Contours

import cv2
import numpy as np

image = cv2.imread("photo.jpg")
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
blurred = cv2.GaussianBlur(gray, (5, 5), 0)
_, binary = cv2.threshold(blurred, 127, 255, cv2.THRESH_BINARY + cv2.THRESH_OTSU)

# Find contours
# RETR_EXTERNAL: only outermost contours (ignores holes)
# CHAIN_APPROX_SIMPLE: compress straight lines to save memory
contours, hierarchy = cv2.findContours(
    binary, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE
)

print(f"Found {len(contours)} contours")

# Draw all contours on a copy
result = image.copy()
cv2.drawContours(result, contours, -1, (0, 255, 0), 2)  # -1 = draw all

# Analyse each contour
for i, contour in enumerate(contours):
    area = cv2.contourArea(contour)
    perimeter = cv2.arcLength(contour, closed=True)
    x, y, w, h = cv2.boundingRect(contour)

    if area > 500:  # Ignore tiny contours
        print(f"Contour {i}: area={area:.0f}, perimeter={perimeter:.0f}, bbox={w}x{h}")
        cv2.rectangle(result, (x, y), (x+w, y+h), (255, 0, 0), 1)

cv2.imwrite("contours.jpg", result)