implementng mdct/imdct

src/main/java/DttRad2.java

@@ -28,52 +28,310 @@
  */
 
 public class DttRad2 {
-	int N = 8;
-	double [][][] CII;
-	double [][][] CIV;
-	double [][] CN1; 
-	double [][] SN1; 
-//	double [][] C_N1M1; 
-//	double [][] S_N1M1; 
+	int N = 0;
+	double [][][] CII=null;
+	double [][][] CIV=null;
+	double [][][] SIV=null;
+	double [][] CN1=null; 
+	double [][] SN1=null; 
 	double      COSPI_1_8_SQRT2 = Math.cos(Math.PI/8)*Math.sqrt(2.0);
 	double      COSPI_3_8_SQRT2 = Math.cos(3*Math.PI/8)*Math.sqrt(2.0);
 	double sqrt2 = Math.sqrt(2.0);
 	double sqrt1_2 = 1/sqrt2;
+	double [] hwindow = null; // half window
+	
 	public DttRad2 (int maxN){ // n - maximal
-		N=maxN;
-		CII = null; // only needed for direct transforms. Assign when first used
-		CIV = null; // same
+		setup_arrays(maxN); // always setup arrays for fast calculations
+	}
+
+	public double [] dct_ii(double[] x){
+		if (x.length > N){
+			N = x.length;
+		}
+		double [] y=  _dctii_recurs(x);
+		double scale = 1.0/Math.sqrt(x.length);
+		for (int i = 0; i < y.length ; i++) y[i] *= scale;
+		return y;
+	}
+
+	public double [] dct_iv(double[] x){
+		double [] y=  _dctiv_recurs(x);
+		double scale = 1.0/Math.sqrt(x.length);
+		for (int i = 0; i < y.length ; i++) y[i] *= scale;
+		return y;
+	}
+	
+	public double [] dst_iv(double[] x){
+		double [] xr= new double[x.length];
+		int j= x.length-1;
+		for (int i=0; i < x.length;i++) xr[i] = x[j--];		
+		double [] y=  _dctiv_recurs(x);
+		double scale = 1.0/Math.sqrt(x.length);
+		for (int i = 0; i < y.length ; i++) {
+			y[i] *= scale;
+			scale = -scale; 
+		}
+		return y;
+	}
+	
+	public double [] mdct_fold (double [] x ) { // x is 2n long
+		int n = x.length/2;
+		int n1 = n/2;
+		int n3 = n+n1;
+		double [] x1 = new double [n];
+		for (int i=0; i<n1; i++){
+			x1[i]=    -hwindow[n1 + i]* x[n3 -1 -i] - hwindow[n1 - i -1] * x[n3     + i]; 
+			x1[i+n1]=  hwindow[     i]* x[       i] - hwindow[n  - i -1] * x[n  - 1 - i]; 
+		}
+		return x1;
+	}
 
