The JVC-240  Hz Camera

By

Gideon Ariel, Ph.D.

Introduction

(You may go to "How it works with the APAS" directly here)

   Lately, the JVC corporation introduced a new camera named, GR-DVL9800.  This camera utilized what the JVC corporation named:   Progressive Scan CCD.  I will explained what it means in a minute, however, it seems that this camera sample a video data at 240 Hz.  The way it is done is very unique and was not designed for biomechanical use. However, utilizing a software developed at Ariel Dynamics Inc., it is possible to extract 240 Hz data. In the following paragraphs I will explain how we are doing it and how we were able to offer this great functionality to the biomechanical World for lowest price possible.   

This exciting new addition to the popular CyberCam line-up, the GR-DVL9500 offers unprecedented resolution -- 500 lines (horizontal) by 480 lines (vertical)* -- thanks to its progressive scan CCD, progressive color filter, and high-band processor. All these features in one unit bring out the full benefits of the DV platform. The resulting quality of both full-motion video and still images sets a new standard for the industry, fully complementing the unit's enhanced multimedia connectivity.

*In progressive recording mode You may go directly to the how it works with the APAS section

   Four Key Technologies for High Picture Quality

JVC has equipped the GR-DVL9500 with four advanced technologies that make the most of digital video and offer outstanding resolution: 500 lines (horizontal) by 480 lines (vertical).

Progressive Scan CCD
Virtually all camcorders, analog or digital, employ the conventional interlace scan system in which only half a frame (a field) is recorded at a time. This works well for full motion images, but a 1/60-second gap exists between the processing of each field. Combining two fields results in smooth full-motion images, but this time gap causes picture blur when paused. To create razor-sharp still images progressive scan technology is needed. This simply means that an entire frame image is recorded in one scan. As there is no time gap, there is no picture blur when frame data is used for stills. This is ideal for playback, and also for printing or capturing still pictures to your computer.
In addition to clear freeze-frame stills, the progressive scan CCD provides extremely high vertical resolution -- the equivalent of 760,000-pixel quality* -- when the two fields are combined into a frame-still image. This is because conventional CCD image sensors combine signals from adjacent scanning lines for processing, whereas the scanning lines of a progressive scan CCD are processed individually.
*The progressive scan system outputs images per frame, the equivalent of doubling the vertical resolution of conventional interlace CCDs which output per field.
Progressive Color Filter
JVC's own progressive complementary color filter generates a pure signal from each scanning line. Together with the progressive scan CCD, this approach raises vertical resolution -- a major determinant of picture quality -- to an impressive 480 lines. Furthermore, the complementary color filter offers greater sensitivity compared to the RGB filter systems found on other DV cameras. Increased sensitivity is also provided by the bright, large-aperture F1.2 lens.
High-band Processor
The third key to ensuring first-rate picture quality is a high-band processor. By restoring the high-band component of the luminance signal that is removed to avoid interference with the chrominance signal, this expands horizontal resolution to 500 lines.
Spline Interpolation (40x & 200x digital zoom)
In addition to the 10x optical zoom, this CyberCam offers a 40x digital zoom and a 200x Super Digital Zoom. To smooth contours and ensure high picture quality, both digital zoom modes generate spline interpolation data from progressive-scan frame images. And since frame signals, not field signals, are processed, vertical resolution is increased, also improving quality.* *Note that picture resolution decreases as the zoom ratio increases.
High-quality Frame-still Picture for Printing or Capturing on to a PC
Progressive recording ensures that you will have clear, blur-free still images as you record your favorite scenes. The fact that progressive scan images are recorded as frame data means that high grade frame-still pictures will be available whether for printing or transfer to computer. With the added superior sensitivity of the progressive color filter and F1.2 lens, full-motion video and still images taken by the GR-DVL9000 set a new standard, complementing the unit's enhanced multimedia connectivity.
Bright F1.2 Lens with 10x Optical Zoom
The large-aperture lens assures enhanced sensitivity, so you can shoot scenes with very low noise in low-light conditions. A 10x optical zoom allows you to shoot your favorite scenes close-up and in detail.
Multimedia Connectivity
As well as connecting to a TV for playback, the GR-DVL9800 can output digital image data with no loss of image quality. A JLIP terminal allows direct connection to the 9-pin serial port (RS-232C) of either desktop or laptop computers (running Microsoft Windows). This makes it possible to capture video stills without the need for a capture board. JLIP (Joint Level Interface Protocol), a communications protocol developed by JVC, enables computer control of the camcorder such-as video-to-video editing. The GR-DVL9800 can also output digital image and sound data via its DV (i.Link, IEEE 1394 compliant) terminal to other equipment with DV input terminals such as JVC's GV-DT1 digital printer. Supplied with this digital video camera are all the software (JLIP Video Capture 2.0, PhotoSuite SE, JLIP Video Producer 1.1)* and cables needed for capturing and processing video stills as well as editing video footage. *For Microsoft Windows 95 or 3.1.

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