Diskutieren Sie mit anderen Lesern über Physik und Philosophie
von galactic32 » Mi 22. Dez 2010, 18:05
Der Haken liegt in der Richtungsabhängigkeit der t'-Werte.Ernst hat geschrieben:Die unterschiedliche "Dichte" darf aber nicht auftreten, da muß man noch mal nachdenken.
von Ernst » Mi 22. Dez 2010, 18:24
scharo hat geschrieben: „Ernst hat doch bereits vorgerechnet, dass die Lorentztransformation die Kugelwelle um den Ursprung des ungestrichenen Systems in eine Kugelwelle um den Ursprung des gestrichenen Systems transformiert.“
Nein, so was hat er nicht vorgerechnet.
sieht man auch, dass die Kugelsphäre S´ bei t = 1s eben nicht um den Ursprung des S´ sich bildet,
von Ernst » Mi 22. Dez 2010, 18:30
Chief hat geschrieben:Unterschiedliche Dichte ergibt sich wegen Doppler.
von Ernst » Mi 22. Dez 2010, 18:32
Chief hat geschrieben:Dass die Zeit in einem gleichförmig bewegten System an verschiedenen Orten unterschiedlich schnell läuft widerspricht dem RP weil alle System-Uhren gleiche Geschwindigkeit besitzen.
von Faber » Mi 22. Dez 2010, 18:59
von Faber » Mi 22. Dez 2010, 19:06
import java.awt.AlphaComposite;
import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Composite;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.geom.Ellipse2D;
import java.awt.geom.Line2D;
import java.awt.geom.Rectangle2D;
import java.awt.image.BufferedImage;
/**
* Erstellt eine GIF-Datei.
* <p>
* Das animierte Bild zeigt die Ausbreitung eines Lichtblitzes in Form einer Lichtsphäre vom
* Ursprung eines Laborsystems aus sowie die Ausbreitung desselben Lichtblitzes in bezug auf ein zum
* Laborsystem relativ bewegtes, gestrichenes System.
* </p>
* <p>
* Man rufe die {@link #main(String...)}-Methode auf.
* </p>
*
* @author Faber
*/
public class LightSphere
{
/** Breite des Bildes in Pixeln. */
private final int w = 256 + 128;
/** Höhe des Bildes in Pixeln. */
private final int h = 512;
/** Lichtgeschwindigkeit in m/s. */
private final double c = 300E6;
/** Relative Schnelligkeit der Bezugssysteme. */
private final double v = 0.5 * c;
/** Gamma-Faktor der Lorentztransformation. */
private final double gamma = 1.0 / Math.sqrt(1 - (v * v) / (c * c));
/**
* Erstellt die Bilddatei.
*
* @see #main(String...)
*/
private LightSphere()
{
final String sv = String.format("%.3f", v / c).substring(2);
final String fileName = String.format("%s-c%s.gif", LightSphere.class.getSimpleName(), sv);
final AnimatedGifEncoder gifenc = new AnimatedGifEncoder();
gifenc.setQuality(10);
gifenc.setRepeat(0);
gifenc.setDelay(100);
gifenc.start(fileName);
final double t0 = 0; // Startzeitpunkt in Sekunden
final double t1 = 1 / c; // Endzeitpunkt in Sekunden
final double dt = (t1 - t0) / 50;
for (double t = t0; t <= t1; t += dt)
{
final BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_3BYTE_BGR);
final Graphics2D graphics2D = image.createGraphics();
try
{
{ // Hintergrund
graphics2D.setColor(new Color(0xE0E0E0));
graphics2D.fillRect(0, 0, w, h);
}
{ // Bilder
paint(graphics2D, t, true);
paint(graphics2D, t, false);
}
}
finally
{
graphics2D.dispose();
}
gifenc.addFrame(image);
}
gifenc.finish();
}
/**
* Malt ein Phasenbild der Animation.
*
* @param graphics2D
* Grafik-Kontext.
* @param t
* Zeitpunkt in Sekunden.
* @param labor
* Zeigt an, ob in bezug auf das Laborsystem gemalt wird.
*/
private void paint(final Graphics2D graphics2D, final double t, final boolean labor)
{
final int R = h / 4;
final int mx = 3 * R / 2;
final int my = labor ? R : 3 * R;
{ // Achsen und Text malen.
final int d = 12;
graphics2D.setColor(Color.BLACK);
graphics2D.setStroke(new BasicStroke());
graphics2D.draw(new Line2D.Double(0, my, w, my));
graphics2D.draw(new Line2D.Double(w - d, my + d, w, my));
graphics2D.draw(new Line2D.Double(w - d, my - d, w, my));
graphics2D.draw(new Line2D.Double(mx, my + R, mx, my - R));
graphics2D.draw(new Line2D.Double(mx - d, my - R + d, mx, my - R));
graphics2D.draw(new Line2D.Double(mx + d, my - R + d, mx, my - R));
graphics2D.drawRect(0, my - R, w - 1, 2 * R - 1);
final Font font = new Font("Courier New", Font.BOLD, 12);
final String text = String.format("%s = %.3fm\n", labor ? "ct" : "ct'", c * t);
final Rectangle2D r = font.getStringBounds(text, graphics2D.getFontRenderContext());
final int th = (int) (r.getHeight() + 0.5);
final int tw = (int) (r.getWidth() + 0.5);
graphics2D.setFont(font);
graphics2D.drawString(text, w - tw - th, my + R - th);
if (!labor)
{
graphics2D.drawString(String.format("v = %.3fc", v / c), w - tw - th, my + R - 2 * th);
}
graphics2D.drawString(labor ? "Laborsystem" : "Gestr. System", th, my - R + th);
}
final Color color = labor ? new Color(0x00A000) : new Color(0xA00000);
final double scale = 0.9 * R;
{ // Blitzgerät malen.
