Curved Gabor Filters for Fingerprint Image Enhancement

Gabor filters play an important role in many application areas for the enhancement of various types of images and the extraction of Gabor features. For the purpose of enhancing curved structures in noisy images, we introduce curved Gabor filters which locally adapt their shape to the direction of flow. These curved Gabor filters enable the choice of filter parameters which increase the smoothing power without creating artifacts in the enhanced image. In this paper, curved Gabor filters are applied to the curved ridge and valley structure of low-quality fingerprint images. First, we combine two orientation field estimation methods in order to obtain a more robust estimation for very noisy images. Next, curved regions are constructed by following the respective local orientation and they are used for estimating the local ridge frequency. Lastly, curved Gabor filters are defined based on curved regions and they are applied for the enhancement of low-quality fingerprint images. Experimental results on the FVC2004 databases show improvements of this approach in comparison to state-of-the-art enhancement methods

The Necessity and Limits of Kant’s Transcendental Logic, with Reference to Nietzsche and Hegel

Engaging with Kant’s transcendental logic seems to be a question of mere scholarly historical interest today. It is most commonly regarded a mixture between logic and psychology or epistemology, and by that, not a serious form of logic. Transcendental logic seems to be of no systematical impact on the concept of logic. My paper aims to disclose a different account on the endeavour of Kant’s transcendental logic in particular and of the “Critique of Pure Reason” (CPR) in general. Kant’s fundamental question is in a revolutionary way aiming to ground the character of necessity of knowledge, which means to justify the claim that thinking in accordance with the forms and principles of formal logic does not lead to sheer tautologies or an unsolved contradiction, but to knowledge that is objectively valid. In a first part, I shall demonstrate the necessity and the significance of this new fundamental question of the CPR with respect to its genesis out of pre-Kantian metaphysics. A brief outline of Kant’s answer to this question, with special emphasis on his revolutionary new comprehension of logical form, will be given as well. A second part shall open up a perspective that lies beyond Kant’s standpoint with reference to Nietzsche and eventually to Hegel. I will answer the question: What knowledge do we achieve about being or actuality by means of formal logic? I will argue that Kant shows that formal logic is the logic of all technical-practical conduct but also, at least indirectly, the limitation of the technical-practical knowledge and its legitimate sphere of application