Dynamic Selective Edge-Based Integer/Fractional-Order Partial Differential Equation for Degraded Document Image Binarization

Conventional thresholding algorithms have had limited success with degraded document images. Recently, partial differential equations (PDEs) have been applied with good results. However, these are usually tailored to handle relatively few specific distortions. In this study, we combine an edge detection term with a linear binarization source term in a PDE formulation. Additionally, a new proposed diffusivity function further amplifies desired edges. It also suppresses undesired edges that comprise bleed-through effects. Furthermore, we develop the fractional variant of the proposed scheme, which further improves results and provides more flexibility. Moreover, nonlinear color spaces are utilized to improve binarization results for images with color distortion. The proposed scheme removes document image degradation such as bleed-through, stains, smudges, etc., and also restores faded text in the images. Experimental subjective and objective results show consistently superior performance of the proposed approach compared to the state-of-the-art PDE-based models.

Simultaneous Two-Photon Fluorescence Microscopy of NADH and FAD Using Pixel-to-Pixel Wavelength-Switching

Two-photon fluorescence (TPF) microscopy of intrinsic fluorophores provides physiological and pathological information from biological tissues. Reduced nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD) are two endogenous fluorescent coenzymes existing on the intracellular scale. Autofluorescence images of NADH and FAD have been applied to noninvasively record changes during metabolism, according to their distributions and concentrations. However, the widely used sequential (non-simultaneous) excitation scheme results in artifacts caused by sample motion or laser power fluctuation. The single-wavelength illumination scheme suffers from low excitation efficiency and spectral bleed-through. In this paper, we demonstrate a new imaging system simultaneously capturing autofluorescence images from NADH and FAD, with high excitation efficiency and negligible spectral bleed-through. Two temporally multiplexed and spatially overlapped excitation beams were achieved with fast-switching light paths based on an electro-optic modulator. The switching beams were centered at 750 and 860 nm, enabling independent excitations of NADH and FAD. Autofluorescence images of NADH and FAD were acquired at the wavelength ranges of 415–455 nm and 500–550 nm, respectively. The electro-optic modulator was synchronized with the pixel clock from the microscope, achieving pixel-to-pixel wavelength-switching. The capability of the system was demonstrated by performing TPF imaging of freshly excised mouse colon tissues. The microenvironment of the colon wall was depicted by the distributions of colonocytes, goblet cells, and crypts of Lieberkühn, and the relative concentrations of NADH and FAD were estimated. The experimental results show that the system can effectively perform simultaneous imaging of NADH and FAD, and is considered a promising tool for investigations into metabolism-associated processes and diseases.

How to quantitatively measure, assess and correct the fluorescence crosstalk in the wide-field microscopy

During the multi-color fluorescence imaging, a fluorophore can be detected in the non-corresponding channel due to the broad spectra of the fluorophore and filters, resulting in the artefact called the crosstalk (crossover or bleed-through). Unfortunately, the fluorescence crosstalk is ubiquitous for the conventional fluorescence microscopy. Significant crosstalk can distort the image and lead to incorrect interpretation. Here, we introduce a simple quantitative metric, the crosstalk factor, to measure the crosstalk effect of a fluorophore on a channel in the wide-field fluorescence microscopy. We describe a cell biologist friendly protocol which should be easily implemented by cell biologists using commonly available image processing software such as ImageJ.

Manifesting desire and anarchy as method: The problem of Inside Pussy Riot

My aim is to consider how anarchy reads and resists punitive regimes in performance, particularly in ‘immersive performance’. Punk troupe Pussy Riot forms a starting point, via Riot Days in 2017–18, with a sustained consideration on Inside Pussy Riot at the Saatchi Gallery in 2017, produced by Les Enfants Terrible. I concentrate on claims for authenticity that seem to lend theatre and performance legitimacy in relation to social change, to critique theatrical work with claims to producing agency, legitimizing hope for social transformation that is predicated on an ‘empowered’ spectator-participant. In the wake of these concerns, questions that bleed through this material relate to the limits of participation in performance and how and whether representations serve to dismantle state institutions. I consider whether the force of replications of cells, yards or gulags enables or disintegrates any activist, anarchist potential in performance. I take a wide-ranging view of anarchism beyond political theory to consider anarchism modelled in performance terms. Building from the example of Pussy Riot, the article defines performance critique through desire and anarchism, ‘manifesting desire’ or ‘anarchy as method’.

Adaptive Spike-Artifact Removal from Local Field Potentials Uncovers Prominent Beta and Gamma Band Neuronal Synchronization

BackgroundMany neurons synchronize their action potentials to the phase of local field potential (LFP) fluctuations in one or more frequency bands. Analyzing this spike-to-LFP synchronization is challenging, however, when neural spikes and LFP are generated in the same local circuit, because the spike’s action potential waveform leak into the LFP and distort phase synchrony estimates. Existing approaches to address this spike bleed-through artifact relied on removing the average action potential waveforms of neurons, but this leaves artifacts in the LFP and distorts synchrony estimates.New MethodWe describe a spike-removal method that surpasses these limitations by decomposing individual action potentials into their frequency components before their removal from the LFP. The adaptively estimated frequency components allow for variable spread, strength and temporal variation of the spike artifact.ResultsThis adaptive approach effectively removes spike bleed-through artifacts in synthetic data with known ground truth, and in single neuron and LFP recordings in nonhuman primate striatum. For a large population of neurons with both narrow and broad action potential waveforms, the use of adaptive artifact removal uncovered 20-35 Hz beta and 35-45 Hz gamma band spike-LFP synchronization that would have remained contaminated otherwise.Comparison with Existing MethodsWe demonstrate that adaptive spike-artifact removal cleans LFP data that remained contaminated when applying existing Bayesian and non-Bayesian methods of average spike-artifact removal.ConclusionsApplying adaptive spike-removal from field potentials allows to estimate the phase at which neurons synchronize and the consistency of their phase-locked firing for both beta and low gamma frequencies. These metrics may prove essential to understand cell-to-circuit neuronal interactions in multiple brain systems.

Improved Variational Methodology Towards Enhancement of Marathi Printed Degraded Documents

Optical Character Recognition (OCR) system aims to translate scanned text to a machine understandable text. To do so, numerous tactics exist for several scripts and so far for good quality documents. Conversely, only a delimited permutation of the same has been investigated for degraded printed Marathi documents. This work offers learning which aims to discover and fetch out a marginal and competent policy of pre-processing in treating OCR for degraded printed Marathi documents. An effective estimation of the offered substitute has been considered by exposing it to documents having bleed-through, border smear, smear inside, low illuminations, unclearness etc. Proposed methodology’s results are examined in MATLAB R2015a. The work produces preprocessed images having better lucidity. Subsequent phases like segmentation, feature extraction, classification etc., offers better results with such preprocessed images having better clarity.