You can use this code to measures 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.

Distance Estimation Youtube Tutorail

Distance & Speed Estimation Youtube Tutorial

✔️ I have included Speed Estimation code is well check that out.

✔️ I have include Distance estimation of multiple objects using Yolo V4 Object Detector Opencv-python

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 focal_length(measured_distance, real_width, width_in_rf_image):

    focal_length_value = (width_in_rf_image * measured_distance) / real_width
    #return focal length.
    return focal_length_value

The Focal Length finder Function Tacks Three Arguments:

measured_distance It is distance which we have measured while capturing reference image:straightruler:. **_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.

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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