final double x = labor ? 0 : -v * t;
final double y = 0;
// Werte in Pixel umrechnen:
final double px = mx + scale * x;
final double py = my - scale * y;
graphics2D.setColor(new Color(0x404040));
graphics2D.fill(new Rectangle2D.Double(px - 4, py - 4, 9, 9));
graphics2D.setColor(color);
graphics2D.fill(new Ellipse2D.Double(px - 2, py - 2, 5, 5));
}
{ // Kreis malen.
final double r = c * t;
final double pr = scale * r;
final Composite composite = graphics2D.getComposite();
graphics2D.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 0.5f));
graphics2D.setColor(color);
graphics2D.draw(new Ellipse2D.Double(mx - pr, my - pr, 2 * pr + 1, 2 * pr + 1));
graphics2D.setComposite(composite);
}
{ // Photonen malen.
for (int k = 0, N = 8; k < N; k++)
{
final double alpha = 2 * Math.PI * k / N;
final double x = labor ? xLabor(alpha, t) : xStrich(alpha, t);
final double y = labor ? yLabor(alpha, t) : yStrich(alpha, t);
// Werte in Pixel umrechnen:
final double px = mx + scale * x;
final double py = my - scale * y;
// Photon malen:
graphics2D.setColor(color);
graphics2D.fill(new Ellipse2D.Double(px - 3, py - 3, 7, 7));
}
}
}
/**
* Liefert die x-Komponente der Trajektorie eines Photons.
*
* @param alpha
* Richtung, in die das Photon im Laborsystem vom Ursprung aus fliegt, in Radian.
* @param t
* Zeitpunkt t im Laborsystem, in Sekunden.
* @return die x-Position des Photons zum Zeitpunkt t in Metern.
*/
public double xLabor(final double alpha, final double t)
{
return c * t * Math.cos(alpha);
}
/**
* Liefert die y-Komponente der Trajektorie eines Photons.
*
* @param alpha
* Richtung, in die das Photon im Laborsystem vom Ursprung aus fliegt, in Radian.
* @param t
* Zeitpunkt t im Laborsystem, in Sekunden.
* @return die y-Position des Photons zum Zeitpunkt t in Metern.
*/
public double yLabor(final double alpha, final double t)
{
return c * t * Math.sin(alpha);
}
/**
* Liefert die x'-Komponente der Trajektorie eines Photons.
* <p>
* Herleitung siehe <a href="http://www.mahag.com/neufor/viewtopic.php?p=20494#p20494">hier</a>.
* </p>
*
* @param alpha
* Richtung, in die das Photon im Laborsystem vom Ursprung aus fliegt, in Radian.
* @param tStrich
* Zeitpunkt t' im gestrichenen System, in Sekunden.
* @return die x'-Position des Photons zum Zeitpunkt t' in Metern.
*/
public double xStrich(final double alpha, final double tStrich)
{
final double denominator = (c - v * Math.cos(alpha));
return c * tStrich * (c * Math.cos(alpha) - v) / denominator;
}
/**
* Liefert die y'-Komponente der Trajektorie eines Photons.
* <p>
* Herleitung siehe <a href="http://www.mahag.com/neufor/viewtopic.php?p=20494#p20494">hier</a>.
* </p>
*
* @param alpha
* Richtung, in die das Photon im Laborsystem vom Ursprung aus fliegt, in Radian.
* @param tStrich
* Zeitpunkt t' im gestrichenen System, in Sekunden.
* @return die y'-Position des Photons zum Zeitpunkt t' in Metern.
*/
public double yStrich(final double alpha, final double tStrich)
{
final double denominator = (c - v * Math.cos(alpha)) * gamma;
return c * tStrich * (c * Math.sin(alpha)) / denominator;
}
/**
* Programmeinstiegspunkt.
*
* @param args
* wird ignoriert.
*/
public static void main(final String... args)
{
new LightSphere();
}
}
import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.awt.image.DataBufferByte;
import java.io.BufferedOutputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
/**
* Class AnimatedGifEncoder - Encodes a GIF file consisting of one or more frames.
*
* <pre>
* Example:
* AnimatedGifEncoder e = new AnimatedGifEncoder();
* e.start(outputFileName);
* e.setDelay(1000); // 1 frame per sec
* e.addFrame(image1);
* e.addFrame(image2);
* e.finish();
* </pre>
*
* No copyright asserted on the source code of this class. May be used for any purpose, however,
* refer to the Unisys LZW patent for restrictions on use of the associated LZWEncoder class. Please
* forward any corrections to kweiner@fmsware.com.
*
* @author Kevin Weiner, FM Software
* @version 1.03 November 2003
*/
public class AnimatedGifEncoder
{
protected int width; // image size
protected int height;
protected Color transparent = null; // transparent color if given
protected int transIndex; // transparent index in color table
protected int repeat = -1; // no repeat
protected int delay = 0; // frame delay (hundredths)
protected boolean started = false; // ready to output frames
protected OutputStream out;
protected BufferedImage image; // current frame
protected byte[] pixels; // BGR byte array from frame
protected byte[] indexedPixels; // converted frame indexed to palette
protected int colorDepth; // number of bit planes
protected byte[] colorTab; // RGB palette
protected boolean[] usedEntry = new boolean[256]; // active palette entries
protected int palSize = 7; // color table size (bits-1)
protected int dispose = -1; // disposal code (-1 = use default)
protected boolean closeStream = false; // close stream when finished
protected boolean firstFrame = true;
protected boolean sizeSet = false; // if false, get size from first frame
protected int sample = 10; // default sample interval for quantizer
/**
* Sets the delay time between each frame, or changes it for subsequent frames (applies to last
* frame added).
