houghiris.h

barcode readers [ from Image]

//
// Routines for iris detection using hough transform.
// FindPupilL:
//    Find the pupil, which is a dark circular region bordered by a lighter region near the center
//    of the image.
// FindScleraL:
//     Find the sclera boundary, which is a light circular region surrounding a darker region, centered on the
//     given pupil center.
//
// Copyright (C) 2003, 2006 by Jon A. Webb (Contact via GMail; username is jonawebb)
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
// 
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.
// 
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
//

#ifndef HoughIris_h
#define HoughIris_h

#include "Image.h"
#include "PipelineStage.h"

#include <e32cons.h>

namespace Algorithm
{
	class CHoughIris: public CBase
	{
		// Lifecycle
	public:
		IMPORT_C static CHoughIris* NewL();
		~CHoughIris(void);
	private:
		CHoughIris();

        // Operations
    public:

        // FindPupilL
        // Find the pupil, which is a dark circular region bordered by a lighter region near the center
        // of the image.
        // Parameters:
        // In:
        //   pImage = color input image. Converted to gray before other processing
        //   nReduce = image reduction factor (horizontal & vertical) before other processing
        //   nStretchLow = image grayvalues are stretched and all values > than this are set to 255
        //   nSmooth = kernel width and height for smoothing applied to image before edge detection
        //   nThreshLow, nThreshHi = thresholds for hysterisis edge detection
        //   nRadiusMin, nRadiusMax = minimum and maximum radii of pupil
        // Out:
        //   returned value is true if it appears iris was detected, false otherwise
        //   cx, cy = pupil center
        //   r = pupil radius
        //   
		IMPORT_C bool FindPupilL(int& cx, int& cy, int& r, Core::CImage pImage,
            int nReduce = 4, int nStretchLow = 64, int nSmooth = 7, int nThreshLow = 200, int nThreshHi = 250,
            int nRadiusMin = 7, int nRadiusMax = 15);

        // FindScleraL
        // Find the sclera boundary, which is a light circular region surrounding a darker region, centered on the
        // given pupil center.
        // Parameters:
        // In:
        //   cx, cy - the pupil center
        //   pImage = color input image. Converted to gray before other processing
        //   nReduce = image reduction factor (horizontal & vertical) before other processing
        //   nStretchHi = image grayvalues are stretched and all values < than this are set to 0
        //   nSmooth = kernel width and height for smoothing applied to image before edge detection
        //   nThreshLow, nThreshHi = thresholds for hysterisis edge detection
        //   nRadiusMin, nRadiusMax = minimum and maximum radii of sclera
        // Out:
        //   returned value is true if it appears sclera was detected, false otherwise
        //   r = sclera radius
        //   
		IMPORT_C bool FindScleraL(int cx, int cy, int& r, Core::CImage pImage,
            int nReduce = 4, int nStretchHi = 192, int nSmooth = 7, int nThreshLow = 200, int nThreshHi = 250,
            int nRadiusMin = 20, int nRadiusMax = 200);

    private:
        // Create a histogram that stretches all the low values (up to nStretchLow) up, and assigns all
        // higher values the value 255. This is used with edge detection to detect an edge between a dark
        // region and the rest of the image.
        void HistStretchLow(float* pHist, int nStretchLow);
        // Create a histogram that stretches the high values (down to nStretchHi) down, and assigns all
        // lower values the value 0.
        void HistStretchHi(float* pHist, int nStretchHi);
    };
};

#endif // HoughIris_h