28b

2020/sketch_2020_07_28b/sketch_2020_07_28b.pyde

@@ -0,0 +1,64 @@
+"""
+Frame Differencing Video Capture library example by Golan Levin.
+Quantify the amount of movement in the video frame using frame-differencing.
+"""
+add_library('video')   # import processing.video.*
+
+
+def setup():
+    global video, num_px, previous_frame
+    size(640, 480)
+    # This the default video input, see the GettingStartedCapture
+    # example if it creates an error
+    video = Capture(this, width, height)
+    # Start capturing the images from the camera
+    video.start()
+    num_px = video.width * video.height
+    # Create an array to store the previously captured frame
+    previous_frame = [0] * num_px
+    loadPixels()
+
+
+def draw():
+    if video.available():
+        # When using video to manipulate the screen, use video.available() and
+        # video.read() inside the draw() method so that it's safe to draw to
+        # the screen
+        video.read()  # Read the new frame from the camera
+        video.loadPixels()  # Make its pixels[] array available
+
+        movement_sum = 0  # Amount of movement in the frame
+        # For each pixel in the video frame...
+        for i in range(num_px):
+            currColor = video.pixels[i]
+            prevColor = previous_frame[i]
+            # Extract the red, green, and blue components from current pixel
+            currR = (currColor >> 16) & 0xFF  # Like red(), but faster
+            currG = (currColor >> 8) & 0xFF
+            currB = currColor & 0xFF
+            # Extract red, green, and blue components from previous pixel
+            prevR = (prevColor >> 16) & 0xFF
+            prevG = (prevColor >> 8) & 0xFF
+            prevB = prevColor & 0xFF
+            # Compute the difference of the red, green, and blue values
+            diffR = abs(currR - prevR)
+            diffG = abs(currG - prevG)
+            diffB = abs(currB - prevB)
+            # Add these differences to the running tally
+            movement_sum += diffR + diffG + diffB
+            # Render the difference image to the screen
+            # diff = color(diffR, diffG, diffB), but done with bitwise operations
+            diff =  0xff000000 | (diffR << 16) | (diffG << 8) | diffB
+            # pixels[i]= diff
+            # pixels[i] = 0xffffffff if brightness(diff) < 64 else 0xff000000
+            pixels[i] = 0xffffffff if diffR+diffG+diffB < 64 else 0xff000000
+            # Save the current into the 'previous' buffer
+            previous_frame[i] = currColor
+
+        # updatePixels()
+        # To prevent flicker from frames that are all black (no movement),
+        # only update the screen if the image has changed.
+        if movement_sum / 1000000 > 2:
+            updatePixels()
+        #     # Print the total amount of movement to the console
+        print(movement_sum / 1000000, frameRate)

README.md

@@ -21,6 +21,12 @@
 
 ---
 
+![sketch_2020_07_28b](2020/sketch_2020_07_28b/sketch_2020_07_28b.gif)
+
+[sketch_2020_07_28b](https://github.com/villares/sketch-a-day/tree/master/2020/sketch_2020_07_28b) [[Py.Processing](https://villares.github.io/como-instalar-o-processing-modo-python/index-EN)]
+
+---
+
 ![sketch_2020_07_27c](2020/sketch_2020_07_27c/sketch_2020_07_27c.gif)
 
 [sketch_2020_07_27c](https://github.com/villares/sketch-a-day/tree/master/2020/sketch_2020_07_27c) [[Py.Processing](https://villares.github.io/como-instalar-o-processing-modo-python/index-EN)]