DIGIC

Digital Imaging Core (usually referred to as DIGIC, sometimes rendered as DiG!C) is Canon Inc.'s name for a family of signal processing and control units for digital cameras and camcorders. DIGIC units are made by Canon and used in its own digital imagery products.

Technically, a DIGIC unit is a proprietary application-specific integrated circuit designed to perform high speed signal processing as well as the control operations incorporated in the respective product. There are several generations of DIGICs distinguished by name appendix.

An open/free firmware for these units has been developed under the CHDK project.^[1] It allows users to non-destructively augment the original firmware and write custom programs with new features.

DIGIC

The original DIGIC was used on the Canon S1 IS (Mar 2004), A520 (Mar 2005), and other cameras. It consists of three separate chips: a video processing IC, an image processing IC and a camera control IC.

DIGIC II

DIGIC II is a single chip (unlike the first DIGIC). This led to a more compact design by reducing the parts. DIGIC II also improved upon the original DIGIC by adding a larger buffer and faster processing speed. It uses high-speed DDR-SDRAM, which improves startup time and AF speed. Canon claims DIGIC II improves color, sharpness, and automatic white balance with its CMOS sensor in its digital SLR camera line. It is used in some advanced consumer-level cameras and many digital SLRs such as Canon EOS 400D and Canon EOS 5D. It can write to memory card at speeds up to 5.8 MB/sec.^[2]

DIGIC III

Front view of Canon PowerShot A720 IS

The DIGIC III Image Processor was advertised to deliver superior image quality, faster operation and extended battery life compared to its predecessor. DIGIC III provides a faster interface to the SD memory card for the Canon PowerShot G7 and G9, SD750, SD800, SD850, SD900, SD 1000, A560, A570 IS, A590 IS, A650 IS, A720 IS, A495, EOS XS/1000D, EOS XSi/450D, EOS 40D, EOS 1D Mark III, EOS 1Ds Mark III, and S5 IS. It also provides higher resolution for their LCD screens.^[3]

New features

DIGIC III provides new Face Detection AF/AE, which finds and tracks up to 9 faces in the frame and controls exposure and flash to ensure proper illumination of the faces as well as the rest of the frame, reducing the detrimental effect of overexposed or darkened faces in a photo. It reverts to the AiAF system if the subject is either not detected or not deemed to be a subject (based on the iSAPS database). The latter is useful at tourist spots where there may be many people around who are not intended to be the subject of the scene.^{[citation needed]}

Scene-recognition

iSAPS Technology is an entirely original scene-recognition technology developed by Canon for digital cameras.^[3] Using an internal database of thousands of different photos, iSAPS also works with the DiG!C III Image Processor to improve focus speed and accuracy, as well as exposure and white balance.^[3]

Dual DIGIC III

DIGIC III is also being used in Canon's Digital SLR cameras (as of 2007). The Canon EOS-1D Mark III uses dual DIGIC III processors to achieve a capture rate of 10 frames per second at 10.1 MP (with a maximum burst of 110 JPEG images, depending on the speed of the attached storage).^[4] The Canon EOS-1Ds Mark III also uses dual DIGIC III processors to achieve a 5 frame per second at 21.1 MP.^[5]

DIGIC 4

The Canon PowerShot SX210 uses the DIGIC 4 processor.

In 2008, Canon introduced the new DIGIC 4 processor, used by the EOS 1100D/Rebel T3, EOS 500D/Rebel T1i, EOS 550D/Rebel T2i, EOS 600D/Rebel T3i, EOS 50D, EOS 60D, EOS 5D Mark II and EOS 1D X (for metering and AF only) . It is also used in newer cameras in Canon's PowerShot lines (A, G, S, SD, and SX).

Canon claims improvements such as:

• Much faster image processing when compared to previous processors
• Improved noise reduction in high-ISO images
• Improved performance while handling larger 14-bit RAW images
• Live Face Detection AF during Live View
• H.264 1080p encoding.^[6]

Dual DIGIC 4

Dual DIGIC 4 processors are used in the EOS 7D and EOS-1D Mark IV.

DIGIC 5

Digic 5 is now featured on Canon compact cameras like PowerShot SX40 HS to achieve a capture rate of 10.3 frames per second at full resolution in High-Speed Burst HQ, Full HD 1080p Videos and Intelligent Image Stabilization. The new Digic 5 processor is 6X faster and creates 75% less noise than the Digic 4 processor.^[7]

DIGIC 5+

Digic 5+ is used in Canon EOS-1D X (available March 2012). The EOS-1D X will include dual Digic 5+ processors allowing for a capture rate of 12 frames per second in RAW.

DIGIC DV

The DIGIC DV is used in Canon's single-chip CCD digital camcorders as well as the DC20 and DC40 DVD camcorders.

DIGIC DV II

The DIGIC DV II utilizes a hybrid noise reduction system and a new gamma system. The processor is used in all of Canon's high-definition camcorders and, with the exception of the DC20 and DC40, all of their DVD camcorders including the new SD camcorders FS100, FS10, FS11.

DIGIC DV III

The DIGIC DV III processor is used in the new Canon's Legria (PAL)/Vixia (NTSC) high-definition HFS100, HFS10, HF200 and HF20.

