You can use this code to measuere the distance from object to camera using single camera 📷 .

I have detect a face in the frame and estimated a distance using the width of face.

git clone https://github.com/Asadullah-Dal17/Distance_measurement_using_single_camera

• Windows

  pip install opencv-python

• install Opencv-python on Linux or Mac

  pip3 install opencv-python

• windows: 👇

  python distance.py

  ------ OR ---------

  python Updated_distance.py

• linux or Mac 👇

  python3 distance.py

  ------ OR ---------

  python3 Updated_distance.py

# focal length finder function
def FocalLength(measured_distance, real_width, width_in_rf_image):
    focal_length = (width_in_rf_image* measured_distance)/ real_width
    return focal_length

The Focal Length finder Function Tacks Three Arguments:

measured_distance It is distance which we have measured while capturing reference image. From object to Camera which is Known_distance = 72.2 #centimeter

real_width Its measure with width of object in real world, here i measure the width of face in real world which was Known_width =14.3 #centimeter

width_in_rf_image it width of object in the image/frame it will be in pixels

# distance estimation function
def Distance_finder (Focal_Length, real_face_width, face_width_in_frame):
    distance = (real_face_width * Focal_Length)/face_width_in_frame
    return distance

This Funciton Taks Three Argument,

Focal_Length it is focal length, out of FocalLength finder function.

real_face_width Its measure width of object in real world, here i measure the width of face in real world which was Known_width =14.3 #centimeter

face_width_in_frame width of face in the frame, unit will pixels here.

You can Which my Video on the Youtube: https://youtu.be/zzJfAw3ASzY

I have also create Face Following Robot which use distance Estimation, if you are interested you can Watch my Youtube Video

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if you have any Query feel free to ask me on my Social Media.