scanengine-3

SRAS Scanning and Instrumentation Control Platform

Overview

scanengine-3 is a unified platform for scanning acoustic microscopy and precision instrumentation control. It integrates multiple hardware control modules into a single cohesive PyQt6-based application.

Key Features

• Stage Control: ThorLabs BBD202/BBD203 motor controller with 3-axis positioning
• Laser Systems: Helios pulsed laser and Genesis CW laser control
• Data Acquisition: Tektronix oscilloscope integration with fast-frame support
• Scan Planning: Automated raster scan generation and execution
• Real-time Monitoring: Live status updates and progress tracking

Hardware Components

Motion Control

• ThorLabs BBD202/BBD203 Motor Controller
  • 3-channel APT protocol driver
  • Precision positioning with encoder feedback
  • Programmable velocity and acceleration
  • Trigger output support for synchronized data acquisition

Laser Systems

• Helios Laser System
  • Frequency control (16.7-125 kHz)
  • Current control (0-7000 mA)
  • Multiple pulse modes
  • Temperature and power monitoring

Data Acquisition

• Tektronix MSO/DPO Series Oscilloscopes
  • Direct socket communication (no VISA overhead)
  • Fast-frame acquisition for high-speed scanning
  • Multi-channel waveform capture
  • Configurable triggering

Rotation / Focus

• T3R four-channel stepper controller
  • Focus axis plus the GR rotation stage (12.5:1 gear train)
  • Custom binary framing protocol over USB serial

Project Structure

The codebase is split so that everything needed to run a scan is importable without PyQt6 or any vendor SDK — core/ is the headless engine, gui/ is the shared Qt layer, and the root scripts are entry points.

scanengine-3/
├── core/                          # Headless: no PyQt6, no vendor SDKs
│   ├── scan_engine.py             # ScanEngine — full acquisition sequence
│   ├── scan_geometry.py           # ScanPlan, rotated-bbox planning, limits
│   ├── scan_resume.py             # Resume planning (frontier rule)
│   ├── scope_sras.py              # Oscilloscope SCPI policy for SRAS
│   ├── rotation.py                # GR rotation axis settings + moves
│   ├── sras_format.py             # v6 .sras writer/reader (memory-mapped)
│   ├── sras_analysis.py           # Image reducers + SAW matched filter
│   └── config.py                  # ScanDefaults ⇄ aui_defaults.json
│
├── hardware/                      # Device drivers (Qt-free)
│   ├── serial_util.py             # Shared 8N1 open + port enumeration
│   ├── t3r_driver.py              # T3R stepper controller
│   ├── t3r_protocol.py            # T3R frame encode/decode
│   ├── helios_laser.py            # Helios pulsed laser
│   ├── tektronix_base.py          # Tektronix oscilloscope (raw SCPI)
│   ├── uc480_camera.py            # IDS/ThorLabs uEye camera (returns QImage)
│   ├── genesis_core.py            # Genesis laser — QUARANTINED, see below
│   └── pybbd202/                  # ThorLabs BBD202 stage (APT protocol)
│
├── gui/                           # Shared PyQt6 layer
│   ├── scan_bridge.py             # QtScanController over core.scan_engine
│   ├── qt_t3r.py                  # Qt adapter over the T3R driver
│   ├── qt_workers.py              # QueueWorker / PollingQueueWorker bases
│   └── widgets.py                 # ConnectionBar, LogConsole, PortSelector…
│
├── sc3_aui_app.py                 # Main acquisition application
├── sras_viewer.py                 # Scan data viewer
├── sras_scan_manager.py           # CLI: inspect/export/delete angles
├── t3r_control_panel.py           # T3R panel (used by the main app)
├── helios_test_app.py             # Per-device test benches
├── bbd202_test_app.py
├── camera_test_app.py
├── sc3-aui-*.ui                   # Qt Designer files loaded at runtime
│
├── tests/                         # pytest suite
│   ├── golden/                    # v6 .sras + geometry fixtures
│   ├── fakes.py                   # Recording fake stage/scope/rotator
│   └── test_*.py
│
├── docs/
│   ├── hardware/                  # Driver notes
│   ├── protocols/                 # Vendor protocol PDFs
│   └── genesis_verification.md    # Bench checklist (see KNOWN_ISSUES.md)
│
├── lib/                           # Vendored IDS uEye SDK (not in git)
├── aui_defaults.json              # Persisted ports / scope IP / save dir
├── scan_format.md                 # .sras binary format specification
├── KNOWN_ISSUES.md                # Open questions needing the hardware
└── requirements.txt

Quick Start

Installation

# Clone or navigate to project directory
cd scanengine-3

# Create virtual environment (recommended)
python -m venv venv
source venv/bin/activate  # On Windows: venv\Scripts\activate

# Install dependencies
pip install -r requirements.txt

Running the Application

# Main acquisition application
python sc3_aui_app.py

# Scan data viewer
python sras_viewer.py

# Inspect / export / delete angles in a .sras file
python sras_scan_manager.py path/to/scan.sras

# Per-device test benches
python helios_test_app.py
python bbd202_test_app.py
python camera_test_app.py

# Genesis laser control tool
python tools/genesis_laser_control.py

Running the tests

The suite is hardware-free: fake drivers and committed fixtures stand in for the rig.

pip install pytest ruff
python -m pytest tests/ -q

Dependencies

• PyQt6 (>=6.4.0) - GUI framework
• pyserial (>=3.5) - Serial communication
• pyvisa (>=1.13.0) - VISA instrument control
• pyvisa-py (>=0.7.0) - Pure Python VISA backend
• pyftdi (>=0.54.0) - FTDI USB device support
• numpy (>=1.20.0) - Array processing
• scipy (>=1.10) - Signal processing (viewer SAW pipeline)
• matplotlib (>=3.7) - Plotting (viewer, live scan preview)
• pyueye (>=4.95.0) - IDS uEye camera SDK bindings (camera only)

Known hardware caveats

hardware/genesis_core.py is quarantined: it diverges from the reference implementation in tools/genesis_laser_gui.py in ways that need the laser on the bench to settle. See KNOWN_ISSUES.md and docs/genesis_verification.md before changing either file.

