ThermalSeek

ThermalSeek is a C++17 and Qt 6 desktop viewer for radiometric thermal cameras. It discovers a supported USB camera, performs the camera-specific calibration and temperature conversion, and displays a live colorized image with minimum, maximum, and center temperatures in Celsius.

The project currently supports one camera family and has been tested on Linux. Camera support is implemented in-tree; ThermalSeek does not build or link libseekthermal.

Features

• Live capture on a dedicated worker thread.
• Camera-derived apparent temperatures with configurable emissivity and reflected-background compensation.
• Per-camera detector fixed-pattern correction with a validated covered-lens calibration workflow and checksummed atomic profile storage.
• Five selectable thermal palettes with a matching temperature scale.
• Automatic, locked, and manually configured display temperature ranges.
• Live minimum, maximum, and center readings with hot/cold image markers.
• Mouse spot readings, pinned measurement points, and ROI statistics.
• Freeze-frame inspection while camera capture continues in the background.
• Resizable Qt Widgets interface.
• Single-key PNG screenshots containing the thermal view, scale, status, overlays, and active radiometric parameters.
• Direct libusb transport with deterministic cleanup and timeout handling.

Supported cameras

Camera	USB ID	Status
Seek Compact / PIR206	289d:0010	Live capture, radiometric temperatures, and fixed-pattern correction

ThermalSeek currently opens the first supported camera it finds. See CONTRIBUTING.md before adding another model: USB transport, calibration, frame layout, and temperature conversion must remain model-specific until their equivalence is demonstrated.

Requirements

• CMake 3.21 or newer
• C++17 compiler
• Qt 6.4 or newer with the Widgets component
• pkg-config
• libusb 1.0 development files

On Ubuntu, the required development packages can be installed with:

sudo apt install build-essential cmake pkg-config qt6-base-dev libusb-1.0-0-dev

Build

git clone ssh://git@git.teske.zip:30009/TeskesLabOrg/ThermalSeek.git
cd ThermalSeek
cmake -S . -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build --parallel

Run the focused correction, display, and inspection tests with:

ctest --test-dir build --output-on-failure

Run the application with:

./build/thermalseek

The camera can take a short time to provide all required calibration frames. The status bar displays Calibrating until a radiometric display frame is available.

Linux USB permissions

ThermalSeek needs permission to claim the camera's USB interface. If the camera is detected but cannot be opened, create a udev rule such as /etc/udev/rules.d/99-thermalseek.rules:

SUBSYSTEM=="usb", ATTR{idVendor}=="289d", ATTR{idProduct}=="0010", MODE="0660", TAG+="uaccess"

Reload the rules and reconnect the camera:

sudo udevadm control --reload-rules
sudo udevadm trigger

Do not run the desktop application as root.

Controls

Key	Action
P	Cycle through thermal palettes
A	Use the automatic per-frame temperature range
L	Lock the currently displayed temperature range
M	Configure a manual temperature range
H	Toggle the hot and cold image markers
R	Configure emissivity and reflected-background temperature
Space	Freeze or resume the displayed thermal frame
Delete	Clear pinned points and the selected ROI
G	Save a screenshot of the ThermalSeek window

The Display menu exposes the same palette, range, marker, freeze, and clear controls. The Measurement menu contains radiometric settings plus fixed-pattern calibration, enable/disable, and profile-deletion controls.

Move the mouse over the thermal image for an exact spot reading. Click to pin a measurement point; click the same detector pixel again to remove it. Drag with the left mouse button to select an ROI with minimum, maximum, average, and center temperatures.

Radiometric correction defaults to emissivity 1.00, which preserves the camera's apparent temperatures exactly. For lower-emissivity targets, open Measurement → Radiometric Settings and provide the target emissivity and the reflected-background temperature. The corrected temperature field drives the image, scale, MIN/MAX markers, spot readings, and ROI statistics. These measurement settings, along with the palette, display range, markers, and window geometry, persist between sessions.

Fixed-pattern correction removes stable detector-local temperature offsets before emissivity/reflected-background compensation. To create a profile, place the lens directly against a smooth, matte, room-temperature surface with no gap, then choose Measurement → Calibrate Fixed-Pattern Correction. Keep the camera covered and still while ThermalSeek collects 96 usable frames spanning at least four shutter refreshes. Capture continues throughout the modeless progress dialog.

ThermalSeek rejects calibration data with excessive target drift, spatial non-uniformity, temporal noise, or detector bias. A valid profile is zero-centered so it does not intentionally shift scene temperature, saved atomically under the platform application-data directory, and keyed by a SHA-256 fingerprint of that camera's factory calibration and device information. Profiles are not portable between cameras. The permanent status shows FPN No profile, FPN Off, FPN On, or calibration progress.

Screenshots are written as PNG files to the platform Pictures directory under a ThermalSeek subdirectory. The filename format is:

ThermalSeek_yyyyMMdd_HHmmss_zzz.png

The status bar reports the saved path or the reason a screenshot failed.

Architecture

Seek Compact USB
       |
       v
seek_compact_usb          discovery, controls, calibration blobs, raw frames
       |
       v
thermal_processor         calibration frames, bad pixels, apparent temperatures
       |
       v
ThermalFrame              immutable camera-apparent Celsius pixels
       |
       v
fixed_pattern_correction  per-camera detector bias subtraction
       |
       v
ThermalFrame              corrected apparent Celsius pixels and statistics
       |
       v
radiometric_correction    emissivity and reflected-background compensation
       |
       v
ThermalFrame              measurement Celsius plus min/max/center and extrema
       |
       v
thermal_renderer          palette/range mapping plus all three frame stages
       |
       v
thermal_image_widget
       |                  display/detector mapping, spot points, ROI, overlays
       v
main_window               measurement controls, scale, status, screenshots

Important source files:

• src/seek_compact_usb.* — direct libusb transport for 289d:0010.
• src/thermal_processor.* — Seek Compact calibration and thermography.
• src/fixed_pattern_correction.* — covered-lens profile training, validation, and detector-bias subtraction.
• src/fixed_pattern_profile_store.* — camera fingerprinting and atomic, checksummed profile persistence.
• src/radiometric_correction.* — emissivity/reflected-background compensation and corrected statistics.
• src/seek_camera_thread.* — capture lifecycle, pooled frame ownership, and UI delivery.
• src/thermal_palette.* — selectable 256-color palette registry.
• src/thermal_renderer.* — display-range mapping and frame orientation.
• src/thermal_inspection.* — display/detector mapping and radiometric statistics.
• src/thermal_image_widget.* — mouse interaction and measurement overlays.
• src/main_window.* — live viewer, scale, controls, status, and screenshots.

Contributing

Camera backends need hardware evidence, documented protocol provenance, safe USB lifecycle handling, and a verified radiometric conversion. Read CONTRIBUTING.md for the required design and validation workflow.

License

ThermalSeek source code is available under the MIT License.

Qt and libusb are dynamically linked third-party dependencies with their own licenses. Binary distributors remain responsible for the applicable Qt and libusb license notices and relinking requirements.