Opencv：检测鼠标在图片上的点击位置

Question

Opencv：检测鼠标在图片上的点击位置

28

我有一段代码，其中我使用OpenCV简单地显示一张图片：

    import numpy as np 
    import cv2

    class LoadImage:
        def loadImage(self):
            self.img=cv2.imread('photo.png')
            cv2.imshow('Test',self.img)

            self.pressedkey=cv2.waitKey(0)

            # Wait for ESC key to exit
            if self.pressedkey==27:
                cv2.destroyAllWindows()

    # Start of the main program here        
    if __name__=="__main__":
        LI=LoadImage()
        LI.loadImage()

当照片显示在窗口中时，我想在控制台（终端）上显示鼠标在图片上单击时的位置。我不知道怎样实现这个功能，请帮忙一下吗？

- user4519127

@berak 这不是同一个问题，我是Python和OpenCV的初学者。 - user4519127

1

只需再次前往那里，打印出所有值并查看即可。 - berak

8个回答

12

以下是我的实现：

不需要存储点击位置，仅显示它：

def onMouse(event, x, y, flags, param):
    if event == cv2.EVENT_LBUTTONDOWN:
       # draw circle here (etc...)
       print('x = %d, y = %d'%(x, y))
cv2.setMouseCallback('WindowName', onMouse)

如果您想在代码的其他位置使用这些位置，可以使用以下方法获取坐标：

posList = []
def onMouse(event, x, y, flags, param):
   global posList
   if event == cv2.EVENT_LBUTTONDOWN:
        posList.append((x, y))
cv2.setMouseCallback('WindowName', onMouse)
posNp = np.array(posList)     # convert to NumPy for later use

- smh

5

import cv2

cv2.imshow("image", img)
cv2.namedWindow('image')
cv2.setMouseCallback('image', on_click)

def on_click(event, x, y, p1, p2):
    if event == cv2.EVENT_LBUTTONDOWN:
        cv2.circle(lastImage, (x, y), 3, (255, 0, 0), -1)

- Omer Meshy

1

欢迎来到SO。请问您能否解释一下为什么这是答案，除了分享的代码之外？ - Mike Poole

1

这是基于类的OpenCV鼠标回调函数的实现，用于获取图像上的点。

import cv2
import numpy as np
#events = [i for i in dir(cv2) if 'EVENT' in i]
#print (events)

class MousePts:
    def __init__(self,windowname,img):
        self.windowname = windowname
        self.img1 = img.copy()
        self.img = self.img1.copy()
        cv2.namedWindow(windowname,cv2.WINDOW_NORMAL)
        cv2.imshow(windowname,img)
        self.curr_pt = []
        self.point   = []

    def select_point(self,event,x,y,flags,param):
        if event == cv2.EVENT_LBUTTONDOWN:
            self.point.append([x,y])
            #print(self.point)
            cv2.circle(self.img,(x,y),5,(0,255,0),-1)
        elif event == cv2.EVENT_MOUSEMOVE:
            self.curr_pt = [x,y]
            #print(self.point)

    def getpt(self,count=1,img=None):
        if img is not None:
            self.img = img
        else:
            self.img = self.img1.copy()
        cv2.namedWindow(self.windowname,cv2.WINDOW_NORMAL)
        cv2.imshow(self.windowname,self.img)
        cv2.setMouseCallback(self.windowname,self.select_point)
        self.point = []
        while(1):
            cv2.imshow(self.windowname,self.img)
            k = cv2.waitKey(20) & 0xFF
            if k == 27 or len(self.point)>=count:
                break
            #print(self.point)
        cv2.setMouseCallback(self.windowname, lambda *args : None)
        #cv2.destroyAllWindows()
        return self.point, self.img

if __name__=='__main__':
    img = np.zeros((512,512,3), np.uint8)
    windowname = 'image'
    coordinateStore = MousePts(windowname,img)

    pts,img = coordinateStore.getpt(3)
    print(pts)

    pts,img = coordinateStore.getpt(3,img)
    print(pts)

    cv2.imshow(windowname,img)
    cv2.waitKey(0)

