Merge pull request #3071 from adafruit/thermal_pi

adding raspberry pi thermal camera code

Author: BlitzCityDIY

Raspberry_Pi_Thermal_Camera_Overlay/code.py

@@ -0,0 +1,316 @@
+# SPDX-FileCopyrightText: 2025 Liz Clark for Adafruit Industries
+#
+# SPDX-License-Identifier: MIT
+"""
+Thermal Camera Overlay for Raspberry Pi 4,
+PiCamera 3 and STEMMA MLX90640
+
+Inspired by PitFusion Thermal Imager
+"""
+
+import time
+import numpy as np
+import cv2
+import board
+import busio
+import adafruit_mlx90640
+from picamera2 import Picamera2
+from PIL import Image
+
+# Temperature range for thermal camera (in Celsius)
+MIN_TEMP = 20.0
+MAX_TEMP = 35.0
+
+# Thermal overlay opacity (0.0 = invisible, 1.0 = fully opaque)
+THERMAL_OPACITY = 0.7
+
+# Display window size
+WINDOW_WIDTH = 1280
+WINDOW_HEIGHT = 720
+
+# Camera settings
+CAMERA_WIDTH = 1280
+CAMERA_HEIGHT = 720
+
+SKIP_FRAMES = 2  # Process every Nth frame for thermal
+frame_counter = 0
+
+# Thermal camera size
+THERMAL_WIDTH = 32
+THERMAL_HEIGHT = 24
+
+# Thermal zoom factor (1.7x to compensate for FoV difference)
+# Thermal camera FoV: 110°x75°, Pi camera FoV: 66°x41°
+# Ratio: 66/110 = 0.6, so we need 1/0.6 = 1.67x zoom
+THERMAL_ZOOM = 1.7
+
+# Camera crop settings to compensate for thermal offset
+# This crops the camera image to match the thermal coverage area
+CAMERA_CROP_LEFT = 65    # Match thermal X offset
+CAMERA_CROP_TOP = 85     # Match thermal Y offset
+CAMERA_CROP_RIGHT = 0    # No crop on right
+CAMERA_CROP_BOTTOM = 0   # No crop on bottom
+
+# Calculate effective camera size after cropping
+CAMERA_CROP_WIDTH = CAMERA_WIDTH - CAMERA_CROP_LEFT - CAMERA_CROP_RIGHT
+CAMERA_CROP_HEIGHT = CAMERA_HEIGHT - CAMERA_CROP_TOP - CAMERA_CROP_BOTTOM
+
+# ============= SETUP THERMAL CAMERA =============
+print("Setting up thermal camera...")
+i2c = busio.I2C(board.SCL, board.SDA)
+mlx = adafruit_mlx90640.MLX90640(i2c)
+mlx.refresh_rate = adafruit_mlx90640.RefreshRate.REFRESH_4_HZ
+
+# Create array to hold thermal data
+thermal_frame = np.zeros(768, dtype=np.float32)
+
+# ============= SETUP REGULAR CAMERA =============
+print("Setting up Pi camera...")
+picam2 = Picamera2()
+camera_config = picam2.create_preview_configuration(
+    main={"size": (CAMERA_WIDTH, CAMERA_HEIGHT), "format": "RGB888"},
+    buffer_count=2,  # Reduce buffer count for lower latency
+    queue=False  # Don't queue frames
+)
+picam2.configure(camera_config)
+picam2.start()
+picam2.set_controls({"ExposureTime": 20000, "AnalogueGain": 1.0})
+time.sleep(2)
+
+# ============= CREATE THERMAL COLORMAP =============
+def create_thermal_colormap():
+    """Create a colormap for thermal visualization"""
+    # Define color points (blue -> cyan -> green -> yellow -> orange -> red)
+    colors = np.array([
+        [0, 0, 64],       # Dark blue (cold)
+        [0, 0, 255],      # Blue
+        [0, 255, 255],    # Cyan
+        [0, 255, 0],      # Green
+        [255, 255, 0],    # Yellow
+        [255, 128, 0],    # Orange
+        [255, 0, 0],      # Red (hot)
+    ], dtype=np.uint8)
+
+    # Create smooth gradient between colors
+    colormap = np.zeros((256, 3), dtype=np.uint8)
+    positions = np.linspace(0, len(colors)-1, 256)
+
+    for i in range(256):
+        pos = positions[i]
+        idx = int(pos)
+        frac = pos - idx
+
+        if idx >= len(colors) - 1:
+            colormap[i] = colors[-1]
+        else:
+            colormap[i] = (1 - frac) * colors[idx] + frac * colors[idx + 1]
+
+    colormap = colormap[::-1]  # Reverse the colormap
+    return colormap
+the_colormap = create_thermal_colormap()
+
+# ============= HELPER FUNCTIONS =============
+def process_thermal_frame(thermal_data, colormap):
+    """Convert thermal data to colored image"""
+    # Calculate temperature statistics
+    min_temp = np.min(thermal_data)