Custom firmware

CHDK firmware, showing the on-screen display editor

The DIGIC board contains an x86 compatible processor (NEC V30 emulation) running Datalight ROM-DOS^[8] and two other chips (the image processor itself and a Motorola 68HC12).^[9]

The DIGIC II and DIGIC III ASICs contain embedded 32-bit ARM architecture processors. Until around 2007, Canon point-and-shoot cameras ran a VxWorks-based operating system, but recent cameras are based on the DRYOS operating system developed in-house by Canon.^[10][11]

CHDK

The free software Canon Hack Development Kit (CHDK) project, started by Andrey Gratchev, has successfully enhanced many Canon PowerShot cameras without replacing the stock firmware.^[12] It allows vast programmatic control of many Canon compact cameras, enabling users to add features, including games and scripts written in UBASIC or Lua. Features include shooting in RAW, USB-cable remote shutter-release, motion-detection triggered photography, customizable high-speed continuous (burst) Tv, Av, ISO, and Focus bracketing (increasing depth of field), 1 Gig video-size limit removed in earlier cameras, Shutter, Aperture, and ISO overrides (shutter speeds of 64" to 1/10,000" and higher).^[13]

For the CHDK project to augment or extend firmware, it was necessary to obtain copies of the cameras' original firmware; in some cases this can be done via a pure software method, while others^[14] rely on a method of using a blinking LED on the camera as an optical serial port to transmit the firmware to a host computer.^[15]

Magic Lantern

Magic Lantern is a firmware add-on written for the Canon 5D Mark II by Trammel Hudson in 2009, and ported to the 550D/T2i/Kiss X4 (1.0.8) in July 2010 by the same author.^[16] Starting september 2010, A1ex from CHDK forum and other people ported this firmware to 550D/T2i (1.0.9), 60D, 500D/T1i/Kiss X3, 600D/T3i/Kiss X5 (1.0.1) and 50D, where a large number of features were added.^[17] It has features that manage video and still photography (without replacing the stock firmware).^[18]

400plus

400plus is a free firmware addon which offers additional functionality for Canon 400D a non-destructive and non-permanent way.^[19]

See also

• Raw image format
• Camera Image File Format

References

1. ^ "CHDK Wiki". Chdk.wikia.com. 2006-03-30. http://chdk.wikia.com. Retrieved 2010-12-30. 
2. ^ [1]^{[dead link]}
3. ^ ^{a b c} "Canon Powershot G7 digital camera". Usa.canon.com. 2006-05-25. http://www.usa.canon.com/consumer/controller?act=ModelFeaturesAct&fcategoryid=144&modelid=14321&pageno=1. Retrieved 2010-12-30. 
4. ^ "Canon UK - EOS 1D Mark III". Canon.co.uk. 2009-10-20. http://www.canon.co.uk/For_Home/Product_Finder/Cameras/Digital_SLR/EOS_1D_Mark_III/index.asp. Retrieved 2010-12-30. 
5. ^ "Canon UK - EOS-1Ds Mark III". Canon.co.uk. 2010-07-23. http://www.canon.co.uk/For_Home/Product_Finder/Cameras/Digital_SLR/EOS-1Ds_Mark_III/index.asp. Retrieved 2010-12-30. 
6. ^ Tomohiro Otsuki, Nikkei Electronics (2008-09-22). "Canon Tips Off Enhanced Capabilities of Its New Image Processor - Tech-On!". Techon.nikkeibp.co.jp. http://techon.nikkeibp.co.jp/english/NEWS_EN/20080922/158348/. Retrieved 2010-12-30. 
7. ^ vashistha pathak, New Camera (2011-09-15). "Canon New Digic V Image Processor". thenewcamera.com. http://thenewcamera.com/?p=6669. Retrieved 2011-10-26. 
8. ^ Tuesday, 24 August 1999  04:00 GMT (1999-08-24). "Canon Pro 70 runs ROM-DOS!: Digital Photography Review". Dpreview.com. http://www.dpreview.com/news/9902/99022402canonromdos.asp. Retrieved 2010-12-30. 
9. ^ "Harware of Canon PS A70 (in czech)". Rayer.ic.cz. http://rayer.ic.cz/hardware/a70.htm. Retrieved 2010-12-30. 
10. ^ "Canon Technologies". Canon. http://www.canon.com/technology/canon_tech/explanation/cp_tech.html#dryos. Retrieved 2011-11-04. 
11. ^ "DryOS Porting - OS Switch". Chdk.wikia.com. http://chdk.wikia.com/wiki/DryOS_Porting#OS_Switch. Retrieved 2010-12-30. 
12. ^ "How to give your low-end Canon digital camera RAW support". Linux.com. http://www.linux.com/feature/118946. Retrieved 2010-12-30. 
13. ^ Slashdot, Hacking Canon Point-and-Shoot Cameras, Posted by kdawson on Tuesday May 06, @04:56PM, from the now-don't-brick-it dept.
14. ^ Canon-hack Development Kit (CHDK) - StereoData Maker
15. ^ "Porting the CHDK - CHDK Wiki". Chdk.wikia.com. 2010-12-18. http://chdk.wikia.com/wiki/Porting_the_CHDK#Hardware-software_solution. Retrieved 2010-12-30. 
16. ^ Magic Lantern Firmware Wiki
17. ^ http://magiclantern.wikia.com/wiki/Unified
18. ^ Digital Convergence Episode 3 - Trammell Hudson and Magic Lantern Firmware for the Canon 5D Mark II
19. ^ User Guide for 400plus

External links

• CHDK project at Wikia
• CHDK Autobuild (An easy way to get the latest CHDK build for your camera)
• http://www.nytimes.com/2010/05/27/technology/personaltech/27basics.html?8dpc, about CHDK in NYT