Python OpenCV – cv2.polylines() method
OpenCV is the huge open-source library for computer vision, machine learning, and image processing and now it plays a major role in real-time operation which is very important in today’s systems. By using it, one can process images and videos to identify objects, faces, or even the handwriting of a human. When it integrated with various libraries, such as Numpuy, python is capable of processing the OpenCV array structure for analysis.
Note: For more information, refer to OpenCV Python Tutorial
cv2.polylines()
cv2.polylines() method is used to draw a polygon on any image.
Syntax: cv2.polylines(image, [pts], isClosed, color, thickness)
Parameters:
image: It is the image on which circle is to be drawn.
pts: Array of polygonal curves.
npts: Array of polygon vertex counters.
ncontours: Number of curves.
isClosed: Flag indicating whether the drawn polylines are closed or not. If they are closed, the function draws a line from the last vertex of each curve to its first
vertex.
color: It is the color of polyline to be drawn. For BGR, we pass a tuple.
thickness: It is thickness of the polyline edges.Return Value: It returns an image.
Image used for all the below examples:
Image used for all the below examples:
Example #1:
# Python program to explain # cv2.polylines() method import cv2import numpy as np # pathpath = gfg.jpeg' # Reading an image in default# modeimage = cv2.imread(path) # Window name in which image is# displayedwindow_name = 'Image' # Polygon corner points coordinatespts = np.array([[25, 70], [25, 160], [110, 200], [200, 160], [200, 70], [110, 20]], np.int32) pts = pts.reshape((-1, 1, 2)) isClosed = True # Blue color in BGRcolor = (255, 0, 0) # Line thickness of 2 pxthickness = 2 # Using cv2.polylines() method# Draw a Blue polygon with # thickness of 1 pximage = cv2.polylines(image, [pts], isClosed, color, thickness) # Displaying the imagewhile(1): cv2.imshow('image', image) if cv2.waitKey(20) & 0xFF == 27: break cv2.destroyAllWindows() |
Output:
Example #2:
# Python program to explain # cv2.polylines() method import cv2import numpy as np # pathpath = r'gfg.jpeg' # Reading an image in default # modeimage = cv2.imread(path) # Window name in which image is # displayedwindow_name = 'Image' # Polygon corner points coordinatespts = np.array([[25, 70], [25, 145], [75, 190], [150, 190], [200, 145], [200, 70], [150, 25], [75, 25]], np.int32) pts = pts.reshape((-1, 1, 2)) isClosed = True # Green color in BGRcolor = (0, 255, 0) # Line thickness of 8 pxthickness = 8 # Using cv2.polylines() method# Draw a Green polygon with # thickness of 1 pximage = cv2.polylines(image, [pts], isClosed, color, thickness) # Displaying the imagewhile(1): cv2.imshow('image', image) if cv2.waitKey(20) & 0xFF == 27: breakcv2.destroyAllWindows() |
Output:
Last Updated on March 1, 2022 by admin