malo06_encoder

PURPOSE ^

Use QDCT65 to quantize the normalized DCTs of a subblock of a 2D signal

SYNOPSIS ^

function RESP=malo06_encoder(s,B,exp,directorio,fichero,RESP)

DESCRIPTION ^

 Use QDCT65 to quantize the normalized DCTs of a subblock of a 2D signal
 (Currently 256 * 256 resolution 4)

 Differences from previous versions :
 - Use the proper normalization of contrasts ( contras2 rather than contrast )
 - Designs the normalization  Kernel taking proper care of the DC component.
 - Including in one function constants from naka8 and naka100
 ( With exponent 2 - naka8 - or 'optimized' exponent  - 0.98 - naka100 )

 Use one or the other parameters as a function of the value of the variable
 Exp:
 Exp = 2 -> values ​​naka8
 Exp = 1 - > values ​​naka100
 - Calculate the parameters once ( constantes_resp ) and then passes them to
 calculation of the response function ( respue5 ) .

 Difference of QDCT62 that allows you to not calculate the eigenvalues ​​of the original
 (if you're not interested in them, it saves time !)

 Represents QDCT62 signal in a domain with (approx.) statistically uncorrelated characteristics
 and uncorrelated perceptually (With perceptual metric identity).
 This is achieved through the divisive normalization: Teo & Heeger, Watson and Simoncelli.
 This transformation depends on its input signal ( state adaptation ) .
 It has been shown that this type of response obtains independent statistics ( Simoncelli99 ) and
 perceptually ( Malo99 ) coefficients , and therefore is a suitable domain for
 a scalar quantizer .

 Since the perceptual metric in this domain is the identity apply uniform quantizers
 and flat bit-allocation per coefficient.

 For each block the invertibility is checked [max( eig ( D_R * h )) ], and the inverse is computed
 by using the analytical expression

 It is normalized to local Michaelson contrast and response according NAKA8.m :

 Norm = [1 1] ................ Normalized by the average luminance
 of the subfield considered (local contrast) .

 Norm = [3 Lm ] ............... Normalized by the fixed value Lm (global contrast)
 the logical choice is to take Lm = mean ( mean ( Im) );
 ( Mean value in digital levels )

 Range to distribute the quantization levels in the domain response is given
 by the maximum diagonal gradient ( acting on contrasts, belonging to
 [ -1.1 ] ) .

 USE : RESP = malo06_encoder(s,B,exp,directorio,fichero,RESP)

 Where:

 S -> compressed image
 B - > Parameter setting of quantization levels
 Exp -> exponent nonlinearity. You can take the values ​​1 or 2
 directorio -> Place where the compressed file will be stored
 fichero -> name with which the compressed file will be stored
 RESP -> Optional parameter : nonlinear transform image
      In the first execution this parameter may not be available,
       but in a loop search of a certain entropy or
       distortion is calculated the first time and avoiding load
       posterior calculation.

CROSS-REFERENCE INFORMATION ^

This function calls: This function is called by:

SOURCE CODE ^

0001 % Use QDCT65 to quantize the normalized DCTs of a subblock of a 2D signal
0002 % (Currently 256 * 256 resolution 4)
0003 %
0004 % Differences from previous versions :
0005 % - Use the proper normalization of contrasts ( contras2 rather than contrast )
0006 % - Designs the normalization  Kernel taking proper care of the DC component.
0007 % - Including in one function constants from naka8 and naka100
0008 % ( With exponent 2 - naka8 - or 'optimized' exponent  - 0.98 - naka100 )
0009 %
0010 % Use one or the other parameters as a function of the value of the variable
0011 % Exp:
0012 % Exp = 2 -> values ​​naka8
0013 % Exp = 1 - > values ​​naka100
0014 % - Calculate the parameters once ( constantes_resp ) and then passes them to
0015 % calculation of the response function ( respue5 ) .
0016 %
0017 % Difference of QDCT62 that allows you to not calculate the eigenvalues ​​of the original
0018 % (if you're not interested in them, it saves time !)
0019 %
0020 % Represents QDCT62 signal in a domain with (approx.) statistically uncorrelated characteristics
0021 % and uncorrelated perceptually (With perceptual metric identity).
0022 % This is achieved through the divisive normalization: Teo & Heeger, Watson and Simoncelli.
0023 % This transformation depends on its input signal ( state adaptation ) .
0024 % It has been shown that this type of response obtains independent statistics ( Simoncelli99 ) and
0025 % perceptually ( Malo99 ) coefficients , and therefore is a suitable domain for
0026 % a scalar quantizer .
0027 %
0028 % Since the perceptual metric in this domain is the identity apply uniform quantizers
0029 % and flat bit-allocation per coefficient.
0030 %
0031 % For each block the invertibility is checked [max( eig ( D_R * h )) ], and the inverse is computed
0032 % by using the analytical expression
0033 %
0034 % It is normalized to local Michaelson contrast and response according NAKA8.m :
0035 %
0036 % Norm = [1 1] ................ Normalized by the average luminance
0037 % of the subfield considered (local contrast) .
0038 %
0039 % Norm = [3 Lm ] ............... Normalized by the fixed value Lm (global contrast)
0040 % the logical choice is to take Lm = mean ( mean ( Im) );
0041 % ( Mean value in digital levels )
0042 %
0043 % Range to distribute the quantization levels in the domain response is given
0044 % by the maximum diagonal gradient ( acting on contrasts, belonging to
0045 % [ -1.1 ] ) .
0046 %
0047 % USE : RESP = malo06_encoder(s,B,exp,directorio,fichero,RESP)
0048 %
0049 % Where:
0050 %
0051 % S -> compressed image
0052 % B - > Parameter setting of quantization levels
0053 % Exp -> exponent nonlinearity. You can take the values ​​1 or 2
0054 % directorio -> Place where the compressed file will be stored
0055 % fichero -> name with which the compressed file will be stored
0056 % RESP -> Optional parameter : nonlinear transform image
0057 %      In the first execution this parameter may not be available,
0058 %       but in a loop search of a certain entropy or
0059 %       distortion is calculated the first time and avoiding load
0060 %       posterior calculation.
0061 
0062 function RESP=malo06_encoder(s,B,exp,directorio,fichero,RESP)
0063 
0064 if nargin<6
0065    RESP=[];
0066 end
0067 
0068 Lb = 16;
0069 Li = 256;
0070 
0071 M = 0.8;
0072 cero = 1;
0073 
0074 Norm = [3 mean(mean(s))];
0075 
0076 Ncuan = 4;
0077 
0078 tam = size(s);
0079 tam = tam(1);
0080 lados = [tam tam];
0081 lcuan = tam/(2^Ncuan);
0082 posai = [tam tam]/2-round(tam/2);
0083 posbd = [tam tam]/2+round(tam/2);
0084 coorcuanai = floor([(posai(1)-1)/lcuan+1 (posai(2)-1)/lcuan+1]);
0085 coorcuanbd = floor([(posbd(1)-1)/lcuan+1 (posbd(2)-1)/lcuan+1]);
0086 if coorcuanai(1) < 1
0087     coorcuanai(1) = 1;
0088 end
0089 if coorcuanai(2) < 1
0090     coorcuanai(2) = 1;
0091 end
0092 if coorcuanbd(1) > (2^Ncuan)
0093     coorcuanbd(1) = 2^Ncuan;
0094 end
0095 if coorcuanai(2) > (2^Ncuan)
0096     coorcuanbd(2) = 2^Ncuan;
0097 end
0098 
0099 pes = ones(lcuan,lcuan);
0100 pes(1,1) = 0;
0101 
0102 pes=[pes pes pes pes pes pes pes pes pes pes pes pes pes pes pes pes];
0103 pes=[pes;pes;pes;pes;pes;pes;pes;pes;pes;pes;pes;pes;pes;pes;pes;pes];
0104 
0105 dcti = dct2r(s,Ncuan);
0106 
0107 [a,Lm] = contras2(dcti,Ncuan,Norm);
0108 
0109 a = pes.*a;
0110 
0111 W = 1;
0112 
0113 val_r = 100;
0114 
0115 e = imdpcm(Lm,W,val_r);
0116 
0117 Nc = round(0.9 * 40);
0118 
0119 me = mini(e);
0120 Me = maxi(e);
0121 
0122 extr_err = [me Me];
0123 
0124 QE = round((Nc -1) * (e - me) / (Me - me));
0125 
0126 [h,kk1,kk2,gamm] = constrains_resp(exp,cero);
0127 
0128 if nargin<6
0129 fprintf('  Computing the non-linear response');
0130 end
0131 
0132 codigazo = [];
0133 bloquecito = 1;
0134 for i=1:Lb:Li
0135 
0136     if nargin<6
0137        fprintf('.');
0138     end
0139 
0140     for j=1:Lb:Li
0141 
0142         aa = a(i:(i+(Lb-1)),j:(j+(Lb-1)));
0143 
0144         if nargin<6
0145 
0146             [h_a,r,GR,alfa2d,beta2d] = respue5(aa,kk1,kk2,gamm,h,0);
0147 
0148             r = zigzag(r);
0149             r = r(2:end);
0150             RESP=[RESP r];
0151 
0152         else
0153             r=RESP(:,bloquecito);
0154         end
0155 
0156         azig = zigzag(aa);
0157         azigsc = azig(2:end);
0158 
0159         cod = round(2^B * r / M);
0160         rc = cod * M / (2^B);
0161 
0162       signo1 = sign(azigsc).*(rc~=0) + (rc==0);
0163 
0164         codigon = signo1 .* rc;
0165         codigonint = signo1 .* cod;
0166 
0167         [codigo,ceros] = rle2(codigonint);
0168         codigazo = [codigazo codigo ceros];
0169 
0170         bloquecito = bloquecito + 1;
0171 
0172     end
0173 end
0174 
0175 ristra = [mean(mean(s)) extr_err(:)' round(QE(:))' B round(codigazo)];
0176 
0177 cd(directorio);
0178 save_code_malo06(ristra,[fichero '.bin']);
0179 
0180 zip(fichero,[fichero '.bin']);
0181 
0182 delete([fichero '.bin']);

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