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Written Artefact Profiling Guide
Written ArtefactProfiling Guide

Photo: CSMC

Written Artefact Profiling Guide

Infrared Reflectography Mobile Imaging System; Opus Instruments: Apollo

CSMC

Infrared reflectography with OPUS Apollo.

The OPUS Apollo Infrared Reflectography (IRR) mobile imaging system is a successor model to the well-known OSIRIS IRR system. This system is used supplementary to XRF measurements in identification of types of inks used in manuscripts, especially identification of carbon presence in mixed inks, and in visualisation of spectral features in paintings such as underdrawings. Instead of the original 40W dimmable halogen lamps (broadband illumination) and the three filters (SWP1250, BP1250–1510 and LWP1510) mounted in front of the IR lens (150 mm, f/5.6–f/45), the objects (approx. size A4–A0) are now illuminated using the purpose-built 4W LED dual-channel panels. The two wavelengths are 1050 and 1450 nm. The cooled InGaAs scanning area sensor operates in the region of 900–1700 nm. The acquisition time for a single 128×128 pixel patch varies between 10–50 ms. A typical full scan will generate an 8-bit TIFF image with a maximum resolution of 5100×5100 pixels in 22 minutes, though smaller regions are selectable. 99% and 2% Spectralon diffuse reflectance standards are used as reflectance reference.

  • General description: infrared reflectography mobile imaging system
  • Application aim: classification of types of used inks and visualisation of spectral features of materials
  • Mobility:  portable; 25 kg in 3 packaging units (sensor head, tripods, light panels)
  • Equipment specifics:
    • Operation wavelength 900–1700 nm (sensor limited)
    • Sensor 128×128 pixel cooled InGaAs area sensor with 10–50 ms acquisition time
    • Lens 6 Element 150 mm focal length, aperture f/5.6 – f/45
    • Illumination (new, default): two 2W Dual Channel LED panels 1050 and 1450 nm
    • Illumination (old): two 20W dimmable halogen lamps (broadband illumination)
    • Reference: Spectralon diffuse reflectance targets 99% and 2%
    • Illumination calibration: Epson Enhanced Matte Finish paper KAF250A2
    • Field of view: 40° horizontal × 40° vertical (200 mm to infinity) (A4 page to 2×2 m)
  • Application requirements: controlled lighting conditions (no sunlight), 10–35°C, non-condensing
  • Sample required: no
  • Contact required: no
  • Limitations: objects sized A3 or smaller can be imaged in a single capture with reasonably good resolution; larger objects will need to be imaged in smaller sections and have the images stitched in postprocessing
  • Set up time: 60 min for set up and calibration
  • Average time for measuring: full scan (5100×5100 pixel) takes 22 minutes; smaller regions of interest can be imaged with shorter measurement times
  • Average time for processing: no extra processing time needed for identification of ink types
  • Software package: Windows 7–11 (USB 2.0)
  • Output: 8-bit TIFF up to 26MP (128×128 – 5100×5100 pixel)
  • Contact: Ivan Shevchuk, ivan.shevchuk"AT"uni-hamburg.de;
    Kyle Ann Huskin, kyle.ann.huskin"AT"uni-hamburg.de
  • Location of the equipment: CSMC Lab (Warburgstr. 28, Hamburg)