-		CN1 = new double[ilog2(N)-1][];
-		SN1 = new double[ilog2(N)-1][];
-//		C_N1M1 = new double[ilog2(N)-1][];
-//		S_N1M1 = new double[ilog2(N)-1][];
+	public double [] mdct_unfold (double [] x) { // x is 2n long
+		int n = x.length;
+		int n1 = n/2;
+		int n3 = n+n1;
+		double [] x1 = new double [2*n];
+		for (int i=0; i<n1; i++){
+			x1[i]=           x[n1+i];
+			x1[n - i - 1] =  x1[i]; 
+			x1[n3 + i]=     -x[i];
+			x1[n1 - i - 1] =-x1[i]; 
+		}
+		return x1;
+	}
+	
+	
+	
+	public double [] mdct_2d(double [] x){
+		return mdct_2d(x, 0, 1 << (ilog2(x.length/4)/2)); 
+	}
+
+	public double [] mdct_2d(double [] x, int mode){
+		return mdct_2d(x, mode, 1 << (ilog2(x.length/4)/2)); 
+	}
+
+	public double [] mdct_2d (double [] x, int mode, int n) { // x is 2n*2n long
+//		int n = 1 << (ilog2(x.length/4)/2);
+		int n2 = 2*n;
+		double [] transp = new double [2*n*n];
+		double [] y =      new double [n*n];
+		double [] line2 = new double[n*2];
+		double [] line = new double[n*2];
+		// first (horizontal) pass
+		for (int i = 0; i < n2; i++){
+			System.arraycopy(x, n2*i, line2, 0, n2);
+			line = mdct_fold(line2);
+			line = ((mode & 1)!=0)? dst_iv(line):dct_iv(line);
+			for (int j=0; j < n;j++) transp[j*n2+i] =line[j]; // transpose 
+		}
+		// second (vertical) pass
+		for (int i = 0; i < n2; i++){
+			System.arraycopy(transp, n2*i, line2, 0, n2);
+			line = mdct_fold(line2);
+			line = ((mode & 2)!=0)? dst_iv(line):dct_iv(line);
+			System.arraycopy(line, 0, y, n*i, n);
+		}
+		return y;
+	}
+
+	public double [] imdct_2d(double [] x){
+		return imdct_2d(x, 1 << (ilog2(x.length)/2)); 
+	}
+
+	public double [] imdct_2d (double [] x, int n) { // x is n*n long
+		int n2 = 2*n;
+		double [] transp = new double [2*n*n];
+		double [] y =      new double [4*n*n];
+		double [] line2 = new double[n*2];
+		double [] line = new double[n*2];
+		// first (horizontal) pass
+		for (int i = 0; i < n2; i++){
+			System.arraycopy(x, n*i, line, 0, n);
+			line = dct_iv(line);
+			line2 = mdct_unfold(line);
+			for (int j=0; j < n2;j++) transp[j*n+i] =line2[j]; // transpose 
+		}
+		// second (vertical) pass
+		for (int i = 0; i < n2; i++){
+			System.arraycopy(transp, n*i, line, 0, n);
+			line = dct_iv(line);
+			line2 = mdct_unfold(line);
+			System.arraycopy(line2, 0, y, n2*i, n2);
+		}
+		return y;
+	}
+	
+	
+	public double [] dttt_iv(double [] x){
+		return dttt_iv(x, 0, 1 << (ilog2(x.length)/2)); 
+	}
+
+	public double [] dttt_iv(double [] x, int mode){
+		return dttt_iv(x, mode, 1 << (ilog2(x.length)/2)); 
+	}
+	public double [] dttt_iv(double [] x, int mode, int n){ // mode 0 - dct,dct 1:dst,dct, 2: dct, dst, 3: dst,dst
+		double [] y = new double [n*n];
+		double [] line = new double[n];
+		// first (horizontal) pass
+		for (int i = 0; i<n; i++){
+			System.arraycopy(x, n*i, line, 0, n);
+			line = ((mode & 1)!=0)? dst_iv(line):dct_iv(line);
+			for (int j=0; j < n;j++) y[j*n+i] =line[j]; // transpose 
+		}
+		// second (vertical) pass
+		for (int i = 0; i<n; i++){
+			System.arraycopy(y, n*i, line, 0, n);
+			line = ((mode & 2)!=0)? dst_iv(line):dct_iv(line);
+			System.arraycopy(line, 0, y, n*i, n);
+		}
+		return y;
+	}
+	
+	public void set_window(){
+		set_window(0);
+	}
+	public void set_window(int mode){
+		set_window(mode, N);
+	}
+	public void set_window(int mode, int len){
+		hwindow = new double[len];
+		double f = Math.PI/(2.0*len);
+
+		if (mode ==0){
+			for (int i = 0; i < len; i++ ) hwindow[i] = Math.sin(f*(i+0.5));
+		} else { // add more types?
+			double s;
+			for (int i = 0; i < len; i++ ) {
