drawing a rectangle around a color as shown?

asked 2018-10-10 05:08:01 -0500

updated 2018-10-10 05:10:40 -0500

I want to detect the color, which I have done with the following code:

import cv2 as cv import numpy as np

cap = cv.VideoCapture(0)


_, frame = cap.read()
# Convert BGR to HSV
hsv = cv.cvtColor(frame, cv.COLOR_BGR2HSV)
# define range of blue color in HSV
lower_blue = np.array([100,55,55])
upper_blue = np.array([105,255,255])
# Threshold the HSV image to get only blue colors
mask = cv.inRange (hsv, lower_blue, upper_blue)
# Bitwise-AND mask and original image
res = cv.bitwise_and(frame,frame, mask= mask)
k = cv.waitKey(5) & 0xFF
if k == 27:


but want to know how to draw a rectangle around it?

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somewhat better, than your last question. however, please spare us duplicate ones to the same topic, thank. you !

berak gravatar imageberak ( 2018-10-10 05:13:52 -0500 )edit

and what you really need, is a tour through the tutorials

berak gravatar imageberak ( 2018-10-10 05:15:08 -0500 )edit

Esp this one

"...Contours can be explained simply as a curve joining all the continuous points (along the boundary), having same color or intensity..."

Sound good to me. Should work.

holger gravatar imageholger ( 2018-10-10 05:31:25 -0500 )edit

I just noticed you already extracted the bbox(ignore comment above) - maybe all you asking for is how to draw rectangles at all? For drawing functions look here

holger gravatar imageholger ( 2018-10-10 05:38:47 -0500 )edit