使用鼠标获取像素位置 click/events

Question

我想在显示图像时通过鼠标右键来收集像素位置(row-i, col-i)。

这是一个关于从互联网上下载的图片的简单示例：

import urllib
import cv2
from win32api import GetSystemMetrics

path_image = urllib.urlretrieve("http://www.bellazon.com/main/uploads/monthly_06_2013/post-37737-0-06086500-1371727837.jpg", "local-filename.jpg")[0]
img = cv2.imread(path_image,0)
width = GetSystemMetrics(0)
height = GetSystemMetrics(1)
scale_width = width / img.shape[1]
scale_height = height / img.shape[0]
scale = min(scale_width, scale_height)
window_width = int(img.shape[1] * scale)
window_height = int(img.shape[0] * scale)
cv2.namedWindow('image', cv2.WINDOW_NORMAL)
cv2.resizeWindow('image', window_width, window_height)
cv2.imshow('image', img)
cv2.waitKey(0)
cv2.destroyAllWindows()

至此，我希望了解在 list 中收集和存储像素位置的最佳方法。

Answer 1

import urllib
import cv2
from win32api import GetSystemMetrics

#the [x, y] for each right-click event will be stored here
right_clicks = list()

#this function will be called whenever the mouse is right-clicked
def mouse_callback(event, x, y, flags, params):

    #right-click event value is 2
    if event == 2:
        global right_clicks

        #store the coordinates of the right-click event
        right_clicks.append([x, y])

        #this just verifies that the mouse data is being collected
        #you probably want to remove this later
        print right_clicks

path_image = urllib.urlretrieve("http://www.bellazon.com/main/uploads/monthly_06_2013/post-37737-0-06086500-1371727837.jpg", "local-filename.jpg")[0]
img = cv2.imread(path_image,0)
scale_width = 640 / img.shape[1]
scale_height = 480 / img.shape[0]
scale = min(scale_width, scale_height)
window_width = int(img.shape[1] * scale)
window_height = int(img.shape[0] * scale)
cv2.namedWindow('image', cv2.WINDOW_NORMAL)
cv2.resizeWindow('image', window_width, window_height)

#set mouse callback function for window
cv2.setMouseCallback('image', mouse_callback)

cv2.imshow('image', img)
cv2.waitKey(0)
cv2.destroyAllWindows()

Answer 2

您可以使用数组或列表来存储像素位置，也可以存储像素值。

在这里，我使用 python 3.x 你可以按照下面的代码。在该代码中，我执行了两个鼠标单击事件。一种是使用鼠标左键单击获取像素位置，第二种是获取 RGB 图像中特定位置的特定像素值。

我还将像素位置值存储在 refPt 变量中。下面是代码。

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()

注意：您需要记住的一件事是，您必须为 namedWindow 输入相同的名称。应该是一样的。在我的代码中，我对所有 window.

使用相同的名称 "image"

您也可以对多张图片执行相同的操作。您只需要传递一个列表而不是单个图像。

如果你想将像素位置存储在某个文本文件中，那么你也可以这样做：

给出存储像素位置值的变量的名称。我使用 refPt 来存储值。所以，我在这里使用它如下：

import csv
with open("D:/pixelLocation.txt", 'w', newline='') as f:
    w = csv.writer(f)
    w.writerows(refPt)

使用鼠标获取像素位置 click/events

Get pixel location using mouse click/events

python

opencv

position