*
* @param ms
* int delay time in milliseconds
*/
public void setDelay(int ms)
{
delay = Math.round(ms / 10.0f);
}
/**
* Sets the GIF frame disposal code for the last added frame and any subsequent frames. Default
* is 0 if no transparent color has been set, otherwise 2.
*
* @param code
* int disposal code.
*/
public void setDispose(int code)
{
if (code >= 0)
{
dispose = code;
}
}
/**
* Sets the number of times the set of GIF frames should be played. Default is 1; 0 means play
* indefinitely. Must be invoked before the first image is added.
*
* @param iter
* int number of iterations.
* @return
*/
public void setRepeat(int iter)
{
if (iter >= 0)
{
repeat = iter;
}
}
/**
* Sets the transparent color for the last added frame and any subsequent frames. Since all
* colors are subject to modification in the quantization process, the color in the final palette
* for each frame closest to the given color becomes the transparent color for that frame. May be
* set to null to indicate no transparent color.
*
* @param c
* Color to be treated as transparent on display.
*/
public void setTransparent(Color c)
{
transparent = c;
}
/**
* Adds next GIF frame. The frame is not written immediately, but is actually deferred until the
* next frame is received so that timing data can be inserted. Invoking <code>finish()</code>
* flushes all frames. If <code>setSize</code> was not invoked, the size of the first image is
* used for all subsequent frames.
*
* @param im
* BufferedImage containing frame to write.
* @return true if successful.
*/
public boolean addFrame(BufferedImage im)
{
if ((im == null) || !started)
{
return false;
}
boolean ok = true;
try
{
if (!sizeSet)
{
// use first frame's size
setSize(im.getWidth(), im.getHeight());
}
image = im;
getImagePixels(); // convert to correct format if necessary
analyzePixels(); // build color table & map pixels
if (firstFrame)
{
writeLSD(); // logical screen descriptior
writePalette(); // global color table
if (repeat >= 0)
{
// use NS app extension to indicate reps
writeNetscapeExt();
}
}
writeGraphicCtrlExt(); // write graphic control extension
writeImageDesc(); // image descriptor
if (!firstFrame)
{
writePalette(); // local color table
}
writePixels(); // encode and write pixel data
firstFrame = false;
}
catch (IOException e)
{
ok = false;
}
return ok;
}
/**
* Flushes any pending data and closes output file. If writing to an OutputStream, the stream is
* not closed.
*/
public boolean finish()
{
if (!started)
return false;
boolean ok = true;
started = false;
try
{
out.write(0x3b); // gif trailer
out.flush();
if (closeStream)
{
out.close();
}
}
catch (IOException e)
{
ok = false;
}
// reset for subsequent use
transIndex = 0;
out = null;
image = null;
pixels = null;
indexedPixels = null;
colorTab = null;
closeStream = false;
firstFrame = true;
return ok;
}
/**
* Sets frame rate in frames per second. Equivalent to <code>setDelay(1000/fps)</code>.
*
* @param fps
* float frame rate (frames per second)
*/
public void setFrameRate(float fps)
{
if (fps != 0f)
{
delay = Math.round(100f / fps);
}
}
/**
* Sets quality of color quantization (conversion of images to the maximum 256 colors allowed by
* the GIF specification). Lower values (minimum = 1) produce better colors, but slow processing
* significantly. 10 is the default, and produces good color mapping at reasonable speeds. Values
* greater than 20 do not yield significant improvements in speed.
*
* @param quality
* int greater than 0.
* @return
*/
public void setQuality(int quality)
{
if (quality < 1)
quality = 1;
sample = quality;
}
/**
* Sets the GIF frame size. The default size is the size of the first frame added if this method
* is not invoked.
*
* @param w
* int frame width.
* @param h
* int frame width.
*/
public void setSize(int w, int h)
{
if (started && !firstFrame)
return;
width = w;
height = h;
if (width < 1)
width = 320;
if (height < 1)
height = 240;
sizeSet = true;
}
/**
* Initiates GIF file creation on the given stream. The stream is not closed automatically.
*
* @param os
* OutputStream on which GIF images are written.
* @return false if initial write failed.
*/
public boolean start(OutputStream os)
{
if (os == null)
return false;
boolean ok = true;
closeStream = false;
out = os;
try
{
writeString("GIF89a"); // header
}
catch (IOException e)
{
ok = false;
}
return started = ok;
}
/**
* Initiates writing of a GIF file with the specified name.
*
* @param file
* String containing output file name.
* @return false if open or initial write failed.
*/
public boolean start(String file)
{
boolean ok = true;
try
{
out = new BufferedOutputStream(new FileOutputStream(file));
ok = start(out);
closeStream = true;
}
catch (IOException e)
{
ok = false;
}
return started = ok;
}
/**
* Analyzes image colors and creates color map.
