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. The objects (approx. max size 60×60 cm) are illuminated using either a) dual-channel 4W LED panels, or b) two 20W dimmable halogen lamps (broadband illumination). Three filters (SWP1250, BP1250–1510 and LWP1510) can be mounted in front of the IR lens (150 mm, f/5.6–f/45) when using halogen illumination. The cooled InGaAs scanning area sensor operates in the region of 900–1700 nm. The acquisition time for a single 128×128-pixel image tile varies between 10 and 50 ms. A typical full scan will generate a 16-bit TIFF image with a maximum resolution of 5176×5176 pixels in 22 minutes. Smaller regions are selectable for faster acquisition. 99% and 2% Spectralon diffuse reflectance standards are used as reflectance reference. A stack of 3–5 sheets of clean Epson Enhanced Matte Finish paper KAF250 is used for flattening. The current lens is not a SWIR Apochromat, so switching the wavelength when using the LED panels, or changing the filter when illuminating with halogen lamps, requires refocusing due to the nature of chromatic aberration. Captured images must be corrected (mainly magnification) to be registered and further processed as stack or layers in an appropriate software (Hoku, GIMP, etc.). See IRR data.

• 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 specifications:
  • 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: 
  • Required space: 2×2 m
  • Light: controlled lighting conditions (no sunlight) 
  • Climate: 10–35°C (non-condensing)
  • Furniture: 1 regular table, 1 chair
  • Electrical power: 230V 50Hz or 120V 60Hz
  • Safety: not advisable to look directly into the LED panels
• Sample required: no
• Contact required: no
• Limitations: objects sized 60×60 cm 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 setup and calibration
• Average time for measuring: full scan (5176×5176 pixels) 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: 16-bit TIFF up to 26MP (128×128–5100×5100 pixels)
• 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)