Detecting landslides using remote sensing images involves converting gray level images into binary images. Given the complex background and non-uniform illumination in the regional remote sensing ...image, the commonly-used global thresholding methods are limited to interpret some landslides those hidden in the shadow. In this paper, we report on an enhanced image thresholding method for the noncontact detection of earthquake-induced landslides. The proposed method incorporates Monte-Carlo simulation into the local thresholding method, and essential issues, regarding complex illumination condition and uncertainties of determining block size in local thresholding method, are addressed. To better separate landslide candidate objects from the background, we incorporate Digital Surface Model (DSM) into the binary image, such that the interferences by built-up areas, terraces, and rivers can be significantly reduced considering the indicator of slope gradient. The described method has been tested using two benchmark tests, showing that the proposed method performs well dealing with the complex background and illumination condition. As a case study, we use the proposed method to detect landslides in a remote sensing image near Beichuan area after the 2008 Ms8.0 Wenchuan earthquake. Results demonstrate that the presented method interprets landslides resembling those of manually visual delineation.
Binarization of digital holograms is used for storage and on-line transfer of registered information and for optical reconstruction of images using binary digital micromirror devices. The ...capabilities of binarization of optically registered holograms by iterative methods with application of the error diffusion method either at each step of varied binarization threshold or only at the final iteration are considered. The variation of method parameters is analyzed and the quality of reconstructed images is compared with the quality of the binarized holograms. It is determined that the method with application of the error diffusion operation only at the final stage increases the quality of image reconstruction by 12
compared to the one-step methods.
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Document images are usually degraded in the course of photocopying, faxing, printing, or scanning. Degradation problems seems negligible to human eyes but can be responsible for an abrupt decline in ...accuracy by the current generation of optical character recognition (OCR) systems. In this paper we present binarization method based on retinex theory followed by a global threshold. High quality results in terms of visual criteria and OCR performance is produced compared to the previous works.
An original local-potential morphometric algorithm for information-entropy estimation of the impact of technogenic chemical pollution on forests was proposed. This algorithm is distinguished by a ...procedure of separation of binary objects—pixel clusters (simply connected, tightly packed sets of white and black pixels)—in satellite photographs by a potential transformation and a procedure of estimation of the changes in the local configuration of pixel clusters by calculating the information entropy for the virtual potential of models of the interaction of pseudoparticles (white and black pixels) of the binary image. This enables one to practically estimate the spatial disturbances in forests by the impact of technogenic chemical pollution using point statistical estimates of the geometric indices of clusters. The proposed algorithm differs from conventional ones that determine the boundaries of binary objects by statistical analysis using co-occurrence matrices or point statistical estimates of the configuration of pixels.
Introduction
Image processing of optical coherence tomography scans through binarization techniques represent a non-invasive way to separately asses and measure choroidal components, in vivo. In this ...review, we systematically search the scientific literature regarding binarization studies published so far.
Methods
A systematic research was conducted at PubMed database, including English literature articles for all of the following terms in various combinations: binarization, choroid/al, enhanced depth spectral domain/swept source optic coherence tomography, and latest publications up to November 2018 were reviewed.
Results
Thirty-seven articles were included and analyzed regarding studied disease, binarization method, studied variables, and outcomes. Most of the studies have focused on the more common retinal pathologies, such as age-related macular degeneration, central serous chorioretinopathy and diabetic retinopathy but binarization techniques have also been applied to the study of choroidal characteristics in ocular inflammatory diseases, corneal dystrophies and in postsurgical follow-up. Advantages and disadvantages of binarization techniques are also discussed.
Conclusion
Binarization of choroidal images seems to represent a promising approach to study choroid subcomponents in an increasingly detailed manner.
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: We aimed to reveal the relationship between the choroid and the outer retina with optical coherence tomography (OCT) in patients with diabetes mellitus (DM) with mild or no diabetic retinopathy ...(DR) in order to find early biomarkers for progressing retinopathy.
: We performed a prospective study including 61 eyes of patients with type 1 or type 2 DM and 36 eyes of healthy controls. All subjects were imaged with Spectralis OCT. The choroid was assesseed using enhanced depth imaging OCT (EDI-OCT). Binarization of subfoveal choroidal images was done with public domain software, ImageJ (version 1.53a; National Institutes of Health, Bethesda, Maryland, USA).
