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Written Artefact Profiling Guide
Written ArtefactProfiling Guide

Photo: CSMC

Written Artefact Profiling Guide

Multispectral Imaging; Eureka Vision E7, MegaVision

CSMC

Multispectral camera system.

The MegaVision MSI system is a state of the art, mobile, non-invasive and non-destructive system. The imaging sensor of the MSI system is either a MegaVision Q15 achromatic, 14-bit digital, QHY411 (Sony IMX411) sensor with a resolution of 14208×10656 pixels (150MP), or a MegaVision E7 achromatic, 14-bit analog/12-bit digital (Kodak KAF50100) sensor with a resolution of 8176×6132 pixels (50MP), both with a sensing range of 350–1100 nm. Both are paired with a MegaVision 120 mm f/4.5 Macro UV-IR Apochromatic custom multispectral imaging lens and NK0-0118 shutter designed by Schneider-Kreuznach. Two filter wheels contain 6 filters (GG400, U360, B47, G58, O22, R25) to capture the fluorescence. The MegaVision EV LED Light Panels contain 19 discrete wavelengths for reflectance and fluorescence capture in the range of 365–1050 nm. Additionally, we use two raking light panels (450, 950 nm) and a transmissive light sheet (500, 580, 735, 940 nm). A single imaging sequence consists of 19 reflectance, 22 fluorescence, 4 raking light and 4 transmissive light images (49 images). The capture sequence takes roughly 7 minutes. An X-Rite ColorChecker Classic Mini Chart M50111 B060 and two Labsphere Spectralon SRS-02-010 and SRS-99-010 Diffuse Reflectance Standards are used for calibration. Epson Enhanced Matte paper (A2 KA250MM) is used for flattening out the illumination irregularities and system artefacts.

  • General description: multispectral imaging system
  • Application aim: recovering damaged and erased writing
  • Mobility: transportable; 106 kg, 5 packages
  • Equipment specifics:
    • Monochrome imaging sensor: E7 (KAF50100) 50 megapixel (8176×6132 pixels, 6.0 μm pixel size), with sensing range 350–1100 nm
    • Monochrome imaging sensor: Q15 (QHY411) 150 megapixel (14208×10656 pixels, 3.76 μm pixel size), with sensing range 350–1100 nm
    • Optics: 120 mm apochromatic quartz lens, f/4.5 aperture, with shutter speeds ranging from 1/60 to 60 seconds
    • Illumination: high-efficiency, low-heat, narrow-band LEDs, 19 wavelengths in the ultraviolet, visible, and near-infrared range (365–1050 nm), 6 filters for fluorescence imaging (U360, GG400, B47, G58, O22, R25)
    • Reflectance targets: Spectralon diffuse reflectance targets, 99% and 2%
    • Illumination calibration: Epson Enhanced Matte Finish paper KAF250A2
    • Colour calibration: X-Rite ColorChecker Classic Mini
    • Control software: MegaVision Photoshoot5 (OS Windows 11, USB 3.0)
    • Image processing software: L3Harris Geospatial ENVI 5.5; GIMP 2.10; Hoku 1.9.3
  • Application requirements:
    • One room that (1) can be completely darkened and has no more than two windows; (2) measures at least 4×4×2.3 m; and (3) is not affected by sources of vibration (e.g., elevators, metro, construction work, bell towers, running generators, etc., or unstable floors or parquet)
    • One sturdy and stable table (roughly 80×160 cm) on which the system and objects are placed
    • One regular table for laptops, hard drives, general preparation, etc.
    • One power outlet
  • Sample required: no
  • Contact required: no
  • Limitations: size of object (in a single frame, optimal size is below A4, possible up to 42×59 cm or A2, though larger objects can be done in tiles with stitching)
  • Set up time: 1 day
  • Average time for measuring: c. 15 minutes per page for setup and image capture
  • Average time for processing: up to 1 day per page, usually less
  • Output: high-resolution, archival-quality TIFF files (greater than 600 ppi/dpi)
  • 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)