摘要 :
Super Resolution (SR) is a technique for improving the resolution of digital images. Super Resolution Image Reconstruction (SRR) is one of the most common SR techniques. However, in addition to SRR, there are several other techniq...
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Super Resolution (SR) is a technique for improving the resolution of digital images. Super Resolution Image Reconstruction (SRR) is one of the most common SR techniques. However, in addition to SRR, there are several other techniques to improve image resolution. A technique called Blind Deconvolution (BD) has been used to process out of focus images in the field of astronomy. When BD was first described, in the 1970s, it was not considered to be a viable candidate to be used for SR. However, the process of improving resolution is very similar to that of focusing images. SRR and BD both use iterations to create a high quality image from low resolution images. Compared with SRR, BD comes with some disadvantages. For example, algorithms sometimes cause divergences or limit cycles which means that the high resolution image cannot be obtained. In this study, we describe a method of fixing the issues that prevent BD from achieving a high-resolution image using simulation to increase its stability. The output from the improved algorithm for BD is compared with the current SR technique, SRR. We show that the BD technique is in fact superior to SRR.
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摘要 :
Super Resolution (SR) is a technique for improving the resolution of digital images. Super Resolution Image Reconstruction (SRR) is one of the most common SR techniques. However, in addition to SRR, there are several other techniq...
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Super Resolution (SR) is a technique for improving the resolution of digital images. Super Resolution Image Reconstruction (SRR) is one of the most common SR techniques. However, in addition to SRR, there are several other techniques to improve image resolution. A technique called Blind Deconvolution (BD) has been used to process out of focus images in the field of astronomy. When BD was first described, in the 1970s, it was not considered to be a viable candidate to be used for SR. However, the process of improving resolution is very similar to that of focusing images. SRR and BD both use iterations to create a high quality image from low resolution images. Compared with SRR, BD comes with some disadvantages. For example, algorithms sometimes cause divergences or limit cycles which means that the high resolution image cannot be obtained. In this study, we describe a method of fixing the issues that prevent BD from achieving a high-resolution image using simulation to increase its stability. The output from the improved algorithm for BD is compared with the current SR technique, SRR. We show that the BD technique is in fact superior to SRR.
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摘要 :
We propose a parametric deformable model that automatically adapts its topology and that recovers accurately image components with a complexity independent from the resolution of the input image. The main idea is to equip the imag...
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We propose a parametric deformable model that automatically adapts its topology and that recovers accurately image components with a complexity independent from the resolution of the input image. The main idea is to equip the image space with a metric that expands interesting features in the image depending on their geometry.
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摘要 :
We propose a parametric deformable model that automatically adapts its topology and that recovers accurately image components with a complexity independent from the resolution of the input image. The main idea is to equip the imag...
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We propose a parametric deformable model that automatically adapts its topology and that recovers accurately image components with a complexity independent from the resolution of the input image. The main idea is to equip the image space with a metric that expands interesting features in the image depending on their geometry.
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摘要 :
We propose a parametric deformable model that automatically adapts its topology and that recovers accurately image components with a complexity independent from the resolution of the input image. The main idea is to equip the imag...
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We propose a parametric deformable model that automatically adapts its topology and that recovers accurately image components with a complexity independent from the resolution of the input image. The main idea is to equip the image space with a metric that expands interesting features in the image depending on their geometry.
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A pyramid approach is developed and implemented for reconstructing binary patterns from two orthogonal projections. The binary patterns are first reconstructed in a lower spatial resolution and then refined from level to level in ...
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A pyramid approach is developed and implemented for reconstructing binary patterns from two orthogonal projections. The binary patterns are first reconstructed in a lower spatial resolution and then refined from level to level in the pyramid structure with an improving spatial resolution. The algorithm is compared with a model-based algorithm, which reconstructed the binary patterns directly in the required resolution. The performance of the pyramid algorithm is investigated from the viewpoint of processing speed and reconstruction quality. It is concluded that the multiresolutional image-reconstruction technique is superior to direct methods.
