Recently, we presented a new OCR-concept  for historic prints. The core part is the glyph recognition based on pattern matching with patterns that are derived from computer font glyphs and are generated on-the-fly. The classification of a sample is organized as a search process for the most similar glyph pattern. In this paper, we investigate several similarity measures which are of vital importance for this concept.
Perceived color is an empirical phenomenon and, to date, is only approximately understood in complex situations.
In general, color spaces or color order systems, as a mathematical characterization of such empirical observations,
address specific applications such that they may not be adequate in other contexts. In this work, we investigate
four device-independent color spaces (color order systems) with regard to their suitability for a specific gamut
mapping concept called "unsharp mapping".
Contrary to high dynamic range imaging, the preservation of details and the avoidance of artifacts is not explicitly considered
in popular color management systems. An effective way to overcome these difficulties is image filtering. In this
paper we investigate several image filter concepts for detail preservation as part of a practical gamut mapping strategy.
In particular we define four concepts including various image filters and check their performance with a psycho-visual
test. Additionally, we compare our performance evaluation to two image quality measures with emphasis on local
contrast. Surprisingly, the most simple filter concept performs highly efficient and achieves an image quality which is
comparable to the more established but slower methods.
In principal, color reproduction on specific devices can be divided into transformation of color coordinates and the
adaptation of colors to a device, called gamut mapping. The well established ICC color management neglects the
latter aspect. This paper presents a practical implementation addressing both an eficient color transformation
and a sophisticated gamut mapping.