Perceptual grouping for symbol chain tracking in digitized topographic maps
Pattern Recognition Letters
Contour Line and Geographic Feature Extraction from USGS Color Topographical Paper Maps
IEEE Transactions on Pattern Analysis and Machine Intelligence
Knowledge-Based Segmentation for Automatic Map Interpretation
Selected Papers from the First International Workshop on Graphics Recognition, Methods and Applications
Segmentation of Thematic Maps Using Colour and Spatial Attributes
GREC '97 Selected Papers from the Second International Workshop on Graphics Recognition, Algorithms and Systems
Recognition in Maps and Geographic Documents: Features and Approach
GREC '99 Selected Papers from the Third International Workshop on Graphics Recognition, Recent Advances
Text/Graphics Separation in Maps
GREC '01 Selected Papers from the Fourth International Workshop on Graphics Recognition Algorithms and Applications
Symbol Recognition: Current Advances and Perspectives
GREC '01 Selected Papers from the Fourth International Workshop on Graphics Recognition Algorithms and Applications
Efficient and robust graphics recognition from historical maps
GREC'11 Proceedings of the 9th international conference on Graphics Recognition: new trends and challenges
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A colour image segmentation (CIS) process for scanned historical maps is presented to overcome common problems associated with segmentation of old documents such as (1) variation in colour values of the same colour layer within one map page, (2) differences in typical colour values between homogeneous areas and thin line-work, which belong both to the same colour layer, and (3) extensive parameterization that results in a lack of robustness. The described approach is based on a two-stage colour layer prototype search using a constrained sampling design. Global colour layer prototypes for the identification of homogeneous regions are derived based on colour similarity to the most extreme colour layer values identified in the map page. These global colour layer prototypes are continuously adjusted using relative distances between prototype positions in colour space until a reliable sample is collected. Based on this sample colour layer seeds and directly connected neighbors of the same colour layer are determined resulting in the extraction of homogeneous colour layer regions. In the next step the global colour layer prototypes are recomputed using a new sample of colour values along the margins of identified homogeneous coloured regions. This sampling step derives representative prototypes of map layer sections that deviate significantly from homogeneous regions of the same layers due to bleaching, mixed or false colouring and ageing of the original scanned documents. A spatial expansion process uses these adjusted prototypes as start criterion to assign the remaining colour layer parts. The approach shows high robustness for map documents that suffer from low graphical quality indicating some potential for general applicability due to its simplicity and the limited need for preliminary information. The only input required is the colours and number of colour layers present in the map.