Why am i getting two different MSE, while using formula and syntax immse?

Question

Samson David Puthenpeedika 2022-1-22

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1634015-why-am-i-getting-two-different-mse-while-using-formula-and-syntax-immse

评论： Samson David Puthenpeedika 2022-1-22

IS there any mistake in the formula applied for mean squarred error?

moving_img= imread("AT3_1m4_02.tif");
fixed_img=  imread("AT3_1m4_03.tif");
crp_mv_img=imcrop(moving_img, [235, 210, 100, 100]);
crp_fx_img=imcrop(fixed_img, [235, 210, 100, 100]);
mse_1=immse(crp_fx_img,crp_mv_img)
mse_1 = 979.2353
[r,c]=size(crp_fx_img);
mse_2= sum((crp_mv_img-crp_fx_img).^2,"all")/(r*c)
mse_2 = 44.0342

Is mse_2 wrong?

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

DGM 2022-1-22

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1634015-why-am-i-getting-two-different-mse-while-using-formula-and-syntax-immse#answer_879655

编辑：DGM 2022-1-22

The reason is that the two images are integer-class. The difference and square may result in data truncation.

moving_img = imread("AT3_1m4_02.tif");
fixed_img = imread("AT3_1m4_03.tif");
crp_mv_img = imcrop(moving_img, [235, 210, 100, 100]);
crp_fx_img = imcrop(fixed_img, [235, 210, 100, 100]);
mse_1 = immse(crp_fx_img,crp_mv_img)
mse_1 = 979.2353
[r,c] = size(crp_fx_img);
se = (double(crp_mv_img)-double(crp_fx_img)).^2; % square error
[min(se(:)) max(se(:))] % values are outside of range for uint8
ans = 1×2
           0       27225
mse_2 = sum(se,"all")/(r*c)
mse_2 = 979.2353