+				s = Math.sin(f*(i+0.5));
+				hwindow[i] = Math.sin(Math.PI*s*s);
+			}
+		}
+	}
+	// Convert 2nx2n overlapping tile to n*n for dct-iv
+	public double [] fold_tile(double [] x) { // x should be 2n*2n
+		return fold_tile(x, 1 << (ilog2(x.length/4)/2));
+	}
+	public double [] fold_tile(double [] x, int n) { // x should be 2n*2n
+		double [] y = new double [n*n];
+		for (int i = 0; i<y.length;i++) y[i] = 0;
+		int n1 = n/2;
+		int n2 = 2*n;
+		for (int tile_y_v=0; tile_y_v<2; tile_y_v++){     // 2 rows of y tiles
+			for (int tile_y_h=0; tile_y_h<2; tile_y_h++){ // 2 columns of y tiles
+				int start_y_addr = n*n1*tile_y_v + n1*tile_y_h; //atart address in the aoutput array
+				int start_x_tl_addr = (2*n*n) * (1 - tile_y_v) + n * (1 - tile_y_h); // address of the top left corner of a group of 4 tiles 
+				for (int tile_x_v=0; tile_x_v<2; tile_x_v++){     // 2 rows of x tiles (contributing to the same y tile)
+					for (int tile_x_h=0; tile_x_h<2; tile_x_h++){ // 2 columns of x tiles (contributing to the same y tile)
+						int dir_x = ((tile_y_h ^ tile_x_h) !=0)? 1 : -1;
+						int dir_y = ((tile_y_v ^ tile_x_v) !=0)? 1 : -1;
+						int start_x_addr =  start_x_tl_addr +
+								            tile_x_v * n *n + // 2n * n/2
+								            tile_x_h * n1 +
+								            ((dir_y < 0)?(n1-1)*2*n : 0)+
+								            ((dir_x < 0)?(n1-1) : 0);
+						int dir_window_vert =  (tile_x_v > 0)? -1 : +1; // same for any tile_y_*
+						int dir_window_hor =   (tile_x_h > 0)? -1 : +1;
+						int start_window_vert =  (tile_y_v > 0)? ((tile_x_v > 0)? n-1: 0 ):((tile_x_v > 0)? n1-1: n1);
+						int start_window_hor =   (tile_y_h > 0)? ((tile_x_h > 0)? n-1: 0 ):((tile_x_h > 0)? n1-1: n1);
+						
+						for (int i = 0; i < n1; i++){             // n1 rows in each y tile
+							for (int j = 0; j < n1; j++){         // n1 columns in each y tile
+								y[start_y_addr+ n*i+j] += hwindow[start_window_vert + dir_window_vert * i] *
+														  hwindow[start_window_hor +  dir_window_hor * j] *
+														  x[start_x_addr + n2 * dir_y * i + dir_x * j];
+							}
+						}
+					}
+				}
+			}
+
+		}
+		return y;
+	}
+
+	public double [] unfold_tile(double [] x) { // x should be n*n
+		return fold_tile(x, 1 << (ilog2(x.length)/2));
+		
+	}
+	public double [] unfold_tile(double [] x, int n) { // x should be 2n*2n
+		double [] y = new double [4*n*n];
+		return y;
+	}
+
+	
+	public double [] dctii_direct(double[] x){
+		int n = x.length;
+		int t = ilog2(n)-1;
+		if (CII==null){
+			setup_CII(N); // just full size
+		}
+		double [] y = new double[n];
+		for (int i = 0; i<n; i++) {
+			y[i] = 0.0;
+			for (int j = 0; j< n; j++){
+				y[i]+= CII[t][i][j]*x[j]; 
+			}
+		}
+		return y;
+	}
+	
+	public double [] dctiv_direct(double[] x){
+		int n = x.length;
+		int t = ilog2(n)-1;
+		if (CIV==null){
+			setup_CIV(N); // just full size
+		}
+		double [] y = new double[n];
+		for (int i = 0; i<n; i++) {
+			y[i] = 0.0;
+			for (int j = 0; j< n; j++){
+				y[i]+= CIV[t][i][j]*x[j]; 
+			}
+		}
+		return y;
+	}
+
+	public double [] dstiv_direct(double[] x){
+		int n = x.length;
+		int t = ilog2(n)-1;
+		if (SIV==null){
+			setup_SIV(N); // just full size
+		}
+		double [] y = new double[n];
+		for (int i = 0; i<n; i++) {
+			y[i] = 0.0;
+			for (int j = 0; j< n; j++){
+				y[i]+= SIV[t][i][j]*x[j]; 
+			}
+		}
+		return y;
+	}
+	private void setup_arrays(int maxN){
+		if (N >= maxN) return;
+		N = maxN;
+		int l = ilog2(N)-1;
+		CN1 = new double[l][];
+		SN1 = new double[l][];
 		
 		for (int t = 0; t<CN1.length; t++) {
 			int n1 = 2 << t; // for N==3: 2, 4, 8
 			double pi_4n=Math.PI/(8*n1); // n1 = n/2
-//			double pi_2n=Math.PI/(4*n1); // n1 = n/2
 			CN1[t] = new double[n1];
 			SN1[t] = new double[n1];
-//			C_N1M1[t] = new double[n1-1];
-//			S_N1M1[t] = new double[n1-1];
 			for (int k=0; k<n1; k++){
 				CN1[t][k] = Math.cos((2*k+1)*pi_4n);
 				SN1[t][k] = Math.sin((2*k+1)*pi_4n);
 			}
-//			for (int k=1; k<n1; k++){
-//				C_N1M1[t][k-1] = Math.cos(k*pi_2n);
-//				S_N1M1[t][k-1] = Math.sin(k*pi_2n);
-//			}
 		} 
-
 	}
 	
-	public void setup_CII(int maxN){
-		CII = new double[ilog2(N)][][]; // only needed for direct? Assign only when needed?
+	private void setup_CII(int maxN){
+		if (maxN > N) setup_arrays(maxN);		
+		int l = ilog2(N);
+		if (!(CII==null) && (CII.length >= l)) return;
+		CII = new double[l][][]; // only needed for direct? Assign only when needed?
 		for (int t = 0; t<CII.length; t++) {
 			int n = 2 << t; // for N==3: 2, 4, 8
-//			System.out.println("t="+t+", n="+n);
 			CII[t] = new double[n][n];
 			double scale = Math.sqrt(2.0/n);
 			double ej;
@@ -87,11 +345,14 @@ public class DttRad2 {
 			}
 		}
 	}
-	public void setup_CIV(int maxN){
-		CIV = new double[ilog2(N)][][];
+
+	private void setup_CIV(int maxN){
+		if (maxN > N) setup_arrays(maxN);		
+		int l = ilog2(N);
+		if (!(CIV==null) && (CIV.length >= l)) return;
+		CIV = new double[l][][];
 		for (int t = 0; t<CIV.length; t++) {
 			int n = 2 << t; // for N==3: 2, 4, 8
-//			System.out.println("t="+t+", n="+n);
 			CIV[t] = new double[n][n];
 			double scale = Math.sqrt(2.0/n);
 			double pi_4n=Math.PI/(4*n);
@@ -101,62 +362,39 @@ public class DttRad2 {
 				}
 				for (int k = j; k<n; k++){
 					CIV[t][j][k] = scale *  Math.cos((2*j+1)*(2*k+1)*pi_4n);
-//                    if (t<2) System.out.println("CIV["+t+"]["+j+"]["+k+"]="+CIV[t][j][k]);
 				}
 			}
 		}
 	}	
+
+	private void setup_SIV(int maxN){
+		if (maxN > N) setup_arrays(maxN);		
+		int l = ilog2(N);
+		if (!(SIV==null) && (SIV.length >= l)) return;
+		SIV = new double[l][][];
+		for (int t = 0; t<SIV.length; t++) {
+			int n = 2 << t; // for N==3: 2, 4, 8
+			SIV[t] = new double[n][n];
+			double scale = Math.sqrt(2.0/n);
+			double pi_4n=Math.PI/(4*n);
+			for (int j=0;j<n; j++){
+				for (int k = 0; k < j; k++){
+					SIV[t][j][k] = SIV[t][k][j];  
+				}
+				for (int k = j; k<n; k++){
+					SIV[t][j][k] = scale *  Math.cos((2*j+1)*(2*k+1)*pi_4n);
+				}
+			}
+		}
+	}	
+	
 	
