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:UsersRajnishDesktopgeeksforgeeksgeeks.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:UsersRajnishDesktopgeeksforgeeksgeeks.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()
