How can I change the background of only white pixels?
Question:
I have two grayscale images of the same size, one of them is this one: 
I’m trying to add a background to this image, which is to just change the white pixels to the respective pixels in the other picture. The best result I’ve managed to do is just a bitwise and of all the pixels of both pictures but the resultant picture is distorted inside James Bond. I also tried a weighted add between the two pictures but when I increase the weight of the James Bond image, it’s white pixels are visible in the resultant image.
Answers:
To combine with a second image, ensure that both images have the same dimensions (which yours do). They can then be combined
import cv2
img_jb = cv2.imread('james_bond.png')
img_007 = cv2.imread('007_logo.png')
height, width, channels = img_jb.shape
img_007_resized = cv2.resize(img_007, (width, height), interpolation=cv2.INTER_CUBIC)
threshold = img_jb > 240
img_jb[threshold] = img_007_resized[threshold]
cv2.imwrite('james_bond_logo.png', img_jb)
Giving you:
numpy allows you to work on the indexes of an array that match a given criteria. This has the effect of copying pixels from the background image into the foreground image where the foreground image has a value above 240.
I have two grayscale images of the same size, one of them is this one:
I’m trying to add a background to this image, which is to just change the white pixels to the respective pixels in the other picture. The best result I’ve managed to do is just a bitwise and of all the pixels of both pictures but the resultant picture is distorted inside James Bond. I also tried a weighted add between the two pictures but when I increase the weight of the James Bond image, it’s white pixels are visible in the resultant image.
To combine with a second image, ensure that both images have the same dimensions (which yours do). They can then be combined
import cv2
img_jb = cv2.imread('james_bond.png')
img_007 = cv2.imread('007_logo.png')
height, width, channels = img_jb.shape
img_007_resized = cv2.resize(img_007, (width, height), interpolation=cv2.INTER_CUBIC)
threshold = img_jb > 240
img_jb[threshold] = img_007_resized[threshold]
cv2.imwrite('james_bond_logo.png', img_jb)
Giving you:
numpy allows you to work on the indexes of an array that match a given criteria. This has the effect of copying pixels from the background image into the foreground image where the foreground image has a value above 240.