Hikvision Thermal Camera, Bi-spectrum Anti-corrosion Bullet, 25 mm Thermal Lens DS-2TD2637-25/QY

What this thermal camera is for

A bi-spectrum camera has two channels in one housing: a thermal channel that forms an image from heat, and an optical channel that shows an ordinary picture. This Hikvision model is made for perimeter protection and fire prevention at critical infrastructure.

It suits a security or facilities team guarding a long fence line or large plant area, and the installer who has to cover it in darkness. The 25 mm thermal lens gives a narrow view that reaches further than a shorter lens would.

How the camera's technology works

• Vanadium oxide sensor: an uncooled sensor that reacts to heat, working in the 8 μm to 14 μm range. That is why heat shows up where visible light does not.
• Bi-spectrum fusion: details from the optical channel are shown on the thermal channel, which makes a heat image easier to read.
• Picture in picture: part of the thermal image sits on the full optical picture, so an operator can see both at once.
• VCA: video content analysis applies rules such as line crossing and intrusion, up to 8 in total, and classifies vehicles and humans.
• Target coloration: highlights targets in white hot and black hot mode.

Where to use it

The -40° C to 65° C working range and IP67 rating suit exposed outdoor positions. The anti-corrosion coating is there for sites where the air attacks ordinary housings.

Its narrow 25.25° × 14.44° optical view and 14.9° × 11.2° thermal view suit long boundaries and distant areas rather than the ground close to the pole. For shorter runs, look at the wider Hikvision thermal range before choosing a lens.

What the figures mean in practice

• Detection, recognition and identification: the camera can detect a person at 735 m, recognise one at 184 m and identify one at 92 m. These are reference figures calculated by Johnson's Criteria, and the environment changes them.
• IFOV 0.68 mrad: instantaneous field of view is the angle one pixel covers. A smaller figure means more detail at distance.
• NETD < 35 mK: the smallest temperature difference the sensor can pick out. A lower figure shows finer differences in heat.
• Temperature rules: 3 rule types, 21 rules in total, made up of 10 points, 10 areas and 1 line, so you can watch several hot spots in one view.

Installing it

• Focus distance: the thermal lens has a 13 m minimum focusing distance, so keep that in mind when choosing the position.
• Alarms: the alarm inputs and outputs can tie in other equipment, with actions such as SD recording, relay output and email linkage.
• Local storage: a MicroSD/SDHC/SDXC card of up to 256 GB can keep footage at the camera, and Auto Network Replenishment fills gaps after a network drop.
• Software: manage it with iVMS-4200 or Hik-Connect.

Planning your system

A PoE switch can power and connect the camera over one cable, and a network video recorder keeps the footage. Add the pole or corner mount if the position needs one.

Thermal products might be subject to export controls. Take legal or compliance advice before moving this camera to another country.

Ratings explained

• IP67: dust tight, and protected against temporary immersion in water.
• IK10: the top of the common impact scale for housings, which helps where vandalism is a risk.
• PoE 802.3af: the standard for power over a network cable, and class 3 is the power level the camera asks for.