TY - JOUR A1 - Palm, Christoph A1 - Lehmann, Thomas M. T1 - Classification of Color Textures by Gabor Filtering JF - Machine GRAPHICS & VISION Y1 - 2002 VL - 11 IS - 2/3 SP - 195 EP - 219 ER - TY - JOUR A1 - Neuschaefer-Rube, C. A1 - Lehmann, Thomas M. A1 - Palm, Christoph A1 - Bredno, J. A1 - Klajman, S. A1 - Spitzer, Klaus T1 - 3D-Visualisierung glottaler Abduktionsbewegungen JF - Aktuelle phoniatrisch-pädaudiologische Aspekte Y1 - 2001 SN - 3-922766-76-5 VL - 2001/2002 IS - 9 SP - 58 EP - 61 PB - Median ER - TY - JOUR A1 - Lehmann, Thomas M. A1 - Palm, Christoph T1 - Color Line Search for Illuminant Estimation in Real World Scenes JF - Journal of the Optical Society of America (JOSA) A N2 - The estimation of illuminant color is mandatory for many applications in the field of color image quantification. However, it is an unresolved problem if no additional heuristics or restrictive assumptions apply. Assuming uniformly colored and roundly shaped objects, Lee has presented a theory and a method for computing the scene-illuminant chromaticity from specular highlights [H. C. Lee, J. Opt. Soc. Am. A 3, 1694 (1986)]. However, Lee’s method, called image path search, is less robust to noise and is limited in the handling of microtextured surfaces. We introduce a novel approach to estimate the color of a single illuminant for noisy and microtextured images, which frequently occur in real-world scenes. Using dichromatic regions of different colored surfaces, our approach, named color line search, reverses Lee’s strategy of image path search. Reliable color lines are determined directly in the domain of the color diagrams by three steps. First, regions of interest are automatically detected around specular highlights, and local color diagrams are computed. Second, color lines are determined according to the dichromatic reflection model by Hough transform of the color diagrams. Third, a consistency check is applied by a corresponding path search in the image domain. Our method is evaluated on 40 natural images of fruit and vegetables. In comparison with those of Lee’s method, accuracy and stability are substantially improved. In addition, the color line search approach can easily be extended to scenes of objects with macrotextured surfaces. Y1 - 2001 U6 - https://doi.org/10.1364/JOSAA.18.002679 VL - 18 IS - 11 SP - 2679 EP - 2691 ER - TY - JOUR A1 - Ilgner, Justus F. R. A1 - Palm, Christoph A1 - Schütz, Andreas G. A1 - Spitzer, Klaus A1 - Westhofen, Martin A1 - Lehmann, Thomas M. T1 - Colour Texture Analysis for Quantitative Laryngoscopy JF - Acta Otolaryngologica N2 - Whilst considerable progress has been made in enhancing the quality of indirect laryngoscopy and image processing, the evaluation of clinical findings is still based on the clinician's judgement. The aim of this paper was to examine the feasibility of an objective computer-based method for evaluating laryngeal disease. Digitally recorded images obtained by 90 degree- and 70 degree-angled indirect rod laryngoscopy using standardized white balance values were made of 16 patients and 19 healthy subjects. The digital images were evaluated manually by the clinician based on a standardized questionnaire, and suspect lesions were marked and classified on the image. Following colour separation, normal vocal cord areas as well as suspect lesions were analyzed automatically using co-occurrence matrices, which compare colour differences between neighbouring pixels over a predefined distance. Whilst colour histograms did not provide sufficient information for distinguishing between healthy and diseased tissues, consideration of the blue content of neighbouring pixels enabled a correct classification in 81.4% of cases. If all colour channels (red, green and blue) were regarded simultaneously, the best classification correctness obtained was 77.1%. Although only a very basic classification differentiating between healthy and diseased tissue was attempted, the results showed progress compared to grey-scale histograms, which have been evaluated before. The results document a first step towards an objective, machine-based classification of laryngeal images, which could provide the basis for further development of an expert system for use in indirect laryngoscopy. KW - diagnostic laryngoscopy KW - electronic imaging KW - endoscopy KW - neoplastic larynx disease Y1 - 2003 U6 - https://doi.org/10.1080/00016480310000412 VL - 123 SP - 730 EP - 734 ER -