75 LEDS, too precise.

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fredfire
 
Posts: 3
Joined: Tue May 01, 2012 1:41 am

75 LEDS, too precise.

Post by fredfire »

Hi,

I have 3 strand of 25 leds behind my projector screen.

The effect is good when the scene is all the same but if the scene had multiple colors, the leds are way too precise.

Is there a way to make them calculate color so they are more blending in?

this is my config :

Code: Select all

// "Adalight" is a do-it-yourself facsimile of the Philips Ambilight concept
// for desktop computers and home theater PCs.  This is the host PC-side code
// written in Processing, intended for use with a USB-connected Arduino
// microcontroller running the accompanying LED streaming code.  Requires one
// or more strands of Digital RGB LED Pixels (Adafruit product ID #322,
// specifically the newer WS2801-based type, strand of 25) and a 5 Volt power
// supply (such as Adafruit #276).  You may need to adapt the code and the
// hardware arrangement for your specific display configuration.
// Screen capture adapted from code by Cedrik Kiefer (processing.org forum)

import java.awt.*;
import java.awt.image.*;
import processing.serial.*;

// CONFIGURABLE PROGRAM CONSTANTS --------------------------------------------

// Minimum LED brightness; some users prefer a small amount of backlighting
// at all times, regardless of screen content.  Higher values are brighter,
// or set to 0 to disable this feature.

static final short minBrightness = 120;

// LED transition speed; it's sometimes distracting if LEDs instantaneously
// track screen contents (such as during bright flashing sequences), so this
// feature enables a gradual fade to each new LED state.  Higher numbers yield
// slower transitions (max of 255), or set to 0 to disable this feature
// (immediate transition of all LEDs).

static final short fade = 75;

// Pixel size for the live preview image.

static final int pixelSize = 20;

// Depending on many factors, it may be faster either to capture full
// screens and process only the pixels needed, or to capture multiple
// smaller sub-blocks bounding each region to be processed.  Try both,
// look at the reported frame rates in the Processing output console,
// and run with whichever works best for you.

static final boolean useFullScreenCaps = true;

// Serial device timeout (in milliseconds), for locating Arduino device
// running the corresponding LEDstream code.  See notes later in the code...
// in some situations you may want to entirely comment out that block.

static final int timeout = 5000; // 5 seconds

// PER-DISPLAY INFORMATION ---------------------------------------------------

// This array contains details for each display that the software will
// process.  If you have screen(s) attached that are not among those being
// "Adalighted," they should not be in this list.  Each triplet in this
// array represents one display.  The first number is the system screen
// number...typically the "primary" display on most systems is identified
// as screen #1, but since arrays are indexed from zero, use 0 to indicate
// the first screen, 1 to indicate the second screen, and so forth.  This
// is the ONLY place system screen numbers are used...ANY subsequent
// references to displays are an index into this list, NOT necessarily the
// same as the system screen number.  For example, if you have a three-
// screen setup and are illuminating only the third display, use '2' for
// the screen number here...and then, in subsequent section, '0' will be
// used to refer to the first/only display in this list.
// The second and third numbers of each triplet represent the width and
// height of a grid of LED pixels attached to the perimeter of this display.
// For example, '9,6' = 9 LEDs across, 6 LEDs down.

static final int displays[][] = new int[][] {
   {0,26,15} // Screen 0, 9 LEDs across, 6 LEDs down
//,{1,9,6} // Screen 1, also 9 LEDs across and 6 LEDs down
};

// PER-LED INFORMATION -------------------------------------------------------

// This array contains the 2D coordinates corresponding to each pixel in the
// LED strand, in the order that they're connected (i.e. the first element
// here belongs to the first LED in the strand, second element is the second
// LED, and so forth).  Each triplet in this array consists of a display
// number (an index into the display array above, NOT necessarily the same as
// the system screen number) and an X and Y coordinate specified in the grid
// units given for that display.  {0,0,0} is the top-left corner of the first
// display in the array.
// For our example purposes, the coordinate list below forms a ring around
// the perimeter of a single screen, with a one pixel gap at the bottom to
// accommodate a monitor stand.  Modify this to match your own setup:

  static final int leds[][] = new int[][] {
  {0,12,14},{0,11,14}, {0,10,14}, {0,9,14}, {0,8,14}, {0,7,14}, {0,6,14}, {0,5,14}, {0,4,14}, {0,3,14}, {0,2,14}, {0,1,14}, {0,0,14},  // Bottom edge, left half
  {0,0,13}, {0,0,12}, {0,0,11}, {0,0,10}, {0,0,9}, {0,0,8}, {0,0,7}, {0,0,6}, {0,0,5}, {0,0,4}, {0,0,3}, {0,0,2}, {0,0,1}, // Left edge
  {0,0,0}, {0,1,0}, {0,2,0}, {0,3,0}, {0,4,0}, {0,5,0}, {0,6,0}, {0,7,0}, {0,8,0}, {0,9,0}, {0,10,0}, {0,11,0}, {0,12,0}, // Top edge
           {0,13,0}, {0,14,0}, {0,15,0}, {0,16,0}, {0,17,0}, {0,18,0}, {0,19,0}, {0,20,0}, {0,21,0}, {0,22,0}, {0,23,0}, {0,24,0}, {0,25,0}, // More top edge
  {0,25,1}, {0,25,2}, {0,25,3}, {0,25,4}, {0,25,5}, {0,25,6}, {0,25,7}, {0,25,8}, {0,25,9}, {0,25,10}, {0,25,11}, {0,25,12}, {0,25,13}, // Right edge
  {0,24,14}, {0,23,14}, {0,22,14}, {0,21,14}, {0,20,14}, {0,19,14}, {0,18,14}, {0,17,14}, {0,16,14}, {0,15,14}, {0,14,14}, {0,13,14}  // Bottom edge, right half

/* Hypothetical second display has the same arrangement as the first.
   But you might not want both displays completely ringed with LEDs;
   the screens might be positioned where they share an edge in common.
 ,{1,3,5}, {1,2,5}, {1,1,5}, {1,0,5}, // Bottom edge, left half
  {1,0,4}, {1,0,3}, {1,0,2}, {1,0,1}, // Left edge
  {1,0,0}, {1,1,0}, {1,2,0}, {1,3,0}, {1,4,0}, // Top edge
           {1,5,0}, {1,6,0}, {1,7,0}, {1,8,0}, // More top edge
  {1,8,1}, {1,8,2}, {1,8,3}, {1,8,4}, // Right edge
  {1,8,5}, {1,7,5}, {1,6,5}, {1,5,5}  // Bottom edge, right half
*/
};

// GLOBAL VARIABLES ---- You probably won't need to modify any of this -------

byte[]           serialData  = new byte[6 + leds.length * 3];
short[][]        ledColor    = new short[leds.length][3],
                 prevColor   = new short[leds.length][3];
byte[][]         gamma       = new byte[256][3];
int              nDisplays   = displays.length;
Robot[]          bot         = new Robot[displays.length];
Rectangle[]      dispBounds  = new Rectangle[displays.length],
                 ledBounds;  // Alloc'd only if per-LED captures
int[][]          pixelOffset = new int[leds.length][256],
                 screenData; // Alloc'd only if full-screen captures
PImage[]         preview     = new PImage[displays.length];
Serial           port;
DisposeHandler   dh; // For disabling LEDs on exit

// INITIALIZATION ------------------------------------------------------------

void setup() {
  GraphicsEnvironment     ge;
  GraphicsConfiguration[] gc;
  GraphicsDevice[]        gd;
  int                     d, i, totalWidth, maxHeight, row, col, rowOffset;
  int[]                   x = new int[16], y = new int[16];
  float                   f, range, step, start;

  dh = new DisposeHandler(this); // Init DisposeHandler ASAP

  // Open serial port.  As written here, this assumes the Arduino is the
  // first/only serial device on the system.  If that's not the case,
  // change "Serial.list()[0]" to the name of the port to be used:
  port = new Serial(this, Serial.list()[0], 115200);
  // Alternately, in certain situations the following line can be used
  // to detect the Arduino automatically.  But this works ONLY with SOME
  // Arduino boards and versions of Processing!  This is so convoluted
  // to explain, it's easier just to test it yourself and see whether
  // it works...if not, leave it commented out and use the prior port-
  // opening technique.
  // port = openPort();
  // And finally, to test the software alone without an Arduino connected,
  // don't open a port...just comment out the serial lines above.