+    max_temp = np.max(thermal_data)
+    avg_temp = np.mean(thermal_data)
+    if min_temp < -100:
+        min_temp = MIN_TEMP
+        avg_temp = (MIN_TEMP + MAX_TEMP) / 2
+
+    # Normalize temperature data to 0-255 range
+    normalized = np.clip(
+        (thermal_data - MIN_TEMP) / (MAX_TEMP - MIN_TEMP) * 255,
+        0, 255
+    ).astype(np.uint8)
+
+    # Apply colormap
+    colored = colormap[normalized]
+
+    # Reshape to 2D image (24x32x3)
+    thermal_image = colored.reshape(THERMAL_HEIGHT, THERMAL_WIDTH, 3)
+
+    # Flip horizontally to match camera view
+    thermal_image = np.fliplr(thermal_image)
+
+    # Scale up to camera size using PIL for smooth interpolation
+    pil_thermal = Image.fromarray(thermal_image)
+
+    # Apply zoom by scaling to a larger size than the camera
+    scaled_width = int(CAMERA_WIDTH * THERMAL_ZOOM)
+    scaled_height = int(CAMERA_HEIGHT * THERMAL_ZOOM)
+    pil_thermal = pil_thermal.resize((scaled_width, scaled_height), Image.BICUBIC)
+
+    # Crop the center to match camera size (this creates the zoom effect)
+    thermal_array = np.array(pil_thermal)
+    crop_x = (scaled_width - CAMERA_WIDTH) // 2
+    crop_y = (scaled_height - CAMERA_HEIGHT) // 2
+    thermal_cropped = thermal_array[crop_y:crop_y+CAMERA_HEIGHT, crop_x:crop_x+CAMERA_WIDTH]
+
+    return thermal_cropped, min_temp, max_temp, avg_temp
+
+def blend_images(camera_image, thermal_image, opacity):
+    """Blend camera and thermal images with position offset"""
+    # Create a canvas the same size as the camera image
+    canvas = camera_image.copy()
+
+    # Calculate position with offset
+    x_offset = 0
+    y_offset = 0
+
+    # Ensure the thermal image fits within bounds
+    x_start = max(0, x_offset)
+    y_start = max(0, y_offset)
+    x_end = min(camera_image.shape[1], x_offset + thermal_image.shape[1])
+    y_end = min(camera_image.shape[0], y_offset + thermal_image.shape[0])
+
+    # Calculate the corresponding region in the thermal image
+    thermal_x_start = max(0, -x_offset)
+    thermal_y_start = max(0, -y_offset)
+    thermal_x_end = thermal_x_start + (x_end - x_start)
+    thermal_y_end = thermal_y_start + (y_end - y_start)
+
+    # Blend only the overlapping region
+    if x_end > x_start and y_end > y_start:
+        canvas[y_start:y_end, x_start:x_end] = (
+            canvas[y_start:y_end, x_start:x_end] * (1 - opacity) +
+            thermal_image[thermal_y_start:thermal_y_end, thermal_x_start:thermal_x_end] * opacity
+        )
+
+    return canvas.astype(np.uint8)
+
+def add_temperature_scale(image, colormap):
+    """Add temperature scale bar to the image"""
+    # Create scale bar
+    scale_height = 20
+    scale_width = 200
+    scale_x = image.shape[1] - scale_width - 20
+    scale_y = 90  # Moved down to make room for buttons
+
+    # Draw temperature gradient
+    for i in range(scale_width):
+        temp_normalized = i / scale_width
+        color_idx = int(temp_normalized * 255)
+        color = colormap[color_idx]
+        cv2.line(image,
+                 (scale_x + i, scale_y),
+                 (scale_x + i, scale_y + scale_height),
+                 color.tolist(), 1)
+
+    # Add temperature labels
+    cv2.putText(image, f"{MIN_TEMP:.0f}C",
+                (scale_x - 35, scale_y + 15),
+                cv2.FONT_HERSHEY_SIMPLEX, 0.5, (255, 255, 255), 1)
+    cv2.putText(image, f"{MAX_TEMP:.0f}C",
+                (scale_x + scale_width + 5, scale_y + 15),
+                cv2.FONT_HERSHEY_SIMPLEX, 0.5, (255, 255, 255), 1)
+
+    # Draw border around scale
+    cv2.rectangle(image,
+                  (scale_x - 1, scale_y - 1),
+                  (scale_x + scale_width + 1, scale_y + scale_height + 1),
+                  (255, 255, 255), 1)
+
+# ============= MAIN LOOP =============
+print("Starting thermal camera overlay...")
