如何使用给定的坐标和python opencv在图像中绘制点？

Question

我有一张图像和一个坐标（X，Y）。如何在此坐标上绘制点。我想使用Python OpenCV。

Answer 1

您可以使用 cv2.circle() 函数 opencv 模块：

image = cv.circle(image, centerOfCircle, radius, color, thickness)

保持半径为 0 以绘制单个点，厚度为负数以绘制实心圆

import cv2
image = cv2.circle(image, (x,y), radius=0, color=(0, 0, 255), thickness=-1)

Answer 2

I'm learning the Python bindings to OpenCV too. Here's one way:

#!/usr/local/bin/python3
import cv2
import numpy as np

w=40
h=20
# Make empty black image
image=np.zeros((h,w,3),np.uint8)

# Fill left half with yellow
image[:,0:int(w/2)]=(0,255,255)

# Fill right half with blue
image[:,int(w/2):w]=(255,0,0)

# Create a named colour
red = [0,0,255]

# Change one pixel
image[10,5]=red

# Save
cv2.imwrite("result.png",image)

这是结果-放大后可以看到。

这是非常简洁但不太有趣的答案：

#!/usr/local/bin/python3
import cv2
import numpy as np

# Make empty black image
image=np.zeros((20,40,3),np.uint8)

# Make one pixel red
image[10,5]=[0,0,255]

# Save
cv2.imwrite("result.png",image)