distance measuring file

measure_distance.py

+# install opencv "pip install opencv-python"
+import cv2
+
+# distance from camera to object(face) measured
+# centimeter
+Known_distance = 76.2
+
+# width of face in the real world or Object Plane
+# centimeter
+Known_width = 14.3
+
+# Colors
+GREEN = (0, 255, 0)
+RED = (0, 0, 255)
+WHITE = (255, 255, 255)
+BLACK = (0, 0, 0)
+
+# defining the fonts
+fonts = cv2.FONT_HERSHEY_COMPLEX
+
+# face detector object
+face_detector = cv2.CascadeClassifier("haarcascade_frontalface_default.xml")
+
+
+# focal length finder function
+def Focal_Length_Finder(measured_distance, real_width, width_in_rf_image):
+    # finding the focal length
+    focal_length = (width_in_rf_image * measured_distance) / real_width
+    return focal_length
+
+
+# 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 the distance
+    return distance
+
+
+def face_data(image):
+    face_width = 0  # making face width to zero
+
+    # converting color image to gray scale image
+    gray_image = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
+
+    # detecting face in the image
+    faces = face_detector.detectMultiScale(gray_image, 1.3, 5)
+
+    # looping through the faces detect in the image
+    # getting coordinates x, y , width and height
+    for (x, y, h, w) in faces:
+        # draw the rectangle on the face
+        cv2.rectangle(image, (x, y), (x + w, y + h), GREEN, 2)
+
+        # getting face width in the pixels
+        face_width = w
+
+    # return the face width in pixel
+    return face_width
+
+
+# reading reference_image from directory
+ref_image = cv2.imread("Ref_image.png")
+
+# find the face width(pixels) in the reference_image
+ref_image_face_width = face_data(ref_image)
+
+# get the focal by calling "Focal_Length_Finder"
+# face width in reference(pixels),
+# Known_distance(centimeters),
+# known_width(centimeters)
+Focal_length_found = Focal_Length_Finder(
+    Known_distance, Known_width, ref_image_face_width)
+
+print(Focal_length_found)
+
+# show the reference image
+cv2.imshow("ref_image", ref_image)
+
+# initialize the camera object so that we
+# can get frame from it
+cap = cv2.VideoCapture(0)
+
+# looping through frame, incoming from
+# camera/video
+while True:
+
+    # reading the frame from camera
+    _, frame = cap.read()
+
+    # calling face_data function to find
+    # the width of face(pixels) in the frame
+    face_width_in_frame = face_data(frame)
+
+    # check if the face is zero then not
+    # find the distance
+    if face_width_in_frame != 0:
+        # finding the distance by calling function
+        # Distance finder function need
+        # these arguments the Focal_Length,
+        # Known_width(centimeters),
+        # and Known_distance(centimeters)
+        Distance = Distance_finder(
+            Focal_length_found, Known_width, face_width_in_frame)
+
+        # draw line as background of text
+        cv2.line(frame, (30, 30), (230, 30), RED, 32)
+        cv2.line(frame, (30, 30), (230, 30), BLACK, 28)
+
+        # Drawing Text on the screen
+        cv2.putText(
+            frame, f"Distance: {round(Distance, 2)} CM", (30, 35),
+            fonts, 0.6, GREEN, 2)
+
+    # show the frame on the screen
+    cv2.imshow("frame", frame)
+
+    # quit the program if you press 'q' on keyboard
+    if cv2.waitKey(1) == ord("q"):
+        break
+
+# closing the camera
+cap.release()
+
+# closing the windows that are opened
+cv2.destroyAllWindows()
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