CCD vs. CMOS: IS ERA OF CCD ALMOST OVER BEFORE IT REALLY BEGUN IN 
PHOTOGRAMMETRY? 
T. Ciceli , T. Fiedler, D. Gajski 
University of Zagreb, Faculty of Geodesy, 10000 Zagreb, Croatia — tciceli@geof.hr, teodor.fiedler(@zg.hinet.hr, dgajski@geof.hr 
  
Commission VI, WG HI/2 
KEY WORDS: CCD, CMOS, Comparasion, 
ABSTRACT: 
This days CCD sensor is dominant in use in digital cameras. Development of CCD and CMOS started almost at the same time. At the 
beginning CCD and CMOS were invented like semiconductor memory for computers, but history took them in different ways CCD 
took primate in digital cameras and CMOS is used for memory, processing and other digital functions. These critical distinctions are 
at heart of the differences in cost, manufacturing and new developments between these two types of image sensor. But last few years 
bring CMOS again in the field of interest with development of new sensors that are considered very serious by leading camera 
manufactures. 
1. INTERDUCTION 
CCD sensor invented by Boyle and Smith in 1969 in Bell Labs 
is from that time until today still leading technology in the field 
of image devices. Incidentally invented technology becomes 
most popular sensor in many cameras in different fields of 
applications. Photogrammetry is only one. New and better 
cameras based on CCD sensor appears almost every day. 
Smaller pixel, bigger resolution, better sensitivity are only some 
of characteristics that are pronounced as relevant for this 
devices. Especially in professional field of use camera based on 
CCD is primary choice. That was true, until last few months. 
Two big companies in the field of imagining devices, Kodak 
and Cannon, presented their products, professional SLR 
cameras based on CMOS sensor. Kodak's DCS pro 14N and 
Cannon's EOS D 60 are today's best proof that domination of 
CCD sensor is going to be questionable very soon. Main 
differences between these two sensors, their advantage and 
disadvantage will be discussed. 
2. TECHNOLOGY 
2.1 CCD 
From it's event, in 1969 by Smith and Boyle, until today CCD 
sensor is still dominant technology in image sensing 
technology. It's performance was for a very long time 
unquestionable in comparations with it's direct competitor 
CMOS. 
Principe of incident light (photons) conversion into electronic 
charge (electrons) using photoelectric effect in silicon wafer is 
main principle used in CCD technology (as well as in CMOS 
technology). 
When a broad wavelength band of visible light fall on silicon, a 
variable number of electrons are released in proportion to the 
photon flux density incident on the surface of a photodiode. The 
number of electrons produced by incident light depending on 
wavelength and intensity are collected in potential well until 
time of illumination is finished (Figure 1.). In CCD sensor 
electrons from potential well are transferred to metering 
register. The electrons are transferred across each photodiode in 
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a multi-step process. Specialized row of gates, serial shift 
register, are answerable for shifting electrons horizontally in 
sequence under control of horizontal shift register clock to an 
output amplifier and off the chip. The entire content of 
horizontal shift register are transferred to the output node prior 
to being loaded with next row of charge from parallel register. 
(Turchetta et. c) 
The Achilles heel of all CCD's is the clock requirement, which 
leads to two disadvantages of CCD sensors; multiple non- 
standard supply voltages and high power consumption. (Denyer, 
1999) 
INCIDENT LIGHT 
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SILICON SLIBSTRATE 
  
Figure 1. Architecture of CCD sensor (Kodak Company, 2000) 
2.2 CMOS 
CMOS imagers convert light in electrical charge in same way 
CCD do. But from the point of sensing onwards differences are 
appearing. Instead transfer, the charge is detected by charge 
sensing amplifiers, which are made from CMOS transistors. 
2.2.1 Passive CMOS sensors. Passive CMOS sensors 
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