- Jerin Antony

1

您可以通过执行各种鼠标单击事件来检测点击图片时的鼠标位置。

在执行鼠标单击事件时，您需要记住一件事情，即无论您在何处使用cv2.imshow或cv2.namedWindow，都应该在所有地方使用相同的窗口名称。

我在以下stackoverflow帖子中提供了使用Python 3.x和OpenCV的工作代码： https://dev59.com/J4_ea4cB1Zd3GeqPOnYe#60445099 您可以参考上面的链接以获得更好的解释。 代码:

import cv2
import numpy as np

#This will display all the available mouse click events  
events = [i for i in dir(cv2) if 'EVENT' in i]
print(events)

#This variable we use to store the pixel location
refPt = []

#click event function
def click_event(event, x, y, flags, param):
    if event == cv2.EVENT_LBUTTONDOWN:
        print(x,",",y)
        refPt.append([x,y])
        font = cv2.FONT_HERSHEY_SIMPLEX
        strXY = str(x)+", "+str(y)
        cv2.putText(img, strXY, (x,y), font, 0.5, (255,255,0), 2)
        cv2.imshow("image", img)

    if event == cv2.EVENT_RBUTTONDOWN:
        blue = img[y, x, 0]
        green = img[y, x, 1]
        red = img[y, x, 2]
        font = cv2.FONT_HERSHEY_SIMPLEX
        strBGR = str(blue)+", "+str(green)+","+str(red)
        cv2.putText(img, strBGR, (x,y), font, 0.5, (0,255,255), 2)
        cv2.imshow("image", img)


#Here, you need to change the image name and it's path according to your directory
img = cv2.imread("D:/pictures/abc.jpg")
cv2.imshow("image", img)

#calling the mouse click event
cv2.setMouseCallback("image", click_event)

cv2.waitKey(0)
cv2.destroyAllWindows()

- Ankit Lad

0

我已经将PyIgnition库从Pygame移植到opencv2。在https://github.com/bunkahle/particlescv2上找到代码。此外，还有几个使用Python粒子引擎的示例。

- bunkus

0

如果有人想要一个基于多进程的GUI来绘制点并拖动它们，这里是一个单文件脚本。

- Jerin Antony

0

如果你想在Python 3中通过悬停在图像上来获取坐标，可以尝试以下方法：

import numpy as np
import cv2 as cv
import os
import sys

# Reduce the size of image by this number to show completely in screen
descalingFactor = 2

# mouse callback function, which will print the coordinates in console
def print_coord(event,x,y,flags,param):
    if event == cv.EVENT_MOUSEMOVE:
        print(f'{x*descalingFactor, y*descalingFactor}\r', end="")

img = cv.imread(cv.samples.findFile('TestImage.png'))
imgheight, imgwidth = img.shape[:2]
resizedImg = cv.resize(img,(int(imgwidth/descalingFactor), int(imgheight/descalingFactor)), interpolation = cv.INTER_AREA)
cv.namedWindow('Get Coordinates')
cv.setMouseCallback('Get Coordinates',print_coord)
cv.imshow('Get Coordinates',resizedImg)
cv.waitKey(0)

- Fawaz Ahmed

网页内容由stack overflow 提供, 点击上面的

可以查看英文原文，
原文链接

- GPPK · Accepted Answer

这是一个示例鼠标回调函数，它捕获左键双击事件。

def draw_circle(event,x,y,flags,param):
    global mouseX,mouseY
    if event == cv2.EVENT_LBUTTONDBLCLK:
        cv2.circle(img,(x,y),100,(255,0,0),-1)
        mouseX,mouseY = x,y

然后您需要将该函数绑定到一个窗口，以捕获鼠标点击事件。

img = np.zeros((512,512,3), np.uint8)
cv2.namedWindow('image')
cv2.setMouseCallback('image',draw_circle)

然后，在一个无限处理循环中（或者您想要的任何其他方式）

while(1):
    cv2.imshow('image',img)
    k = cv2.waitKey(20) & 0xFF
    if k == 27:
        break
    elif k == ord('a'):
        print mouseX,mouseY

这段代码是用来做什么的？

它会在你双击黑色窗口并按下a键时，将鼠标位置存储在全局变量mouseX和mouseY中。

elif k == ord('a'):
    print mouseX,mouseY

每次按下a键时，将打印出当前存储的鼠标点击位置。

代码“借用”自这里。