-	public int ilog2(int n){
+	private int ilog2(int n){
 		int i;
 		for (i=0; n>1; n= n >> 1) i++;
 		return i;
 	}
 	
-	public double [] dctii_direct(double[] x){
-		int n = x.length;
-		int t = ilog2(n)-1;
-		if (CII==null){
-			setup_CII(N); // just full size
-		}
-		double [] y = new double[n];
-		for (int i = 0; i<n; i++) {
-			y[i] = 0.0;
-			for (int j = 0; j< n; j++){
-				y[i]+= CII[t][i][j]*x[j]; 
-			}
-		}
-		return y;
-	}
-	
-	public double [] dctiv_direct(double[] x){
-		int n = x.length;
-		int t = ilog2(n)-1;
-		if (CIV==null){
-			setup_CIV(N); // just full size
-		}
-		double [] y = new double[n];
-		for (int i = 0; i<n; i++) {
-			y[i] = 0.0;
-			for (int j = 0; j< n; j++){
-				y[i]+= CIV[t][i][j]*x[j]; 
-			}
-		}
-		return y;
-	}
-	public double [] dctii_recurs(double[] x){
-		double [] y=  _dctii_recurs(x);
-		double scale = 1.0/Math.sqrt(x.length);
-		for (int i = 0; i < y.length ; i++) y[i] *= scale;
-		return y;
-	}
-
-	public double [] dctiv_recurs(double[] x){
-		double [] y=  _dctiv_recurs(x);
-		double scale = 1.0/Math.sqrt(x.length);
-		for (int i = 0; i < y.length ; i++) y[i] *= scale;
-		return y;
-	}
 
 	private double [] _dctii_recurs(double[] x){
 		int n = x.length;
@@ -213,10 +451,6 @@ public class DttRad2 {
 		if (n ==2) {
 			double [] y= {COSPI_1_8_SQRT2*x[0] + COSPI_3_8_SQRT2*x[1],
 					      COSPI_3_8_SQRT2*x[0] - COSPI_1_8_SQRT2*x[1]};
-			for (int j = 0; j< n; j++){
-//				System.out.println("_dctiv_recurs(2): y["+j+"]="+y[j]);
-			}		
-			
 			return y;
 		}
 
@@ -237,10 +471,6 @@ public class DttRad2 {
 		double [] w0 = new double [n1];
 		double [] w1 = new double [n1];
 
-		for (int j = 0; j< n1; j++){
-//			System.out.println("v0["+j+"]="+v0[j]+", v1["+j+"]="+v1[j]);
-		}		
-		
 		w0[0] =     sqrt2 * v0[0];
 		w1[n1-1] =     sqrt2 * v1[0];
 		for (int j = 0; j< n1; j++){
@@ -248,17 +478,12 @@ public class DttRad2 {
 			if (j > 0)	    w0[j] = v0[j]   - sgn * v1[n1 - j]; 
 			if (j < (n1-1))	w1[j] = v0[j+1] - sgn * v1[n1 - j -1]; 
 		}		
-		for (int j = 0; j< n1; j++){
-//			System.out.println("w0["+j+"]="+w0[j]+", w1["+j+"]="+w1[j]);
-		}		
+
 		double [] y = new double[n];
 		for (int j = 0; j< n1; j++){
 			y[2*j] =     w0[j];
 			y[2*j+1] =   w1[j];
 		}
-		for (int j = 0; j< n; j++){
-//			System.out.println("y["+j+"]="+y[j]);
-		}		
 		return y;
 	}
 }

src/main/java/Eyesis_Correction.java

@@ -2517,8 +2517,8 @@ private Panel panel1,panel2,panel3,panel4,panel5,panel5a, panel6,panel7,panelPos
     	x[1] = 1.0;
     	y=   dtt.dctiv_direct(x);
     	xr=  dtt.dctiv_direct(y);
-    	y1=  dtt.dctiv_recurs(x);
-    	xr1= dtt.dctiv_recurs(y1);
+    	y1=  dtt.dct_iv(x);
+    	xr1= dtt.dct_iv(y1);
     	
     	
         PlotWindow.noGridLines = false; // draw grid lines