Browsing by Author "Wu, Hsien-Ming"

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Analysis of Land Cover Classification Using Multi-Wavelength LiDAR System
(2017-07-01)
Teo, Tee-Ann
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Wu, Hsien-Ming
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土木工程學系
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Department of Civil Engineering
The airborne multi-wavelength light detection and ranging (LiDAR) system measures different wavelengths simultaneously and usually includes two or more active channels in infrared and green to acquire both topographic and hydrographic information. The reflected multi-wavelength energy can also be used to identify different land covers based on physical properties of materials. This study explored the benefits of multi-wavelength LiDAR in object-based land cover classification, focusing on three major issues: (1) the evaluation of single- and multi-wavelength LiDARs for land cover classification; (2) the performance of spectral and geometrical features extracted from multi-wavelength LiDAR; and (3) the comparison of the vegetation index derived from active multi-wavelength LiDAR and passive multispectral images. The three-wavelength test data were acquired by Optech Titan in green, near-infrared, and mid-infrared channels, and the reference data were acquired from Worldview-3 image. The experimental results show that the multi-wavelength LiDAR provided higher accuracy than single-wavelength LiDAR in land cover classification, with an overall accuracy improvement rate about 4-14 percentage points. The spectral features performed better compared to geometrical features for grass, road, and bare soil classes, and the overall accuracy improvement is about 29 percentage points. The results also demonstrated the vegetation indices from Worldview-3 and Optech Titan have similar characteristics, with correlations reaching 0.68 to 0.89. Overall, the multi-wavelength LiDAR system improves the accuracy of land cover classification because this system provides more spectral information than traditional single-wavelength LiDAR.
Color calibration of swine gastrointestinal tract images acquired by radial imaging capsule endoscope
(2016-01-01)
Mang Ou-Yang
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Jeng, Wei-De
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Lai, Chien-Cheng
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Wu, Hsien-Ming
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Lin, Jyh-Hung
The type of illumination systems and color filters used typically generate varying levels of color difference in capsule endoscopes, which influence medical diagnoses. In order to calibrate the color difference caused by the optical system, this study applied a radial imaging capsule endoscope (RICE) to photograph standard color charts, which were then employed to calculate the color gamut of RICE. Color gamut was also measured using a spectrometer in order to get a high-precision color information, and the results obtained using both methods were compared. Subsequently, color-correction methods, namely polynomial transform and conformal mapping, were used to improve the color difference. Before color calibration, the color difference value caused by the influences of optical systems in RICE was 21.45 +/- 1.09. Through the proposed polynomial transformation, the color difference could be reduced effectively to 1.53 +/- 0.07. Compared to another proposed conformal mapping, the color difference value was substantially reduced to 1.32 +/- 0.11, and the color difference is imperceptible for human eye because it is <1.5. Then, real-time color correction was achieved using this algorithm combined with a field-programmable gate array, and the results of the color correction can be viewed from real-time images. (C) 2016 Society of Photo-Optical Instrumentation Engineers (SPIE)
Functional Analyses of Endometriosis-Related Polymorphisms in the Estrogen Synthesis and Metabolism-Related Genes
(2012-11-06)
Wang, Hsin-Shih
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Wu, Hsien-Ming
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Cheng, Bi-Hwa
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Yen, Chih-Feng
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Chang, Pi-Yueh
Endometriosis is determined by genetic factors, and the prevalence of genetic polymorphisms varies greatly depending on the ethnic group studied. The objective of this study was to investigate the relationship between single nucleotide polymorphisms (SNPs) of 9 genes involved in estrogen biosynthesis and metabolism and the risks of endometriosis. Three hundred patients with endometriosis and 337 non-endometriotic controls were recruited. Thirty four non-synonymous SNPs, which change amino acid residues, were analyzed using matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF MS). The functions of SNP-resulted amino acid changes were analyzed using multiple web-accessible databases and phosphorylation predicting algorithms. Among the 34 NCBI-listed SNPs, 22 did not exhibit polymorphism in this study of more than 600 Taiwanese Chinese women. However, homozygous and heterozygous mutants of 4 SNPs - rs6165 (genotype GG+GA, 307(Ala/Ala)+307(Ala/Thr)) of FSHR, rs 6166 (genotype GG+GA, 680(Ser/Asn)+680(Ser/Ser)) of FSHR, rs2066479 (genotype AA+AG, 289(Ser/Ser)+289(Ser/Gly)) of HSD17B3 and rs700519 (genotype TT+TC, 264(Cys/Cys)+264(Cys/Arg)) of CYP19, alone or in combination, were significantly associated with decreased risks of endometriosis. Bioinformatics results identified 307(Thr) of FSHR to be a site for O-linked glycosylation, 680(Ser) of FSHR a phosphorylated site by protein kinase B, and 289(Ser) of HSD17B3 a phosphorylated site by protein kinase B or ribosomal protein S6 kinase 1. Results of this study suggest that non-synonymous polymorphisms of FSHR, HSD17B3 and CYP19 genes may modulate the risk of endometriosis in Taiwanese Chinese women. Identification of the endometrosis-preferential non-synonymous SNPs and the conformational changes in those proteins may pave the way for the development of more disease-specific drugs.
