Machine vision camera for continuous shooting, external power

Street-level capture at road speed, all day, driven from your own software, is a different purchase from a lab camera. The specification usually reads: an electronic shutter that cannot wear out, programmable continuous or command-triggered shooting, external power for a full shift, and stabilization. One family of cameras answers all four: an industrial area-scan camera with a global shutter and Power over Ethernet. It has no mechanical shutter at all, it takes its commands over the same cable that powers it, and every frame streams to your storage as fast as the sensor produces it. Below are the decision, the wiring, the data-rate arithmetic and a worked lens and exposure example for facades at 50 km/h.

The decision in one line

Buy a global-shutter area-scan camera with a GigE Vision interface and Power over Ethernet, mount it on a damped bracket, and let your software free-run it or fire one frame per command. Every item on the wish list is a standard machine-vision feature:

Choose the interface first, because it decides power and storage. In the area scan cameras finder, 904 of the 1,287 models have global shutters and 597 are GigE. Take GigE for one-cable power and data with a 100 m reach; take USB3 when the host rides within about 3 to 5 m and you need roughly 400 MB/s; take 10GigE or CoaXPress for 25 MP sensors at full frame rate.

Shutter: electronic always, global while moving

An industrial area-scan camera is electronic-only: exposure is a readout schedule in silicon, with no foil curtain and no actuation rating. The comparison that matters is a consumer SLR, whose mechanical shutter is rated for roughly 100,000 to 400,000 releases. A survey firing two frames per second logs about 58,000 a day, so on this job a mechanical shutter is a consumable and an electronic one is not.

Readout type is the real choice. A rolling shutter reads the sensor line by line, so the top and bottom rows of a frame are different instants; a global shutter exposes every pixel at the same instant. On a moving vehicle the difference is shear: at 30 km/h the vehicle travels 8.33 m/s × 0.020 s ≈ 167 mm during a typical 20 ms full-frame readout. Against the 11.8 m-wide frame of the worked example below, that is 58 pixels of lean baked into every facade. The sensor-level trade-offs are covered in global vs rolling shutter sensors for moving targets; for street work the rule is simple: global while moving, rolling only when parked.

Triggering: free-run or one command per frame

Both shooting styles are standard features. Continuous acquisition lets the camera free-run while your code pulls frames from the stream; software triggering sends one GenICam TriggerSoftware command per frame with TriggerSource set to Software. Commands and pixels share the Ethernet cable, so the separate USB or serial control line from the original wish list is not needed. The mechanics are laid out in continuous camera acquisition mode for live image loops and in commanding a GigE Vision camera over Ethernet.

For geo-referenced capture, prefer free-run with timestamps: synchronize the camera clock to GNSS time over IEEE 1588 PTP and log each frame's own timestamp instead of trusting when a trigger command happened to arrive. If you do command frame by frame, keep the acquisition armed between shots — wrappers that open a session per image drop frames, the failure mode dissected in software trigger timeouts in one-shot capture.

Power: PoE on the link, or a GPIO cable from the rail

Power over Ethernet puts the supply on the data cable. A PoE switch or injector in the vehicle — fed from the 12 or 24 V system through a DC-DC converter — delivers power and gigabit data on one Cat5e/6 run, and the Ethernet channel limit of 100 m dwarfs any vehicle harness. PoE is a per-model feature, not an interface guarantee: the check is in does my camera support PoE: check the port before you buy.

Without PoE, feed the camera through its I/O connector from the vehicle rail. The wiring options are compared in camera power: USB vs external 5 V, and the cable itself is the subject of a camera GPIO cable for image acquisition. The LS-CBL-0300 is a 7 m M8 8-pin power and I/O cable rated for drag-chain use. For bench set-up and the download dock, the power supplies category carries enclosed 12, 24 and 48 V units; the LRS-75-48 is a 48 V, 76.8 W enclosed supply. A locking data cable and a power cable close the loop:

The LS-CBL-0117 is a 15 m RJ45 camera data cable with a locking stud — the connector that stays put on rough roads.

Storage: the interface is the memory card

No industrial camera carries a card slot: frames stream to the vehicle computer at the link rate and the disk is the memory. Size it with two multiplications. A 4000 × 3000 mono 8-bit frame is 12.0 MB. The LS-CMR-0166 streams exactly that — 4000 × 3000 frames at 30 fps over USB3. Thirty frames of 12.0 MB is 360 MB/s sustained, which is what a 5 Gbit/s link delivers once overheads take their share (625 MB/s line rate, roughly 400 MB/s usable). A GigE link manages about 100 to 115 MB/s sustained of its 125 MB/s line rate, so 12 MP continuous capture tops out near 8 to 9 fps per camera.

Daily volume at a survey pace of 2 fps: 2 × 28,800 s = 57,600 frames a day, × 12.0 MB = 690 GB in mono, 2.1 TB stored as RGB. Five mono days fit a 4 TB SSD with room for the operating system.

Rigs that cover a full intersection hang four to eight cameras. Give each GigE camera its own link into a switch with a 10GigE uplink, or budget one USB3 host controller per camera — the trap and the arithmetic are in multiple USB cameras on one host: bandwidth and power budget.

