ABSTRACT Vickers microindentation imagery is segmented using the Chan-Vese level-set approach. In... more ABSTRACT Vickers microindentation imagery is segmented using the Chan-Vese level-set approach. In order to find a suitable initialization, we propose to apply a Shape-Prior gradient descent approach to a significantly resolution-reduced image. Subsequent local Hough transform leads to a very high accuracy of the overall approach.
EURASIP Journal on Image and Video Processing, 2016
Besides a high distinctiveness, robustness (or invariance) to image degradations is very desirabl... more Besides a high distinctiveness, robustness (or invariance) to image degradations is very desirable for texture feature extraction methods in real-world applications. In this paper, focus is on making arbitrary texture descriptors invariant to blur which is often prevalent in real image data. From previous work, we know that most state-of-the-art texture feature extraction methods are unable to cope even with minor blur degradations if the classifier's training stage is based on idealistic data. However, if the training set suffers similarly from the degradations, the obtained accuracies are significantly higher. Exploiting that knowledge, in this approach the level of blur of each image is increased to a certain threshold, based on the estimation of a blur measure. Experiments with synthetically degraded data show that the method is able to generate a high degree of blur invariance without loosing too much distinctiveness. Finally, we show that our method is not limited to ideal Gaussian blur.
ABSTRACT To measure the hardness of a material, an indenter is pressed into the material and the ... more ABSTRACT To measure the hardness of a material, an indenter is pressed into the material and the deformation is measured. As we focus on Vickers hardness testing, our exercise is to compute the diagonal lengths of a square indentation. We especially investigate if it is possible to reconstruct the shape of the indentation by the use of the Shape-from-Focus method. We show that the shape information alone does not contain enough information for a robust segmentation. However, we incorporate the depth information into an effective existing approach and achieve significantly better results.
Tenth International Conference on Quality Control by Artificial Vision, 2011
ABSTRACT Current algorithms for automated processing of Vickers hardness testing images are unsui... more ABSTRACT Current algorithms for automated processing of Vickers hardness testing images are unsuitable for a broad range of images that are taken in industrial environments because such images show great variations in the Vickers indentation as well as in the specimen surface. The authors present a three-stage multiresolution template matching algorithm that shows excellent results, even for such challenging images. The capabilities of this algorithm are compared to known algorithms from the literature and results are presented. The comparison is conducted on two significant indentation image databases with 150 and 216 highly varying images. The applicability of the proposed algorithm is further illustrated by its competitive runtime performance. (C) 2012 SPIE and IS&T. [DOI: 10.1117/1.JEI.21.2.021109]
ABSTRACT Vickers microindentation imagery is segmented using the Chan-Vese level-set approach. In... more ABSTRACT Vickers microindentation imagery is segmented using the Chan-Vese level-set approach. In order to find a suitable initialization, we propose to apply a Shape-Prior gradient descent approach to a significantly resolution-reduced image. Subsequent local Hough transform leads to a very high accuracy of the overall approach.
EURASIP Journal on Image and Video Processing, 2016
Besides a high distinctiveness, robustness (or invariance) to image degradations is very desirabl... more Besides a high distinctiveness, robustness (or invariance) to image degradations is very desirable for texture feature extraction methods in real-world applications. In this paper, focus is on making arbitrary texture descriptors invariant to blur which is often prevalent in real image data. From previous work, we know that most state-of-the-art texture feature extraction methods are unable to cope even with minor blur degradations if the classifier's training stage is based on idealistic data. However, if the training set suffers similarly from the degradations, the obtained accuracies are significantly higher. Exploiting that knowledge, in this approach the level of blur of each image is increased to a certain threshold, based on the estimation of a blur measure. Experiments with synthetically degraded data show that the method is able to generate a high degree of blur invariance without loosing too much distinctiveness. Finally, we show that our method is not limited to ideal Gaussian blur.
ABSTRACT To measure the hardness of a material, an indenter is pressed into the material and the ... more ABSTRACT To measure the hardness of a material, an indenter is pressed into the material and the deformation is measured. As we focus on Vickers hardness testing, our exercise is to compute the diagonal lengths of a square indentation. We especially investigate if it is possible to reconstruct the shape of the indentation by the use of the Shape-from-Focus method. We show that the shape information alone does not contain enough information for a robust segmentation. However, we incorporate the depth information into an effective existing approach and achieve significantly better results.
Tenth International Conference on Quality Control by Artificial Vision, 2011
ABSTRACT Current algorithms for automated processing of Vickers hardness testing images are unsui... more ABSTRACT Current algorithms for automated processing of Vickers hardness testing images are unsuitable for a broad range of images that are taken in industrial environments because such images show great variations in the Vickers indentation as well as in the specimen surface. The authors present a three-stage multiresolution template matching algorithm that shows excellent results, even for such challenging images. The capabilities of this algorithm are compared to known algorithms from the literature and results are presented. The comparison is conducted on two significant indentation image databases with 150 and 216 highly varying images. The applicability of the proposed algorithm is further illustrated by its competitive runtime performance. (C) 2012 SPIE and IS&T. [DOI: 10.1117/1.JEI.21.2.021109]
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Papers by Michael Gadermayr