CODEWITHSUNDEEP
pythonopencv
Ferguzz
Ferguzz

Reputation: 6107

set a block of pixels to a colour opencv

is there a way to set a rectangular block of pixels to a colour in opencv (specifically in python) other than looping through them? e.g. some kind of 2d slice syntax or once an ROI is set change all inside.

i have tried im[0:100, 200:300] = (255,255,255) with no luck

Upvotes: 0

Views: 3967

Answers (2)

Abid Rahman K
Abid Rahman K

Reputation: 52646

im[0:100,200:300] = [255,255,255] works fine for me.

Eg:

>>> im = cv2.imread('baboon.jpg')
>>> im[0:2,200:202]
array([[[180, 200, 181],
        [164, 190, 166]],

       [[170, 182, 164],
        [124, 134, 118]]], dtype=uint8)
>>> im[0:100,200:300] = [255,255,255]
>>> im[0:2,200:202]
array([[[255, 255, 255],
        [255, 255, 255]],

       [[255, 255, 255],
        [255, 255, 255]]], dtype=uint8)

Another method is cv2.rectangle

cv2.rectangle(im,(200,0),(300,100),(255,255,255),-1)

But it seems cv2.rectangle is more faster (around 5x) than previous slicing method(as per my tesing)

Upvotes: 2

jlengrand
jlengrand

Reputation: 12827

You should have a look at CV.Rectangle, which does exactly what you want :) http://opencv.willowgarage.com/documentation/python/core_drawing_functions.html?highlight=rectangle#Rectangle

Upvotes: 2

Related Questions