Question

我想从视频流中保存图像，然后在显示的图像上绘制一个矩形以生成感兴趣的区域。稍后，将该ROI保存在文件中。我使用opencv python grabcut示例来使用setMouseCallback函数。但我不知道我做错了什么，因为它没有给出我期望的结果。我希望在mouse input窗口中显示的静态图像上绘制绿色矩形，并将roi保存到文件中。请帮助调试此代码或显示更好的方法：

import cv2

rect = (0,0,1,1)
rectangle = False
rect_over = False  
def onmouse(event,x,y,flags,params):
    global sceneImg,rectangle,rect,ix,iy,rect_over

    # Draw Rectangle
    if event == cv2.EVENT_LBUTTONDOWN:
        rectangle = True
        ix,iy = x,y

    elif event == cv2.EVENT_MOUSEMOVE:
        if rectangle == True:
            cv2.rectangle(sceneImg,(ix,iy),(x,y),(0,255,0),2)
            rect = (min(ix,x),min(iy,y),abs(ix-x),abs(iy-y))

    elif event == cv2.EVENT_LBUTTONUP:
        rectangle = False
        rect_over = True
        cv2.rectangle(sceneImg,(ix,iy),(x,y),(0,255,0),2)
        rect = (min(ix,x),min(iy,y),abs(ix-x),abs(iy-y))

        x1,y1,w,h = rect        
        roi = sceneImg[y1:y1+h, x1:x1+w]

        cv2.imwrite('roi.jpg', roi)

# Named window and mouse callback
cv2.namedWindow('video')
cv2.namedWindow('mouse input')
cv2.setMouseCallback('mouse input',onmouse)

camObj = cv2.VideoCapture(-1)
keyPressed = None
running = True
scene = False
# Start video stream
while running:
    readOK, frame = camObj.read()

    keyPressed = cv2.waitKey(5)
    if keyPressed == ord('s'):
        scene = True

        cv2.imwrite('sceneImg.jpg',frame)
        sceneImg = cv2.imread('sceneImg.jpg')

        cv2.destroyWindow('video')
        cv2.imshow('mouse input', sceneImg)

    elif keyPressed == ord('r'):
        scene = False
        cv2.destroyWindow('mouse input')

    elif keyPressed == ord('q'):
        running = False

    if not scene:
        cv2.imshow('video', frame)

cv2.destroyAllWindows()
camObj.release()

Answer 1

每次调用{event == cv2.EVENT_MOUSEMOVE：}时，您都需要重置图像。

您的代码应如下所示：

if event == cv2.EVENT_LBUTTONDOWN:
    rectangle = True
    ix,iy = x,y

elif event == cv2.EVENT_MOUSEMOVE:
    if rectangle == True:
        sceneImg = sceneImg2.copy()
        cv2.rectangle(sceneImg,(ix,iy),(x,y),(0,255,0),2)
        rect = (min(ix,x),min(iy,y),abs(ix-x),abs(iy-y))


elif event == cv2.EVENT_LBUTTONUP:
    rectangle = False
    rect_over = True

    cv2.rectangle(sceneImg,(ix,iy),(x,y),(0,255,0),2)
    rect = (min(ix,x),min(iy,y),abs(ix-x),abs(iy-y))

Answer 2

这是我目前的工作，我再次在mouse input上呈现EVENT_LBUTTONUP窗口。为了避免在ROI中显示的边界框保存到文件中，我使用了输入场景的副本：

import cv2

rect = (0,0,1,1)
rectangle = False
rect_over = False  
def onmouse(event,x,y,flags,params):
    global sceneImg,rectangle,rect,ix,iy,rect_over, roi

    # Draw Rectangle
    if event == cv2.EVENT_LBUTTONDOWN:
        rectangle = True
        ix,iy = x,y

    elif event == cv2.EVENT_MOUSEMOVE:
        if rectangle == True:
#            cv2.rectangle(sceneCopy,(ix,iy),(x,y),(0,255,0),1)
            rect = (min(ix,x),min(iy,y),abs(ix-x),abs(iy-y))

    elif event == cv2.EVENT_LBUTTONUP:
        rectangle = False
        rect_over = True

        sceneCopy = sceneImg.copy()
        cv2.rectangle(sceneCopy,(ix,iy),(x,y),(0,255,0),1)

        rect = (min(ix,x),min(iy,y),abs(ix-x),abs(iy-y))       
        roi = sceneImg[rect[1]:rect[1]+rect[3], rect[0]:rect[0]+rect[2]]

        cv2.imshow('mouse input', sceneCopy)
        cv2.imwrite('roi.jpg', roi)

# Named window and mouse callback
cv2.namedWindow('mouse input')
cv2.setMouseCallback('mouse input',onmouse)
cv2.namedWindow('video')

camObj = cv2.VideoCapture(-1)
keyPressed = None
running = True
scene = False
# Start video stream
while running:
    readOK, frame = camObj.read()

    keyPressed = cv2.waitKey(5)
    if keyPressed == ord('s'):
        scene = True
        cv2.destroyWindow('video')

        cv2.imwrite('sceneImg.jpg',frame)
        sceneImg = cv2.imread('sceneImg.jpg')

        cv2.imshow('mouse input', sceneImg)

    elif keyPressed == ord('r'):
        scene = False
        cv2.destroyWindow('mouse input')

    elif keyPressed == ord('q'):
        running = False

    if not scene:
        cv2.imshow('video', frame)

cv2.destroyAllWindows()
camObj.release()

因此，我可以看到应该绑定ROI的矩形，但是当鼠标左键按下并且鼠标光标移动时，我仍然不知道如何可视化边界框。该可视化在抓取示例中起作用，但在我的情况下我无法弄清楚。在EVENT_MOUSEMOVE期间取消注释绘制矩形的线时，我会在图像上绘制多个矩形。如果有人用一种方法来回答单个矩形的可视化，我可以接受它。

Python OpenCV：绘制矩形的鼠标回调

2 个答案: