Zoom and pan two images simultaneously in opencv

Question

I have two images with similar sizes that show similar scenes. How can we show two images in two frames and when panning or zooming in the left image, it pans and zooms in the right one? I don't want to concatenate the images though.

Is there a solution to do this? Both python or c++ OpenCV are fine.

There are 2 same images? You wanna show them seperately? You wanna change 1st image by mouse zooming or panning? You want 2nd image to change automatically in the same time? Am I right? — Yunus Temurlenk, Jun 10 '20 at 06:11
That's correct, images are not exactly the same though, they are like stereo images. — Bruce, Jun 10 '20 at 09:03

score 0 · Answer 1 · answered May 22 '22 at 13:59

About zoom in/out:

The basic idea is deciding the scale changed every time on mouse wheel. After you get the current scale (v.s. origin image) and correct region of image you want to show on screen, you can get the position and length of rectangle on scaled image. So you can draw this rectangle on scaled image.

In my github，checking OnMouseWheel () and RefreshSrcView () in Fastest_Image_Pattern_Matching/ELCVMatchTool/ELCVMatchToolDlg.cpp may give what you want.

About showing two images simutaneouly with same region:

use two picture boxes with MFC framework or other UI builder.
or use two cv::namedWindow () without framework

Effect:

Part of the code:

BOOL CELCVMatchToolDlg::OnMouseWheel (UINT nFlags, short zDelta, CPoint pt)
{
    POINT pointCursor;
    GetCursorPos (&pointCursor);
    ScreenToClient (&pointCursor);
    // TODO: 在此加入您的訊息處理常式程式碼和 (或) 呼叫預設值
    if (zDelta > 0)
    {
        if (m_iScaleTimes == MAX_SCALE_TIMES)
            return TRUE;
        else
            m_iScaleTimes++;
    }
    if (zDelta < 0)
    {
        if (m_iScaleTimes == MIN_SCALE_TIMES)
            return TRUE;
        else
            m_iScaleTimes--;
    }
    CRect rect;
    //GetWindowRect (rect);
    GetDlgItem (IDC_STATIC_SRC_VIEW)->GetWindowRect (rect);//重要

    if (m_iScaleTimes == 0)
        g_dCompensationX = g_dCompensationY = 0;

    int iMouseOffsetX = pt.x - (rect.left + 1);
    int iMouseOffsetY = pt.y - (rect.top + 1);

    double dPixelX = (m_hScrollBar.GetScrollPos () + iMouseOffsetX + g_dCompensationX) / m_dNewScale;
    double dPixelY = (m_vScrollBar.GetScrollPos () + iMouseOffsetY + g_dCompensationY) / m_dNewScale;


    m_dNewScale = m_dSrcScale * pow (SCALE_RATIO, m_iScaleTimes);

    if (m_iScaleTimes != 0)
    {
        int iWidth = m_matSrc.cols;
        int iHeight = m_matSrc.rows;

        
        m_hScrollBar.SetScrollRange (0, int (m_dNewScale * iWidth - m_dSrcScale * iWidth) - 1 + BAR_SIZE);
        m_vScrollBar.SetScrollRange (0, int (m_dNewScale * iHeight - m_dSrcScale * iHeight) - 1 + BAR_SIZE);
        int iBarPosX = int (dPixelX * m_dNewScale - iMouseOffsetX + 0.5);
        m_hScrollBar.SetScrollPos (iBarPosX);
        m_hScrollBar.ShowWindow (SW_SHOW);
        g_dCompensationX = -iBarPosX + (dPixelX * m_dNewScale - iMouseOffsetX);

        int iBarPosY = int (dPixelY * m_dNewScale - iMouseOffsetY + 0.5);
        m_vScrollBar.SetScrollPos (iBarPosY);
        m_vScrollBar.ShowWindow (SW_SHOW);
        g_dCompensationY = -iBarPosY + (dPixelY * m_dNewScale - iMouseOffsetY);

        //滑塊大小
        SCROLLINFO infoH;
        infoH.cbSize = sizeof (SCROLLINFO);
        infoH.fMask = SIF_PAGE;
        infoH.nPage = BAR_SIZE;
        m_hScrollBar.SetScrollInfo (&infoH);

        SCROLLINFO infoV;
        infoV.cbSize = sizeof (SCROLLINFO);
        infoV.fMask = SIF_PAGE;
        infoV.nPage = BAR_SIZE;
        m_vScrollBar.SetScrollInfo (&infoV);
        //滑塊大小

    }
    else
    {
        m_hScrollBar.SetScrollPos (0);
        m_hScrollBar.ShowWindow (SW_HIDE);
        m_vScrollBar.SetScrollPos (0);
        m_vScrollBar.ShowWindow (SW_HIDE);
    }
    RefreshSrcView ();
    return CDialogEx::OnMouseWheel (nFlags, zDelta, pt);
}

Zoom and pan two images simultaneously in opencv

1 Answers1