When High Definition cameras first appeared in the surveillance sector, it was enough for them to deliver 1920 x 1080 video streams at real time. Often just the provision of an HD stream was enough to use up all available processing power. Using any other features such as WDR, low light performance or event handling impacted on the video quality. Today things are very different. Advances in processing mean that even cameras aimed at the budget-conscious end of the market can offer consistent video alongside a host of additional features and functions. Benchmark took a closer look at the Dahua DH-IPC-HFW8281EP-Z to see if it can support image quality and advanced performance.
[dropcap]S[/dropcap]ometimes it is interesting to step back in time and consider what was once considered as cutting-edge. Technology moves so fast, as do our expectations. It is not uncommon to spend more time anticipating change than appreciating what it gives us when it arrives. Take HD as an example. The promise of higher definition video with real-time frame rates, balanced colour rendition and smooth motion was the ‘holy grail’ for many in surveillance. It was – we all agreed – just what we wanted.
Benchmark was the first publication to get its hands on an HD camera built specifically for the video surveillance sector. It was a pre-production sample, but the video quality was stunning.
Reading back over the test notes for that camera serves as a reminder that early HD video cameras weren’t great. They ticked the box with regards to image quality, but other functionality was below par.
Low light performance was poor, WDR was unstable, motion detection had to be disabled to prevent video freezes and latency made focus and set-up an ordeal. Also, the camera was costly, and together with the lens was above what most end users would pay.
Despite these many negatives, all who saw it appreciated that it was a very small first step down a road that would bring CCTV into the modern digital age.
That initial view of HD technology was made through some very rose-tinted glasses! As more cameras emerged, the thrill of seeing an HD1080p stream lessened, and the video quality became more typical. People became less forgiving of the weaknesses of the cameras, and manufacturers worked harder to improve features and functions. Gradually overall performance improved.
Today’s HD cameras are radically different beasts. Good quality video streams are demanded as standard. We also expect enhanced low light performance and WDR functionality. The cameras should preferably include smart detection. Dahua claims to have ticked these boxes with its DH-IPC-HFW8281EP-Z cost-effective camera.
The Dahua DH-IPC-HFW8281EP-Z is a part of the ‘Ultra-Smart’ range of cameras. The unit is a bullet-type integrated camera with an IP66-rated housing, integral bracket, day/night camera, varifocal lens and integral infrared illuminators with a stated range of 50 metres.
The camera makes use of a 1/1.9 inch 2 megapixel progressive scan CMOS sensor. Signal to noise ratio is claimed to be more than 50dB, and sensitivity is claimed as 0.005 lux at F1.65 for a colour image. The camera carries a ‘Starlight’ designation hinting at its low light potential.
The camera supports H.264 compression (High, Main and Base) as well as M-JPEG. Triple streaming is supported: the main stream can be HD1080p or HD720p, at rates of up to 50fps; the second stream can be either D1 or CIF at rates of up to 25fps; the third stream can be either HD1080p, HD720p or D1 at rates of up to 25fps.
Bit rate can be up to 8Mbps: this is quite a healthy ceiling for an HD stream and previous Benchmark tests have identified 6-8Mbps as good for general HD surveillance and 8-10Mbps as ideal for more motion-heavy HD video scenes.
The lens is a 4-8mm F1.65 varifocal unit. It is motorised to simplify focus when setting up the camera.
When looking at functionality, the camera boasts the usual features for a good mainstream device: day/night, BLC, auto white balance, AGC, AES, 3D noise reduction, image stabilisation, privacy masking, regions of interest, two-way audio, alarm I/Os, edge recording via a microSD card slot, a choice of PoE or low power, app-based viewing, etc..
It also boasts smart detection and intelligent functions. The former includes analytics rules for virtual tripwire, intrusion into alarm zones, scene change, object left/missing, camera defocus detection, face detection and audio detection. The latter intelligent functions include people counting and heat mapping.
Connections are made via a captive flylead. This includes an RJ45 socket for LAN and PoE, a modular socket for low power (12V DC or 24V AC), phono ports for audio in and out, and four wires for alarm connections.
Given that the camera is aimed at the budget-conscious sector of the market, it does carry a depth of functionality alongside the expected HD video performance. On paper, the DH-IPC-HFW8281EP-Z appears to offer all that Dahua has promised, but we all know that real-world security applications aren’t installed on paper!
The DH-IPC-HFW8281EP-Z is supplied with a paper quick start guide, a drill template and a miniature CD. The disk includes installation utilities, documentation and the Dahua Smart PSS (Pro Surveillance System) software.
According to the quick start guide the camera should have also included ‘installation accessories’. It doesn’t go into greater detail, but we’d guess at a connector for the alarm I/Os and an allen key for the security screws that lock the bracket and give access to the microSD slot.
Luckily the screw is a very common profile and most installers and integrators will either have a wrench or driver-bit that will fit. Despite this, accessories should be included so it is a slight blot on the DH-IPC-HFW8281EP-Z’s copybook.
Initial set-up is done using the camera’s quick configuration tool. Alternatively you can use the camera’s default IP address.
The notes for the config tool point out that it only works if the camera and server are on the same network segment. That actually undersells its performance. It found our test camera immediately and identified that it was on another network segment. It then allowed the IP address to be changed, uploaded the change very quickly, and enabled us to log in to the device.
We’ve used morey IP utilities than we care to remember, and aside from a few good ones we usually give up on them fairly quickly and opt for the static address as its faster. However, the current version of the Dahua config tool works well, and is both fast and stable.
The unit was on the network and fully operational in less than a minute, and to be fair some of the so-called IP-centric manufacturers can’t match that sort of speed or ease of use!
