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Barrel-Type Distortion Compensated Fourier Feature Extraction [chapter]

Michael Gadermayr, Andreas Uhl, Andreas Vécsei
2013 Lecture Notes in Computer Science  
In case of endoscopic imaging, often significant barrel-type distortions affect the feature extraction.  ...  We introduce and evaluate three strategies to partially or completely compensate the geometric distortion in combination with Fourier features.  ...  Therefore, in this work, we investigate different ways of extracting barrel-type distortion corrected Fourier features.  ... 
doi:10.1007/978-3-642-41914-0_6 fatcat:32ofaq2vtjbandfu5doaqi2lyu

Distortion Adaptive Image Classification – An Alternative to Barrel-Type Distortion Correction [chapter]

Michael Gadermayr, Andreas Uhl, Andreas Vécsei
2013 Lecture Notes in Computer Science  
The endoscopes, utilized in computer aided celiac disease diagnosis are equipped with wide-angle lenses, which introduce significant barrel-type distortions.  ...  Previous work is on rectifying the distortions prior to the feature extraction. However, due to new arising inadequacies this often even decreases the classification accuracy.  ...  neighbor patch, in case of classifying barrel-type distorted celiac disease images.  ... 
doi:10.1007/978-3-642-41939-3_45 fatcat:7dojnmu3ozh2ddlzk4gjkchbb4

Problems in Distortion Corrected Texture Classification and the Impact of Scale and Interpolation [chapter]

Michael Gadermayr, Michael Liedlgruber, Andreas Uhl, Andreas Vécsei
2013 Lecture Notes in Computer Science  
In the field of computer aided celiac disease diagnosis, wide-angle endoscopy lenses are employed which introduce significant barrel type distortions.  ...  Although the images can be rectified using distortion correction methods, computer based diagnosis suffers from missing information in highly distorted image regions.  ...  In this approach, the circular barrel type distortion is modeled by the division model [3] .  ... 
doi:10.1007/978-3-642-41181-6_52 fatcat:pdibbcg4kzgy7og3wvk5qckvru

Is a Precise Distortion Estimation Needed for Computer Aided Celiac Disease Diagnosis? [chapter]

Michael Gadermayr, Andreas Uhl, Andreas Vécsei
2014 Lecture Notes in Computer Science  
Particularly, we identify one simple but especially for certain features highly effective approximative distortion model.  ...  Knowing the discriminative power of all sensible distortion configurations, the model parameters are estimated.  ...  In this approach, the circular barrel type distortion is modeled by the division model [1] .  ... 
doi:10.1007/978-3-319-07998-1_71 fatcat:ecv3syl6tzg3fjactmtqfj47cy

Examining Barrel Distortion, Super-resolution on Single-view-based Ear Biometrics Rotated in Depth

Daishi WATABE, Takanari MINAMIDANI, Wenbo ZHAO, Hideyasu SAI, Jianting CAO
2015 International Journal of Affective Engineering  
Empirical demonstrations show that, using barrel-distorted images and super-resolution images, accuracy decreases.  ...  Numerical simulations were performed using super-resolution images and barrel-distorted images to improve the viability of the authors' previous work regarding single-view-based ear biometrics.  ...  Images with barrel distortions Fisheye lenses, which take hemispherical views, have barrel distortion to map an infinitely wide object plane into a finite image area.  ... 
doi:10.5057/ijae.14.103 fatcat:wochqwywnfh3vdsa3d2526l7hm

Applying and extending ISO/TC42 digital camera resolution standards to mobile imaging products

Don Williams, Peter D. Burns
2007 Image Quality and System Performance IV  
In particular, accommodation of optical flare, shading non-uniformity and distortion are recommended.  ...  (a) Edge displacement observed because of barrel lens(1)and(2)ripple type distortion. (b) Measured SFR for undistorted edge. Sampling is at 400 ppi.  ...  Barrel distortion was introduced in software, with 5% effective optical distortion at the corners.  ... 
doi:10.1117/12.703645 fatcat:ihapnpjhizeenmekbjlqe37sxa

Multiperspective mosaics for under-vehicle inspection

Andreas F. Koschan, Jin-Choon Ng, Mongi A. Abidi, Grant R. Gerhart, Chuck M. Shoemaker, Douglas W. Gage
2004 Unmanned Ground Vehicle Technology VI  
Fig. 7(b) shows the result of barrel distortion correction.  ...  Hence, perspective distortion Camera's path Camera's principal axis correction is used to compensate for this.  ... 
doi:10.1117/12.542795 fatcat:mewyrzv4rbdyjb22fly4ejz3di

Microscope calibration using laser written fluorescence

Alexander D. Corbett, Michael Shaw, Andrew Yacoot, Andrew Jefferson, Lothar Schermelleh, Tony Wilson, Martin Booth, Patrick S. Salter
2018 Optics Express  
We report on the use of two laser written patterns to measure the lateral resolution, illumination uniformity, lens distortion and colour plane alignment using confocal and structured illumination fluorescence  ...  Distortion characterisation Distortion is a spatially dependent magnification change and is typically manifested as either a pincushion or barrel distortion of the microscope image.  ...  Finally, as the beads themselves are distributed randomly across the field of view, it is not possible to extract any measures of image distortion across the field of view.  ... 
doi:10.1364/oe.26.021887 pmid:30130891 pmcid:PMC6238825 fatcat:5neivxswkbe7jmi725mhmff47q

