Prepared by: Yashodhan Tarte Dept. of Electrical and Computer Engineering Utah State University

1. ECE5320 MechatronicsAssignment#01: Literature Survey on Sensors and Actuators Charge-Coupled Device (CCD) Image Sensors Prepared by: Yashodhan Tarte Dept. of Electrical and Computer Engineering Utah State University E: y.tarte@usu.edu ; T: (435)797-2845 3/11/2005

2. Outline • Reference list • To explore further • Major applications • Examples of CCD sensors • Basics of digital imaging • CCD formats • CCD architectures • Basic working • A specific application of CCDs • Limitations • Application issues ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

3. Reference list • The Image Sensor Market by Tom Hausken, StrategiesUnlimited • Atmel CCD sensors • Understanding how image sensors work 4.Charge-Coupled Device (CCD) Image Sensors, Eastman Kodak Company, Rochester, New York 5. Nikon Inc., USA • Sony Electronics e-Solutions Company LLC, USA 7. CCD vs. CMOS: Facts and Fiction by Dave Litwiller ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

4. To explore further • To know the history of evolution of CCD sensors, go to: http://ranier.hq.nasa.gov/Sensors_page/DD/HST&GLL_CCD.html • To explore CMOS image sensors, go to: http://www.beyondlogic.org/imaging/camera.htm • You may also want to look at The Mechatronics Handbook by Robert H Bishop ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

5. Major applications • Robotics6 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

6. Major applications (cont.) • Digital photography5 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

7. Major applications (cont.) • Space imaging2 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

8. Major applications (cont.) • Biomedical imaging2 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

9. Major applications (cont.) • Industrial inspection2 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

10. Examples of CCD sensors • CCD Linescan arrays2 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

11. Examples of CCD sensors (cont.) • CCD Area Arrays2 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

12. Basics of digital imaging3 • Digital cameras use a solid-state device called an image sensor to capture and store an image. • These fingernail-sized silicon chips contain millions of photosensitive diodes called photosites. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

13. Basics of digital imaging (cont.)3 • In the brief flickering instant that the shutter is open, each  photosite records the intensity or brightness of the light that falls on it by accumulating a charge; the more light, the higher the charge. • The brightness recorded by each photosite is then stored  as a set of numbers that can then be used to set the color and brightness of dots to reconstruct the image. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

14. Basics of digital imaging (cont.)3 • Digital photographs are made up of hundreds of thousands or millions of tiny squares called picture elements, or just pixels. • Each of these pixels is captured by a single photosite on the image sensor when you take the photo. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

15. Basics of digital imaging (cont.)3 • On an image sensor, each photosite captures the brightness of a single pixel. • The layout of the photosites can take the form of a grid or honeycomb. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

16. Basics of digital imaging (cont.)3 • Photosites arranged in a grid layout ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

17. Basics of digital imaging (cont.)3 • Photosites arranged in a honeycomb layout ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

18. CCD formats4 • Point Scanning: Sequentially detecting scene information at discrete XY coordinates using a single pixel. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

19. CCD formats (cont.)4 • Line Scanning: An array of single cell detectors can be placed along a single axis such that scanning now takes place only in one direction. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

20. CCD formats (cont.)4 • Area Scanning: A two dimensional array of detectors can be created such that the entire image can be captured with one exposure. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

21. CCD architectures4 • Full-Frame CCDs:Images are optically projected onto the parallel array that acts as the image plane. The device takes the scene information and partitions the image into discrete elements that are defined by the number of pixels thus "quantizing" the scene. The resulting rows of scene information are then shifted in a parallel fashion to the serial register that subsequently shifts the row of Information to the output as a serial stream of data. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

22. CCD architectures (cont.)4 • Full-Frame CCDs: ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

23. CCD Architectures (cont.)4 • Frame-Transfer CCDs: They are very much like FF architectures. The difference is that a separate and identical parallel register, called a storage array, is added which is not light sensitive. The idea is to shift a captured scene from the photosensitive, or image array, very quickly to the storage array. Readout off chip from the storage register is then performed as previously described in the FF device while the storage array is integrating the next frame. This enables shutterless operation. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

24. CCD architectures (cont.)4 • Frame-Transfer CCDs: ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

25. CCD architectures (cont.)4 • Interline CCDs:These perform photo-detecting and readout functions by forming isolated photosensitive regions in between lines of non-sensitive or light shielded parallel readout CCDs. After integrating a scene, the signal collected in every pixel is transferred, all at once, into the light shielded parallel CCD. Transfer to the output is then carried out similarly to FF and FT CCDs. This helps in achieving high frame rate and improves the image smear during readout. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

26. CCD architectures (cont.)4 • Interline CCDs: ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

27. Basic working4 CCD imaging is performed in a three step process: • Exposure which converts light into an electronic charge at discrete sites called pixels; • Charge transfer which moves the packets of charge within the silicon substrate; and, • Charge to voltage conversion and output amplification. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

28. A specific application of CCDs2 • ATMEL Large Format Machine Vision Sensors: Camelia 1.6M CCD type: Area array No. of pixels: 1536 X 1024 Output: 12 bit digital Frames/sec.: 10 F/s ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

29. Limitations • Blooming • High power consumption • Higher cost • Complexity of design and fabrication • Complex support circuitry ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

30. Application issues7 Things to look for in a CCD sensor: • Responsivity • Dynamic range • Antiblooming • Shuttering • Speed • Uniformity • Windowing ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

31. Application issues (cont.)7 CCD image sensor manufacturers: • Sony Corporation • Panasonic • Sharp • Atmel • Eastman Kodak ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators