36,574 research outputs found
Adaptive Filters for 2-D and 3-D Digital Images Processing
Práce se zabývá adaptivními filtry pro vizualizaci obrazů s vysokým rozlišením. V teoretické části je popsán princip činnosti konfokálního mikroskopu a matematicky korektně zaveden pojem digitální obraz. Pro zpracování obrazů je volen jak frekvenční přístup (s využitím 2-D a 3-D diskrétní Fourierovy transformace a frekvenčních filtrů), tak přístup pomocí digitální geometrie (s využitím adaptivní ekvalizace histogramu s adaptivním okolím). Dále jsou popsány potřebné úpravy pro práci s neideálními obrazy obsahujícími aditivní a impulzní šum. Závěr práce se věnuje prostorové rekonstrukci objektů na základě jejich optických řezů. Veškeré postupy a algoritmy jsou i prakticky zpracovány v softwaru, který byl vyvinut v rámci této práce.The thesis is concerned with filters for visualization of high dynamic range images. In the theoretical part, the principle of confocal microscopy is described and the term digital image is defined in a mathematically correct way. Both frequency approach (using 2-D and 3-D discrete Fourier transform and frequency filters) and digital geometry approach (using adaptive histogram equalization with adaptive neighbourhood) are chosen for the processing of images. Necessary adjustments when working with non-ideal images containing additive and impulse noise are described as well. The last part of the thesis is interested in 3-D reconstruction from optical cuts of an object. All the procedures and algorithms are also implemented in the software developed as a part of this thesis.
Improving utility of brain tumor confocal laser endomicroscopy: objective value assessment and diagnostic frame detection with convolutional neural networks
Confocal laser endomicroscopy (CLE), although capable of obtaining images at
cellular resolution during surgery of brain tumors in real time, creates as
many non-diagnostic as diagnostic images. Non-useful images are often distorted
due to relative motion between probe and brain or blood artifacts. Many images,
however, simply lack diagnostic features immediately informative to the
physician. Examining all the hundreds or thousands of images from a single case
to discriminate diagnostic images from nondiagnostic ones can be tedious.
Providing a real-time diagnostic value assessment of images (fast enough to be
used during the surgical acquisition process and accurate enough for the
pathologist to rely on) to automatically detect diagnostic frames would
streamline the analysis of images and filter useful images for the
pathologist/surgeon. We sought to automatically classify images as diagnostic
or non-diagnostic. AlexNet, a deep-learning architecture, was used in a 4-fold
cross validation manner. Our dataset includes 16,795 images (8572 nondiagnostic
and 8223 diagnostic) from 74 CLE-aided brain tumor surgery patients. The ground
truth for all the images is provided by the pathologist. Average model accuracy
on test data was 91% overall (90.79 % accuracy, 90.94 % sensitivity and 90.87 %
specificity). To evaluate the model reliability we also performed receiver
operating characteristic (ROC) analysis yielding 0.958 average for the area
under ROC curve (AUC). These results demonstrate that a deeply trained AlexNet
network can achieve a model that reliably and quickly recognizes diagnostic CLE
images.Comment: SPIE Medical Imaging: Computer-Aided Diagnosis 201
Confocal microscopy of colloidal particles: towards reliable, optimum coordinates
Over the last decade, the light microscope has become increasingly useful as
a quantitative tool for studying colloidal systems. The ability to obtain
particle coordinates in bulk samples from micrographs is particularly
appealing. In this paper we review and extend methods for optimal image
formation of colloidal samples, which is vital for particle coordinates of the
highest accuracy, and for extracting the most reliable coordinates from these
images. We discuss in depth the accuracy of the coordinates, which is sensitive
to the details of the colloidal system and the imaging system. Moreover, this
accuracy can vary between particles, particularly in dense systems. We
introduce a previously unreported error estimate and use it to develop an
iterative method for finding particle coordinates. This individual-particle
accuracy assessment also allows comparison between particle locations obtained
from different experiments. Though aimed primarily at confocal microscopy
studies of colloidal systems, the methods outlined here should transfer readily
to many other feature extraction problems, especially where features may
overlap one another.Comment: Accepted by Advances in Colloid and Interface Scienc
Prospects for Theranostics in Neurosurgical Imaging: Empowering Confocal Laser Endomicroscopy Diagnostics via Deep Learning
Confocal laser endomicroscopy (CLE) is an advanced optical fluorescence
imaging technology that has the potential to increase intraoperative precision,
extend resection, and tailor surgery for malignant invasive brain tumors
because of its subcellular dimension resolution. Despite its promising
diagnostic potential, interpreting the gray tone fluorescence images can be
difficult for untrained users. In this review, we provide a detailed
description of bioinformatical analysis methodology of CLE images that begins
to assist the neurosurgeon and pathologist to rapidly connect on-the-fly
intraoperative imaging, pathology, and surgical observation into a
conclusionary system within the concept of theranostics. We present an overview
and discuss deep learning models for automatic detection of the diagnostic CLE
images and discuss various training regimes and ensemble modeling effect on the
power of deep learning predictive models. Two major approaches reviewed in this
paper include the models that can automatically classify CLE images into
diagnostic/nondiagnostic, glioma/nonglioma, tumor/injury/normal categories and
models that can localize histological features on the CLE images using weakly
supervised methods. We also briefly review advances in the deep learning
approaches used for CLE image analysis in other organs. Significant advances in
speed and precision of automated diagnostic frame selection would augment the
diagnostic potential of CLE, improve operative workflow and integration into
brain tumor surgery. Such technology and bioinformatics analytics lend
themselves to improved precision, personalization, and theranostics in brain
tumor treatment.Comment: See the final version published in Frontiers in Oncology here:
https://www.frontiersin.org/articles/10.3389/fonc.2018.00240/ful
Three-dimensional measurements with a novel technique combination of confocal and focus variation with a simultaneous scan
The most common optical measurement technologies used today for the three dimensional measurement of technical surfaces are Coherence Scanning Interferometry (CSI), Imaging Confocal Microscopy (IC), and Focus Variation (FV). Each one has its benefits and its drawbacks. FV will be the ideal technology for the measurement of those regions where the slopes are high and where the surface is very rough, while CSI and IC will provide better results for smoother and flatter surface regions. In this work we investigated the benefits and drawbacks of combining Interferometry, Confocal and focus variation to get better measurement of technical surfaces. We investigated a way of using Microdisplay Scanning type of Confocal Microscope to acquire on a simultaneous scan confocal and focus Variation information to reconstruct a three dimensional measurement. Several methods are presented to fuse the optical sectioning properties of both techniques as well as the topographical information. This work shows the benefit of this combination technique on several industrial samples where neither confocal nor focus variation is able to provide optimal results.Postprint (author's final draft
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