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The Resolution Enhancement Compression (REC) technique is a coded excitation method developed for improving the axial resolution of ultrasound images. It consists on emitting an amplitude modulated chirp signal that transmits more...
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The Resolution Enhancement Compression (REC) technique is a coded excitation method developed for improving the axial resolution of ultrasound images. It consists on emitting an amplitude modulated chirp signal that transmits more energy at the frequencies where the ultrasound transducer is less efficient. The focus of this study is to elaborate a new beamforming strategy, which consists of implementing the REC technique in combination with coherent plane wave compounding. The first objective is to get a better performance in term of axial resolution than Conventional Pulse Ultrafast Imaging (CP-UI). The second objective is to demonstrate that in ultrafast imaging, REC offers a larger bandwidth than the one provided by CP-UI.
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The performance of a pinhole collimator for I-131 SPECT of the head was evaluated. The evaluation included planar and SPECT spatial resolution, sensitivity in air and in water, reconstructed image quality, and activity quantitatio...
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The performance of a pinhole collimator for I-131 SPECT of the head was evaluated. The evaluation included planar and SPECT spatial resolution, sensitivity in air and in water, reconstructed image quality, and activity quantitation within a simple phantom that models tumor uptake in the head. The pinhole collimator was compared to medium and high energy parallel hole collimators. The pinhole collimator showed improved resolution/sensitivity trade-off compared with the parallel hole collimators over the range of distances relevant to head imaging. Penetration artifacts were not apparent in the reconstructed pinhole images. The accuracy of activity quantitation with the pinhole and parallel hole collimators was dependent on the segmentation threshold and calibration procedure. These results indicate that pinhole collimation can provide improved performance over conventional parallel hole collimators for I-131 imaging in the head.
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Single-image super-resolution, reconstructing a high resolution (HR) image from a low resolution (LR) one, is an ill-posed problem. Regularization, a method for ill-posed problem, is widely used in super-resolution. The definition...
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Single-image super-resolution, reconstructing a high resolution (HR) image from a low resolution (LR) one, is an ill-posed problem. Regularization, a method for ill-posed problem, is widely used in super-resolution. The definition of the fidelity term in regularization energy is a key to the performance of regularization based super-resolution. Traditional fidelity is defined as the energy of error image between down-sampled version of HR image estimated and the observed LR image. Since the mpixels not in sampled positions are not considered, the gradient of traditional fidelity is non-stationary. To avoid this problem in traditional fidelity, we propose to define the fidelity term as the energy of error image between the estimated HR image estimate and its blurred version. When gradient decent is used to optimize the regularization energy, we propose an error interpolation fidelity gradient (EIFG) method to estimate a stationary gradient of proposed fidelity. Compared with other methods, experimental results show that our method improve both qualitative and quantitative performances of reconstructed HR image.
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摘要 :
Single-image super-resolution, reconstructing a high resolution (HR) image from a low resolution (LR) one, is an ill-posed problem. Regularization, a method for ill-posed problem, is widely used in super-resolution. The definition...
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Single-image super-resolution, reconstructing a high resolution (HR) image from a low resolution (LR) one, is an ill-posed problem. Regularization, a method for ill-posed problem, is widely used in super-resolution. The definition of the fidelity term in regularization energy is a key to the performance of regularization based super-resolution. Traditional fidelity is defined as the energy of error image between down-sampled version of HR image estimated and the observed LR image. Since the mpixels not in sampled positions are not considered, the gradient of traditional fidelity is non-stationary. To avoid this problem in traditional fidelity, we propose to define the fidelity term as the energy of error image between the estimated HR image estimate and its blurred version. When gradient decent is used to optimize the regularization energy, we propose an error interpolation fidelity gradient (EIFG) method to estimate a stationary gradient of proposed fidelity. Compared with other methods, experimental results show that our method improve both qualitative and quantitative performances of reconstructed HR image.
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