Survey on computer aided decision support for diagnosis of celiac disease

Sebastian Hegenbart, Andreas Uhl, Andreas Vécsei
2015 Computers in Biology and Medicine  
Consequently, distortion adaptive classification [38, 40] , distortion compensated features based on the Fourier transform [37] as well as intrinsic distortion correction [41] have been proposed.  ...  Such barrel-type distortions introduce non-linear changes in the images, leading to a significantly smaller visualization of outer areas.  ... 
doi:10.1016/j.compbiomed.2015.02.007 pmid:25770906 pmcid:PMC4593300 fatcat:wxhi536np5exheqmzgodfctgsi


B. Sridhar
2017 International Journal on Smart Sensing and Intelligent Systems  
In order to detect watermarks from the pre-warped image with barrel distortion, an estimation method of the barrel distortion is proposed for HMDs.  ...  Then, the same warp is enforced on the embedded watermark mask with the estimated parameters of barrel distortion.  ... 
doi:10.21307/ijssis-2017-217 fatcat:wamzxdqkifgc7l7f4k2y6ihsxa

Robust Retina-Based Person Authentication Using The Sparse Classifier

Alexandru Condurache, Johannes Kotzerke, A. Mertins
2012 Zenodo  
This type of feature extraction offers us an additional set of invariance properties to some simple transformation of the SIFT descriptors.  ...  The person-related distortions are small rotations, translations and scalings of the original image, the optics-related distortion are blurring, barrel and pincushion transforms applied to the original  ... 
doi:10.5281/zenodo.52386 fatcat:mwa64ubn4bcavgc6r67yw43cu4

Quantifying distortions in two-photon remote focussing microscope images using a volumetric calibration specimen

Alexander D. Corbett, Rebecca A. B. Burton, Gil Bub, Patrick S. Salter, Simon Tuohy, Martin J. Booth, Tony Wilson
2014 Frontiers in Physiology  
Finally, by first approximating and then compensating the distortion in imaging data from whole heart rodent studies, the variance of sarcomere length (SL) measurements was reduced by almost 50%.  ...  The origin of the distortion is first identified through simulation of a remote focussing microscope.  ...  Whilst this necessarily introduces distortions, if the distortions are known then they can be compensated for in post-processing.  ... 
doi:10.3389/fphys.2014.00384 pmid:25339910 pmcid:PMC4189333 fatcat:nwb5chlt5rcdvobafsvbutn2je

Imaging properties of large field-of-view quadratic metalenses and their applications to fingerprint detection [article]

Emmanuel Lassalle, Tobias W. W. Mass, Damien Eschimese, Anton V. Baranikov, Egor Khaidarov, Shiqiang Li, Ramon Paniagua-Dominguez, Arseniy I. Kuznetsov
2021 arXiv   pre-print
In this work, we provide an in-depth analysis of the imaging properties of quadratic metalenses and, in particular, show that due to their intrinsic barrel distortion or fish-eye effect, there is a fundamental  ...  how to harness the full potential of quadratic metalenses, we apply these considerations to the fingerprint detection problem, and demonstrate experimentally the full imaging of a 5mm fingerprint with features  ...  The barrel distortion in itself is not a problem for imaging since it can be compensated with a post-processing treatment (see next Section).  ... 
arXiv:2102.07999v2 fatcat:xiketm32ffgrpk5nenwdzkzp6q

Design, implementation, and characterization of a kinematically aligned, cascaded spot- array generator for a modulator-based free-space optical interconnect

Daniel F.- Brosseau, Frédéric Lacroix, Michael H. Ayliffe, Eric Bernier, Brian Robertson, Frank A. P. Tooley, David V. Plant, Andrew G. Kirk
2000 Applied Optics  
OPS Module Degrees of FreedomDesign Requirement Optical-Optomechanical Solution Spots on a uniform grid Low-distortion Fourier lens Spot pitch of 1600 m ϫ 800 m Adjust focal length of Fourier lens with  ...  It also provides a large field size ͑7.7 mm͒, while maintaining low field curvature and distortion ͑ f Ϫ sin distortion of less than 0.025% across the 20.7°fi eld of view͒.  ... 
doi:10.1364/ao.39.000733 pmid:18337948 fatcat:npgmjac3s5d7lhlalmii33swpy

Biologically Inspired Motion Encoding for Robust Global Motion Estimation

Evangelos Sariyanidi, Hatice Gunes, Andrea Cavallaro
2017 IEEE Transactions on Image Processing  
by barrel distortion; (c) Ego-centric3, a scene with barrel distortions and large outlier motions; (d) Flower, a scene with elements of varying depth; (e) Coastguard, two (visually salient) ships are  ...  In addition to outlier local motions (e.g. moving robot, people), these sequences have the challenge of high barrel (lens) distortion, which is not possible to compensate with homographic transformations  ... 
doi:10.1109/tip.2017.2651394 pmid:28129154 fatcat:qi7ixrpaqndcxgbjjda6ftgtxy
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