--- title: Three camera decisions behind RoadInspect (and why none of them were obvious) description: Find out why RoadInspect chose GMSL cameras, two outdoor cameras, and S-mount optics, and learn about the challenges involved in designing a vehicle camera system. image: https://blog.pcb-arts.com/hubfs/Three-camera-decisions-behind-RoadInspect.jpg --- [Zu Content springen](https://blog.pcb-arts.com/pcb-arts-gmbh-blog/three-camera-decisions-behind-roadinspect-and-why-none-of-them-were-obvious#main-content) [![PCB-Arts\_Blog\_Logo](https://blog.pcb-arts.com/hs-fs/hubfs/PCB-Arts_Blog_Logo.png?width=300&height=150&name=PCB-Arts_Blog_Logo.png)Startseite](https://blog.pcb-arts.com/pcb-arts-gmbh-blog) - Menu - [Blog Home](https://blog.pcb-arts.com/pcb-arts-gmbh-blog) - [Website](https://www.pcb-arts.com/) - [LinkedIn](https://www.linkedin.com/company/pcb-arts-gmbh/posts/?feedView=all&viewAsMember=true) - [X](https://x.com/PcbArts) - Menu - [Blog Home](https://blog.pcb-arts.com/pcb-arts-gmbh-blog) - [Website](https://www.pcb-arts.com/) - [LinkedIn](https://www.linkedin.com/company/pcb-arts-gmbh/posts/?feedView=all&viewAsMember=true) - [X](https://x.com/PcbArts) ![](https://blog.pcb-arts.com/hs-fs/hubfs/Three-camera-decisions-behind-RoadInspect.jpg?width=3840&height=1989&name=Three-camera-decisions-behind-RoadInspect.jpg) Machine Vision Report Edge AI # Three camera decisions behind RoadInspect (and why none of them were obvious) ![Saber Kaygusuz, Teamlead Software ](https://blog.pcb-arts.com/hs-fs/hubfs/3.png?width=48&height=48&name=3.png) Saber Kaygusuz, Teamlead Software  20\. Oktober 2026 When we designed RoadInspect, three decisions come up in almost every customer conversation: why GMSL cameras instead of USB, MIPI, or Ethernet; why two outdoor cameras instead of one wide lens; and why S-Mount optics instead of something more industrial. None of the three were arbitrary. Each one follows directly from the constraints of putting a camera system inside a moving vehicle, at a cost that still works for series production. ##### **GMSL Cameras: why not USB, MIPI, or Ethernet?** The obvious alternatives to GMSL are a direct MIPI CSI-2 connection, a USB3 camera, or Ethernet. All three work fine on a bench. None of them hold up the same way inside a vehicle. MIPI CSI-2 is a short-reach interface, typically good for tens of centimeters before signal integrity becomes a problem. RoadInspect's cameras sit at the windshield; the compute unit (Helium) sits in the glovebox. That's a cable run of a meter or more, routed through the interior lining, flexing every time a door closes or the car goes over a bump. USB3 does better on distance, but it's unstable in the ways that actually matter for us. A USB3 camera needs a MIPI-to-USB converter on board, which adds complexity and generates extra heat, and that's a real problem in a lightweight plastic housing, since plastic conducts heat poorly.  Ethernet runs into a related set of issues, plus a power problem of its own: you either run a separate power cable to each camera or use PoE. Standard Cat6 cabling is far too thick to retrofit through a car's interior lining, so the realistic option would be Single Pair Ethernet. It's thin enough and carries power over the same cable, but it tops out at 1 Gbit/s and still needs power-hungry active electronics in the camera. GMSL sidesteps all of it: video, control data, and power run over a single thin coax cable, with up to 6 Gbit/s of throughput per camera. That's more headroom than we need, and without the heat, complexity, or cable-thickness trade-offs of the alternatives. It's the same interface family we use across our camera lineup. We go deeper on the GMSL2 ecosystem specifically in our [Thorium 16x GMSL2 deep dive](https://blog.pcb-arts.com/pcb-arts-gmbh-blog/thorium-16x-gmsl2-40-gbit/s-for-multi-camera-edge-ai), and it's the reason RoadInspect's installation is genuinely three cables through the interior lining, not a wiring loom. ##### **Why two outdoor cameras instead of one?