Image Sensor- CMOS VS CCD

8/10/2019 Image Sensor- CMOS VS CCD

http://slidepdf.com/reader/full/image-sensor-cmos-vs-ccd 1/21

Image sensor

BIJOY KUNDUEXAM ROLL: 110907012

Electronics n! "eleco##$nic tionDe% rt#ent

27-03-2012



1. What is an Image sensor?2. Possible uses for Image Sensors3. Working of Image Sensors-CCD

&CM S Sensors!. Colour filter-"a#er filter$. Image %oise. Com'arison bet(een CM S an)

CCD sensors*. Con+lusion

KEY POINTS



, n Image Sensor is a 'hotosensiti e )e i+ethat +on erts light signals into )igitalsignals /+olours0 " )ata .

4(o main t#'es in +ommon use are CCDan) CM S sensors an) are mainl# use) in)igital +ameras an) other imaging )e i+es.

CCD stan)s for Charge)-Cou'le) De i+ean) CM S stan)s for Com'lementar#Metal5 6i)e5Semi+on)u+tor

What is an Image Sensor?



Blo ! "iagram O# $ "I%IT$&'$(E)$ SYSTE(



, Image sensors are notonl# limite) to )igital+ameras.

Image sensors are use)in other fiel)s su+h as7, stronom#8 most

notabl# in the 9ubbleS'a+e 4eles+o'eMa+hineision0sensing:; S'e+tros+o'#<t+.

*ses o+ Image Sensors



"oth CCD an) CM Ssensors (ork b#em'lo#ing'hotosensiti e +ir+uitr#

that rea+ts to light an)stores the analogsignals as )igital )ata8namel# an image.

4he# both use )ifferentmetho)s to a+hie e

this.

,o Image Sensors Wor!



CCD8 or a Charge)-Cou'le) De i+e8 is a'hotosensiti e analog )e i+e that re+or)s light as asmall ele+tri+al +harge in ea+h of its 'i6els or +ells.In essen+e a CCD is a +olle+tion of CCD +ells.

4he signal +a'ture) b# the CCD re=uires a))itional+ir+uitr# to +on ert the analog light )ata into area)able )igital signal.

4his is mainl# la#ers of +a'a+itors +alle) Stages(hi+h a+t as a (a# to trans'ort the analog signal to

an arra# of fli'-flo's (hi+h store the )ata all+ontrolle) b# a +lo+k signal.

4his is basi+all# an nalog Shift egister.

''"



Imaging s.stem in ''"te hnolog.



''"When light strikes a CCD8 it a+=uires an ele+tri+al+harge a++or)ing to ho( mu+h light has hit the'arti+ular CCD +ell.

<a+h CCD +ell +an transfer its +harge to itsneighboring +ell an) then off to e6ternal +ir+uitr#.

4he +harge is then rea) off b# an analog-to-)igital+on erter as an integer on a range of > to !> $for most mo)ern DS@ +ameras. @o(er rangese6ist8 su+h as >-2$$8 for lo(er =ualit# +ameras.



Imaging s.stem in '(OSte hnolog.



CM S8 or Com'lementar# Metal 6i)eSemi+on)u+tor8 ea+h 'i6el has neighboringtransistors (hi+h lo+all# 'erform the analog to)igital +on ersion.

4his )ifferen+e in rea)out has man# im'li+ationsin the o erall organiAation an) +a'abilit# of the+amera.

<a+h one of these 'i6el sensors are +alle) an+ti e Pi6el Sensor / PS .

9o(e er8 PSs are transistor-base)8 (hi+h meansthat CM S +hi's +an be +hea'l# manufa+ture) on

'(OS



3T '(OS Sensor



'olo/r +iltering

4#'i+al 'hoto-sensors )ete+t light intensit# (ithlittle or no (a elength s'e+ifi+it#8 an) therefore+annot se'arate +olor information.

4(o +ommon +olor registration metho)s are "/ e)8 reen8 an) "lue an) CM /C#an8 Magenta8 ello(8 an) reen



4he "a#er arrangement of +olorfilters on the 'i6el arra# of animage sensor

B$YE) #iltero

It is a " +olour filter.o Its is arrange) in grou's offour +ells o erthe 'i6el arra#. 4he filter 'attern is $>green8 2$ re) an) 2$ blue.

o 4he reasoning behin) the t(ogreen +ells is be+ause thehuman e#e is more sensiti e togreen light an) it is more+on enient to use a ! 'i6elfilter than a 3 'i6el filter/har)er to im'lement



Image NoiseImage noise is ran)om /not 'resent in the obEe+t image) ariation of brightness or +olor information in images8 an) is usuall# an as'e+t of ele+troni+ noise.

"i++erent t. es o+ noises

o

m'lifier noise / aussian noiseo Salt-an)-'e''er noise

o Shot noise

o FuantiAation noise /uniform noise

o Gilm grain

Salt an) 'a'er noise

http://en.wikipedia.org/wiki/Image_noise


















''"

%ee)s e6tra +ir+uitr#to +on ert to )igitalsignal an) for othersignal 'ro+essing

@ess noise )ue to lesson-+hi' +ir+uitr#

Po(er +onsum'tion ishigh

'(OS

In+or'oratesam'lifiers8 0D-+on erters an) often+ir+uitr# for a))itional'ro+essing

@o(er +om'le6it# onthe sensor lea)ing tofaster image +a'ture

e)u+e) 'o(er+onsum'tion

'om arison



'om arison

'(OSo ne +harge-to- oltage+on erter 'er 'i6el

o CM S sensor allo(sH(in)o(ing an)multi- ie( streaming

o Gaster rea)out

''"o one +harge-to- oltage+on erter 'er sensor

o Win)o(ing an) multi-ie( streaming notallo(e)

o 9eat issues (ith CCDsensors +an in+reaseinterferen+e



'on l/sionCCD an) CM S sensors ha e )ifferent a) antages.

With e olution of te+hnolog#8 CM S sensors ha ebetter future.

"ase) on the nee) of the imaging )e i+e8 sensorsare )esigne).



)e+eren es• ''" s '(OS 8 b# Da e @it(iller from Photoni+s S'e+tra 2>>1

• . D#+k an) . We+kler /1 J . KIntegrate) arra#s of sili+on'hoto)ete+tors for image sensingK. I<<< 4rans. <le+tron De i+es E"-1 /! 7 1 52>1.

• ''" an4 '(OS 8 Pa)makumar . ao et al.8 KCCD stru+turesim'lemente) in stan)ar) >.1J Lm CM S te+hnolog#

• Margaret "ro(n /2>>! 8 -) an+e) Digital Photogra'h#8 Me)iaPublishing

• $44ing &5 to )%B% 6 Ma# 138 2>>J b# Neff Mather

• K'olor #ilter $rra. 2 086 9. Nohn Com'ton an) Nohn 9amilton /2>>*-> -1! . - 4housan) %er)s7 - Oo)ak blog . r+hi e) from the original on2>>*->*-2>. etrie e) 2>11->2-2$.

• le6an)er . Di+kinson et al.8 K +ti e 'i6el sensor an) imaging s#stemha ing )ifferential mo)eK8 :S $ 31*>!



$n. :/estions

or'omments?



49 %O :

Image Sensor- CMOS VS CCD

Documents

Transcript of Image Sensor- CMOS VS CCD