The bench test 2: Round the clock

What our experts say …
While we are awaiting the arrival of a universal colour camera that can see in all lighting conditions from near darkness to bright sunshine, there has been a steady stream of integrated day/night cameras that perform this useful feat, either by using built-in infra-red illuminators or by switching from colour to black and white operation as light levels fall below a pre-set threshold. The Ikegami ICD-848P falls into the latter category. At its heart is a ½-inch interline CCD with 440k pixels (752 x 582) giving a claimed 480-line resolution. This yields a low light sensitivity of 0.15 lux and 0.015 lux in colour and black & white modes respectively.

Switching between colour and black & white operation can be controlled manually in camera, remotely or automatically; low light performance is enhanced by a moveable IR cut filter that slides across the front of the image sensor, driven by a small motor. The CCD features an on-chip lens for reduced smear and the camera has a good selection of camera and exposure controls, including user-set colour/monochrome switching, spot backlight compensation, manual/auto white balance, auto electronic shutter, manual shutter and switchable AGC. There is also a camera ident, external genlock, auto iris lens option (video or DC controlled) and everything is controlled by a simple to use on-screen display system.

The design/layout is conventional and it is housed in a sturdy metal case measuring 64W x 54H x 120D with a two-part steel shell and lightweight cast alloy end caps. A block with threaded bosses for mounting hardware can be attached to the top or the bottom half of the case. At the front is a standard C/CS lens mount attached to a simple back-focus mechanism, which is set using a large thumbwheel and locking screw set into the left of the case. On the right are a four-pin square socket for an auto-iris lens and a tiny switch for selecting DC or video-control modes. Around the back is a pair of BNC sockets for video input and an external genlock. Between them there is a switch for selecting 'high' or 75 Ohm impedance. On the right is a cluster of five small buttons for accessing the on-screen displays (OSD) and in the centre a two-way spring terminal handles connections to an optional remote control unit (RCU-701), which duplicates the camera's on-board menu controls.

The model looked at has a built-in mains power supply and the captive power cable enters the back panel just below the OSD control buttons; a 12v DC/24v AC version is also available. A green power on LED is positioned just above the mains cable entry point. Most of the bottom half of the case is occupied by the mains power supply. Above that are two large PCBs, running the length of the case containing the electronics for the camera's signal processing and control systems. These are firmly bolted to an internal chassis forming a very rigid structure.

The on-screen display appears after the Enter button has been held down for a couple of seconds. There are eight options; the first is for enabling and setting up the camera ID. This can be up to 16 characters long and it may be positioned anywhere in the screen area. The second menu option is for Day/Night operation: the choices are on, off and remote, and if enabled there is a sub menu for setting the switchover points for colour to B/W and B/W to colour.

The third menu option is for the electronic shutter; selecting the variable mode brings up another sub menu for manual setting, 1/50 – 1/10,000 second: this is unusually precise. It can be set coarsely in nine steps, or fractions of a second in something like 400 steps.

The fourth menu is used to select auto exposure or lens-controlled iris and the backlight option. The latter has two sub menus for adjusting the backlight level or configuring the area of the screen for 'spot' backlight control. When selected, a shaded block is superimposed on the image and this can be positioned and re-sized to accommodate bright lights or windows in the scene area. Menu option five is for selecting gain, either normal AGC or 'Hyper' AGC. Below that is the white balance control; ATW1 varies between 2600 and 6000k, ATW2 covers 2000 to 6000k (to compensate for sodium lighting); AWC allows the white balance to be set to a white card reference and Manual brings up adjustments for individually setting red and blue gain levels.

The fifth menu option is used for switching between internal or external synchronisation, with a sub menu for setting line-lock. And finally there is a menu lock that disables the OSD. It can only be unlocked by pressing the control buttons in a set sequence. Most menu screens have a Reset function, which returns the displayed adjustment to its factory default. We were surprised to discover two faulty pixels in the displayed image. One was on the vertical centre line, about a quarter of the way down the screen and was always on, producing a notice-able white spot in the picture that was fairly prominent in both colour and black & white operation. The second was a little to the right of the first bit. This was a lot dimmer, only showing up in low light/night operation.

Camera manufacturers' tolerance towards faulty pixels varies. Most will reject an image sensor if the pixel in question is brightly lit or close to the centre of the screen; the two on our sample were arguably borderline but we suspect these two are sufficiently visible not to have made it through Ikegami's normally scrupulous quality control checks and probably failed after final inspection Colour/black & white switching is quite sedate and the function appears to be heavily damped to stop it happening when lighting levels drop suddenly, due to passing shadows etc. Even so it is quite slow and it can take 12 – 15 secs for the switchover to occur, if for example the scene lighting is switched on or off. The motor used to shift the filter grinds a bit. Picture quality is excellent and in a typical well-lit scene resolution on our sample was very close to the manufacturer's specs. The image is packed with fine detail, noise levels are exceptionally low and the auto white balance system managed to produce natural looking colours in both mixed and natural light. At lower lighting levels there is a progressive increase in noise in a colour image but it ratchets down again as the camera switches to black & white mode and does not reappear until light levels approach the lower extreme. Quality of construction and mechanical stability are beyond reproach.

What the manufacturer says ...
The ICD-848P is a multi functional camera that can switch between colour and monochrome images according to changes in illumination. It is ideally suited for use in round-the-clock surveillance such as city centre applications. It achieves a minimum subject illumination of 0.15 lux/F1.4 in colour and 0.015 lux/F1.4 in monochrome.

The switching can be set for Auto Mode for automatic switching, Remote Mode for switching in response to an extraneous control signal or Manual Mode for manual switching.

The camera features a high-sensitivity on-chip lens CCD to provide a smear level of -126dB. Appropriate video can be attained even when, for example, a car headlight is directly captured at night.

With the Spot Backlight Compensation feature it is possible to reproduce an optimal image, even when a car numberplate or a person are captured in a backlight situation.

In addition to auto tracking Auto White Balance (ATW1) the camera also features ATW2 which is fully compatible with sodium vapour, commonly used for street lighting.

All the above, coupled with its state-of-the-art ½" 480 TVL Digital Process Circuitry, means that the ICD-848 can produce a rock-solid, sharp image in virtually any CCTV surveillance environment. Couple that to an industry-leading five-year warranty and you have a package that leaves the competition in its wake!