02_DigitalImagesAndMatlab (1).ppt

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February 9, 2016 1

Image Processing

Instructor: Juyong [email protected]

htt!:""sta##.ustc.eu.cn"$juyong

Digital Images and Matlab

. {. . . .
mailto:[email protected]://staff.ustc.edu.cn/~juyonghttp://staff.ustc.edu.cn/~juyongmailto:[email protected]


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%igita& Image

a grid of squares,

each of whichcontains a single

color

each square is

called a pixel (for

picture element)

Color images have 3 values perpixel monochrome images have !

value per pixel"

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' igita& image,I, is a ma!!ing #rom a 2% grio# uni#orm&y s!ace iscrete !oints, (p = )r,c*+,

into a set o# !ositie integer a&ues, (I)p*+, or aset o# ector a&ues, e.g., (-RGB#)p*+.

't each co&umn &ocation in each ro/ o#Ithereis a a&ue.

he !air )p, I)p** is ca&&e a !ie&3 )#orpicture element*.

Pie&s

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p = )r,c*is the !ie& &ocation inee by ro/, r,an co&umn, c.

I)p* = I)r,c* is the a&ue o# the !ie& at &ocationp.

I#I)p* is a sing&e number thenIismonochrome.

I#I)p* is a ector )orere &ist o# numbers* thenI has mu&ti!&e bans )e.g.,a co&or image*.

Pie&s

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Pie&s

Pixel Location:p = )r ,c*

Pixel Value:I)p*= I)r ,c* Pixel :$p, I)p*

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Pixel :$p, I)p*Pie&s

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7oing

Matlab

%penC&

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ea a rueco&or Image into at&ab

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7ro! the Image

First, select aregion usingthe magnifier.

left click here and hold

drag to here and release

Cut out a region

from the image

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ea a 7o&orma!!e Image into at&ab

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ea a 7o&orma!!e Image into at&ab

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7o&orma!!e s. rueco&or in at&ab

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row: 231

co

l:

326

T(231,326,:)

image class' uintimage tpe' truecolor

227

222

96

Intensity valuesare integersbetween and !"".

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row: 231

co

l:

326

T(231,326,:)

image class' doubleimage tpe' truecolor

0.89

0.87

0.38

Intensity valuesare numbersbetween and #.

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image class' uint

image tpe' colormapped

255 = [226 231 65]TI(231,326,:) =0.1804 0.1882 0.0627

0.6863 0.7098 0.2902

0.8863 0.9059 0.2549

red green blue

colormap

214

1

256

row: 231

co

l:

326 226

231

65

$umber at %ixellocation is an indexinto a colorma%.

Intensity valuesare integersbetween and #.

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http://../Fall%202007/Lectures/%20%20%20%200.1804%20%20%20%200.1882%20%20%20%200.0627%0D%0A%20%20%20%200.6863%20%20%20%200.7098%20%20%20%200.2902%0D%0A%20%20%20%200.8863%20%20%20%200.9059%20%20%20%200.2549http://../Fall%202007/Lectures/%20%20%20%200.1804%20%20%20%200.1882%20%20%20%200.0627%0D%0A%20%20%20%200.6863%20%20%20%200.7098%20%20%20%200.2902%0D%0A%20%20%20%200.8863%20%20%20%200.9059%20%20%20%200.2549http://../Fall%202007/Lectures/%20%20%20%200.1804%20%20%20%200.1882%20%20%20%200.0627%0D%0A%20%20%20%200.6863%20%20%20%200.7098%20%20%20%200.2902%0D%0A%20%20%20%200.8863%20%20%20%200.9059%20%20%20%200.2549http://../Fall%202007/Lectures/%20%20%20%200.1804%20%20%20%200.1882%20%20%20%200.0627%0D%0A%20%20%20%200.6863%20%20%20%200.7098%20%20%20%200.2902%0D%0A%20%20%20%200.8863%20%20%20%200.9059%20%20%20%200.2549http://../Fall%202007/Lectures/%20%20%20%200.1804%20%20%20%200.1882%20%20%20%200.0627%0D%0A%20%20%20%200.6863%20%20%20%200.7098%20%20%20%200.2902%0D%0A%20%20%20%200.8863%20%20%20%200.9059%20%20%20%200.2549


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7o&orma!!e Image, Inices, = 7o&or a!

>> [M,CMAP] = imread(button_mapped.bmp,bmp);

! "# "# $ "# $

$ ! "# !

! "# $ "# $ ! "# ! $

$% $.&'## $."$& $.#" $ $.!%& $.'&% $.!#!"

$."$& $."' $.'%& ! $.' $."$# $.&'##

$.!#!" $.!%& $."'

