--- /dev/null
+#! /usr/bin/env octave
+cv;
+highgui;
+
+file_name = "../c/baboon.jpg";
+
+global Gbrightness;
+global Gcontrast;
+global hist_size;
+global ranges;
+global src_image;
+global dst_image;
+global hist_image;
+global hist;
+global lut;
+
+_brightness = 100;
+_contrast = 100;
+Gbrightness = 100;
+Gcontrast = 100;
+
+hist_size = 64;
+range_0={0,256};
+ranges = { range_0 };
+src_image=[];
+dst_image=[];
+hist_image=[];
+hist=[];
+lut=cvCreateMat(256,1,CV_8U);
+
+## brightness/contrast callback function
+function update_brightness( val )
+ global Gbrightness # global tag is required, or we get UnboundLocalError
+ Gbrightness = val;
+ update_brightcont( );
+endfunction
+
+function update_contrast( val )
+ global Gcontrast; # global tag is required, or we get UnboundLocalError
+ Gcontrast = val;
+ update_brightcont( );
+endfunction
+
+function update_brightcont()
+ global Gbrightness;
+ global Gcontrast;
+ global hist_size;
+ global ranges;
+ global src_image;
+ global dst_image;
+ global hist_image;
+ global hist;
+ global lut;
+ global cvCalcHist; # use cv namespace for these instead
+ global cvZero;
+ global cvScale;
+
+ brightness = Gbrightness - 100;
+ contrast = Gcontrast - 100;
+ max_value = 0;
+
+ ## The algorithm is by Werner D. Streidt
+ ## (http://visca.com/ffactory/archives/5-99/msg00021.html)
+ if( contrast > 0 )
+ delta = 127.*contrast/100;
+ a = 255./(255. - delta*2);
+ b = a*(brightness - delta);
+ else
+ delta = -128.*contrast/100;
+ a = (256.-delta*2)/255.;
+ b = a*brightness + delta;
+ endif
+
+ for i=0:256-1,
+ v = cvRound(a*i + b);
+ if( v < 0 )
+ v = 0;
+ endif
+ if( v > 255 )
+ v = 255;
+ endif
+ lut(i) = v;
+ endfor
+
+ cvLUT( src_image, dst_image, lut );
+ cvShowImage( "image", dst_image );
+
+ cvCalcHist( dst_image, hist, 0, [] );
+ cvZero( dst_image );
+ [min_value, max_value] = cvGetMinMaxHistValue( hist );
+ cvScale( hist.bins, hist.bins, double(hist_image.height)/max_value, 0 );
+ ##cvNormalizeHist( hist, 1000 );
+
+ cvSet( hist_image, cvScalarAll(255));
+ bin_w = cvRound(double(hist_image.width)/hist_size);
+
+ for i=0:hist_size-1,
+ cvRectangle( hist_image, cvPoint(i*bin_w, hist_image.height), cvPoint((i+1)*bin_w, hist_image.height - cvRound(cvGetReal1D(hist.bins,i))), cvScalarAll(0), -1, 8, 0 );
+ endfor
+
+ cvShowImage( "histogram", hist_image );
+endfunction
+
+
+## Load the source image. HighGUI use.
+if size(argv, 1)>1
+ file_name = argv(){1}
+endif
+
+src_image = cvLoadImage( file_name, 0 );
+
+if (!swig_this(src_image))
+ printf("Image was not loaded.\n");
+ exit(-1);
+endif
+
+
+dst_image = cvCloneImage(src_image);
+hist_image = cvCreateImage(cvSize(320,200), 8, 1);
+hist = cvCreateHist({hist_size}, CV_HIST_ARRAY, ranges, 1);
+
+cvNamedWindow("image", 0);
+cvNamedWindow("histogram", 0);
+
+cvCreateTrackbar("brightness", "image", _brightness, 200, @update_brightness);
+cvCreateTrackbar("contrast", "image", _contrast, 200, @update_contrast);
+
+update_brightcont();
+cvWaitKey(0);