answer.py

import cv2
import numpy as np

COLOR_RANGES_BGR = {
    'red': ([0, 0, 200], [50, 50, 255]),
    'green': ([0, 200, 0], [50, 255, 50]),
    'blue': ([200, 0, 0], [255, 50, 50]),
}

MIN_PIXELS_FOR_BIG_BALL = 35
CENTER_LINE_X = 320
COOLDOWN_FRAMES = 15
crossed_colors = []
last_seen = {color: -999 for color in COLOR_RANGES_BGR}

cap = cv2.VideoCapture('video1.mp4')
frame_index = 0

while cap.isOpened():
    ret, frame = cap.read()
    if not ret:
        break

    line_pixels = frame[:, CENTER_LINE_X, :]
    line_strip = line_pixels.reshape(-1, 1, 3)

    for color, (lower, upper) in COLOR_RANGES_BGR.items():
        lower = np.array(lower, dtype=np.uint8)
        upper = np.array(upper, dtype=np.uint8)
        mask = cv2.inRange(line_strip, lower, upper)
        pixel_count = cv2.countNonZero(mask)

        if pixel_count > MIN_PIXELS_FOR_BIG_BALL and frame_index - last_seen[color] > COOLDOWN_FRAMES:
            crossed_colors.append(color)
            last_seen[color] = frame_index

    frame_index += 1

cap.release()
print(crossed_colors)