+print("Use Up/Down keys to increase/decrease max temp")
+print("Use Left/Right keys to increase/decrease min temp")
+print("Use +/- keys to increase/decrease overlay opacity")
+print("Use Q key to exit")
+
+cv2.namedWindow('Thermal Overlay', cv2.WINDOW_NORMAL)
+cv2.resizeWindow('Thermal Overlay', WINDOW_WIDTH, WINDOW_HEIGHT)
+
+# Temperature statistics
+temp_stats = {"min": 0, "max": 0, "avg": 0}
+last_thermal_colored = None
+
+try:
+    while True:
+
+        # Read thermal data (only every SKIP_FRAMES frames)
+        if frame_counter % SKIP_FRAMES == 0:
+            try:
+                mlx.getFrame(thermal_frame)
+                # Process thermal data to colored image
+                last_thermal_colored, temp_stats["min"], temp_stats["max"], temp_stats["avg"] = process_thermal_frame(thermal_frame, the_colormap) # pylint: disable=line-too-long
+            except Exception as e: # pylint: disable=broad-except
+                print(f"Thermal read error: {e}")
+
+        frame_counter += 1
+
+        # Use the last processed thermal frame
+        if last_thermal_colored is not None:
+            thermal_colored = last_thermal_colored
+        else:
+            # Create a blank thermal image if we don't have one yet
+            thermal_colored = np.zeros((CAMERA_HEIGHT, CAMERA_WIDTH, 3), dtype=np.uint8)
+
+        # Capture camera frame
+        camera_frame = picam2.capture_array()
+
+        # Crop the camera frame to match thermal coverage area
+        camera_cropped = camera_frame[
+            CAMERA_CROP_TOP:CAMERA_HEIGHT-CAMERA_CROP_BOTTOM,
+            CAMERA_CROP_LEFT:CAMERA_WIDTH-CAMERA_CROP_RIGHT
+        ]
+
+        # Resize cropped camera back to full display size
+        camera_resized = cv2.resize(camera_cropped, (CAMERA_WIDTH, CAMERA_HEIGHT),
+                                                   interpolation=cv2.INTER_LINEAR)
+
+        # Blend camera and thermal images (now both are aligned)
+        overlay_image = blend_images(camera_resized, thermal_colored, THERMAL_OPACITY)
+
+        # Add temperature scale
+        add_temperature_scale(overlay_image, the_colormap)
+
+        # Add status text with temperature statistics and FPS
+        status_text = f"Range: {MIN_TEMP:.0f}-{MAX_TEMP:.0f}C | Opacity: {THERMAL_OPACITY:.1f} | "
+        status_text += f"Min: {temp_stats['min']:.1f}C | Max: {temp_stats['max']:.1f}C | Avg: {temp_stats['avg']:.1f}C | "  # pylint: disable=line-too-long
+        cv2.putText(overlay_image, status_text,
+                    (10, overlay_image.shape[0] - 10),
+                    cv2.FONT_HERSHEY_SIMPLEX, 0.6, (255, 255, 255), 2)
+
+        # Display the image
+        cv2.imshow('Thermal Overlay', overlay_image)
+
+        # Check if window was closed
+        if cv2.getWindowProperty('Thermal Overlay', cv2.WND_PROP_VISIBLE) < 1:
+            break
+
+        key_action = cv2.waitKey(1) & 0xFF
+        if key_action == ord('q'):
+            raise KeyboardInterrupt
+        if key_action == 82:
+            MAX_TEMP = min(MAX_TEMP + 1, 100)
+            print(f"Max temp: {MAX_TEMP:.1f}C")
+        elif key_action == 84:
+            MAX_TEMP = max(MAX_TEMP - 1, MIN_TEMP + 1)
+            print(f"Max temp: {MAX_TEMP:.1f}C")
+        elif key_action == 81:
+            MIN_TEMP = max(MIN_TEMP - 1, -20)
+            print(f"Min temp: {MIN_TEMP:.1f}C")
+        elif key_action == 83:
+            MIN_TEMP = min(MIN_TEMP + 1, MAX_TEMP - 1)
+            print(f"Min temp: {MIN_TEMP:.1f}C")
+        elif key_action == ord('+'):
+            THERMAL_OPACITY = min(THERMAL_OPACITY + 0.1, 1.0)
+            print(f"Opacity: {THERMAL_OPACITY:.1f}")
+        elif key_action == ord('-'):
+            THERMAL_OPACITY = max(THERMAL_OPACITY - 0.1, 0.0)
+            print(f"Opacity: {THERMAL_OPACITY:.1f}")
+        elif key_action == ord('z'):
+            THERMAL_OPACITY = not THERMAL_OPACITY
+            print(f"Opacity: {THERMAL_OPACITY:.1f}")
+
+except KeyboardInterrupt:
+    print("\nShutting down...")
+
+finally:
+    print("Cleaning up...")
+    cv2.destroyAllWindows()
+    cv2.waitKey(1)
+    picam2.stop()