Usage Examples

Running a scan without any GUI

The acquisition sequence lives in core.scan_engine and takes plain drivers plus callbacks, so a script (or a future simpler GUI) can drive the identical scan the main app runs:

from pathlib import Path
from core.scan_engine import ScanCallbacks, ScanEngine
from core.scan_geometry import build_plan
from core.rotation import RotationAxis
from hardware.pybbd202 import ThorlabsServoDriver
from hardware.tektronix_base import TektronixOscilloscopeBase
from hardware.t3r_driver import T3RDriver

plan = build_plan(x_start=10.0, y_start=10.0, x_delta=20.0, y_delta=10.0,
                  num_angles=3, row_spacing=0.25,
                  laser_freq_hz=20000.0, velocity_mm_s=100.0)

stage = ThorlabsServoDriver(); stage.connect("/dev/ttyUSB0")
scope = TektronixOscilloscopeBase("192.168.100.105"); scope.connect()
t3r = T3RDriver(); t3r.open("/dev/ttyACM0")

engine = ScanEngine(stage, scope, RotationAxis(t3r), plan,
                    Path("/data/SRAS/demo.sras"),
                    callbacks=ScanCallbacks(on_status=print,
                                            prompt=lambda t, m: input(f"{t}: {m} ")))
result = engine.run()          # blocking; engine.abort() is thread-safe
print(f"wrote {result.rows_written} rows to {result.path}")

Reading a scan file

SrasFile memory-maps the data block, so opening a multi-gigabyte scan costs only the pages actually touched:

from core.sras_format import SrasFile
from core.sras_analysis import CH4_IDX, ChannelCalibration, compute_dc_image

with SrasFile("/data/SRAS/demo.sras") as sras:
    print(sras.header.n_angles, "angles")
    for st in sras.angle_status():          # handles aborted/partial files
        print(f"  angle {st.index}: {st.n_rows_available}/{st.n_rows} rows ({st.status})")

    view = sras.load_angle(0)               # (rows, channels, frames, samples)
    calib = ChannelCalibration.from_preambles(sras.preambles)
    dc_mv = calib.adc_to_mv(compute_dc_image(view, CH4_IDX), CH4_IDX)

Stage control

from hardware.pybbd202 import AXIS_X, AXIS_Y, ThorlabsServoDriver

stage = ThorlabsServoDriver()
stage.connect("/dev/ttyUSB0")               # raises if no bay responds
stage.enable_axis(AXIS_X)
stage.home_axis(AXIS_X, timeout=120.0)
stage.move_axis_absolute(AXIS_X, 25.0, timeout=30.0)

Oscilloscope acquisition

from core.scope_sras import configure_acquisition, configure_channels
from hardware.tektronix_base import TektronixOscilloscopeBase

scope = TektronixOscilloscopeBase("192.168.100.105", port=4000)
scope.connect()
configure_channels(scope)                   # standard SRAS front-end setup
samples_per_frame = configure_acquisition(scope)

Laser control

from hardware.helios_laser import HeliosLaser

laser = HeliosLaser()
laser.connect("/dev/ttyUSB1")
laser.set_current_ma(1200)
laser.set_laser_enable(True)
print(laser.get_diode_temp_c(), "°C")
laser.disconnect()                          # always explicit — no __del__

Camera control

from hardware.uc480_camera import UC480Camera, find_camera_bus_conflicts

find_camera_bus_conflicts()                 # warns about USB bus contention
camera = UC480Camera(camera_id=1)
camera.initialize()
camera.start_capture()

Configuration

Persisted settings

aui_defaults.json holds the ports, scope IP, and save directory the main app last used. It is read and written through core.config.ScanDefaults, which always writes every field — see KNOWN_ISSUES.md history for why partial writes were a problem.

Fixed acquisition settings

Scan velocity, laser frequency, sample rate, and the ramp geometry are constants in core/scan_engine.py and core/scope_sras.py, not user settings; a .sras file records them so resume can refuse a mismatch.

Serial port configuration

• BBD202: USB serial, APT protocol (/dev/ttyUSB*)
• T3R: USB serial, custom binary framing (/dev/ttyACM*)
• Helios: RS-232 (9600 baud, 8N1)
• Genesis: USB serial, I2C-over-serial
• Oscilloscope: Ethernet/LXI (TCP socket on port 4000)

Development

Adding New Hardware

1. Create driver module in hardware/ directory
2. Implement connection, control, and status methods
3. Add UI elements to main window or create new dialog
4. Connect signals in main_window.py

Testing Without Hardware

All hardware modules include stub implementations or simulation modes. The GUI can be developed and tested without physical devices connected.

Documentation

Detailed documentation available in project subdirectories:

• BBD202/203 Driver Guide
• BBD202/203 Connection Guide
• BBD202/203 Communications Protocol
• Helios Laser Guide
• Genesis Laser Guide
• Laser Control Implementation Guide
• Setup Instructions

License

Copyright (C) 2025 Thomas Ales Licensed under GNU General Public License v2.0

See LICENSE file for full license text.

Support

For issues, questions, or contributions, please refer to the project documentation or contact the development team.

Version

scanengine-3 v0.1.0 - Initial unified release