*/
protected void analyzePixels()
{
int len = pixels.length;
int nPix = len / 3;
indexedPixels = new byte[nPix];
NeuQuant nq = new NeuQuant(pixels, len, sample);
// initialize quantizer
colorTab = nq.process(); // create reduced palette
// convert map from BGR to RGB
for (int i = 0; i < colorTab.length; i += 3)
{
byte temp = colorTab[i];
colorTab[i] = colorTab[i + 2];
colorTab[i + 2] = temp;
usedEntry[i / 3] = false;
}
// map image pixels to new palette
int k = 0;
for (int i = 0; i < nPix; i++)
{
int index = nq.map(pixels[k++] & 0xff, pixels[k++] & 0xff, pixels[k++] & 0xff);
usedEntry[index] = true;
indexedPixels[i] = (byte) index;
}
pixels = null;
colorDepth = 8;
palSize = 7;
// get closest match to transparent color if specified
if (transparent != null)
{
transIndex = findClosest(transparent);
}
}
/**
* Returns index of palette color closest to c
*/
protected int findClosest(Color c)
{
if (colorTab == null)
return -1;
int r = c.getRed();
int g = c.getGreen();
int b = c.getBlue();
int minpos = 0;
int dmin = 256 * 256 * 256;
int len = colorTab.length;
for (int i = 0; i < len;)
{
int dr = r - (colorTab[i++] & 0xff);
int dg = g - (colorTab[i++] & 0xff);
int db = b - (colorTab[i] & 0xff);
int d = dr * dr + dg * dg + db * db;
int index = i / 3;
if (usedEntry[index] && (d < dmin))
{
dmin = d;
minpos = index;
}
i++;
}
return minpos;
}
/**
* Extracts image pixels into byte array "pixels"
*/
protected void getImagePixels()
{
int w = image.getWidth();
int h = image.getHeight();
int type = image.getType();
if ((w != width) || (h != height) || (type != BufferedImage.TYPE_3BYTE_BGR))
{
// create new image with right size/format
BufferedImage temp = new BufferedImage(width, height, BufferedImage.TYPE_3BYTE_BGR);
Graphics2D g = temp.createGraphics();
g.drawImage(image, 0, 0, null);
image = temp;
}
pixels = ((DataBufferByte) image.getRaster().getDataBuffer()).getData();
}
/**
* Writes Graphic Control Extension
*/
protected void writeGraphicCtrlExt() throws IOException
{
out.write(0x21); // extension introducer
out.write(0xf9); // GCE label
out.write(4); // data block size
int transp, disp;
if (transparent == null)
{
transp = 0;
disp = 0; // dispose = no action
}
else
{
transp = 1;
disp = 2; // force clear if using transparent color
}
if (dispose >= 0)
{
disp = dispose & 7; // user override
}
disp <<= 2;
// packed fields
out.write(0 | // 1:3 reserved
disp | // 4:6 disposal
0 | // 7 user input - 0 = none
transp); // 8 transparency flag
writeShort(delay); // delay x 1/100 sec
out.write(transIndex); // transparent color index
out.write(0); // block terminator
}
/**
* Writes Image Descriptor
*/
protected void writeImageDesc() throws IOException
{
out.write(0x2c); // image separator
writeShort(0); // image position x,y = 0,0
writeShort(0);
writeShort(width); // image size
writeShort(height);
// packed fields
if (firstFrame)
{
// no LCT - GCT is used for first (or only) frame
out.write(0);
}
else
{
// specify normal LCT
out.write(0x80 | // 1 local color table 1=yes
0 | // 2 interlace - 0=no
0 | // 3 sorted - 0=no
0 | // 4-5 reserved
palSize); // 6-8 size of color table
}
}
/**
* Writes Logical Screen Descriptor
*/
protected void writeLSD() throws IOException
{
// logical screen size
writeShort(width);
writeShort(height);
// packed fields
out.write((0x80 | // 1 : global color table flag = 1 (gct used)
0x70 | // 2-4 : color resolution = 7
0x00 | // 5 : gct sort flag = 0
palSize)); // 6-8 : gct size
out.write(0); // background color index
out.write(0); // pixel aspect ratio - assume 1:1
}
/**
* Writes Netscape application extension to define repeat count.
*/
protected void writeNetscapeExt() throws IOException
{
out.write(0x21); // extension introducer
out.write(0xff); // app extension label
out.write(11); // block size
writeString("NETSCAPE" + "2.0"); // app id + auth code
out.write(3); // sub-block size
out.write(1); // loop sub-block id
writeShort(repeat); // loop count (extra iterations, 0=repeat forever)
out.write(0); // block terminator
}
/**
* Writes color table
*/
protected void writePalette() throws IOException
{
out.write(colorTab, 0, colorTab.length);
int n = (3 * 256) - colorTab.length;
for (int i = 0; i < n; i++)
{
out.write(0);
}
}
/**
* Encodes and writes pixel data
*/
protected void writePixels() throws IOException
{
LZWEncoder encoder = new LZWEncoder(width, height, indexedPixels, colorDepth);
encoder.encode(out);
}
/**
* Write 16-bit value to output stream, LSB first
*/
protected void writeShort(int value) throws IOException
{
out.write(value & 0xff);
out.write((value >> 8) & 0xff);
}
/**
* Writes string to output stream
*/
protected void writeString(String s) throws IOException
{
for (int i = 0; i < s.length(); i++)
{
out.write((byte) s.charAt(i));
}
}
}
/*
* NeuQuant Neural-Net Quantization Algorithm ------------------------------------------ Copyright
* (c) 1994 Anthony Dekker NEUQUANT Neural-Net quantization algorithm by Anthony Dekker, 1994. See
* "Kohonen neural networks for optimal colour quantization" in "Network: Computation in Neural
* Systems" Vol. 5 (1994) pp 351-367. for a discussion of the algorithm. Any party obtaining a copy
* of these files from the author, directly or indirectly, is granted, free of charge, a full and
* unrestricted irrevocable, world-wide, paid up, royalty-free, nonexclusive right and license to
* deal in this software and documentation files (the "Software"), including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
* Software, and to permit persons who receive copies from any such party to do so, with the only
* requirement being that this copyright notice remain intact.
