Acquisition Modes

The Image Acquisition Engine supports four distinct acquisition modes. Each orchestration loop checks the current mode and delegates to the appropriate handler.

Mode Overview

SINGLE Mode

Handler: StandardModeFunctions

The default mode. Captures a single image from the camera at a configured interval.

Flow

1. Call RequestSingleImageFromDevice activity
2. VAPIX client fetches the image (AWF format preferred, standard fallback)
3. SingleImageStorageService stores the image + generates thumbnail
4. Metadata is saved to Table Storage
5. Image metadata is broadcast via SignalR to connected frontends
6. Orchestration sleeps for the configured interval
7. Loop repeats

Image Routing

The activity function routes based on device type:

• Real cameras → VAPIX client (IVAPIXClient.GetAWFImageAsync())
• Simulated cameras → HTTP request to the Mock Camera API

PANO Mode

Handler: StandardModeFunctions

Captures multiple images from different PTZ positions and stitches them into a panoramic image.

Flow

1. The orchestration checks if the scheduled panoramic time has been reached
2. If yes, switches from SINGLE to PANO mode
3. Call RequestPanoFromDevice activity:
   • Internal pano: Captures 6+ images at different pan positions, stitches them using System.Drawing (JPEG quality 50)
   • External pano (UCSD): Fetches from UCSD Alert CA API, re-stitches with corrected orientation
4. Component images are saved as a ZIP archive via PreStitchedImageStorageService
5. Stitched panorama is saved via PanoImageStorageService
6. After completion, mode transitions back to SINGLE

Stitching

Images are stitched horizontally using Graphics.DrawImage(). The resulting panorama width equals the sum of all component image widths.

LEASED Mode

Handler: LeaseModeFunctions

Manual control mode where external users (frontend operators) take direct control of a camera's PTZ.

Flow

1. An operator requests a lease via the camera control queue
2. The orchestration enters LEASED mode
3. The command queue is checked for PTZ/focus/brightness commands
4. Commands are executed as activity functions
5. An image is captured after each command
6. Idle timeout: If no commands are received for 1 minute, the lease closes
7. Hard timeout: After 5 minutes total, mode returns to SINGLE

Why Leased Mode Exists

Live camera control needs immediate response. In SINGLE mode, the orchestration might be sleeping for 10+ seconds between captures. LEASED mode reduces the loop interval so PTZ commands are picked up and executed with minimal delay.

TURBO Mode

Handler: TurboModeFunctions → delegates to IntervalAcquisitionFunctions

High-speed capture mode for urgent situations (e.g., active wildfires) where images need to be captured more frequently than the standard rate.

Flow

1. Turbo mode is activated via the Admin API or by a system event
2. TurboModeFunctions delegates to IntervalAcquisitionFunctions with a reduced interval
3. Images are captured at the turbo rate until turboEndTime expires
4. When the timer expires, mode transitions back to SINGLE

Key Difference from SINGLE

TURBO uses a shorter, fixed interval regardless of the camera's configured acquisition rate. This provides maximum image freshness during critical events.

Mode Transition Summary

From	To	Trigger
SINGLE	PANO	Scheduled panoramic time reached
PANO	SINGLE	Panoramic capture complete
SINGLE	LEASED	Lease request via camera control queue
LEASED	SINGLE	5-minute hard timeout
SINGLE	TURBO	Turbo activation via Admin API
TURBO	SINGLE	turboEndTime expired

All mode transitions are managed by OrchestrationModeHelper and persisted on the CameraState durable entity.