What is DIGIC Image Processing?

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.

Free software from the CHDK project allows users to non-destructively modify the firmware and write custom programs with new features.

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


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.


Front view of Canon PowerShot A720 ISThe 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, SD100%, SD800, SD850, SD900, SD 1000, A560, A570 IS, A590 IS, A650 IS, A720 IS, 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.

Some DIGIC III cameras can be modified with CHDK

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.


iSAPS Technology is an entirely original scene-recognition technology developed by Canon for digital cameras. 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.


DIGIC III is also being used in Canon's latest (as of 2007) Digital SLR cameras. 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) . The Canon EOS-1Ds Mark III also uses dual DIGIC III processors to achieve a 5 frame per second at 21.1 MP


In 2008, Canon announced a new chip. The 50D, 5D Mark II and 500D use the DIGIC 4 processor. 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.
Also, some new PowerShot cameras include the chip. It adds some new features compared to the DIGIC III.


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


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.


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

Custom firmware

CHDK firmware, showing the on-screen display editorThe DIGIC board contains x86 compatible processor (NEC V30 emulation) running Datalight ROM-DOS and two other chips (the image processor itself and Motorola 68HC12).

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.

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. It allows vast programmatic control of many Canon compact cameras, enabling users to add features, up to games and BASIC scripting. 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).

For the CHDK project to modify 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 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.

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