Display only bounding box region and neglect other part

Question

I have this code of haarcascade which detect face and draw bounding box around it. I want to display only bounding box area in the original image in its original place and black out all other part just like we do it in color detection from opencv. Is there any way to do so?

cascPath = "haarcascade_frontalface_default.xml"
image = cv2.imread(imagePath)

faceCascade = cv2.CascadeClassifier(cascPath)


gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
=
faces = faceCascade.detectMultiScale(
    gray,
    scaleFactor=1.1,
    minNeighbors=5,
    minSize=(30, 30),
    flags = cv2.CASCADE_SCALE_IMAGE
)

print("Found {0} faces!".format(len(faces)))

for ((x, y, w, h),i) in zip(faces,range(len(faces))):
    a=cv2.rectangle(image, (x, y), (x+w, y+h), 2)
    roi_color=image[y:y+h, x:x+w]

Answer 1

I would try to crop the ROI and then put it in a img which is a all black rectangle. In Pillow this is very easy to do.

as I don't have face images is hard to reproduce your code. I will use some random image but It should look something like this:

I put blue color just to highlight the background, but it's just a matter to change it to whatever color you want

from PIL import Image
img = Image.open('watch.jpeg', 'r')
img_w, img_h = img.size


left = img_w/8
top = img_h/8
right = 3 * img_w/8
bottom = 3 * img_h/8
cropped_img = img.crop((left, top, right, bottom))
cropped_img.save("cropped.png")
background = Image.new('RGB', (1440, 900), (0, 0, 255))
bg_w, bg_h = background.size
offset = ((bg_w - img_w) // 2, (bg_h - img_h) // 2)
background.paste(cropped_img, offset)
background.save('out.png')

input image :

output image :