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MITSUBISHI CCD-200E COLOUR VIDEO CAMERA
COPY
The layout of general purpose video surveillance
cameras has changed little in the past thirty or so years. The overwhelming
majority of them still comprise a fixed lens attached to a box, containing the
pickup device and video processing circuitry. Admittedly there has been a major
revolution in image sensors and electronics over the last few years, but the
design and construction of camera lenses has remained virtually unaltered,
since the C-mount fitting was first introduced in the 1920s. The Mitsubishi
CCD-200 colour video camera marks a significant change in design philosophy,
not only is the lens built inside the body of the camera, it has been equipped
with power zoom and auto-focusing facilities. This approach gives the installer
and end-user far more flexibility over camera location and targeting, it also eliminates
the need for specialist lenses, and opens up a range of new possibilities in
remotely controlled surveillance systems.
The CCD-200 was designed in collaboration
with Mitsubishi’s consumer division, the lens assembly was originally developed
for use in the company’s domestic camcorders. It incorporates a motorised 8x
zoom, controlled by a pair of buttons on the rear of the case. The module contains
a full-range inner-focus lens system, with a focal range extending from 1cm
(wide-angle) to 80cm (telephoto). The sensor is a high-performance 1/3-inch CCD
with a 470k pixel array (440k effective) and it will produce a useable image
down to light levels as low as 1 lux, (in the gain-up mode).
Although the lens unit is extremely compact,
it has meant that the case is slightly taller than usual, however, because the
optics are built-in are no frontal projections, so it is no longer than a
normal compact video camera plus lens. Overall it measures 145 x 76 x 4.6.5 mm,
and weighs just 490 grams. The front of the lens is fitted with a 37mm filter
thread; Mitsubishi have no immediate plans to make use of this facility, but it
can be used to mount a range of wide-angle and telephoto adaptor lenses, intended for camcorders. In addition to the
two zoom buttons the rear panel has two further buttons (for on-screen display,
and auto-focus); in addition there are sockets for composite and S-Video (Y/C) output
and DC power-in socket, plus a green power-on LED indicator. Standard mounting
threads are fitted to the top and bottom of the steel case. The camera is
powered by an external 12 volt DC supply.
The CCD-200 has a number of additional
features, accessed from a menu-driven on screen display. They are: pre-settable
white balance, shutter-speed, backlight compensation, camera ident and manual
or auto-focus. The white balance options include auto and lock; in the auto
mode the camera adjusts the white balance according to the prevailing lighting
conditions. The lock mode is used to fix colour balance to a white reference,
typically a white card or sheet of paper placed in front of the lens. It has
two further presets, for natural (outdoor) and artificial (indoor) lighting. The
electronic shutter has a range of 7-speeds, from the ‘normal’ setting of 1/50th
second, to 1/10,000th of a second. The backlight compensation adjustment has
three settings: off, on and gain-up, the latter increases the camera’s
low-light sensitivity. A camera ident can be superimposed on the bottom right
hand corner of the image, the display shows a letter ‘C’ followed by a number
which can be set from 1 to 16.
When the camera is switched on it displays a
focus set-up message, which indicates that it is returning to the last pre-set
position; white balance and shutter settings are also retained in the camera’s non-volatile
memory when the power is removed. The initial alignment procedure is very
straightforward. White balance, shutter speed and backlight settings are
selected and set from the menu. The focus options are on a second menu screen;
when this is displayed the zoom buttons are used to adjust the focus manually,
alternatively the autofocus system can be momentarily engaged at any time, by
pressing the focus button on the back of the case. If no selections are made after
30 seconds the menu disappears and the camera reverts back to normal operation.
On the CCD-200 the adjustments have to be
made with the camera in-situ, however, Mitsubishi have recently introduced a
second version, (CCD-300), which has an RS232 serial port, enabling all of the
camera’s main functions to be remotely controlled from a dedicated control unit.
This model would be particularly suitable for installations in inaccessible
locations, or used as part of a more wide-ranging surveillance system, in
conjunction with a motorised pan/tilt head. Both models have an end-user price
of £780.
PERFORMANCE
Using a Y/C feed between the camera and a
colour video monitor (we used a Mitsubishi EM1490 for the tests), the CCD-200
managed to resolve in excess of 430-lines. Changing to a composite feed resulted
in a small reduction in picture detail and resolution fell to just over 380-lines.
In both cases picture noise levels were very low, though on composite video hook-ups
there was a slight increase in patterning around fine detail. Colour fidelity in
good natural light is excellent, bright reds are slightly overstated, but there
is no noticeable spillage, or mis-registration. In lower light levels colours
loose vibrancy and there is an increase in noise but the image remains coherent.
The auto WB system copes well with most forms of artificial light, though tube
lighting needs care, and should be set manually using the lock option as it can
result in a slightly yellowish caste. The manual focus controls are reasonably
well-damped, minimising overshoot, but unless the scene contains multiple or moving
targets, the autofocus system can be relied on to produce a sharp lock almost
every time.
OVERALL ASSESSMENT
The CCD-200 is a remarkably versatile design,
well suited to a wide range of applications, from security to audio-visual
presentation. Mitsubishi also tell us they are considering plans to incorporate
the camera into teleconferencing systems, indeed, using one as a fixed-scene surveillance
camera would be a sad waste of its talents, though undoubtedly that’s a job it
does extremely well, moreover the zoom lens frees the installer from having to
choose a specialist lens for each location. There is a price premium to be
paid, though in some circumstances it may be relatively small, compared with
the cost of a similarly specified camera and separate lens.
PRODUCT ASSESSMENT
Design and design features *****
Circuitry and components *****
Ease of installation and wiring ****
Range and variety of functions ****
Accompanying instructions ****
Technical advice and backup ****
Value for money
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Ó R.Maybury 1995 1705
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