*/
// Ported to Java 12/00 K Weiner
class NeuQuant
{
protected static final int netsize = 256; /*
* number of colours used
*/
/* four primes near 500 - assume no image has a length so large */
/* that it is divisible by all four primes */
protected static final int prime1 = 499;
protected static final int prime2 = 491;
protected static final int prime3 = 487;
protected static final int prime4 = 503;
protected static final int minpicturebytes = (3 * prime4);
/* minimum size for input image */
/*
* Program Skeleton ---------------- [select samplefac in range 1..30] [read image from input
* file] pic = (unsigned char*) malloc(3*width*height); initnet(pic,3*width*height,samplefac);
* learn(); unbiasnet(); [write output image header, using writecolourmap(f)] inxbuild(); write
* output image using inxsearch(b,g,r)
*/
/*
* Network Definitions -------------------
*/
protected static final int maxnetpos = (netsize - 1);
protected static final int netbiasshift = 4; /*
* bias for colour values
*/
protected static final int ncycles = 100; /*
* no. of learning cycles
*/
/* defs for freq and bias */
protected static final int intbiasshift = 16; /*
* bias for fractions
*/
protected static final int intbias = (((int) 1) << intbiasshift);
protected static final int gammashift = 10; /*
* gamma = 1024
*/
protected static final int gamma = (((int) 1) << gammashift);
protected static final int betashift = 10;
protected static final int beta = (intbias >> betashift); /*
* beta = 1/1024
*/
protected static final int betagamma = (intbias << (gammashift - betashift));
/* defs for decreasing radius factor */
protected static final int initrad = (netsize >> 3); /*
* for 256 cols, radius starts
*/
protected static final int radiusbiasshift = 6; /*
* at 32.0 biased by 6 bits
*/
protected static final int radiusbias = (((int) 1) << radiusbiasshift);
protected static final int initradius = (initrad * radiusbias); /*
* and decreases by a
*/
protected static final int radiusdec = 30; /*
* factor of 1/30 each cycle
*/
/* defs for decreasing alpha factor */
protected static final int alphabiasshift = 10; /*
* alpha starts at 1.0
*/
protected static final int initalpha = (((int) 1) << alphabiasshift);
protected int alphadec; /*
* biased by 10 bits
*/
/* radbias and alpharadbias used for radpower calculation */
protected static final int radbiasshift = 8;
protected static final int radbias = (((int) 1) << radbiasshift);
protected static final int alpharadbshift = (alphabiasshift + radbiasshift);
protected static final int alpharadbias = (((int) 1) << alpharadbshift);
/*
* Types and Global Variables --------------------------
*/
protected byte[] thepicture; /*
* the input image itself
*/
protected int lengthcount; /*
* lengthcount = H*W*3
*/
protected int samplefac; /*
* sampling factor 1..30
*/
// typedef int pixel[4]; /* BGRc */
protected int[][] network; /*
* the network itself - [netsize][4]
*/
protected int[] netindex = new int[256];
/* for network lookup - really 256 */
protected int[] bias = new int[netsize];
/* bias and freq arrays for learning */
protected int[] freq = new int[netsize];
protected int[] radpower = new int[initrad];
/* radpower for precomputation */
/*
* Initialise network in range (0,0,0) to (255,255,255) and set parameters
* -----------------------------------------------------------------------
*/
public NeuQuant(byte[] thepic, int len, int sample)
{
int i;
int[] p;
thepicture = thepic;
lengthcount = len;
samplefac = sample;
network = new int[netsize][];
for (i = 0; i < netsize; i++)
{
network[i] = new int[4];
p = network[i];
p[0] = p[1] = p[2] = (i << (netbiasshift + 8)) / netsize;
freq[i] = intbias / netsize; /* 1/netsize */
bias[i] = 0;
}
}
public byte[] colorMap()
{
byte[] map = new byte[3 * netsize];
int[] index = new int[netsize];
for (int i = 0; i < netsize; i++)
index[network[i][3]] = i;
int k = 0;
for (int i = 0; i < netsize; i++)
{
int j = index[i];
map[k++] = (byte) (network[j][0]);
map[k++] = (byte) (network[j][1]);
map[k++] = (byte) (network[j][2]);
}
return map;
}
/*
* Insertion sort of network and building of netindex[0..255] (to do after unbias)
* -------------------------------------------------------------------------------
*/
public void inxbuild()
{
int i, j, smallpos, smallval;
int[] p;
int[] q;
int previouscol, startpos;
previouscol = 0;
startpos = 0;
for (i = 0; i < netsize; i++)
{
p = network[i];
smallpos = i;
smallval = p[1]; /* index on g */
/* find smallest in i..netsize-1 */
for (j = i + 1; j < netsize; j++)
{
q = network[j];
if (q[1] < smallval)
{ /* index on g */
smallpos = j;
smallval = q[1]; /* index on g */
}
}
q = network[smallpos];
/* swap p (i) and q (smallpos) entries */
