Vandal Hunt: The HTC-11H/3.6-9IR colour dome camera from Hunt Electronics

What our experts say…

In the discreet, semi-anonymous world of video surveillance, it is not strictly necessary for manufacturers to come up with snappy names for their products. A simple model number is usually more than sufficient, but Hunt Electronics clearly feels that the designation HTC-111H/3.6-9IR, for one of the most recent additions to its camera range, lacks pizzazz, which may explain why it has been dubbed the ‘IR Vandal Dome’.

Hunt is unlikely to win any marketing awards for such a catchy title but it’s short, succinct and neatly sums up what this tough little camera is all about. The IR Vandal Dome, as the name broadly implies, is designed for use in physically challenging and poorly-lit environments. In fact it is a true day/night camera and will operate in zero lux, thanks to its built in IR illuminator.

The camera module is based around a 1/3-inch CCD with a 752 x 582 (440k pixel) sensor that has a claimed resolution of 520 lines. It is fitted with a 3.6-9mm auto-iris lens and IR cut filter that slides out from in front of the sensor when it switches to night mode. At the same time a semi-circular ring of twelve 900nm IR LEDs, mounted around the lens, light up, providing a pool of illumination immediately in front of the lens. Switching is fully automatic and controlled by a light sensor mounted above the lens, between the IR LEDs.

A simple gimbal arrangement allows the camera to swing though almost 160 degrees, rotate through 180 degrees and tilt around 30 degrees either side of the centre line. Control options are confined to a switchable AGC, auto electronic shutter (AES) and backlight compensation, otherwise all normal exposure and colour balance operations are handled automatically.

Focus and tele/wide settings on the lens can be fine-tuned, but apart from that installation mainly involves fixing the camera in place and connecting up the power supply (DC 12 volts) and video output. These are handled by a short flying lead that emerges through an aperture in the base (or the side of the housing) and this is terminated with a DC power connector and BNC socket.

The two-part case comprises an alloy base and a removable plastic top cover and transparent dome. The two parts are linked by a short suspension cable. A rubber gasket provides a weatherproof seal between the case and the dome cover and this is held in place by four tamper-resistant screws; a tool is included in the fixing kit that accompanies the camera.

Inside the case there is the aforementioned camera mounting bracket and a single small PCB that carries the power and video connections plus a 3-way DIP-switch, for the AES, AGC and backlight functions. The camera module is connected to the board by two short cable looms. Everything is very neatly laid out, accessible and unlikely to cause any problems for installers or during cleaning and maintenance.

Setup and operation

The instructions are sparsely printed on just two sheets of A4 paper, and this says it all, really. Installation of the Vandal Dome couldn’t be much simpler and basically entails fixing it to a ceiling or wall – using the screws and wall plugs provided – and routing the power/video cable. In fact it’s probably best not to read the instructions too closely, as they were obviously translated in quite a hurry. Apart from the shaky grammar there are some real gems like ‘Adjust the camera horizontal angel’ and a mysterious component on the parts list referred to as an ‘iron spring flake’…

Once it has been mounted all that remains is to align the camera, by slackening off four thumbscrews on the support bracket then setting the AES, AGC and backlight switches as necessary. A black plastic shroud inside the dome, designed to cut down internal reflections and mask the innards, may need re-aligning, to ensure the camera view is unobstructed and this is accomplished by loosening two retaining screws on the inside of the cover. The day/night switching function can be easily checked by covering the light sensor, at which point the IR filter mechanism should click and the IR illuminators will emit a dull red glow.

Performance

One unusual characteristic of this camera is that the image doesn’t change instantly from colour to black and white when the LED illuminators and IR filter switch over. Instead there is a progressive reduction in colour saturation and a steady increase in grain and noise as the AGC ramps up.

This is not a problem, however, but a threshold control might prove useful in some circumstances as the image can appear a little confused if there are any bright lights or well lit surfaces in the image area, and the processing circuitry can’t quite make up its mind whether to display a colour or monochrome picture. The IR illuminators work well enough but with only 12 LEDs coverage is necessarily quite limited so it is really only useful for lighting objects and subjects within three or four metres of the lens.

Otherwise, in good natural or mixed light the image is very clean with a lot of fine detail that’s within a whisker of the manufacturer’s resolution figure. Unusually for a dome camera the image is largely free of internal reflections. The auto white balance system works well too; colours are bright and accurately rendered. Moreover noise levels are very low and only become significant at or close to the day/night switcher point. Stability is excellent with no disruption to the picture when the camera is subjected to vigorous mechanical shock.