  // Initialize screen capture code for each display's dimensions.
  dispBounds = new Rectangle[displays.length];
  if(useFullScreenCaps == true) {
    screenData = new int[displays.length][];
    // ledBounds[] not used
  } else {
    ledBounds  = new Rectangle[leds.length];
    // screenData[][] not used
  }
  ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
  gd = ge.getScreenDevices();
  if(nDisplays > gd.length) nDisplays = gd.length;
  totalWidth = maxHeight = 0;
  for(d=0; d<nDisplays; d++) { // For each display...
    try {
      bot[d] = new Robot(gd[displays[d][0]]);
    }
    catch(AWTException e) {
      System.out.println("new Robot() failed");
      continue;
    }
    gc              = gd[displays[d][0]].getConfigurations();
    dispBounds[d]   = gc[0].getBounds();
    dispBounds[d].x = dispBounds[d].y = 0;
    preview[d]      = createImage(displays[d][1], displays[d][2], RGB);
    preview[d].loadPixels();
    totalWidth     += displays[d][1];
    if(d > 0) totalWidth++;
    if(displays[d][2] > maxHeight) maxHeight = displays[d][2];
  }

  // Precompute locations of every pixel to read when downsampling.
  // Saves a bunch of math on each frame, at the expense of a chunk
  // of RAM.  Number of samples is now fixed at 256; this allows for
  // some crazy optimizations in the downsampling code.
  for(i=0; i<leds.length; i++) { // For each LED...
    d = leds[i][0]; // Corresponding display index

    // Precompute columns, rows of each sampled point for this LED
    range = (float)dispBounds[d].width / (float)displays[d][1];
    step  = range / 16.0;
    start = range * (float)leds[i][1] + step * 0.5;
    for(col=0; col<16; col++) x[col] = (int)(start + step * (float)col);
    range = (float)dispBounds[d].height / (float)displays[d][2];
    step  = range / 16.0;
    start = range * (float)leds[i][2] + step * 0.5;
    for(row=0; row<16; row++) y[row] = (int)(start + step * (float)row);

    if(useFullScreenCaps == true) {
      // Get offset to each pixel within full screen capture
      for(row=0; row<16; row++) {
        for(col=0; col<16; col++) {
          pixelOffset[i][row * 16 + col] =
            y[row] * dispBounds[d].width + x[col];
        }
      }
    } else {
      // Calc min bounding rect for LED, get offset to each pixel within
      ledBounds[i] = new Rectangle(x[0], y[0], x[15]-x[0]+1, y[15]-y[0]+1);
      for(row=0; row<16; row++) {
        for(col=0; col<16; col++) {
          pixelOffset[i][row * 16 + col] =
            (y[row] - y[0]) * ledBounds[i].width + x[col] - x[0];
        }
      }
    }
  }

  for(i=0; i<prevColor.length; i++) {
    prevColor[i][0] = prevColor[i][1] = prevColor[i][2] =
      minBrightness / 3;
  }

  // Preview window shows all screens side-by-side
  size(totalWidth * pixelSize, maxHeight * pixelSize, JAVA2D);

  // A special header / magic word is expected by the corresponding LED
  // streaming code running on the Arduino.  This only needs to be initialized
  // once (not in draw() loop) because the number of LEDs remains constant:
  serialData[0] = 'A';                              // Magic word
  serialData[1] = 'd';
  serialData[2] = 'a';
  serialData[3] = (byte)((leds.length - 1) >> 8);   // LED count high byte
  serialData[4] = (byte)((leds.length - 1) & 0xff); // LED count low byte
  serialData[5] = (byte)(serialData[3] ^ serialData[4] ^ 0x55); // Checksum

  // Pre-compute gamma correction table for LED brightness levels:
  for(i=0; i<256; i++) {
    f           = pow((float)i / 255.0, 2.8);
    gamma[i][0] = (byte)(f * 255.0);
    gamma[i][1] = (byte)(f * 240.0);
    gamma[i][2] = (byte)(f * 220.0);
  }
}

