# Common Issues

## Why is my OAK camera not detected?

Common causes when an OAK camera is not detected include missing udev rules on Linux, a USB 2 port or a charge-only cable,
insufficient USB power (use a powered hub or Y-adapter), and, for PoE, the camera and host being on different subnets or a
firewall or VPN blocking discovery. For RVC2 PoE cameras, update the bootloader with `oakctl rvc2 bootloader update`.

Learn more: [USB deployment guide](https://docs.luxonis.com/hardware/platform/deploy/usb-deployment-guide.md) · [RVC2 PoE device
not found](https://docs.luxonis.com/software-v3/support/troubleshooting/rvc2-poe-device-not-found-after-booting.md) ·
[Troubleshooting](https://docs.luxonis.com/software-v3/support/troubleshooting.md)

## How do I improve spatial detection accuracy?

Spatial detection accuracy depends mostly on depth quality. On OAK cameras, add texture to the scene with the IR dot projector
(Pro models), keep targets within the camera's rated depth range, shrink the depth region of interest inside the bounding box to
avoid background pixels, and enable subpixel mode.

Learn more: [SpatialDetectionNetwork
node](https://docs.luxonis.com/software-v3/depthai/depthai-components/nodes/spatial_detection_network.md) · [Configuring stereo
depth](https://docs.luxonis.com/hardware/platform/depth/configuring-stereo-depth.md)

## Can I run multiple OAK cameras on one host?

Yes. One host can run multiple OAK cameras at once over USB or PoE, each with its own DepthAI pipeline. PoE scales more easily
because each camera gets its own cable and power. Luxonis also supports hardware synchronization (FSYNC) across cameras for
multi-camera capture.

Learn more: [Multi-device setup](https://docs.luxonis.com/software-v3/depthai/tutorials/multi-device-setup.md) · [Hardware
sync](https://docs.luxonis.com/hardware/platform/deploy/data-sync/hardware-sync.md)

## Do OAK cameras need recalibration?

All OAK cameras, except the modular OAK FFC line, are calibrated before shipment, and the calibration is stored on the device. OAK
FFC setups must be calibrated after the camera modules are mounted, and you should recalibrate after replacing a camera module.
Dynamic calibration can restore stereo accuracy after thermal shifts, mechanical shocks, or mounting changes.

Learn more: [Dynamic calibration](https://docs.luxonis.com/hardware/platform/depth/dynamic-calibration.md) · [Manual
calibration](https://docs.luxonis.com/hardware/platform/depth/manual-calibration.md)