Opencv：检测鼠标点击图片的位置

Question

我有这段代码，我只是在其中使用 OpenCV 显示图像：

    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()

一旦窗口显示其中的照片，我想在控制台（终端）上显示当我点击图片时鼠标的位置。我不知道如何执行此操作。有什么帮助吗？

Answer 1

如果有人想要一个基于多进程的 GUI 来绘制点并拖动以移动它们，这里有一个 single file script 。

Answer 2

下面是我的实现：

不需要存储点击位置，只显示它：

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)

如果你想在代码的其他地方使用位置，你可以使用以下方式获取坐标：

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

Answer 3

如果您想通过在 Python 3 中将鼠标悬停在图像上来获取坐标，您可以试试这个：

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)

Answer 4

这里是一个鼠标回调函数示例，捕获左键双击

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将捕获鼠标点击的窗口

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

然后，在无限处理循环中（或任何你想要的）

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

这段代码有什么作用？

它将鼠标位置存储在全局变量mouseX和mouseY中，每次在黑色窗口内双击并按a键将被创建。

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

每次按下 a 按钮时都会打印当前存储的鼠标点击位置。

---

代码“借用”here.

Answer 5

这是基于类的 OpenCV 鼠标回调以获取图像点的实现，

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)

Answer 6

您可以通过执行各种鼠标点击事件来检测鼠标点击图片的位置。

在执行鼠标点击事件时，您只需记住一件事，无论您使用 cv2.imshow 或 cv2，您都必须在所有位置使用相同的窗口名称.namedWindow

我在下面的stackoverflow帖子中给出了使用python 3.x和opencv的工作代码： https://stackoverflow.com/a/60445099/11493115

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()

Answer 7

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)

Answer 8

我已将 PyIgnition 库从 Pygame 移植到 opencv2。在https://github.com/bunkahle/particlescv2 找到代码 还有几个例子介绍了如何使用 Python 的粒子引擎。