// Open and return serial connection to Arduino running LEDstream code.  This
// attempts to open and read from each serial device on the system, until the
// matching "Ada\n" acknowledgement string is found.  Due to the serial
// timeout, if you have multiple serial devices/ports and the Arduino is late
// in the list, this can take seemingly forever...so if you KNOW the Arduino
// will always be on a specific port (e.g. "COM6"), you might want to comment
// out most of this to bypass the checks and instead just open that port
// directly!  (Modify last line in this method with the serial port name.)

Serial openPort() {
  String[] ports;
  String   ack;
  int      i, start;
  Serial   s;

  ports = Serial.list(); // List of all serial ports/devices on system.

  for(i=0; i<ports.length; i++) { // For each serial port...
    System.out.format("Trying serial port %s\n",ports[i]);
    try {
      s = new Serial(this, ports[i], 115200);
    }
    catch(Exception e) {
      // Can't open port, probably in use by other software.
      continue;
    }
    // Port open...watch for acknowledgement string...
    start = millis();
    while((millis() - start) < timeout) {
      if((s.available() >= 4) &&
        ((ack = s.readString()) != null) &&
        ack.contains("Ada\n")) {
          return s; // Got it!
      }
    }
    // Connection timed out.  Close port and move on to the next.
    s.stop();
  }

  // Didn't locate a device returning the acknowledgment string.
  // Maybe it's out there but running the old LEDstream code, which
  // didn't have the ACK.  Can't say for sure, so we'll take our
  // changes with the first/only serial device out there...
  return new Serial(this, ports[0], 115200);
}


// PER_FRAME PROCESSING ------------------------------------------------------

void draw () {
  BufferedImage img;
  int           d, i, j, o, c, weight, rb, g, sum, deficit, s2;
  int[]         pxls, offs;

  if(useFullScreenCaps == true ) {
    // Capture each screen in the displays array.
    for(d=0; d<nDisplays; d++) {
      img = bot[d].createScreenCapture(dispBounds[d]);
      // Get location of source pixel data
      screenData[d] =
        ((DataBufferInt)img.getRaster().getDataBuffer()).getData();
    }
  }

  weight = 257 - fade; // 'Weighting factor' for new frame vs. old
  j      = 6;          // Serial led data follows header / magic word

  // This computes a single pixel value filtered down from a rectangular
  // section of the screen.  While it would seem tempting to use the native
  // image scaling in Processing/Java, in practice this didn't look very
  // good -- either too pixelated or too blurry, no happy medium.  So
  // instead, a "manual" downsampling is done here.  In the interest of
  // speed, it doesn't actually sample every pixel within a block, just
  // a selection of 256 pixels spaced within the block...the results still
  // look reasonably smooth and are handled quickly enough for video.

  for(i=0; i<leds.length; i++) {  // For each LED...
    d = leds[i][0]; // Corresponding display index
    if(useFullScreenCaps == true) {
      // Get location of source data from prior full-screen capture:
      pxls = screenData[d];
    } else {
      // Capture section of screen (LED bounds rect) and locate data::
      img  = bot[d].createScreenCapture(ledBounds[i]);
      pxls = ((DataBufferInt)img.getRaster().getDataBuffer()).getData();
    }
    offs = pixelOffset[i];
    rb = g = 0;
    for(o=0; o<256; o++) {
      c   = pxls[offs[o]];
      rb += c & 0x00ff00ff; // Bit trickery: R+B can accumulate in one var
      g  += c & 0x0000ff00;
    }

    // Blend new pixel value with the value from the prior frame
    ledColor[i][0]  = (short)((((rb >> 24) & 0xff) * weight +
                               prevColor[i][0]     * fade) >> 8);
    ledColor[i][1]  = (short)(((( g >> 16) & 0xff) * weight +
                               prevColor[i][1]     * fade) >> 8);
    ledColor[i][2]  = (short)((((rb >>  8) & 0xff) * weight +
                               prevColor[i][2]     * fade) >> 8);

