i have this below code and want do a subtract such:
final azimuth = altitude every stage running – altitude previous stage.
for example if we are in 4 times of iteration final altitude must be such: altitude 4 times – altitude 3 times.
i ask AI many questions but the results are same in while the altitude in every stage are changing due to changes in photo and line length. and final altitude and final azimuths are changing.
my codes are:

import time
import numpy as np
import cv2
import serial
from math import atan, sqrt, degrees

# Initialize the serial port
ser = serial.Serial('COM7', baudrate=9600, timeout=1)

def captureImage():
    print('Capturing image')
    videoCaptureObject = cv2.VideoCapture(1)

    result = True
    while(result):
        ret, frame = videoCaptureObject.read()
        cv2.imwrite("Newpicture.jpg", frame)
        result = False
        videoCaptureObject.release()
        im = np.random.randint(0, 256, size=(256, 256, 3), dtype=np.uint8)
        return im

def processImage(im):
    print('Processing image')
    image = cv2.imread('C:/Users/Stk/Desktop/Newpicture.jpg')

    # Convert image to grayscale
    gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
    
    # Apply Gaussian blur to reduce noise
    blurred = cv2.GaussianBlur(gray, (5, 5), 0)
    
    # Apply edge detection
    edges = cv2.Canny(blurred, 50, 150)
    
    # Find contours in the edge-detected image
    contours, _ = cv2.findContours(edges, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
    
    if contours:
        # Get the largest contour (assuming it's the line)
        c = max(contours, key=cv2.contourArea)
        
        # Get the extreme points of the contour (line)
        x1, y1 = c[c[:, :, 0].argmin()][0]
        x2, y2 = c[c[:, :, 0].argmax()][0]
        
        # Calculate the length of the line
        length = sqrt((x2 - x1)**2 + (y2 - y1)**2)
        
        # Calculate azimuth and altitude angles
        azimuth = atan((x2 - x1) / (y2 - y1))
        altitude = atan(length / 13)
        
        # Convert angles to degrees
        solaraltitude = degrees(altitude)
        solarazimuth = degrees(azimuth)
        
        # Convert negative azimuth angles to positive
        if solarazimuth < 0:
            solarazimuth += 360
        
        return x1, y1, x2, y2, solaraltitude, solarazimuth
    else:
        return None, None, None, None, None, None

N = 7
previous_altitude = 0
previous_azimuth = 0
fix_altitude = 60
fix_azimuth = 45

for i in range(N):
    im = captureImage()
    result = processImage(im)
    if result[0] is not None and result[1] is not None and result[2] is not None and result[3] is not None:
        x1, y1, x2, y2, altitude, azimuth = result
        if i == N - 1:  # Check if it's the last iteration
            final_altitude_integer = fix_altitude // 6
            final_azimuth_integer = fix_azimuth // 6
        else:
            if i == 0:
                final_altitude = altitude - fix_altitude
                final_azimuth = azimuth - fix_azimuth
            else:
                final_altitude = altitude - previous_altitude
                final_azimuth = azimuth - previous_azimuth
        
            final_altitude_integer = int(final_altitude) // 6
            final_azimuth_integer = int(final_azimuth) // 6
        
        print("Final altitude (Integer):", final_altitude_integer)
        print("Final azimuth (Integer):", final_azimuth_integer)
        
        # Send final altitude and azimuth integers to Arduino via serial
        ser.write(f"{final_altitude_integer} {final_azimuth_integer}".encode())
        
        time.sleep(100)
        previous_altitude = altitude
        previous_azimuth = azimuth
    else:
        print("No lines detected in the image.")

and results are

`Capturing image
Processing image
Final altitude (Integer): 4
Final azimuth (Integer): -5
Capturing image
Processing image
Final altitude (Integer): 0
Final azimuth (Integer): 0
Capturing image
Processing image
Final altitude (Integer): 0
Final azimuth (Integer): 0
Capturing image
Processing image
Final altitude (Integer): 0
Final azimuth (Integer): 0
Capturing image
Processing image
Final altitude (Integer): 0
Final azimuth (Integer): 0`

i do not accept these results because the altitudes are changing in every stage.
how i can fix these problems thanks.