matlab实现jpeg算法进行图像压缩的源代码.docx

functionjpeg

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closeall;

%==================
%section1.2+1.3
%==================
%thefollowinguseofthefunction:
%
%plot_bases(base_size,resolution,plot_type)
%
%willplotthe64wantedbases.Iwilluse"zero-padding"forincreasedresolution
%NOTETHATTHESEARETHESAMEBASES!
%forreferenceIplotthefollowing3graphs:
%a)3Dplotwithbasicresolution(64plotsof8x8pixels)using"surf"function
%b)3Dplotwithx20resolution(64plotsof160x160pixels)using"mesh"function
%c)2Dplotwithx10resolution(64plotsof80x80pixels)using"mesh"function
%d)2Dplotwithx10resolution(64plotsof80x80pixels)using"imshow"function
%
%NOTE:matrixsizeofpictures(b),(c)and(d),cansupporthigherfrequency=higherbases
%butIamnotaskedtodrawthese(higherbases)inthissection!
%thezeropaddingisusedONLYforresolutionincrease!
%
%getallbasepictures(3Dsurfacefigure)
plot_bases(8,1,'surf3d');

%getallbasepictures(3Dsurfacefigure),x20resolution
plot_bases(8,20,'mesh3d');

%getallbasepictures(2Dmeshfigure),x10resolution
plot_bases(8,10,'mesh2d');

%getallbasepictures(2Dmeshfigure),x10resolution
plot_bases(8,10,'gray2d');

%==================
%section1.4+1.5
%==================
%foreachpicture{'0'..'9'}performa2dimensionaldcton8x8blocks.
%savethedctinsideacellofthesize:10cellsof128x128matrix
%showforeachpicture,it'sdct8x8blocktransform.

foridx=0:9

%loadapicture
switchidx
case{0,1},input_image_128x128=im2double(imread(sprintf('%d.tif',idx),'tiff'));
otherwise,input_image_128x128=im2double(imread(sprintf('%d.tif',idx),'jpeg'));
end

%performDCTin2dimensionoverblocksof8x8inthegivenpicture
dct_8x8_imag