https://hdl.handle.net/10481/5460 Fri, 17 Apr 2026 20:21:33 GMT 2026-04-17T20:21:33Z https://hdl.handle.net/10481/102064 Evaluation of Binarization Methods fo r Hyperspectral Samples of 16th and 17th Century Family Trees Moronta-Montero, Francisco; Fernández-Gualda, Ramón; López-Baldomero, Ana B.; Buzzelli, Marco; Martínez-Domingo, Miguel Ángel; Valero, Eva M. https://hdl.handle.net/10481/102064 https://hdl.handle.net/10481/102063 Hyperspectral Database of Synthetic Historical Inks López-Baldomero, Ana B.; Valero, Eva M.; Reichert, Anna S.; Moronta-Montero, Francisco; Martínez-Domingo, Miguel Ángel; López-Montes, Ana The aim of this work is to provide the cultural heritage community with a comprehensive hyperspectral image database of handwritten laboratory samples, including various writing inks commonly found in historical documents. The database contains 195 samples registered in the VNIR (400-1000 nm) and SWIR (900-1700 nm) spectral ranges, along with complete information about the ink recipes (components and concentrations used for each ink and mixture), and their corresponding Ground Truth images. The database is now publicly available as part of a bigger database related to the Hyperdoc project and can be used to perform different tasks. We present here one example: the classification of iron gall vs non-iron gall inks. https://hdl.handle.net/10481/102063 https://hdl.handle.net/10481/102061 Endmember Extraction for Pigment Identification Pre- and Post-intervention: A Case Study from a XVIth Century Copper Plate Painting López-Baldomero, Ana B.; Martínez-Domingo, Miguel Ángel; Hernández-Andrés, Javier; Blanc, Rosario; Vilchez-Quero, J. L.; López-Montes, Ana; Valero, Eva M. Three endmember extraction methods (NFINDR, NMF and manual extraction) are compared in two stages (pre- and post- intervention) of the same painting, a Maternity on copper plate, under study for the formulation of a hypothesis on the authorship and the dating. The endmembers are extracted from spectral images in the 400-1000 nm range. The main aim is to determine if simple automatic endmember extraction is enough for pigment and re-painted areas identification in this case study. https://hdl.handle.net/10481/102061 https://hdl.handle.net/10481/102060 Selection of optimal spectral metrics for classification of inks in historical documents using hyperspectral imaging data López-Baldomero, Ana B.; Martínez-Domingo, Miguel Ángel; Valero, Eva M.; Fernández-Gualda, Ramón; López-Montes, Ana; Blanc-García, Rosario; Espejo, Teresa Hyperspectral imaging has been increasingly used for non-destructive analysis of historical documents. Spectral reflectance data allow material identification and mapping using a library of reference spectra. Similarity metrics are crucial for quantifying the differences between reference and test spectra. Despite the apparent simplicity of the metrics, little work has been done on comparing their performance in the classification of historical inks. In this work, we propose three methods for selection of optimal spectral metrics, with an application to classification of historical inks. Hyperspectral images of laboratory and real historical samples are acquired in VNIR [400-1000 nm] and SWIR [900- 1700 nm] spectral ranges. Two spectral reflectance libraries are obtained (one for each range) including eight inks: iron gall, sepia, and carbon-based inks, and some mixtures. Six spectral similarity metrics are used: RMSE, SAM, SID, SIDSAM, NS3, and JMSAM. Firstly, metrics values in laboratory samples are studied to determine the classification confidence threshold of each metric. Then, the optimal metrics found for classification are selected using diverse approaches: (1) considering the confidence threshold; (2) evaluating classification performance metrics; (3) studying the probability of spectral discrimination and the power of spectral discrimination of each metric. Finally, inks of historical samples are classified by searching through the spectral libraries using optimal spectral metrics. Our method can correctly identify inks in both laboratory and historical samples in a simple and semi-supervised way. https://hdl.handle.net/10481/102060 https://hdl.handle.net/10481/96457 Color-quality control using color-difference formulas: progress and problems Melgosa Latorre, Manuel; Gómez Robledo, Luis; García, P. A.; Morillas, Samuel; Fernández Maloigne, Christine; Richard, Noël; Huang, Min; Li, Changjun; Cui, G. We report on some recent advances in industrial color-difference evaluation focused in three main fields: Development of reliable experimental visual datasets; proposal of new color spaces and color-difference formulas; tools to evaluate the merits of color-difference formulas. The use of fuzzy techniques to assign consistency degrees to color pairs in combined visual datasets is described. The CIE/ISO joint proposal of the CIEDE2000 color-difference formula as a standard will facilitate the communication among companies and users. The CIE recommendation of the STRESS index to assess observers’ variability and relative merits of different color-difference formulas is reported. Power functions are an efficient method to improve the performance of modern color-difference formulas. We need of advanced color-difference formulas accounting for new materials with different kind of textures and gonioapparent effects. Ministry of Economy and Competitiveness of the National Government of Spain, research projects FIS2013-40661-P and FIS2016-80983-P, with support from European Regional Development Fund (ERDF). https://hdl.handle.net/10481/96457