How to convert an image from np.uint16 to np.uint8?

Question

I am creating an image so:

image = np.empty(shape=(height, width, 1), dtype = np.uint16)

After that I convert the image to BGR model:

Answer 1

I suggest you to use this :

outputImg8U = cv2.convertScaleAbs(inputImg16U, alpha=(255.0/65535.0))

this will output a uint8 image & assign value between 0-255 with respect to there previous value between 0-65535

exemple :
pixel with value == 65535 will output with value 255 
pixel with value == 1300 will output with value 5 etc...

Answer 2

You can use cv2.convertScaleAbs for this problem. See the Documentation.

Check out the command terminal demo below :

>>> img = np.empty((100,100,1),dtype = np.uint16)
>>> image = cv2.cvtColor(img,cv2.COLOR_GRAY2BGR)

>>> cvuint8 = cv2.convertScaleAbs(image)

>>> cvuint8.dtype
dtype('uint8')

Hope it helps!!!