if (i != smallpos)
{
j = q[0];
q[0] = p[0];
p[0] = j;
j = q[1];
q[1] = p[1];
p[1] = j;
j = q[2];
q[2] = p[2];
p[2] = j;
j = q[3];
q[3] = p[3];
p[3] = j;
}
/* smallval entry is now in position i */
if (smallval != previouscol)
{
netindex[previouscol] = (startpos + i) >> 1;
for (j = previouscol + 1; j < smallval; j++)
netindex[j] = i;
previouscol = smallval;
startpos = i;
}
}
netindex[previouscol] = (startpos + maxnetpos) >> 1;
for (j = previouscol + 1; j < 256; j++)
netindex[j] = maxnetpos; /* really 256 */
}
/*
* Main Learning Loop ------------------
*/
public void learn()
{
int i, j, b, g, r;
int radius, rad, alpha, step, delta, samplepixels;
byte[] p;
int pix, lim;
if (lengthcount < minpicturebytes)
samplefac = 1;
alphadec = 30 + ((samplefac - 1) / 3);
p = thepicture;
pix = 0;
lim = lengthcount;
samplepixels = lengthcount / (3 * samplefac);
delta = samplepixels / ncycles;
alpha = initalpha;
radius = initradius;
rad = radius >> radiusbiasshift;
if (rad <= 1)
rad = 0;
for (i = 0; i < rad; i++)
radpower[i] = alpha * (((rad * rad - i * i) * radbias) / (rad * rad));
// fprintf(stderr,"beginning 1D learning: initial radius=%d\n", rad);
if (lengthcount < minpicturebytes)
step = 3;
else if ((lengthcount % prime1) != 0)
step = 3 * prime1;
else
{
if ((lengthcount % prime2) != 0)
step = 3 * prime2;
else
{
if ((lengthcount % prime3) != 0)
step = 3 * prime3;
else
step = 3 * prime4;
}
}
i = 0;
while (i < samplepixels)
{
b = (p[pix + 0] & 0xff) << netbiasshift;
g = (p[pix + 1] & 0xff) << netbiasshift;
r = (p[pix + 2] & 0xff) << netbiasshift;
j = contest(b, g, r);
altersingle(alpha, j, b, g, r);
if (rad != 0)
alterneigh(rad, j, b, g, r); /* alter neighbours */
pix += step;
if (pix >= lim)
pix -= lengthcount;
i++;
if (delta == 0)
delta = 1;
if (i % delta == 0)
{
alpha -= alpha / alphadec;
radius -= radius / radiusdec;
rad = radius >> radiusbiasshift;
if (rad <= 1)
rad = 0;
for (j = 0; j < rad; j++)
radpower[j] = alpha * (((rad * rad - j * j) * radbias) / (rad * rad));
}
}
// fprintf(stderr,"finished 1D learning: final alpha=%f
// !\n",((float)alpha)/initalpha);
}
/*
* Search for BGR values 0..255 (after net is unbiased) and return colour index
* ----------------------------------------------------------------------------
*/
public int map(int b, int g, int r)
{
int i, j, dist, a, bestd;
int[] p;
int best;
bestd = 1000; /* biggest possible dist is 256*3 */
best = -1;
i = netindex[g]; /* index on g */
j = i - 1; /* start at netindex[g] and work outwards */
while ((i < netsize) || (j >= 0))
{
if (i < netsize)
{
p = network[i];
dist = p[1] - g; /* inx key */
if (dist >= bestd)
i = netsize; /* stop iter */
else
{
i++;
if (dist < 0)
dist = -dist;
a = p[0] - b;
if (a < 0)
a = -a;
dist += a;
if (dist < bestd)
{
a = p[2] - r;
if (a < 0)
a = -a;
dist += a;
if (dist < bestd)
{
bestd = dist;
best = p[3];
}
}
}
}
if (j >= 0)
{
p = network[j];
dist = g - p[1]; /* inx key - reverse dif */
if (dist >= bestd)
j = -1; /* stop iter */
else
{
j--;
if (dist < 0)
dist = -dist;
a = p[0] - b;
if (a < 0)
a = -a;
dist += a;
if (dist < bestd)
{
a = p[2] - r;
if (a < 0)
a = -a;
dist += a;
if (dist < bestd)
{
bestd = dist;
best = p[3];
}
}
}
}
}
return (best);
}
public byte[] process()
{
learn();
unbiasnet();
inxbuild();
return colorMap();
}
/*
* Unbias network to give byte values 0..255 and record position i to prepare for sort
* -----------------------------------------------------------------------------------
*/
public void unbiasnet()
{
for (int i = 0; i < netsize; i++)
{
network[i][0] >>= netbiasshift;
network[i][1] >>= netbiasshift;
network[i][2] >>= netbiasshift;
network[i][3] = i; /* record colour no */
}
}
/*
* Move adjacent neurons by precomputed alpha*(1-((i-j)^2/[r]^2)) in radpower[|i-j|]
* ---------------------------------------------------------------------------------
*/
protected void alterneigh(int rad, int i, int b, int g, int r)
{
int j, k, lo, hi, a, m;
int[] p;
lo = i - rad;
if (lo < -1)
lo = -1;
hi = i + rad;
if (hi > netsize)
hi = netsize;
j = i + 1;
k = i - 1;
m = 1;
while ((j < hi) || (k > lo))
{
a = radpower[m++];
if (j < hi)
{
p = network[j++];
try
{
p[0] -= (a * (p[0] - b)) / alpharadbias;
p[1] -= (a * (p[1] - g)) / alpharadbias;
p[2] -= (a * (p[2] - r)) / alpharadbias;
}
catch (Exception e)
{
} // prevents 1.3 miscompilation
}
if (k > lo)
{
p = network[k--];
try
{
p[0] -= (a * (p[0] - b)) / alpharadbias;
p[1] -= (a * (p[1] - g)) / alpharadbias;
p[2] -= (a * (p[2] - r)) / alpharadbias;
}
catch (Exception e)
{
}
}
}
}
/*
* Move neuron i towards biased (b,g,r) by factor alpha
* ----------------------------------------------------
*/
protected void altersingle(int alpha, int i, int b, int g, int r)
{
/* alter hit neuron */
