convert openCV image into PIL Image in Python (for use with Zbar library)

Question

I'm trying to use the Zbar library's QR code detection methods on images I extract with OpenCV's camera methods. Normally the QR code detection methods work with images (jpg, png, etc.) on my computer, but I guess the captured frames of OpenCV are different.
Is there a way of making the captured frame into a PIL Image?

Thank you.

from PIL import Image
import zbar
import cv2.cv as cv

capture = cv.CaptureFromCAM(1)
imgSize = cv.GetSize(cv.QueryFrame(capture))
img = cv.QueryFrame(capture)

#SOMETHING GOES HERE TO TURN FRAME INTO IMAGE
img = img.convert('L')
width, height = img.size

scanner = zbar.ImageScanner()
scanner.parse_config('enable')
zbar_img = zbar.Image(width, height, 'Y800', img.tostring())

# scan the image for barcodes
scanner.scan(zbar_img)

for symbol in zbar_img:
    print symbol.data

score 92 · Accepted Answer · answered Aug 10 '13 at 05:37

92

With the python CV2, you can also do this:

import Image, cv2

cap = cv2.VideoCapture(0) # says we capture an image from a webcam
_,cv2_im = cap.read()
cv2_im = cv2.cvtColor(cv2_im,cv2.COLOR_BGR2RGB)
pil_im = Image.fromarray(cv2_im)
pil_im.show()

answered Aug 10 '13 at 05:37

s_kanawat

944
7
2

score 9 · Answer 2 · answered Nov 27 '12 at 01:44

9

I think I may have found the answer. I'll edit later with results.

OpenCV to PIL Image

import Image, cv
cv_im = cv.CreateImage((320,200), cv.IPL_DEPTH_8U, 1)
pi = Image.fromstring("L", cv.GetSize(cv_im), cv_im.tostring())

Source: http://opencv.willowgarage.com/documentation/python/cookbook.html

answered Nov 27 '12 at 01:44

QuantumRich

886
2
9
21

So far I'm having some trouble in which the converted image is not really the image I captured. – QuantumRich Nov 27 '12 at 02:19
Hey, I had the same problem as you and this worked, but the actual accepted answer didnt. You should mark this as accepted – Tales Pádua Jun 17 '16 at 20:54

score 4 · Answer 3 · answered May 28 '13 at 23:10

Are you trying to obtain a RGB image? If that is the case, you need to change your parameters from this:

cv_im = cv.CreateImage((320,200), cv.IPL_DEPTH_8U, 1)
pi = Image.fromstring("L", cv.GetSize(cv_im), cv_im.tostring())

to that:

cv_im = cv.CreateImage((320,200), cv.IPL_DEPTH_8U, 3)
pi = Image.fromstring("RGB", cv.GetSize(cv_im), cv_im.tostring())

since it is documented almost nowhere, but the 'L' parameter of Image.fromstring is for 8-bit B&W images. Besides, you need to change the argument of your cv.CreateImage function from 1 (single channel image) to 3 (3 channels=RGB).

Hope it works for you. Cheers

score 1 · Answer 4 · answered Jan 23 '19 at 06:27

A simple way is to directly swap the channels. Suppose you are trying to convert a 3-channel image file between OpenCV format and PIL format. You can just use:

img[...,[0,2]]=img[...,[2,0]]

In this way, you won't be bothered with cv2.cvtColor as this function only works on images with certain depth.

convert openCV image into PIL Image in Python (for use with Zbar library)

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