Stabilization: buy exposure, not moving glass

No industrial C-mount or F-mount lens offers optical stabilization, and that is the correct state of affairs: stabilization shifts the image between frames, which breaks the frame-to-frame geometry a survey depends on. The working substitute is exposure time. Road shake is slow compared with an electronic shutter: a 1 mm vibration at 30 Hz peaks at 0.001 m × 2π × 30 = 0.19 m/s, so during a 200 µs exposure the camera moves 0.19 × 0.0002 ≈ 38 µm — 1.3% of the 2.9 mm ground pixel from the worked example. Fix what remains mechanically: a damped bracket, locked connectors, and exposure set from the blur budget below.

Worked example: 12 MP facades at 50 km/h from 10 m

The case: one side-looking camera, 10 m from the facades (kerb, parked cars, sidewalk), vehicle at the 50 km/h town limit, sharp to one ground pixel.

Inputs: a 4096 × 3000 sensor of 3.45 µm pixels — the 1.1" 12 MP global-shutter class in the finder; 10 m working distance; 50 km/h = 13.9 m/s; a one-pixel blur budget; full sun at 100,000 lx on a facade of 40% reflectance.

Geometry: sensor width = 4096 × 3.45 µm = 14.1 mm. For a 10 m slice of street, m = 14.1/10,000 = 0.00141 and f = 10,000 × 0.00141/1.00141 = 14.1 mm. Stock C-mount lenses come in 12 mm and 16 mm; take the 12 mm: m ≈ 12/10,000 = 0.0012, field of view = 14.1/0.0012 = 11.8 m, GSD = 11.8 m/4096 = 2.87 mm per pixel. A 100 mm letter on a sign spans 35 pixels — readable.

Blur: at 13.9 m/s, one pixel of smear allows 2.87/13,900 = 0.21 ms. Set 200 µs: smear = 13.9 × 0.0002 = 2.78 mm = 0.97 pixel.

Light: a 40% facade under full sun has luminance 100,000 × 0.4/π = 12,700 cd/m². At f/2.8 with 80% lens transmission the sensor sees π × 12,700 × 0.8/(4 × 2.8²) = 1,020 lx, so a 200 µs exposure deposits 0.20 lx·s. At 550 nm, 1 lx·s delivers about 4,000 photons per µm²; a 3.45 µm pixel is 11.9 µm², so at 40% quantum efficiency that is 19,000 electrons per lx·s — the frame carries 0.20 × 19,000 ≈ 3,900 e-, about 40% of a typical 10,000 e- full well at this pixel size. That is on target at base gain.

Decision: order the 12 mm lens, lock exposure at 200 µs, hold f/2.8 in sun. Under overcast light open to f/2 (twice the light) and add gain, or accept 2 to 3 pixels of smear at 500 µs. Above 70 km/h, cut to 100 µs — 1.9 mm of smear, 0.7 pixel. Run your own street width and speed through the focal-length calculator:

The picks, case by case

Moving capture, one camera: the MV-CH120-11UC is a 12 MP USB3 camera with a 1.1" sensor, a C-mount and a global shutter — the class the worked example is built on, with the host riding in the vehicle. The sensor-level trade-offs across that range are compared in USB3 machine vision camera selection.

A compact networked second angle: the MV-CU020-90GC is a 2.5 MP GigE camera with a global shutter and a 1/1.7" sensor. Maximum detail with the vehicle parked at each position: the MV-CS200-10GC puts 20 MP on a 1" sensor over GigE, and its rolling shutter costs nothing when the wheels stop. Full detail while moving: the MV-CH250-25TC-F-NF is a 25 MP 10GigE camera with a global shutter and an F-mount. Four models span the range:

All 4 share: Certification CE, RoHS, KC; Mono/color Color. Values as printed in each product's data sheet; open a part for its drawing and full specifications.

Checks before you order

• Global shutter on the exact model: Shutter: Global in the camera finder leaves 904 of 1,287 models.
• PoE on the exact model, or add the power and I/O cable plus a 12/24 V feed.
• Disk sustained write rate above the link: 120 MB/s for one GigE camera, 400 MB/s for USB3.
• Lens image circle covers the sensor: a 1.1" format needs a lens rated for 1.1", not 2/3".
• Aperture reaches f/2.8 at least; f/2 buys back overcast days.
• Locking connectors on both ends; a plain RJ45 latch works loose on rough roads.
• PTP enabled if frames are geo-tagged against GNSS time.
• The mount clears the driver's view and airbag paths, and the cable run is strain-relieved at the bracket.

When the usual answer is wrong

Long vehicles defeat USB3. Passive USB3 runs hold up over about 3 to 5 m; a camera on a roof rack with a host computer inside the cabin needs GigE or fiber.

25 MP while moving defeats GigE. A 25 MP mono frame is about 25 MB, so one GigE link sustains under 5 fps at that size. For motion at that resolution take 10GigE or CoaXPress — the MV-CH250-90YC-M58S-NN is a 25 MP CoaXPress camera with a global shutter and an M58 mount.

Night work defeats the daylight math. The 200 µs exposure above lives on sunlight; after dark the honest options are a daylight-only survey or a lighting rig sized like a production line — the pulse and duty-cycle arithmetic is in LED strobe duty cycle: matching lights and controllers.

And do not fix a rolling shutter in post: deshake and skew correction interpolate pixels and soften exactly the lettering you went out to read.

Where to start

Start at the camera step of the system configurator with the worked example's numbers, or filter the finder on Global and GigE and compare. For a multi-camera ring, send the vehicle's power and data budget through the contact page — expert support comes with every order, and the harness is where mobile rigs succeed or fail.