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We present a simulations study of the collimator sensitivity/resolution compromise as it affects the image quality of hot lesions in SPECT iterative reconstruction. We investigate three parallel-beam hexagonal-hole collimators with resolution in the center of the field of view equal to 11 mm, 15 mm, and 19 mm. We scan the Esser hot-rod phantom with 60 views and we reconstruct the images using MLEM...
Electronic portal mega-electronvolt (MV) monitoring for radiation therapy is very important for tumor localization. Furthermore, in the latest systems, before the radiation treatment, the patient is also positioned on the treatment bed with a flat-panel detector (FPD) based kilo-electronvolt (kV) CT scan for better soft tissue visibility. In the article we prove by measurement and imaging that a regular...
To have a unique solution of an ill-posed inverse problem, the usual way is to embed prior information in terms of regularizer or smoothness criterion. In this work, both the inverse mechanism (the relationship of blur and sharp patches) and the smoothness prior are learned simultaneously from the image itself, in multiple scales. We have shown experimentally that the proposed method outperform the...
This paper describes a novel method for single-image super-resolution (SR) based on a neighbor embedding technique which uses coupled feature spaces under surveillance scenarios. For surveillance face images, traditional neighbor embedding SR approaches could not offer counterintuitive results because consistency between high resolution images and low resolution images is destroyed by serious noise...
Single-image superresolution has become a widely-studied subject in image processing in recent years. Although considerable effort has been devoted in this context to contour enhancement, much less has been done to improve the textures of a degraded image. In this study, we present a novel algorithm which utilizes the power-law spectra of approximated 1/f processes, fitting a model of degraded natural...
We present in this paper a fast single image defogging method that uses a novel approach to refining the estimate of amount of fog in an image with the Locally Adaptive Wiener Filter. We provide a solution for estimating noise parameters for the filter when the observation and noise are correlated by decorrelating with a naively estimated defogged image. We demonstrate our method is 50 to 100 times...
The super-resolution approach has attracted substantial attention in the field of image processing in view of its capability of providing higher resolution from low resolution image sequences. Interesting techniques have been developed and practical results have been obtained. However, in several theoretical investigations, good results are often corroborated by simulations, which limits the use of...
The swallowing process affects several aspects of one's welfare, as nutrition, hydration, respiration and hearing. Magnetic resonance imaging (MRI) has been a valuable tool to study swallowing, since it is a non-invasive procedure that can dynamically capture the shapes of the tongue and other elements involved in the process. The resolution enhancement of the MRI frames support directly diseases...
Localization of a single fluorescent particle with sub-diffraction limit accuracy is a key merit in fluorescence microscopy. Implementation of nonlinear filtering algorithms prior the localization process can improve the localization accuracy of standard existing methods and also enable the localization of overlapping particles, allowing the use of increased fluorophore activation density, and thereby...
An optimized occlusion detection method for true orthophoto make is proposed in this paper, aimed at solving the occlusion and shadow problems caused by rectification using digital surface model (DSM). This method draws lessons from sweep way of angle-based detection method and idea of radial tracing detection method. It adds three judge rules to the occlusion detection process to increase its executing...
To enhance high frequency details of image super-resolution restoration, an algorithm based on improved MAP estimation is proposed. In this paper, POCS and MAP are combined in a special way. POCS is used in the MAP estimation so that advantages of the both algorithms can be taken. Experiment shows it is effective by comparing with the results of typical MAP method.
This paper addresses important computer vision problem of defining a measure for the strength (intensity) of edges in an image. The importance of the problem arises from the fact that images are typically represented in the multi - colour RGB format, hence each pixel requires more than one parameter to be defined. The α image is created using local colour statistics based on the size of the neighbourhood,...
The contribution of computer graphics in geophysics mainly embodies on the application of scientific computing visualization. In order to obtain the structural features and spatial distribution of various types of stratigraphic structure surface, it is necessary to carry out visual analysis on gigantic seismic data. However, the process of signal-noise separation requires enormous operations before...
This paper presents a novel incremental Σ-Δ ADC using two-step conversion and the fully-floating double-sampling integrator to greatly reduce the converting time. With a special procedure to solve the accuracy loss problem, the resolution of ADC is improved by one bit at the same time. What's more, another comparison is added during the conversion to detect redundant pixels in the image so that data...
This paper put forward an edge detection algorithm which based on the law of gravity adaptive threshold. This algorithm is not only has good effect for common image edge detection, but also for the noise of the image edge detection and good results have been achieved. According to the law of universal gravitation of physics, the author designs a kind of template which applied to edge detection. Then,...
The image resolution and the tissue contrast of MR neuro-imaging data are key factors for image analysis algorithms such that segmentation and registration. In this article, we focus on one of these two major components and we study image reconstruction techniques for image resolution enhancement. This issue is addressed in the general context of inverse problems. For such ill-posed problems, some...
Super-resolution localization microscopy relies on sparse activation of photo-switchable probes. Such activation, however, introduces limited temporal resolution. High-density imaging overcomes this limitation by allowing several neighboring probes to be activated simultaneously. In this work, we propose an algorithm that incorporates a continuous-domain sparsity prior into the high-density localization...
A tool developed for simulating RADARSAT-2 (RS2) Maritime Satellite Surveillance Radar (MSSR) mode data from higher resolution data is described. RS2 Fine and Fine Quad images containing validated ship and iceberg targets were resampled to low resolution ScanSAR Narrow (SCN) and MSSR mode data. This tool can be adopted to use other image modes as inputs and simulate other outputs as well and the simulated...
We introduce a general and computationally efficient approach to 3-D localization microscopy. The main idea is to construct a continuous-domain representation of the PSF by expanding it in a polynomial B-spline basis. This allows us to fit the PSF to the data with sub-pixel accuracy. Since the basis functions are compactly supported, the evaluation of the PSF is computationally efficient. Furthermore,...
Image pre-processing techniques are used to improve the quality of an image before processing into an application. This uses a small neighborhood of a pixel in an input image to get a new brightness value in the output image. These preprocessing techniques are also called as filtration and resolution enhancement. The medical image quality parameters are mainly noise and resolution. The main objective...
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