piekenius' Blog

import cv2
import numpy as np

# Color ranges for laser pointers (covering common colors such as red, green, and blue)
COLOR_RANGES = {
    'red': (np.array([160, 100, 100]), np.array([180, 255, 255])),   # Red
    'green': (np.array([40, 70, 70]), np.array([80, 255, 255])),     # Green
    'blue': (np.array([100, 150, 0]), np.array([140, 255, 255]))     # Blue
}

# Initialize the camera
cap = cv2.VideoCapture(0)

while True:
    # Read a frame
    ret, frame = cap.read()
    if not ret:
        break

    # Convert to HSV color space
    hsv = cv2.cvtColor(frame, cv2.COLOR_BGR2HSV)

    for color_name, (lower, upper) in COLOR_RANGES.items():
        # Apply color thresholds to create a mask
        mask = cv2.inRange(hsv, lower, upper)

        # Use morphological opening to remove small noise
        kernel = np.ones((5, 5), np.uint8)
        mask = cv2.morphologyEx(mask, cv2.MORPH_OPEN, kernel)

        # Apply Gaussian blur to smooth the mask
        blurred = cv2.GaussianBlur(mask, (15, 15), 0)

        # Find contours
        contours, _ = cv2.findContours(blurred, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)

        # Iterate through contours
        for contour in contours:
            area = cv2.contourArea(contour)
            
            # Filter out noise based on area
            if area > 50:  # Adjust the area threshold based on experimentation to filter out noise
                # Get the smallest enclosing circle
                (x, y), radius = cv2.minEnclosingCircle(contour)
                center = (int(x), int(y))
                radius = int(radius)

                # Calculate the distance (assuming calibration through actual measurement)
                distance = 200 / (radius + 1)  # Adjust the formula based on experimental results

                # Check if within the valid distance range
                if 190 <= distance <= 210:
                    # Draw different colors for laser spots of different colors
                    color = (0, 255, 0) if color_name == 'green' else (255, 0, 0) if color_name == 'blue' else (0, 0, 255)
                    
                    # Draw a circular marker and color label on the frame
                    cv2.circle(frame, center, radius, color, 2)
                    cv2.putText(frame, f"{color_name.capitalize()} Laser - Distance: {distance:.2f} cm",
                                (center[0] - 20, center[1] - 20),
                                cv2.FONT_HERSHEY_SIMPLEX, 0.5, color, 2)

    # Display the image
    cv2.imshow("Laser Pointer Detection", frame)

    # Exit on key press
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

# Release resources
cap.release()
cv2.destroyAllWindows()