/* 
 * PROJECT: NyARToolkit
 * --------------------------------------------------------------------------------
 * This work is based on the original ARToolKit developed by
 *   Hirokazu Kato
 *   Mark Billinghurst
 *   HITLab, University of Washington, Seattle
 * http://www.hitl.washington.edu/artoolkit/
 *
 * The NyARToolkit is Java version ARToolkit class library.
 * Copyright (C)2008 R.Iizuka
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * 
 * This program 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 General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this framework; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 * 
 * For further information please contact.
 *	http://nyatla.jp/nyatoolkit/
 *	<airmail(at)ebony.plala.or.jp>
 * 
 */
package jp.nyatla.nyartoolkit.core2.rasteranalyzer.threshold;

import jp.nyatla.nyartoolkit.NyARException;
import jp.nyatla.nyartoolkit.core.raster.*;
import jp.nyatla.nyartoolkit.core.rasterreader.INyARBufferReader;
import jp.nyatla.nyartoolkit.core.types.*;

/**
 * 微分ヒストグラム法による閾値検出
 * 
 */
public class NyARRasterThresholdAnalyzer_DiffHistgram implements INyARRasterThresholdAnalyzer
{
	private int _threshold;

	public NyARRasterThresholdAnalyzer_DiffHistgram()
	{
	}

	private int createHistgram(int[] in_buf,NyARIntSize i_size, int[] o_histgram) throws NyARException
	{
		int[][] fil1={
				{-1,-2,-1},
				{ 0, 0, 0},
				{ 1, 2, 1}};

		// ヒストグラムを作成
		for (int i = 0; i < 256; i++) {
			o_histgram[i] = 0;
		}
		int sam;
		int sam1,sam2;
		for (int y = 1; y < i_size.h-1; y++) {
			for (int x = 1; x < i_size.w-1; x++) {
				int v = in_buf[y* i_size.w+x];
				sam1=sam2=0;
				for(int yy=0;yy<3;yy++){
					for(int xx=0;xx<3;xx++){
						int v2=in_buf[(y+yy-1)* i_size.w+(x+xx-1)];
						sam1+=v2*fil1[xx][yy];
						sam2+=v2*fil1[yy][xx];
					}					
				}
				sam=sam1*sam1+sam2*sam2;
				o_histgram[v]+=sam;
			}
		}
		int th=0;
		int max=o_histgram[0];
		for(int i=1;i<256;i++){
			if(max<o_histgram[i]){
				th=i;
				max=o_histgram[i];
			}
		}
		return th;
	}

	public void analyzeRaster(INyARRaster i_input) throws NyARException
	{
		final INyARBufferReader buffer_reader=i_input.getBufferReader();	
		assert (buffer_reader.isEqualBufferType(INyARBufferReader.BUFFERFORMAT_INT1D_GLAY_8));
		int[] histgram = new int[256];
		this._threshold = createHistgram((int[])buffer_reader.getBuffer(),i_input.getSize(), histgram);
	}

	/**
	 * デバック用の関数です。 ヒストグラムをラスタに書き出します。
	 * 
	 * @param i_output
	 * 書き出し先のラスタオブジェクト 256ピクセル以上の幅があること。
	 */
	public void debugDrawHistgramMap(INyARRaster i_input, INyARRaster i_output) throws NyARException
	{
		INyARBufferReader in_buffer_reader=i_input.getBufferReader();	
		INyARBufferReader out_buffer_reader=i_output.getBufferReader();	
		assert (in_buffer_reader.isEqualBufferType(INyARBufferReader.BUFFERFORMAT_INT1D_GLAY_8));
		assert (out_buffer_reader.isEqualBufferType(INyARBufferReader.BUFFERFORMAT_INT1D_GLAY_8));
		NyARIntSize size = i_output.getSize();

		int[] out_buf = (int[]) out_buffer_reader.getBuffer();
		// 0で塗りつぶし
		for (int y = 0; y < size.h; y++) {
			for (int x = 0; x < size.w; x++) {
				out_buf[y* size.w+x] = 0;
			}
		}
		// ヒストグラムを計算
		int[] histgram = new int[256];
		int threshold = createHistgram((int[])in_buffer_reader.getBuffer(),i_input.getSize(), histgram);

		// ヒストグラムの最大値を出す
		int max_v = 0;
		for (int i = 0; i < 255; i++) {
			if (max_v < histgram[i]) {
				max_v = histgram[i];
			}
		}
		// 目盛り
		for (int i = 0; i < size.h; i++) {
			out_buf[i* size.w+0] = 128;
			out_buf[i* size.w+128] = 128;
			out_buf[i* size.w+255] = 128;
		}
		// スケーリングしながら描画
		for (int i = 0; i < 255; i++) {
			out_buf[(histgram[i] * (size.h - 1) / max_v)* size.w+i] = 255;
		}
		// 値
		for (int i = 0; i < size.h; i++) {
			out_buf[i* size.w+threshold] = 255;
		}
		return;
	}

	public int getThreshold()
	{
		return this._threshold;
	}
}