int[] n = network[i];
n[0] -= (alpha * (n[0] - b)) / initalpha;
n[1] -= (alpha * (n[1] - g)) / initalpha;
n[2] -= (alpha * (n[2] - r)) / initalpha;
}
/*
* Search for biased BGR values ----------------------------
*/
protected int contest(int b, int g, int r)
{
/* finds closest neuron (min dist) and updates freq */
/* finds best neuron (min dist-bias) and returns position */
/* for frequently chosen neurons, freq[i] is high and bias[i] is negative */
/* bias[i] = gamma*((1/netsize)-freq[i]) */
int i, dist, a, biasdist, betafreq;
int bestpos, bestbiaspos, bestd, bestbiasd;
int[] n;
bestd = ~(((int) 1) << 31);
bestbiasd = bestd;
bestpos = -1;
bestbiaspos = bestpos;
for (i = 0; i < netsize; i++)
{
n = network[i];
dist = n[0] - b;
if (dist < 0)
dist = -dist;
a = n[1] - g;
if (a < 0)
a = -a;
dist += a;
a = n[2] - r;
if (a < 0)
a = -a;
dist += a;
if (dist < bestd)
{
bestd = dist;
bestpos = i;
}
biasdist = dist - ((bias[i]) >> (intbiasshift - netbiasshift));
if (biasdist < bestbiasd)
{
bestbiasd = biasdist;
bestbiaspos = i;
}
betafreq = (freq[i] >> betashift);
freq[i] -= betafreq;
bias[i] += (betafreq << gammashift);
}
freq[bestpos] += beta;
bias[bestpos] -= betagamma;
return (bestbiaspos);
}
}
// ==============================================================================
// Adapted from Jef Poskanzer's Java port by way of J. M. G. Elliott.
// K Weiner 12/00
class LZWEncoder
{
private static final int EOF = -1;
private int imgW, imgH;
private byte[] pixAry;
private int initCodeSize;
private int remaining;
private int curPixel;
// GIFCOMPR.C - GIF Image compression routines
//
// Lempel-Ziv compression based on 'compress'. GIF modifications by
// David Rowley (mgardi@watdcsu.waterloo.edu)
// General DEFINEs
static final int BITS = 12;
static final int HSIZE = 5003; // 80%
// occupancy
// GIF Image compression - modified 'compress'
//
// Based on: compress.c - File compression ala IEEE Computer, June 1984.
//
// By Authors: Spencer W. Thomas (decvax!harpo!utah-cs!utah-gr!thomas)
// Jim McKie (decvax!mcvax!jim)
// Steve Davies (decvax!vax135!petsd!peora!srd)
// Ken Turkowski (decvax!decwrl!turtlevax!ken)
// James A. Woods (decvax!ihnp4!ames!jaw)
// Joe Orost (decvax!vax135!petsd!joe)
int n_bits; // number of
// bits/code
int maxbits = BITS; // user
// settable
// max #
// bits/code
int maxcode; // maximum
// code,
// given
// n_bits
int maxmaxcode = 1 << BITS; // should
// NEVER
// generate
// this code
int[] htab = new int[HSIZE];
int[] codetab = new int[HSIZE];
int hsize = HSIZE; // for
// dynamic
// table
// sizing
int free_ent = 0; // first
// unused
// entry
// block compression parameters -- after all codes are used up,
// and compression rate changes, start over.
boolean clear_flg = false;
// Algorithm: use open addressing double hashing (no chaining) on the
// prefix code / next character combination. We do a variant of Knuth's
// algorithm D (vol. 3, sec. 6.4) along with G. Knott's relatively-prime
// secondary probe. Here, the modular division first probe is gives way
// to a faster exclusive-or manipulation. Also do block compression with
// an adaptive reset, whereby the code table is cleared when the compression
// ratio decreases, but after the table fills. The variable-length output
// codes are re-sized at this point, and a special CLEAR code is generated
// for the decompressor. Late addition: construct the table according to
// file size for noticeable speed improvement on small files. Please direct
// questions about this implementation to ames!jaw.
int g_init_bits;
int ClearCode;
int EOFCode;
// output
//
// Output the given code.
// Inputs:
// code: A n_bits-bit integer. If == -1, then EOF. This assumes
// that n_bits =< wordsize - 1.
// Outputs:
// Outputs code to the file.
// Assumptions:
// Chars are 8 bits long.
// Algorithm:
// Maintain a BITS character long buffer (so that 8 codes will
// fit in it exactly). Use the VAX insv instruction to insert each
// code in turn. When the buffer fills up empty it and start over.
int cur_accum = 0;
int cur_bits = 0;
int masks[] = { 0x0000, 0x0001, 0x0003, 0x0007, 0x000F, 0x001F, 0x003F, 0x007F, 0x00FF, 0x01FF,
0x03FF, 0x07FF, 0x0FFF, 0x1FFF, 0x3FFF, 0x7FFF, 0xFFFF };
// Number of characters so far in this 'packet'
int a_count;
// Define the storage for the packet accumulator
byte[] accum = new byte[256];
// ----------------------------------------------------------------------------
LZWEncoder(int width, int height, byte[] pixels, int color_depth)
{
imgW = width;
imgH = height;
pixAry = pixels;
initCodeSize = Math.max(2, color_depth);
}
// Add a character to the end of the current packet, and if it is 254
// characters, flush the packet to disk.