: Luminal area, stromal area and total choroidal area were significantly decreased in diabetic patients compared to control: 0.23 ± 0.07 vs. 0.28 ± 0.08,
= 0.012; 0.08 ± 0.03 vs. 0.10 ± 0.04,
= 0.026; 0.31 ± 0.09 vs. 0.38 ± 0.11,
= 0.008. The thickness of retinal pigment epithelium (RPE) correlated positively with the choroidal vascularity index (CVI). The correlations between outer nuclear layer (ONL), photoreceptors (PR) and foveal choroidal thickness (FChT) were moderately negative.
: Thicker RPE and a thinner PR layer may be assigned the role of early biomarkers signaling the conversion time to progressing retinopathy.
It has been revealed in past research that by uniformly down-sampling the object image prior to the numerical generation, and subsequent binarization of its digital Fresnel hologram, the ...reconstructed image can preserve the shaded content with favorable visual quality. However, the down-sampling process also severs the lines and blurs the edge patterns that are important in representing the detail information of an image scene. In this paper, we propose a method to overcome this dilemma with an integration of a fast adaptive down-sampling and the uniform down-sampling process. Experimental evaluation has demonstrated that our method is capable of preserving lines and edges, as well as the shaded regions, resulting in superior visual quality of the reconstructed image as compared with the existing approach. In addition, the computation time on the integrated down-sampling method is less than 200ms on a typical personal computer.
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To assess precision and accuracy of a new objective algorithm using binarization in a software for identifying the hyperautofluorescent ring (AF ring) in retinitis pigmentosa (RP) compared with ...subjective visual inspection.
Ultra-widefield AF images were obtained from 23 eyes of 13 patients with retinitis pigmentosa (RP). We defined the borders of the AF rings using semiautomatic binarization algorithm in Fiji software. We compared the degree of precision (intra- and interrater agreements) of this algorithm and that of subjective visual inspection (freehand method) using Jaccard indices (JIs). To compare the classification performance (whether 68 points of Humphrey Field Analyzer is classified as inside, on, or outside AF rings), we calculated percent agreement and weighted kappa statistic between the two methods. The relationship between the distance from the AF ring and retinal sensitivities was also investigated.
The binarization method showed significantly higher JIs than the freehand method (for interrater: 0.94-0.95 vs. 0.73-0.78, respectively,
= 0.002; for intrarater: 0.95 vs. 0.68-0.71, respectively,
= 0.005). Percent agreement for classification between the two methods were 0.94 and weighted kappa statistic was 0.94 (
< 0.001). The retinal sensitivities decreased significantly and eccentrically from 2° inside to 3° outside the AF ring.
Defining the AF ring in RP using the binarization algorithm showed significantly higher precision and the same degree of accuracy compared with visual inspection.
This novel method may enable quantitative analysis of the AF ring, an indicator of retinal function in RP.
Past research has revealed that by down-sampling the projected intensity profile of a source object scene with a regular sampling lattice, a binary Fresnel hologram can be generated swiftly to ...preserve favorable quality on its reconstructed image. However, this method also results in a prominent textural pattern which is conflicting to the geometrical profile of the object scene, leading to an unnatural visual perception. In this paper, we shall overcome this problem with a down-sampling process that is adaptive to the geometry of the object. Experimental results demonstrate that by applying our proposed method to generate a binary hologram, the reconstructed image is rendered with a texture which abides with the shape of the three-dimensional object(s).
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The serial number recognition has played a crucial role in financial market. And the character segmentation is the most important part for serial number recognition. In this paper, in order to deal ...with the noises and complex textures of the banknotes, we propose a novel method which is composed of a hybrid binarization algorithm (HybridB) and an adaptive character extraction algorithm (ACE). The HybridB algorithm utilizes both the global information of the whole image as well as the local information of the pixels which can eliminate the interferences of the noises and background. The ACE algorithm adjusts the boundaries of each character by the local contrast average value information and the distance between its gravity and center, and a decreasing step strategy is also employed to optimize the boundaries to get more accurate segmentation results. To validate the performance of the proposed method, we take experiments on the datasets of RMB, GBP and USD. The binarization results and character extraction results show that our proposed method outperforms the other state-of-the-art algorithms in most cases.
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