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Charged Coupled Device Imaging. By Marc Castro 17443948. CCD Imaging Process. (3 step process) 1. Exposure Converts light into an electronic charge at discrete sites called pixels, photo sites, photodiodes or capacitors. 2. Charge Transfer One of the CCD architectures is used.

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charged coupled device imaging

Charged Coupled DeviceImaging


Marc Castro


ccd imaging process
CCD Imaging Process

(3 step process)

1. Exposure

Converts light into an electronic charge at discrete sites called pixels, photo sites, photodiodes or capacitors.

2. Charge Transfer

One of the CCD architectures is used.

3. Charge to voltage

Signal conversion from analog (electrical charges)

to digital (0’s and 1’s).

how does it look like
How does it look like?

Charged Couple Device

what is it
What is it?
  • Charged Coupled Device (CCD)
    • an analog shift register, that enables the transportation of analog signals (electric charges) through successive stages (pixels) controlled by a clock signal.
  • Primary uses:
    • Memory
    • Delaying samples of analog signals
    • In an array of photoelectric light sensors (image sensors)
  • Invented in 1969
    • Creators: Willard Boyle and George E. Smith
    • Location: AT&T Bell Labs. Currently part of Lucent Technologies
    • Motivation: the lab was working on the picture phone and on the development of the semiconductor bubble memory.
    • CCD – originally designed as an electronic memory device that can be charged by light.
ccd fabrication
CCD Fabrication
  • Made using photolithography techniques.

Individual pixel gate fabricated on a silicon wafer

Courtesy of Olympus

end product
End Product

Don Groom LBNL


Capturing Images


- comprised of many individual signal capture units (photo sites, capacitors, pixels)

CDD - 2D Pixel Array


Capturing Images

How charges are stored

  • CCDs are comprised of pixels (capacitors) which are MOS (Metal Oxide Semiconductors).
  • MOS allow electron charges to build up within the wells.
capturing images
Capturing Images
  • Light – incoming photons falls onto the surface of a pixel.
  • (CDD - 2D array of pixel elements)
  • Result- generates free electrons in the silicon of the CCD due to the photoelectric effect, proportional to the number of photons striking it. These electrons collect in little packets.
  • Point- the total charge is proportional to the light intensity at that pixel.
  • A brighter image ( higher electrical charge).
  • A darker image ( lower electrical charge).
  • Drawback- only measures intensity. Not color!!!
  • CCD’s normally have 1 to 5 million packets of charge.

CCD Scanning Formats

CCDs can be used to collect an image in one of three ways, either one pixel at a time, one row at a time, or as an entire area at once.

methods to capture color
Methods to capture color

Method 1: Beam Splitter

Method 2: Bayer Pattern

Courtesy of HowStuffWorks

2 d pixel array with bayer pattern
2-D Pixel Array with Bayer Pattern
  • Used over the CCD (color grid over imaging array)
  • Each square (4 pixels) contains
    • One red
    • One blue
    • Two green
transfer image from array
Transfer image from array.
  • General Idea –
    • Control circuit causes each pixel to transfer its contents to its neighbor using a clocking scheme. The last pixel in the array dumps its charge into a charge amplifier, which converts the charge into a voltage.
    • The controlling circuit converts the entire semiconductor contents of the array to a sequence of voltages, which it samples, digitizes and stores in some form of memory.
readout architecture
Readout Architecture
  • Full Frame
  • Frame Transfer
  • Interline
    • They are the most common
full frame architecture
Full Frame Architecture

Courtesy of Molecular Expressions

frame transfer architecture
Frame Transfer Architecture

Courtesy of Molecular Expressions

interline architecture
Interline Architecture

Courtesy of Molecular Expressions

storing the image
Storing the image
  • Analog to digital converter
    • Samples the analog signal and turns the information into bytes of (1’s and 0’s).
    • Charge amplifier – converts the charge into voltage.
  • Record bytes in a storage medium
    • Memory Cards
    • Hard Drive
    • DVD

Digital Photography



Electron Microscopy

Medical Fluoroscopy

Optical and UV Spectroscopy

  • Astronomical Telescopes
  • Scanners
  • Bar code readers
  • Machine vision for robots.
  • Optical character recognition (OCR)
works cited
Works Cited
  • Tom Harris. “How Camcorders Work.” HowStuffWorks.
  • “Charge-coupled device.” Wikipedia.
  • “Building A Charge-Coupled Device.” Olympus Microscopy Resource Center.
  • Tom Thompson. “Charge-Coupled Device.” ComputerWorld.
  • “What is a Charge-Coupled Device.” Tech-Faq.
  • Lucent Technologies. “CCD-The History of CCDs or Charge Coupled Devices.” Inventors.
  • “Charge-Coupled Device (CCD) sensor.” MIR. http://www/mir/
  • “Charge-coupled deivce.”,,sid5_gci295633
works cited23
Works Cited
  • “Anatomy of a Charge-Coupled Device.” Molecular Expressions Optical Microscopy Primer: Digital Imaging in Optical Microscopy.
  • Eric Meisenzahl. “Charge-Coupled Device Image Sensors.” Eastman Kodak Co.
  • “Charge-couple device.”