void char_out(byte c, OutputStream outs) throws IOException
{
accum[a_count++] = c;
if (a_count >= 254)
flush_char(outs);
}
// Clear out the hash table
// table clear for block compress
void cl_block(OutputStream outs) throws IOException
{
cl_hash(hsize);
free_ent = ClearCode + 2;
clear_flg = true;
output(ClearCode, outs);
}
// reset code table
void cl_hash(int hsize)
{
for (int i = 0; i < hsize; ++i)
htab[i] = -1;
}
void compress(int init_bits, OutputStream outs) throws IOException
{
int fcode;
int i /* = 0 */;
int c;
int ent;
int disp;
int hsize_reg;
int hshift;
// Set up the globals: g_init_bits - initial number of bits
g_init_bits = init_bits;
// Set up the necessary values
clear_flg = false;
n_bits = g_init_bits;
maxcode = MAXCODE(n_bits);
ClearCode = 1 << (init_bits - 1);
EOFCode = ClearCode + 1;
free_ent = ClearCode + 2;
a_count = 0; // clear packet
ent = nextPixel();
hshift = 0;
for (fcode = hsize; fcode < 65536; fcode *= 2)
++hshift;
hshift = 8 - hshift; // set hash code range bound
hsize_reg = hsize;
cl_hash(hsize_reg); // clear hash table
output(ClearCode, outs);
outer_loop: while ((c = nextPixel()) != EOF)
{
fcode = (c << maxbits) + ent;
i = (c << hshift) ^ ent; // xor hashing
if (htab[i] == fcode)
{
ent = codetab[i];
continue;
}
else if (htab[i] >= 0) // non-empty slot
{
disp = hsize_reg - i; // secondary hash (after G. Knott)
if (i == 0)
disp = 1;
do
{
if ((i -= disp) < 0)
i += hsize_reg;
if (htab[i] == fcode)
{
ent = codetab[i];
continue outer_loop;
}
}
while (htab[i] >= 0);
}
output(ent, outs);
ent = c;
if (free_ent < maxmaxcode)
{
codetab[i] = free_ent++; // code -> hashtable
htab[i] = fcode;
}
else
cl_block(outs);
}
// Put out the final code.
output(ent, outs);
output(EOFCode, outs);
}
// ----------------------------------------------------------------------------
void encode(OutputStream os) throws IOException
{
os.write(initCodeSize); // write "initial code size" byte
remaining = imgW * imgH; // reset navigation variables
curPixel = 0;
compress(initCodeSize + 1, os); // compress and write the pixel data
os.write(0); // write block terminator
}
// Flush the packet to disk, and reset the accumulator
void flush_char(OutputStream outs) throws IOException
{
if (a_count > 0)
{
outs.write(a_count);
outs.write(accum, 0, a_count);
a_count = 0;
}
}
final int MAXCODE(int n_bits)
{
return (1 << n_bits) - 1;
}
// ----------------------------------------------------------------------------
// Return the next pixel from the image
// ----------------------------------------------------------------------------
private int nextPixel()
{
if (remaining == 0)
return EOF;
--remaining;
byte pix = pixAry[curPixel++];
return pix & 0xff;
}
void output(int code, OutputStream outs) throws IOException
{
cur_accum &= masks[cur_bits];
if (cur_bits > 0)
cur_accum |= (code << cur_bits);
else
cur_accum = code;
cur_bits += n_bits;
while (cur_bits >= 8)
{
char_out((byte) (cur_accum & 0xff), outs);
cur_accum >>= 8;
cur_bits -= 8;
}
// If the next entry is going to be too big for the code size,
// then increase it, if possible.
if (free_ent > maxcode || clear_flg)
{
if (clear_flg)
{
maxcode = MAXCODE(n_bits = g_init_bits);
clear_flg = false;
}
else
{
++n_bits;
if (n_bits == maxbits)
maxcode = maxmaxcode;
else
maxcode = MAXCODE(n_bits);
}
}
if (code == EOFCode)
{
// At EOF, write the rest of the buffer.
while (cur_bits > 0)
{
char_out((byte) (cur_accum & 0xff), outs);
cur_accum >>= 8;
cur_bits -= 8;
}
flush_char(outs);
}
}
}von Faber » Mi 22. Dez 2010, 19:28
von Ernst » Mi 22. Dez 2010, 20:13
Chief hat geschrieben:Die Uhren laufen in S' überall gleich schnell. Sie zeigen aber an verschiedenen Orten eine unterschiedliche Zeit.
Das ist physikalisch nicht möglich weil sie zuerst auf Null gestellt wurden.
von Faber » Mi 22. Dez 2010, 20:28
Highway hat geschrieben:Tipp: Wenn man in diesem Forum auf die Grafiken einen Klick mit der linken Maustaste ausführt, dann verschwindet der Scrollbalken an der rechten Seite und das Bild wird im Forum direkt in voller Größe angezeigt.
Highway hat geschrieben:Noch eine Bitte, wenn es nicht zu viel verlangt ist. Kann man ähnlich wie in Franz Embaches Animation die Reflektion der Photonen und die "Spiegelwände" mit darstellen?
von Mordred » Mi 22. Dez 2010, 20:37
Eben zwei differente Systeme.Faber hat geschrieben:Fazit:
* Ein und dasselbe Geschehen kann nicht gleichberechtigt in dem einen oder anderen Bezugssystem beschrieben werden. Die Beschreibungen liefern unterschiedliches Geschehen.
Find ich auch, (auch wenn das unter den Cracks hier nicht viel bedeuten mag)Faber hat geschrieben: * Die Lorentztransformation ist nicht geeignet, das Relativitätsprinzip mit dem Prinzip der konstanten und isotropen Lichtausbreitung zu vereinen.
Mitglieder in diesem Forum: 0 Mitglieder und 13 Gäste