How to fast change image brightness with python + OpenCV?

Question

I have a sequence of images. I need to average brightness of these images.

First example (very slow):

img = cv2.imread(\'test.jpg\')         


        

Answer 1

def change_brightness(img, alpha, beta):
   return cv2.addWeighted(img, alpha, np.zeros(img.shape, img.dtype),0, beta)

Here alpha & beta are input parameters. Each pixel of the input image will change according to this formula.

 alpha(pixel_value) + beta.

Lower value of alpha like 2 or 3 is good