Driver Mode and Pipeline Index/Latency¶
Once a PhotonCamera has been created, robot code can switch between vision pipelines, enable driver mode, and read the processing latency.
Toggling Driver Mode¶
Driver mode provides an unfiltered camera view intended for the driver instead of processing the image through a vision pipeline.
# Enable driver mode
self.camera.setDriverMode(True)Setting the Pipeline Index¶
Use setPipelineIndex() to switch pipelines while the robot is running. The index must match the pipeline number shown in the PhotonVision UI.
# Switch to pipeline 2
self.camera.setPipelineIndex(2)Getting Pipeline Latency¶
Pipeline latency is stored on the PhotonPipelineResult and represents the time PhotonVision spent processing the frame.
latencyMilliseconds = result.getLatencyMillis()
latencySeconds = latencyMilliseconds / 1000.0
captureTimestamp = result.getTimestampSeconds()The capture timestamp is more useful than the current time when adding a vision measurement to a pose estimator because it allows WPILib to compensate for camera and processing delay.
Camera Status and Control¶
PhotonCamera can report its current state and whether PhotonVision is actively sending frames. A camera is enabled by default, but it can be temporarily disabled to stop its processing.
cameraName = self.camera.getName()
isConnected = self.camera.isConnected()
isEnabled = self.camera.getEnabled()
isDriverMode = self.camera.getDriverMode()
activePipeline = self.camera.getPipelineIndex()
# Temporarily disable or re-enable camera processing
self.camera.setEnabled(False)
self.camera.setEnabled(True)Controlling LEDs¶
Supported PhotonVision hardware allows its vision LEDs to be controlled through PhotonCamera.setLEDMode(). The available VisionLEDMode values are kOff, kOn, kBlink, and kDefault. The default mode follows the LED setting of the selected pipeline.
from photonlibpy.photonCamera import VisionLEDMode
# Blink the camera's vision LEDs
self.camera.setLEDMode(VisionLEDMode.kBlink)
# Read the current LED mode
ledMode = self.camera.getLEDMode()FPS Limiter¶
The FPS limiter reduces how many frames a camera processes each second. It is intended to save power, especially when using a high-frame-rate camera with a powerful coprocessor.
# Read the current limit
limit = self.camera.getFPSLimit()
# Process at most 10 frames per second
self.camera.setFPSLimit(10)
# Remove the limit
self.camera.setFPSLimit(-1)The default value is -1, which disables the limiter and allows PhotonVision to process frames as quickly as it normally would.