respue5

PURPOSE ^

RESPUE5 compute the response ( and gradient ) to a local DCT2D

SYNOPSIS ^

function [IN,R,GR,alfa,beta]=respue5(dctinic,k1,k2,gamm,H,calc_grad)

DESCRIPTION ^

 RESPUE5 compute the response ( and gradient ) to a local DCT2D
 (expressed in contrast) considering interactions between the coefficients,
 simulating the HVS frequency detectors.

 DCTN (f) = ( k1 (f) DCT (f) ) ^ g / (k2 (f) + [ H * ( k1 (f) DCT (f) ) ^ g ] (f) )

 Inputs:
 H, k1, k2 (only frequency dependence) and g,

 Returns :

 interac = interaction = H * abs ( a) ^ g
 Resp = response,
 Grad = The Jacobian of the response
 If you decide not to calculate the Jacobian , the program sets GR = 0
 The parameters k1 and k2 in a matrix form , KK1 , KK2

 NOTE : It is assumed that the block gets into the function is already expressed in
 contrast ( see CONTRAST)

 USE : [interac,Resp,Grad,kk1,kk2]=respue5(dctinic,k1,k2,gamm,H,calc_grad)

CROSS-REFERENCE INFORMATION ^

This function calls: This function is called by:

SOURCE CODE ^

0001 %
0002 % RESPUE5 compute the response ( and gradient ) to a local DCT2D
0003 % (expressed in contrast) considering interactions between the coefficients,
0004 % simulating the HVS frequency detectors.
0005 %
0006 % DCTN (f) = ( k1 (f) DCT (f) ) ^ g / (k2 (f) + [ H * ( k1 (f) DCT (f) ) ^ g ] (f) )
0007 %
0008 % Inputs:
0009 % H, k1, k2 (only frequency dependence) and g,
0010 %
0011 % Returns :
0012 %
0013 % interac = interaction = H * abs ( a) ^ g
0014 % Resp = response,
0015 % Grad = The Jacobian of the response
0016 % If you decide not to calculate the Jacobian , the program sets GR = 0
0017 % The parameters k1 and k2 in a matrix form , KK1 , KK2
0018 %
0019 % NOTE : It is assumed that the block gets into the function is already expressed in
0020 % contrast ( see CONTRAST)
0021 %
0022 % USE : [interac,Resp,Grad,kk1,kk2]=respue5(dctinic,k1,k2,gamm,H,calc_grad)
0023 %
0024 
0025 function [IN,R,GR,alfa,beta]=respue5(dctinic,k1,k2,gamm,H,calc_grad)
0026 
0027    tam=size(dctinic);
0028    tam=tam(1);
0029    lados=[tam tam];
0030 
0031    lcuan=lados(1);
0032 
0033    k1=simrev(k1);
0034    k1=zigzag(k1);
0035    k2=simrev(k2);
0036    k2=zigzag(k2);
0037 
0038    alfa=k1;
0039    beta=k2;
0040 
0041 cub=dctinic;
0042 
0043 cub=zigzag(cub);
0044 
0045 cub=abs(cub);
0046 
0047 cucu=(k1.*cub).^gamm;
0048 
0049 interacc=H*[0;cucu(2:length(cucu))];
0050 
0051 R=cucu./(k2+interacc);
0052 R(1)=sqrt(cub(1));
0053 
0054 if calc_grad==1
0055 
0056     I=eye(lcuan^2);
0057     GR=zeros(lcuan^2,lcuan^2);
0058     GR(1,1)=1;
0059 
0060     for i=2:lcuan^2,
0061       for j=2:lcuan^2,
0062 
0063           GR(i,j)= gamm*(abs(  (cucu(i).^(1/gamm)).^(gamm-1)  )/(k2(i)+interacc(i))*I(i,j)-(cucu(i)*abs( ((cucu(j)).^(1/gamm)).^(gamm-1) )/((k2(i)+interacc(i))^2))*H(i,j));
0064       end
0065     end
0066 
0067 else
0068     GR=0;
0069 end
0070 
0071 R=dezigzag(R);
0072 IN=dezigzag(interacc);

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