How to choose a camera for your bar: 4K, WDR, angles, PoE
AI bottle and level detection depends entirely on input image quality. Bars are demanding environments: dark areas, coloured lighting, reflective glass, hand movement in the foreground. A well-chosen camera doubles accuracy: a poorly chosen one yields a 40% false positive rate.
Key parameters
Resolution: 4K (3840×2160) is the sweet spot
FullHD (1080p) is sufficient for bottle detection, but measuring the liquid level requires enough pixels on the vertical axis. From a distance of 2 metres with a 30 cm high bottle, 1080p yields ~200 px per bottle, too coarse. At 4K it is ~400 px, which is reliable.
WDR (Wide Dynamic Range): MANDATORY
Behind the bar, an LED strip typically emits white or warm light, bottles are backlit, and the area in front of the bar is darker. Without WDR, you will get either blown-out whites or black holes. Look for at least 120 dB WDR.
Low light: f/1.6 or brighter
A standard bar has 100-300 lux during the day and 20-50 lux in the evening. An f/2.0 lens already produces noise at 50 lux. f/1.6 or f/1.4 is a safe choice. If the camera features ColorVu or similar technology, it is even better - it preserves colours in low light, aiding brand recognition.
PoE (Power over Ethernet): yes
One cable instead of two. The camera draws both power and data from a single Ethernet switch. If the pub lacks network cabling up to the bar, you must run UTP, but this is a one-off task requiring no sockets.
Lens: 2.8 mm for back bar, 4 mm for wider view
- 2.8 mm fixed - wide-angle; for a back bar 2-3 m wide, one overhead camera is sufficient.
- 4 mm fix - narrower, more detailed. For long bars divided into zones.
- Vario (zoom) is not recommended: expensive and unnecessary for a static application.
Specific models
| Model | Resolution | WDR | f/ | Price | For |
|---|---|---|---|---|---|
| Reolink RLC-823S | 4K 8MP | 120 dB | f/1.6 | ~7 000 Kč | Default choice. ColorVu, PoE, robust construction. |
| Reolink Duo 3 PoE | 4K 16MP | 120 dB | f/1.6 | ~10 000 Kč | Two lenses: covers a wider shelf without a second camera. |
| Hikvision DS-2CD2387G2H | 4K 8MP | 140 dB | f/1.0 | ~12 000 Kč | ColorVu 2.0, extreme low-light performance. Enterprise build. |
| Dahua IPC-HDBW3849H | 4K 8MP | 120 dB | f/1.2 | ~10 000 Kč | Full-colour night mode, ONVIF. |
How many cameras do you need
- Small back bar (up to 50 bottles, 2 m wide): 1 overhead camera + on request 1 camera for the work surface for pour events. Total: 2.
- Medium-sized bar (50-150 bottles, 4-5 m): 2 overhead cameras (splitting the shelf into two zones) + 1 on the work surface. Total: 3.
- Large bar / hotel lobby (150+ bottles, 8m+): 3-4 overhead cameras + 1-2 work cameras. Total: 4-6.
Location
Overhead camera above the shelf
Ideally, a ceiling height of 2.5-3 m above the shelf, slightly angled downwards towards the shelf. Advantage: does not capture guests' or bartenders' faces, simplifying GDPR compliance. Disadvantage: cannot detect pour events (pouring into a glass outside the shelf).
Camera over the work surface
Suspended above the area where the bartender pours. Captures hands and bottle over the glass. Detects pour events (tilt angle + liquid flow). Must capture faces as little as possible, top-down angle, not horizontal.
What not to skimp on
- Wireless devices (Wi-Fi cameras). Unstable stream, frame loss, unsuitable for real-time AI.
- Fisheye 360°. Edge distortion prevents accurate level estimation.
- Cheap Chinese no-name. Usually cannot be disconnected from the manufacturer's cloud; a GDPR nightmare.
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