    // Boost pixels that fall below the minimum brightness
    sum = ledColor[i][0] + ledColor[i][1] + ledColor[i][2];
    if(sum < minBrightness) {
      if(sum == 0) { // To avoid divide-by-zero
        deficit = minBrightness / 3; // Spread equally to R,G,B
        ledColor[i][0] += deficit;
        ledColor[i][1] += deficit;
        ledColor[i][2] += deficit;
      } else {
        deficit = minBrightness - sum;
        s2      = sum * 2;
        // Spread the "brightness deficit" back into R,G,B in proportion to
        // their individual contribition to that deficit.  Rather than simply
        // boosting all pixels at the low end, this allows deep (but saturated)
        // colors to stay saturated...they don't "pink out."
        ledColor[i][0] += deficit * (sum - ledColor[i][0]) / s2;
        ledColor[i][1] += deficit * (sum - ledColor[i][1]) / s2;
        ledColor[i][2] += deficit * (sum - ledColor[i][2]) / s2;
      }
    }

    // Apply gamma curve and place in serial output buffer
    serialData[j++] = gamma[ledColor[i][0]][0];
    serialData[j++] = gamma[ledColor[i][1]][1];
    serialData[j++] = gamma[ledColor[i][2]][2];
    // Update pixels in preview image
    preview[d].pixels[leds[i][2] * displays[d][1] + leds[i][1]] =
     (ledColor[i][0] << 16) | (ledColor[i][1] << 8) | ledColor[i][2];
  }

  if(port != null) port.write(serialData); // Issue data to Arduino

  // Show live preview image(s)
  scale(pixelSize);
  for(i=d=0; d<nDisplays; d++) {
    preview[d].updatePixels();
    image(preview[d], i, 0);
    i += displays[d][1] + 1;
  }

  println(frameRate); // How are we doing?

  // Copy LED color data to prior frame array for next pass
  arraycopy(ledColor, 0, prevColor, 0, ledColor.length);
}


// CLEANUP -------------------------------------------------------------------

// The DisposeHandler is called on program exit (but before the Serial library
// is shutdown), in order to turn off the LEDs (reportedly more reliable than
// stop()).  Seems to work for the window close box and escape key exit, but
// not the 'Quit' menu option.  Thanks to phi.lho in the Processing forums.

public class DisposeHandler {
  DisposeHandler(PApplet pa) {
    pa.registerDispose(this);
  }
  public void dispose() {
    // Fill serialData (after header) with 0's, and issue to Arduino...
    Arrays.fill(serialData, 6, serialData.length, (byte)0);
    if(port != null) port.write(serialData);
  }
}


User avatar
pburgess
 
Posts: 4161
Joined: Sun Oct 26, 2008 2:29 am

Re: 75 LEDS, too precise.

Post by pburgess »

Is there a way to make them calculate color so they are more blending in?
In principle, yes, but it would be kind of complicated and ugly. So if you're okay with a more hack-ish solution, here's a few ideas:

- Try changing the value of 'fade' (default is 75 -- try higher numbers). This won't change the detail level, but will change how abruptly LEDs fade from one color to the next, which may have a smoothing effect.

- Try changing displays[0] for a coarser resolution (so there's half as many pixels around the perimeter), then tweaking the leds[][] array so that LEDs are paired up within pixel boxes. Because you have an odd number of LEDs, one of those pixel boxes will need to contain either one or three LEDs for it all to line up.

- Rather than software, you might be able to diffuse the light using physical means -- for example, most hardware stores will sell diffuser panels for in-ceiling kitchen lights. You could cut one of these into strips that mount atop your LEDs. (Since this one involves some capital investment, you might want to experiment first with materials on-hand...for example, maybe a simple paper diffuser covering the LEDs along one edge, see if that helps before committing to the whole thing.)

User avatar
fredfire
 
Posts: 3
Joined: Tue May 01, 2012 1:41 am

Re: 75 LEDS, too precise.

Post by fredfire »

Thanks, The diffuser is an idea I tought!

Also I found the code of my led arrays is reversed. I am currently at least making sure the good leds light up ;)

I will try the two suggestions and will give feedback.

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