画圈
Syntax: cv2.circle(image, center_coordinates, radius, color, thickness)
Parameters:
image: It is the image on which circle is to be drawn.
center_coordinates: It is the center coordinates of circle. The coordinates are represented as tuples of two values i.e. (X coordinate value, Y coordinate value).
radius: It is the radius of circle.
color: It is the color of border line of circle to be drawn. For BGR, we pass a tuple. eg: (255, 0, 0) for blue color.
thickness: It is the thickness of the circle border line in px. Thickness of -1 px will fill the circle shape by the specified color.
Return Value: It returns an image.
# Python program to explain cv2.circle() method
# importing cv2
import cv2
# path
path = r'C:\Users\Rajnish\Desktop\geeksforgeeks\geeks.png'
# Reading an image in default mode
image = cv2.imread(path)
# Window name in which image is displayed
window_name = 'Image'
# Center coordinates
center_coordinates = (120, 50)
# Radius of circle
radius = 20
# Blue color in BGR
color = (255, 0, 0)
# Line thickness of 2 px
thickness = 2
# Using cv2.circle() method
# Draw a circle with blue line borders of thickness of 2 px
image = cv2.circle(image, center_coordinates, radius, color, thickness)
# Displaying the image
cv2.imshow(window_name, image)
写字
Syntax: cv2.putText(image, text, org, font, fontScale, color[, thickness[, lineType[, bottomLeftOrigin]]])
Parameters:
image: It is the image on which text is to be drawn.
text: Text string to be drawn.
org: It is the coordinates of the bottom-left corner of the text string in the image. The coordinates are represented as tuples of two values i.e. (X coordinate value, Y coordinate value).
font: It denotes the font type. Some of font types are FONT_HERSHEY_SIMPLEX, FONT_HERSHEY_PLAIN, , etc.
fontScale: Font scale factor that is multiplied by the font-specific base size.
color: It is the color of text string to be drawn. For BGR, we pass a tuple. eg: (255, 0, 0) for blue color.
thickness: It is the thickness of the line in px.
lineType: This is an optional parameter.It gives the type of the line to be used.
bottomLeftOrigin: This is an optional parameter. When it is true, the image data origin is at the bottom-left corner. Otherwise, it is at the top-left corner.
Return Value: It returns an image.
# Python program to explain cv2.putText() method
# importing cv2
import cv2
# path
path = r'C:\Users\Rajnish\Desktop\geeksforgeeks\geeks.png'
# Reading an image in default mode
image = cv2.imread(path)
# Window name in which image is displayed
window_name = 'Image'
# font
font = cv2.FONT_HERSHEY_SIMPLEX
# org
org = (50, 50)
# fontScale
fontScale = 1
# Blue color in BGR
color = (255, 0, 0)
# Line thickness of 2 px
thickness = 2
# Using cv2.putText() method
image = cv2.putText(image, 'OpenCV', org, font,
fontScale, color, thickness, cv2.LINE_AA)
# Displaying the image
cv2.imshow(window_name, image)
保存图像
import cv2
# read image as grey scale
grey_img = cv2.imread('/home/img/python.png', cv2.IMREAD_GRAYSCALE)
# save image
status = cv2.imwrite('/home/img/python_grey.png',grey_img)
print("Image written to file-system : ",status)
ref
geeksforgeeks_cv2.circle()
geeksforgeeks_cv2.putText()
OpenCV Python Save Image – cv2.imwrite()
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