PSNR计算

purpose_857

im1=imread('lena2.bmp');
$ `3 w/ y% E+ o! k2 C0 O" ^%im1=im2double(im1);
$ B8 v' s  q; v0 A& \$ @& |+ r9 X; Uim2=imread('lena_rbhv.bmp');
%im2=im2double(im2);
   
if (size(im1))~=(size(im2))
    error('错误：两个输入图象的大小不一致');
# R% E7 a; S8 S+ }0 oend

    [m,n] = size(im1);
+ |/ Z: J! N6 [6 R    A = double(im1);
    B = double(im2);
    D = sum( sum( (A-B).^2 ) );%||A-B||^2
4 x0 m2 y* D0 [* Q    MSE = D / (m * n);
if  D == 0
, e7 s1 [$ o! v  p' o' ]( T    error('两幅图像完全一样');
    PSNR = 200;
else
    PSNR = 10*log10( (255^2) / MSE );                                                        
end

, |/ f/ F) ]# \. B: f
从网上COPY了下 稍微改了下  我不知道这一行为什么出错  请指教
??? Subscript indices must either be real positive integers or logicals.
. ^* _* |1 z2 \7 T4 w; h* \
' k" j3 |* L5 S2 RError in ==> PSNR_ERRO at 14
    D = sum( sum( (A-B).^2 ) );%||A-B||^2
8 C9 w+ I4 Q& T

I_believe

D = sum( sum( (A-B).^2 ) );指的是什么，为什么有两从sum？

peerless2021

function main()
clc; close all;
* ^. T' k9 }, }; d4 XI=imread('cameraman.tif'); %用的是原图
I1=imnoise(I,'gaussian',0,0.01);
' o7 p% j& a) T' C' hfigure;
. l0 o- n4 y! _! Usubplot(1, 2, 1); imshow(I); title('原图像');
subplot(1, 2, 2); imshow(I1); title('加噪声图像');
[PSNR, MSE] = psnr(I, I1)
% 图像峰值信噪比PSNR、均方根误差MSE
4 g; ~) Y1 ~; |" j  d0 b; A1 z% ~function [PSNR, MSE] = psnr(X, Y)
% 计算峰值信噪比PSNR、均方根误差MSE
1 h5 A9 i1 t( \: I. I" \  G% 如果输入Y为空，则视为X与其本身来计算PSNR、MSE
4 k4 |  _' U& Y# T5 |' F
if nargin<2
    D = X;
% n* ~/ ?1 I# X& I2 t+ Uelse
, H, ]% p0 u/ C    if any(size(X)~=size(Y))
        error('The input size is not equal to each other!');
    end
    D = X-Y;
end
' Q6 I- M; _2 t% y/ O% AMSE = sum(D(: ).*D(: ))/prod(size(X));
( l3 P5 i+ [$ N/ k$ @: X: Q+ i2 [+ H8 [PSNR = 10*log10(255^2/MSE);
function main()
5 {% n/ Z% V- V! C# W- G& ~3 Vclc; close all;
% d) F' q- Y8 V5 ZI=imread('cameraman.tif'); %用的是原图
I1=imnoise(I,'gaussian',0,0.01);
figure;
subplot(1, 2, 1); imshow(I); title('原图像');
subplot(1, 2, 2); imshow(I1); title('加噪声图像');
[PSNR, MSE] = psnr(I, I1)
% 图像峰值信噪比PSNR、均方根误差MSE
function [PSNR, MSE] = psnr(X, Y)
% 计算峰值信噪比PSNR、均方根误差MSE
& E5 S/ A' _; h6 {% 如果输入Y为空，则视为X与其本身来计算PSNR、MSE
: L/ e5 O7 J& V7 Q* r; d* C; i+ ]
if nargin<2
    D = X;
else
0 l7 S& b, Y( V! R$ Q2 `: C! j0 G    if any(size(X)~=size(Y))
# C4 C. m; D& X2 j! m: y8 S( a$ D        error('The input size is not equal to each other!');
    end
: J! R2 D1 y) G5 |$ Z$ [& M/ \2 N    D = X-Y;
3 d+ x$ s! |* P4 C! @  Q) Z8 U' rend
MSE = sum(D(: ).*D(: ))/prod(size(X));
PSNR = 10*log10(255^2/MSE);
  [" t2 T3 _3 b! V% r用这个算法算下吧，I为原图 I1为加噪图像