (vector<Mat>::iterator iter = frameList_rotated.begin(); iter != frameList_rotated.end(); iter++)
        {
            Mat frame = *iter;
            if (n==0) imwrite("after_push_rotated1.jpg",frame);
            if (n==1) imwrite("after_push_rotated2.jpg",frame);
            if (n==2) imwrite("after_push_rotated3.jpg",frame);
            n++;
        }

        i++;
        } //for

        return frameList_rotated;

}

void main()
{
    vector<Mat> frameList_rotated = checkOrientationAndRotate();
}

最佳答案

[我最近没有使用过OpenCV,所以我可能是错的,请告诉我是否是:)]
Mat表示图像 header ,而不是图像数据。 OpenCV在内部维护引用计数机制,以避免在不同区域之间复制大量图像像素数据。意思是说当你说:

Mat a = b; // Only headers are copied, both a and b refer to the same image.

在上述情况下,如果您修改b,则更改也将反射(reflect)在a中。在这种情况下,您需要使用的是:
Mat a = b.clone();

关于您的情况,我真的认为以下代码可以解决问题(如果没有,则控制流程可能还有其他问题,呵呵):

尝试更换:
Mat transposedFrame;
Mat rotatedFrame;

与:
 //create a new image, not just the headers..
Mat transposedFrame(Size(image_width, image_height), image.type());
Mat rotatedFrame(Size(image_width, image_height), image.type());

10-07 19:53
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