** The tempting shortcut is a single ultra-wide or fisheye lens: one camera, one lens, done. We use two standard-FoV cameras stitched into one image instead, mainly for a reason that has less to do with optics and more to do with sensor economics. A global shutter sensor above 5 MP is enormously expensive, and often only works with C-Mount lenses, which was never an option for a compact, windshield-mounted housing (more on that below). So instead of one large, costly sensor, RoadInspect stitches two Sony IMX900 sensors, each a comparatively affordable 3.2 MP. Individually inexpensive, but genuinely capable for the job. Stitching two cameras also happens to sidestep the usual downside of a single wide-angle lens: a fisheye spreads the same resolution across a much wider angle, so the edges of the frame, often exactly where you need to detect a vehicle merging in or a pedestrian at the curb, lose both resolution and geometric fidelity. That's a trade-off we cover in more general terms in our [lens-selection guide](https://blog.pcb-arts.com/pcb-arts-gmbh-blog/choosing-the-right-lens-for-your-vision-application). Two overlapping cameras, each using a conventional, low-distortion lens, keep full pixel density across the stitched field of view, and add a bit of redundancy besides: if one channel is temporarily degraded (glare, dirt on one lens), the system doesn't lose the whole field of view at once. ##### **Why S-Mount?** Once the sensor and cable interface are decided, the lens mount follows almost automatically. S-Mount (M12 × 0.5) is the standard mount for compact, board-level camera modules like the IMX900 units RoadInspect uses. It's small and light in a way a C-Mount barrel and housing simply isn't. We go through the full mount comparison (S-Mount vs. C-Mount vs. CS-Mount) in the lens-selection guide linked above. For RoadInspect, size was non-negotiable: the entire camera unit has to sit unobtrusively at the top of the windshield. Earlier units used a 3M adhesive pad, and we're moving to a dedicated mechanical mount for series production. Either way, there's no room for a C-Mount lens barrel. S-Mount keeps the optics small and light enough for that form factor, while still giving us access to an established supply chain, which matters for a product built for series production, not a one-off. ## Diesen Beitrag teilen [mailto:https%3A%2F%2Fblog.pcb-arts.com%2Fpcb-arts-gmbh-blog%2Fthree-camera-decisions-behind-roadinspect-and-why-none-of-them-were-obvious](mailto:https%3A%2F%2Fblog.pcb-arts.com%2Fpcb-arts-gmbh-blog%2Fthree-camera-decisions-behind-roadinspect-and-why-none-of-them-were-obvious) ## Weiterlesen ### [![](https://blog.pcb-arts.com/hs-fs/hubfs/the-missing-middle-jetson-t3000-t2000-1.png?width=1200&height=627&name=the-missing-middle-jetson-t3000-t2000-1.png) NVIDIA Jetson Deep Dive T2000/T3000 – The Missing Middle Between Orin NX and T5000](https://blog.pcb-arts.com/pcb-arts-gmbh-blog/t2000-t3000-the-missing-middle-between-orin-nx-and-t5000) ### [![](https://blog.pcb-arts.com/hs-fs/hubfs/heatsink-thorium-all-1.png?width=1200&height=627&name=heatsink-thorium-all-1.png) Hardware Engineering Electronics Manufacturing Report What you need to think about when designing a heatsink for dense electronics](https://blog.pcb-arts.com/pcb-arts-gmbh-blog/what-you-need-to-think-about-when-designing-a-heatsink-for-dense-electronics) --- PCB Arts GmbH Kurgartenstraße 37, 90762 Fürth [mail@pcb-arts.com](mailto:mail@pcb-arts.com) +49 (0) 911 88183981 [Privacy Policy](https://www.pcb-arts.com/en/privacy_policy) · [Legal](https://www.pcb-arts.com/en/imprint) · © 2026. 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