Image stitching and image reconstruction of intestines captured using radial imaging capsule endoscope
(2012-05-01)
Mang Ou-Yang
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Jeng, Wei-De
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Wu, Yin-Yi
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Dung, Lan-Rong
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Wu, Hsien-Ming
This study investigates image processing using the radial imaging capsule endoscope (RICE) system. First, an experimental environment is established in which a simulated object has a shape that is similar to a cylinder, such that a triaxial platform can be used to push the RICE into the sample and capture radial images. Then four algorithms (mean absolute error, mean square error, Pearson correlation coefficient, and deformation processing) are used to stitch the images together. The Pearson correlation coefficient method is the most effective algorithm because it yields the highest peak signal-to-noise ratio, higher than 80.69 compared to the original image. Furthermore, a living animal experiment is carried out. Finally, the Pearson correlation coefficient method and vector deformation processing are used to stitch the images that were captured in the living animal experiment. This method is very attractive because unlike the other methods, in which two lenses are required to reconstruct the geometrical image, RICE uses only one lens and one mirror. (C) 2012 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.OE.51.5.057004]
Improve the image discontinuous problem by using color temperature mapping method
(2011)
Jeng, Wei-De
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Ou-Yang, Mang
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Lai, Chien-Cheng
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Wu, Hsien-Ming
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電控工程研究所
This article mainly focuses on image processing of radial imaging capsule endoscope (RICE). First, it used the radial imaging capsule endoscope (RICE) to take the images, the experimental used a piggy to get the intestines and captured the images, but the images captured by RICE were blurred due to the RICE has aberration problems in the image center and lower light uniformity affect the image quality. To solve the problems, image processing can use to improve it. Therefore, the images captured by different time can use Person correlation coefficient algorithm to connect all the images, and using the color temperature mapping way to improve the discontinuous problem in the connection region.
Radiometric Block Adjustment for Multi-Strip Airborne Waveform Lidar Data
(2015-12-01)
Teo, Tee-Ann
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Wu, Hsien-Ming
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土木工程學系
;
Department of Civil Engineering
The airborne lidar system has been shown to be an effective and reliable method for spatial data collection. Lidar records the coordinates of point and intensity, dependent on range, incident angle, reflectivity of object, atmospheric condition, and several external factors. To fully utilize the intensity of a lidar system, several researchers have proposed correction models from lidar equations. The radiometric correction models are divided into physically-oriented models and data-oriented models. The lidar acquisition often contains multiple flight lines, and the radiation energy of each flight line can be calibrated independently by calibration coefficient. However, the calibrated radiances in the overlapped area have slightly different measurements. These parameters should be implicitly taken into account if calibrating radiances back to reflectance using known calibration targets. This study used a single-strip physically-oriented model to obtain a backscattering coefficient and a data-oriented model to obtain corrected intensity. We then selected homogeneous tie regions in the overlapped areas, and the differences between strips were compensated by gain and offset parameters in multi-strip radiometric block adjustment. The results were evaluated by the radiometric differences. Nine strips were acquired by Rigel Q680i system, and the experimental results showed that the delta intensity and delta backscattering coefficient of tie regions were improved up to 60% after multi-strip block adjustment.