Technology Used in Digital Camcorders
Digital video images require advanced digital imaging technology that differs from that used for photography. Canon produces advanced full-HD camcorders that realize high-speed data processing, compact size and low power consumption.
Image Processing for Digital Camcorders
Camcorders incorporate a camera function, which converts signals of images of the subject into video, and a recorder function, which records and plays back the images from the recording media. Every stage of image processing is supported by proprietary Canon technologies.
Conversion into signals
HD codec engine
Compression / Decompression
Recording / Playback
DIGIC DV III
Image Processor for Camcorders with Dramatically Improved Processing Speed
DIGIC DV III is Canon's latest image processor for digital video camcorders. With image processing for digital video camcorders, reducing noise*1 is important, particularly in flat and dark areas. Canon uses proprietary video image processing algorithms to reduce noise and enable the recording of beautiful images with vivid color reproduction and rich gradation.
DIGIC DV III dramatically improves processing speed. It also supports full HD CMOS sensors, providing even higher image quality in video and still images. It also incorporates Face Detection technology, with controls such as face detection AF / AE and face tracking suited for video and photos of people.
In addition, the camera control microprocessor that had previously been on a separate chip has been integrated into DIGIC DV III. Processing speed has been increased through various technologies including Canon's unique architecture for creating ultra-large LSIs.
- *1 Video noise
Random noise is more noticeable in video than in still images and occurs more frequently when shooting in dark conditions. Remedying noise in video camcorders requires a different approach than still cameras.
HD Video Lenses with Image Stabilization and AF Function
Supporting High-resolution HD Images
Full HD-compatible lenses require a high level of resolving power. Canon utilizes glass aspherical lens elements*2 in the lens system, optimizing the position and shape of the elements to achieve the best possible lens configuration for HD video images.
Also, as zoom magnification increases, the effects of camera shake become more pronounced. To counteract this problem Canon employed optical lens-shift image stabilization, which detects a wide range of vibrations from low to high frequencies, and corrects accordingly. This image stabilizing technology shifts the correcting lens element in parallel to the image plane to correct the optical axis in response to image shake.
Furthermore, Canon has developed a "3D Real-time Lens Mechanism" that combines a "Lens-Shift Image Stabilization Correction Lens" that moves perpendicular to the light axis, and a "Zoom Lens" that moves in parallel to the light axis. Models incorporating this lens mechanism maintain excellent image stabilization performance and achieve a wide angle of view while keeping the product size compact.
As out-of-focus images are easily noticed when shooting HD video, Canon's digital camcorders incorporate Instant AF functions to provide fast and accurate focus tracking.
The system employs an external AF sensor to compute the distance to the subject while detecting the contrast based on the image output from the CMOS sensor to deliver fast and accurate focusing performance. The use of two sensors to focus on the subject enables quick and accurate focusing performance.
- *2 Aspherical lens
A lens that is not spherical, but has a curved surface with a radius of curvature that continually changes in the direction of the lens diameter. While it is difficult for a single spherical lens to converge light sharply at a single point, it is possible with an aspherical lens.
Full High-Definition (HD) CMOS Sensors
Providing High Sensitivity, Wide Dynamic Range and Low Noise
The CMOS sensors utilized in Canon digital camcorders needed to be small to make products smaller. The sensor also had to support the reading and recording of full high-definition 1,920 x 1,080 pixel resolution (a total of approximately 2.07 million pixels), creating the need to densely mount the pixels on the sensor to realize outstanding HD-quality images.
Adapting the CMOS sensor technology utilized in its digital SLR cameras, Canon succeeded in developing, and is currently producing, a full HD*3 CMOS sensor for camcorders.
The HD CMOS PRO high-performance sensor, developed by Canon for professional camcorders, incorporates 2.07 million pixels, which is optimal for full HD video. This sensor increases light-gathering capability by increasing the area of each pixel. Furthermore, the curvature of the on-chip microlenses placed on each pixel has also been increased. In addition to increasing the surface area of photodiodes, the charge that can be stored has also been increased by increasing the depth at which electrons are stored. This enables the provision of high sensitivity, wide dynamic range and low noise. It is possible to achieve high-quality video expression approaching professional-level quality.
Consumer digital camcorders incorporating the HD CMOS PRO produce little noise even when shooting in dark places, enabling the shooting of video with high image quality and beautiful color gradation from dark areas to bright areas even when shooting subjects with large differences between bright and dark areas.
In addition to offering high-speed reading of images in full HD with low power consumption, the CMOS sensor also utilizes a primary color filter featuring comprehensive color information that achieves faithful color reproduction while minimizing false colors and moiré patterns. The CMOS sensor incorporates On Chip Noise Reduction Technology that supports low-noise recording in low-light conditions on the sensor side, providing high-quality images in combination with DIGIC DV III's signal processing technology for reducing noise.
- *3 Full HD (compliant)
Digital television signals may be standard-definition (SDTV) with 480 scan lines, the same as analog television, or high-definition (HDTV), with 720 or 1,080 scan lines. Full HD refers to 1,080 scan line systems, which provide the highest level of resolution. With HDTV1080i, the effective number of pixels is 1,920 ÁE1,080, with 1,440 ÁE1,080 pixels per frame.