# Structural Similarity (SSIM) Example # # Note: You will need an SD card to run this example. # # This example shows off how to use the SSIM algorithm on your OpenMV Cam # to detect differences between two images. The SSIM algorithm compares # 8x8 blocks of pixels between two images to determine a similarity # score between two images. import sensor, image, pyb, os, time # The image has likely changed if the sim.min() is lower than this. MIN_TRIGGER_THRESHOLD = -0.4 sensor.reset() # Initialize the camera sensor. sensor.set_pixformat(sensor.RGB565) # or sensor.GRAYSCALE sensor.set_framesize(sensor.QVGA) # or sensor.QQVGA (or others) sensor.skip_frames(time = 2000) # Let new settings take affect. sensor.set_auto_whitebal(False) # Turn off white balance. clock = time.clock() # Tracks FPS. if not "temp" in os.listdir(): os.mkdir("temp") # Make a temp directory print("About to save background image...") sensor.skip_frames(time = 2000) # Give the user time to get ready. sensor.snapshot().save("temp/bg.bmp") print("Saved background image!") while(True): clock.tick() # Track elapsed milliseconds between snapshots(). img = sensor.snapshot() # Take a picture and return the image. sim = img.get_similarity("temp/bg.bmp") change = "- Change -" if sim.min() < MIN_TRIGGER_THRESHOLD else "- No Change -" print(clock.fps(), change, sim)