Camera Head Technology
November 14, 2002
Thomson Grass Valley: Capturing Your HD Vision
Mark Chiolis, Senior Marketing Manager, Acquisition & Production, Thomson Grass Valley
At Thomson Grass Valley, we recognize that the type of image a camera produces drives our customers' purchasing decisions. To that end, we have spent years continuing to perfect the renowned ãnatural lookä of our LDK series of camera products.
With the advent of high definition digital production, the need for higher-quality technology capable of capturing and processing the increased resolution and wider aspect ratio is critical. While most professional cameras on the market use the same three 2/3-inch CCDs, the method in which they capture red, green, and blue signals differs greatly.
The most common approach to image capture is achieved using Frame Interline Transfer (FIT) and Interline Transfer (IT) CCDs. In addition to capturing an image on a CCD, they use a portion of the CCD's surface for image transfer. This approach may add aliasing and other artifacts to the picture, as the cameraâs electronic circuitry must fill in portions of the image that are missing because the entire CCD was not used to capture the frame.
Thomson Grass Valley takes a different, two-step approach to cameras. The first step is to use as much of the surface area of the CCD as possible for the actual image capture. Consider the LDK 5000, LDK 6000 Mk II, and LDK 6000 Mk II WorldCam cameras. Each uses a 9.2-million-pixel CCD to capture an entire frame of information and then move it from the CCD imager and buffer it while the next frame is put into place. As the image is being moved between the imaging area of the CCD and the buffer store, a mechanical shutter (similar to that on a film camera) covers the lens, enabling a new video frame to be created from scratch and ensuring that there are no remnants of a prior frame mixed in with it. This image-capture process, which uses Frame Transfer technology, completely eliminates vertical smearing from the cameras.
The second part of the Thomson Grass Valley image-capture architecture is a patented technology called Dynamic Pixel Management (DPM). In order to acquire as much picture information as possible, DPM technology allows a camera to over-sample information on a CCD.
The DPM process, which is unique to the Thomson Grass Valley camera family, ensures that users don't have to compromise their production choices because of the sensor inside their camera. Their priceless images are captured in full resolution in any mode.
Using HD DPM+, pixels are grouped and combined to produce a native HD video image in either 1080i or 720p without lowering resolution by "chopping off" either the left and right sides, or the top and bottom.
HD DPM+ also allows a broadcaster to purchase the SD LDK 5000 today, and upgrade whenever they're ready to the LDK6000 Mk II switchable 1080i/720p60 camera÷or to the LDK 6000 Mk II WorldCam, which provides the highest number of natively switched formats (720p 23.98, 24, 25, 29.97, 30, 50, 60 and 1080p 23.98, 24, 25, 29.97, 30 and 1080i 50 and 60) at the touch of a button.
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