How to remove background and video from facial landmarks

Question

Im using this code to detect teh 468 facial landmarks from a face:

import cv2
import mediapipe as mp
import time

cap = cv2.VideoCapture(0)
pTime = 0

mpDraw = mp.solutions.drawing_utils
mpFaceMesh = mp.solutions.face_mesh
faceMesh = mpFaceMesh.FaceMesh(max_num_faces=2)
drawSpec = mpDraw.DrawingSpec(thickness=1, circle_radius=2)

while True:
    success, img = cap.read()
    imgRGB = cv2.cvtColor(img, cv2.COLOR_BGR2RGB)
    results = faceMesh.process(imgRGB)
    if results.multi_face_landmarks:
        for faceLms in results.multi_face_landmarks:
            mpDraw.draw_landmarks(img, faceLms, mpFaceMesh.FACEMESH_CONTOURS,
                                  drawSpec,drawSpec)
            for id,lm in enumerate(faceLms.landmark):
                #print(lm)
                ih, iw, ic = img.shape
                x,y = int(lm.x*iw), int(lm.y*ih)
                print(id,x,y)

    cTime = time.time()
    fps = 1 / (cTime - pTime)
    pTime = cTime
    cv2.putText(img, f'FPS: {int(fps)}', (20, 70), cv2.FONT_HERSHEY_PLAIN,
                3, (255, 0, 0), 3)
    cv2.imshow("Image", img)
    cv2.waitKey(1)

When I run this script, I can see the facial landmarks printed on my face, but what I want to achieve is that I display the facial landmarks on a black background without actually showing a face.

How can I achieve that?

Answer 1

You can create an image with dark (black) pixels (0) of the same dimensions of the frame captured by the camera. And carry out your drawings there

# create the dark image
black = np.zeros(img.shape , np.uint8)

# Replace the `img` with `black` while drawing the landmarks
mpDraw.draw_landmarks(black, faceLms, mpFaceMesh.FACEMESH_CONTOURS, drawSpec,drawSpec)

# Display the result
cv2.imshow("Result", black)