OpenCV Drawing a Line

How To Draw a Line In OpenCV Python?

To draw a line, we need to select the starting and ending coordinates of the line. First, let's create a black image and draw a green line. We need to use the code below to create a black image:

image = np.zeros((360,360,3), np.uint8)

Now we can create our line.

cv2.line(image,(0,0),(511,511),(0,255,0),5)

The code for creating a line is as follows:

import numpy as np
import cv2

image = np.zeros((360,360,3), np.uint8)

cv2.line(image,(0,0),(511,511),(0,255,0),5)

cv2.imshow("image",image)

cv2.waitKey(0)
cv2.destroyAllWindows()

Output:

Another Example

import numpy as np
import cv2

image = np.zeros((360,360,3), np.uint8)

cv2.line(image,(0,180),(360,180),(0,255,0),5)

cv2.imshow("image",image)

cv2.waitKey(0)
cv2.destroyAllWindows()

Output:

Comments

OpenCV Add Border to Image in Python

How to add border to image in python? To create a frame around the image, the function cv2.copyMakeBorder () is used. This function takes the following arguments: src - login image top, bottom, left, right - edge width in number of pixels in corresponding directions borderType - defines what type of border to add. There may be the following types cv2.BORDER_CONSTANT cv2.BORDER_REFLECT - cv2.BORDER_REFLECT_101 cv2.BORDER_REPLICATE cv2.BORDER_WRAP value - Color of border if border type is cv2.BORDER_CONSTANT import cv2 import numpy as np from matplotlib import pyplot as plt BLUE = [ 255 , 0 , 0 ] img1 = cv2.imread( 'flower.jpg' ) replicate = cv2.copyMakeBorder(img1 , 10 , 10 , 10 , 10 , cv2.BORDER_REPLICATE) reflect = cv2.copyMakeBorder(img1 , 10 , 10 , 10 , 10 , cv2.BORDER_REFLECT) reflect101 = cv2.copyMakeBorder(img1 , 10 , 10 , 10 , 10 , cv2.BORDER_REFLECT_101) wrap = cv2.copyMakeBorder(img1 , 10 , 10 , 10 , 10 , cv2.BORDER_WRAP) constant= cv2.copyMakeBorder(img1 ...

OpenCV Get Frame Width and Height in Python

Opencv Get Frame Width and Height import cv2 capture = cv2.VideoCapture( 'readvideo.mp4' ) if capture.isOpened(): w = capture.get(cv2.cv.CV_CAP_PROP_FRAME_WIDTH) h = capture.get(cv2.cv.CV_CAP_PROP_FRAME_HEIGHT) w = capture.get( 3 ) h = capture.get( 4 ) f = capture.get(cv2.cv.CV_CAP_PROP_FPS)

How to create trackbar in Opencv Python?

Create trackbar in Opencv and Python import cv2 import numpy as np def func ( x ): pass img = cv2.imread( "flower.jpg" ) cv2.namedWindow( 'image' ) cv2.createTrackbar( 'R' , 'image' , 0 , 255 , func) cv2.createTrackbar( 'G' , 'image' , 0 , 255 , func) cv2.createTrackbar( 'B' , 'image' , 0 , 255 , func) switch = '0 : OFF \n 1 : ON' cv2.createTrackbar(switch , 'image' , 0 , 1 , func) while ( 1 ): cv2.imshow( 'image' , img) k = cv2.waitKey( 1 ) & 0xFF if k == 27 : break r = cv2.getTrackbarPos( 'R' , 'image' ) g = cv2.getTrackbarPos( 'G' , 'image' ) b = cv2.getTrackbarPos( 'B' , 'image' ) s = cv2.getTrackbarPos(switch , 'image' ) if s == 0 : img[:] = 0 else : img[:] = [b , g , r] cv2.destroyAllWindows() Trackbar

Image Processing Blog

Search This Blog