Image processing - Revision history

Polas: 16 revisions imported

2019-04-15T15:44:45Z

16 revisions imported

Polas: /* Download */

2013-05-03T12:14:49Z

‎Download

Polas: /* Source Code */

2013-05-03T12:07:15Z

‎Source Code

Polas: /* Download */

2013-01-18T18:21:58Z

‎Download

Polas: /* Source Code */

2013-01-18T18:15:15Z

‎Source Code

Polas: /* Source Code */

2013-01-18T18:14:55Z

‎Source Code

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Polas at 14:21, 14 January 2013

2013-01-14T14:21:18Z

Polas at 11:36, 3 July 2010

2010-07-03T11:36:49Z

Polas: /* Performance */

2010-01-11T18:02:15Z

‎Performance

Polas at 18:01, 11 January 2010

2010-01-11T18:01:38Z

@@ Line 259: / Line 259: @@
 You can download the entire Image processing package [http://www.mesham.com/downloads/fftimage.zip here] there is also a legacy version for Mesham 0.5 [http://www.mesham.com/downloads/fftimage-0.5.zip here]
-There is also a simplified FFT code available [http://www.mesham.com/downloads/fft.mesh here] which the imaging processing was based upon.
+There is also a simplified FFT code available [http://www.mesham.com/downloads/fft.mesh here] which the imaging processing was based upon and a version which can be run with any number of processes decided at runtime [http://www.mesham.com/downloads/fft-dynamic.mesh here].
 [[Category:Example Codes]]

@@ Line 23: / Line 23: @@
   var n:=256; // image size
   var m:=4; // number of processors
+  var filterThreshold:=10; // filtering threshold for high and low pass filters
   function void main() {
@@ Line 100: / Line 76: @@
         writefile("newclown.ppm", a);
      };
   };
@@ Line 118: / Line 118: @@
         var j;
         for j from 0 to n - 1 {
            data[i][j].r:=data[i][j].r / (n * n) ;
-           var xnumy:Double;
+           data[i][j].i:=-(data[i][j].i / (n * n));
         };
      };
@@ Line 142: / Line 139: @@
      var f0:Double;
      var f1:Double;
      var increvec;
      for increvec from 2 to n {
@@ Line 156: / Line 151: @@
               f1:=(data[i0 + i1 + (increvec / 2)].r * sinusoid[i0 << i2].i)+ (data[i0 + i1 + (increvec / 2)].i * sinusoid[i0 << i2].r);
-              f2:=data[i0 + i1].r;
+              data[i0 + i1 + (increvec / 2)].r:= data[i0 + i1].r- f0;
-             f3:=data[i0 + i1].i;
+              data[i0 + i1 + (increvec / 2)].i:=data[i0 + i1].i - f1;
-              data[i0 + i1 + (increvec / 2)].r:= f2- f0;
+              data[i0 + i1].r := data[i0 + i1].r + f0;
-             data[i0 + i1 + (increvec / 2)].i:=f3 - f1;
+              data[i0 + i1].i := data[i0 + i1].i + f1;
               i1:=(i1 + increvec) - 1;
@@ Line 210: / Line 203: @@
   function Int lowpass(var i:Int, var j:Int) {
      var val:=sqr(i) + sqr(j);
-     if (sqrt(val) < 225) return 1;
+     if (sqrt(val) < filterThreshold) return 1;
      return 0;
   };
@@ Line 216: / Line 209: @@
   function Int highpass(var i:Int, var j:Int) {
      var val:=sqr(i) + sqr(j);
-     if (sqrt(val) > 190) return 1;
+     if (sqrt(val) > (255-filterThreshold)) return 1;
      return 0;
   };
@@ Line 225: / Line 218: @@
         var j;
         for j from 0 to n - 1 {
-           data[i][j].r:=data[i][j].r * lowpass(i,j);
+           data[i][j].r:=data[i][j].r * lowpass(i,j) * highpass(i,j);
-           data[i][j].i:=data[i][j].i * lowpass(i,j);
+           data[i][j].i:=data[i][j].i * lowpass(i,j) * highpass(i,j);
         };
      };

@@ Line 264: / Line 264: @@
 == Download ==
-You can download the entire Image processing package [http://www.mesham.com/downloads/fftimage.zip here]
+You can download the entire Image processing package [http://www.mesham.com/downloads/fftimage.zip here] there is also a legacy version for Mesham 0.5 [http://www.mesham.com/downloads/fftimage-0.5.zip here]
 [[Category:Example Codes]]

@@ Line 79: / Line 79: @@
         invert(a);
      };
-−
      s:=a;
      par p from 0 to m - 1 {

← Older revision		Revision as of 14:21, 14 January 2013
Line 265:		Line 265:

	You can download the entire Image processing package [http://www.mesham.com/downloads/fftimage.zip here]		You can download the entire Image processing package [http://www.mesham.com/downloads/fftimage.zip here]
		+
		+	[[Category:Example Codes]]

← Older revision	Revision as of 15:44, 15 April 2019
(No difference)

← Older revision		Revision as of 11:36, 3 July 2010
Line 1:		Line 1:
		+	<metadesc>Mesham is a type oriented programming language allowing the writing of high performance parallel codes which are efficient yet simple to write and maintain</metadesc>
	== Overview ==		== Overview ==

@@ Line 9: / Line 9: @@
 Performance of the Fast Fourier Transform (FFT) has been evaluated on a super computer cluster. Two different experiments were performed, one with an image size of 128MB and the other with an image size of 2GB. Evaluations were performed against the Fastest Fourier Transformation in the West (FFTW) and a book example for 128MB. As can be seen with an uneven distribution of data (10 and 20 processors) FFTW experiences severe slowdowns whereas the Mesham version does not (the compiler will optimise the code in this case to avoid any slow down.)
-[[Image:128.jpg|500px|right|Fast Fourier Transformation with 128MB of data]]
+[[Image:128.jpg|500px|left|Fast Fourier Transformation with 128MB of data]]
-[[Image:2gb.jpg|500px|left|Fast Fourier Transformation with 2GB of data]]
+[[Image:2gb.jpg|500px|right|Fast Fourier Transformation with 2GB of data]]
 <br style="clear: both" />