The menus and sub-menus are relatively straightforward. There are a fair few of them, and with tabbed content it is worth taking your time and working through them in a logical fashion to ensure nothing is missed.
The main menus are for Camera, Network, Event, Storage, System and Information. The sub-menus are well laid out and allow installers and integrators to make good progress without being confusing.
Most are self-explanatory, and the only ones where you might make a quick reference to the manual are for the smart IVA options. These are flagged in the documentation as optional but all worked as standard. However, the intelligent options – people counting and heat mapping – were notably absent.
In truth, whilst the manual isn’t the best or highly detailed, we found our way around the DH-IPC-HFW8281EP-Z with no real problems, and even the IVA set-up was relatively intuitive once you got used to the layout: for example the fact that the ‘Enabled’ box (which prevents anything from working until it’s ticked) isn’t the first thing on the menu!
The first and most obvious place to start with any HD camera is the basic video performance. With compression set at H.264 High Profile, bit-rate at the maximum 8Mbps and resolution set as HD1080p at 50fps, in typical daytime lighting the image is crisp and clean. The auto-focus function works well and is fairly rapid too.
Image quality was high, and detail was clear and well defined. Even towards the edges of the image the camera delivered what was obviously a clean HD video stream. Given that frame rate was 50fps, motion was understandably smooth with no visible blur.
Colour accuracy was also very good. There was a very slight bias towards warmer tones, which is quite usual for video cameras. Sometimes fully balanced images can look stark and most consumer products tend to slightly favour the warmer end of the spectrum. The differences were only obvious when using charts. The charts also highlighted that greyscale replication was pretty accurate.
Fast motion in decent lighting was also smooth and free of blur.
The general video functionality worked well, and the only function that we didn’t give a good workout to was the defog feature. Sadly we were treated to a fairly mild autumnal period during testing. However, everything else functioned as expected.
Dahua likes to apply the ‘smart’ tag to a number of the features, and they could be accused of being a little bit liberal with it. For example, smart triple streaming might be better described as triple streaming. However, the smart detection does add to the overall motion detection offered by the camera.
In truth, the motion detection is as you’d expect from a camera. Once a region is drawn you can set sensitivity and threshold. A histogram gives a waveform-visual to indicate the level of motion against the alarm settings, which helps with configuration. However, ambient lighting changes will also affect the general VMD performance.
The ‘smart’ options include virtual tripwire (lines can be segmented to create perimeter lines, with directional discriminations), intrusion (polygonal shapes can be set with enter, leave or enter and leave discriminations), object monitoring (again polygonal shapes are created with an option for object appear or disappear) and scene change (triggers on general alterations to the viewed scene).
With each IVA option (excluding scene change) there is an option to configure target sizes, thus eliminating spurious alarm events. The tripwire rule can be used in conjunction with either the intrusion or object monitoring rules, but the latter two cannot be used together.
The IVA rules work well and certainly add to the event management features of the camera. They’re not as configurable as the video analytics on some top-end cameras, but you certainly get more for your money than you might imagine.
The final performance criteria that many will be interested in is low light. There are two sides to this. The first is the Dahua sensitivity specification. Are you really going to achieve 0.005 lux for a colour image? The answer is a very firm ‘no’ if you want the type of image that a customer will expect having invested in an HD video surveillance system.
If you want to sacrifice colour fidelity, motion, image detail and usability, then feel free to try to hit that number. Remember, however, that as soon as you lose 25fps by chasing slow shutter video to hit pointless low light figures, the image stream is no longer an HD standards-compliant one!
However, if you want to be sensible about low light performance, achieving usable colour video until noise appears, then switching to clean and crisp monochrome streams, the DH-IPC-HFW8281EP-Z won’t disappoint.
Day/night switching has three levels: Low, Medium and High. With the majority of cameras that Benchmark tests – and predominantly at the lower cost end of the market – the day/night switching points are set too low. We’ve often asked why, as this can make a camera next to useless in twilight applications.
It’s almost as if some manufacturers try to justify their quoted sensitivity figures. We’ve wondered if allowing switching at a usable level contradicts those sensitivity claims.
Dahua cameras – amongst many others – have suffered from this in previous tests. However, this seemingly has changed, on this model at least!
In general use, with an HD1080p stream and 50fps, you’ll see noise creep in at around 3 lux. Admittedly taking measurements using 50fps isn’t ever going to flatter a camera. Our thinking was that if you specify a camera that delivers 50fps, the reason is probably that you require that enhanced frame rate, and if the investment is justified then it’s still relevant as light levels fall. Okay, we’re being a little bit finicky as well. We tested the low light at 50fps, but as you’ll be aware at 25fps it’ll hold out for longer.
Even at the higher frame rate, just as noise becomes visible at around 3 lux, the camera switches, even on the lowest setting. If you want to preserve a cleaner image it will switch at 6 lux on the highest setting. In short, it works well and does offer a discernable performance difference!
Once switched, the infrared illuminators kick in, and coverage is decent. It’s not as good as a high quality dedicated infrared illuminator would be, but it’s certainly more than acceptable. In monochrome mode detail is sharp, motion is clean, and you’ll be glad the camera switched at a sensible level.
The DH-IPC-HFW8281EP-Z is a camera clearly aimed at the mainstream market. It doesn’t try to compete with the high end HD cameras out there, but neither does it carry their price tag. Given its price point, it’s a very good camera, and with regard to image quality and low light performance it certainly can stand its ground in most mainstream applications.
Performance in low light applications is sensible. Image quality is high. The smart functionality works well. In fact, the DH-IPC-HFW8281EP-Z does what it sets out to do, and does it with a touch more capability than many might give it credit for.
There are things that could be improved, but it would be a tad churlish to expect more from a camera that delivers a level of value for money that some at the ‘budget’ end of the market would do well to mimic.