$% !$ !&

$ '& "$ ! !$ ## '! ! & $"

! '&

##

Indices contained in &'!"(:!"),!"(:!")* actual values in +&P'#-:##,:*

!""/+&P'#-:##,:*

0 1 2

0 1 2Last

cols.only

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>o/ to conert a co&orma!!e image to true co&or

>> [M,*map] = imread(button_mapped.bmp,bmp);

>> + = uint#(re-ape(*map(M,/),[i0e(M) ])1!'');

& is a "#!x"#!x#, )3bit image.It has !4!,#(( %ixels.5ach %ixel has a value between 6 !"".

cma% is the colorma% that is stored in 7button8ma%%ed.bm%9along with image. cma% is a !"4x ty%e3double matrix, eachrow of which lists a color in terms of its 0, 1, 6 2 intensities,which are given as fractions between and #.

2y concatenating &9s columns, &atlabrearranges & into a !4!,#(( x # list. 5achnumber in the list 'if it has # added to it*refers to a row of the colorma%. hen,cma%'&;#,:* %roduces a !4!,#(( x matrix ofintensity values of ty%e double between 6 #.

he !4!,#(( x matrix ofintensity values is resha%edinto a "#!x"#!x image ofty%e double. he values arescaled to lie between 6 !""then converted to ty%e uint).

['! '!]

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?aing Images as Fi&es

>>>> 2 true*o3or a .bmp

>> im4rite(5,ima6e_name.bmp,bmp);>>

>> 2 true*o3or a .7p6 (de8au3t 9ua3it: = ')

>> im4rite(5,ima6e_name.7p6,7p6);

>>>> 2 true*o3or a .7p6 (9ua3it: = $$)

>> im4rite(5,ima6e_name.7p6,7p6,ua3it:,$$);

>>>> 2 *o3ormapped a .bmp

>> im4rite(5,*map,ima6e_name.bmp,bmp);>>

>> 2 *o3ormapped a .6i8

>> im4rite(5,*map,ima6e_name.6i8,6i8);>>

ssuming that7I9 contains the imageof the correct class,

that

7cma%9 is a colorma%,and that

7image8name9 is thefile3name that youwant.

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he 5cstasy of +ecelia

%oub&e


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>> *d


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%oub&e > B = imread( ima6e(B)

>> truei0e

>> tit3e( F3abe3( MG = imread( ima6e(MG)>> truei0e

>> tit3e( F3abe3( [GMG,CMG,MG] = i0e(MG);

>> [GB,CB,B] = i0e(B);

>> rb = round((GBDGMG)I!);

>> *b = round((CBDCMG)I!);>> Bp3uMG = uint#((doub3e(B(rb/(rbGMGD),*b/(*bCMGD),/))doub3e(MG))I!);

>> 8i6ure

>> ima6e(Bp3uMG)>> truei0e

>> tit3e( F3abe3(


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>> *d


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>> *d


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Intensity asing:u&ti!&ying /o Images

he 5cstasy of +ecelia

0ayden =oodring > 2um%erillo 5cstasy '?*

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Intensity asing: u&ti!&ying /o Images>> B = imread( rb = round((GBDGMG)I!);

>> *b = round((CBDCMG)I!);

>> Bp3uMG = uint#((doub3e(B(rb/(rbGMGD),*b/(*bCMGD),/))doub3e(MG))I!);

>> 8i6ure

>> ima6e(Bp3uMG)

>> truei0e

>> tit3e( F3abe3( BtimeMG = doub3e(B(rb/(rbGMGD),*b/(*bCMGD),/)).1doub3e(MG);

>> M = maF(BtimeMG(/));

>> m = min(BtimeMG(/));

>> BtimeMG = uint#(!''1(doub3e(BtimeMG)Dm)I(MDm));

>> 8i6ure>> ima6e(BtimeMG)

>> truei0e

>> tit3e(


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Intensity asing: u&ti!&ying /o Images>> B = imread( rb = round((GBDGMG)I!);

>> *b = round((CBDCMG)I!);

>> Bp3uMG = uint#((doub3e(B(rb/(rbGMGD),*b/(*bCMGD),/))doub3e(MG))I!);

>> 8i6ure

>> ima6e(Bp3uMG)

>> truei0e

>> tit3e( F3abe3( BtimeMG = doub3e(B(rb/(rbGMGD),*b/(*bCMGD),/)).1doub3e(MG);

>> M = maF(BtimeMG(/));

>> m = min(BtimeMG(/));

>> BtimeMG = uint#(!''1(doub3e(BtimeMG)Dm)I(MDm));

>> 8i6ure>> ima6e(BtimeMG)

>> truei0e

>> tit3e(


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Pie& Ineing in at&ab>> 5 = imread(> r = randperm('&);>> * = randperm();

>> B = 5(r,*,/);>> 8i6ure

>> ima6e(B)

>> truei0e>> tit3e( F3abe3(


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Pie& Ineing in at&ab

>> >> F3abe3( (r,*,/) = B;

>> 8i6ure

>> ima6e()>> truei0e>> tit3e( F3abe3(

02_DigitalImagesAndMatlab (1).ppt

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