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1.
Sensors (Basel) ; 24(6)2024 Mar 08.
Article in English | MEDLINE | ID: mdl-38544013

ABSTRACT

Earth observation by remote sensing plays a crucial role in granite extraction, and many current studies use thermal infrared data from sensors such as ASTER. The challenge lies in the low spatial resolution of these satellites, hindering precise rock type identification. A breakthrough emerges with the Thermal Infrared Spectrometer (TIS) on the Sustainable Development Science Satellite 1 (SDGSAT-1) launched by the Chinese Academy of Sciences. With an exceptional 30 m spatial resolution, SDGSAT-1 TIS opens avenues for accurate granite extraction using remote sensing. This study, exemplified in Xinjiang's Karamay region, introduces the BR-ISauvola method, leveraging SDGSAT-1 TIS data. The approach combines band ratio with adaptive k-value selection using local grayscale statistical features for Sauvola thresholding. Focused on large-scale granite extraction, results show F1 scores above 70% for Otsu, Sauvola, and BR-ISauvola. Notably, BR-ISauvola achieves the highest accuracy at 82.11%, surpassing Otsu and Sauvola by 9.62% and 0.34%, respectively. This underscores the potential of SDGSAT-1 TIS data as a valuable resource for granite extraction. The proposed method efficiently utilizes spectral information, presenting a novel approach for rapid granite extraction using remote sensing TIS imagery, even in scenarios with low spectral resolution and a single data source.

2.
Sensors (Basel) ; 23(22)2023 Nov 14.
Article in English | MEDLINE | ID: mdl-38005560

ABSTRACT

Land desertification is one of the serious ecological and environmental problems facing mankind today, which threatens the survival and development of human society. China is one of the countries with the most serious land desertification problems in the world. Therefore, it is of great theoretical value and practical significance to carry out accurate identification and monitoring of land desertification and its influencing factors in ecologically fragile areas of China. This is conducive to curbing land desertification and ensuring regional ecological security. Minqin County, Gansu Province, located in northwestern China, is one of the most serious areas of land desertification, which is also one of the four sandstorm sources in China. Based on ENVINet5, this paper constructs a high-precision land desertification identification method with an accuracy of 93.71%, which analyzes the trend and reasons of land desertification in this area, provides suggestions for disaster prevention in Minqin County. and provides a reference for other similar areas to make corresponding desertification control policies.

3.
Sensors (Basel) ; 22(16)2022 Aug 18.
Article in English | MEDLINE | ID: mdl-36015957

ABSTRACT

Climate change, characterized by global warming, is profoundly affecting the global environment, politics, economy, and social security. Finding the main causes of climate change and determining their quantitative contributions are key points to making climate decisions on responses to climate change. The Tibetan Plateau (TP) is sensitive to global climate change. Taking the 100 km buffer zones of 45 meteorological stations in the eastern TP as research objects, we conducted an experimental study on temperature change and its influencing factors. Using the least squares multivariate statistical analysis method, a model between the annual and seasonal standardized temperature change and its dynamic influencing factors in the past 20 years was established. The results showed that, in the eastern TP, temperature change was affected by different factors in different periods. Vegetation cover and snow cover were the most correlated factors to temperature change. The influence of carbon dioxide, vegetation cover, and water cover was subject to seasonal changes. Urban cover and bare land cover did not pass the t-test. This research not only provides a theoretical basis for the analysis of temperature change over the TP, but also points out the direction for the analysis of temperature change causes in three polar regions.


Subject(s)
Climate Change , Snow , China , Temperature , Tibet
4.
Andrologia ; 54(1): e14312, 2022 Feb.
Article in English | MEDLINE | ID: mdl-34799875

ABSTRACT

It has been reported that circular RNA hsa_circ_0074032 (circ_0074032) has a higher level in prostate cancer (PCa) tissues. However, the role and regulatory mechanism of circ_0074032 in PCa are still unknown. Circ_0074032 was overexpressed in PCa, and high circ_0074032 level was associated with worse PCa-related prognosis. Functionally, circ_0074032 silencing decreased xenograft tumour growth in vivo and induced cell apoptosis, curbed cell proliferation, migration and invasion in PCa cells in vitro. Furthermore, circ_0074032 was identified as a miR-198 decoy, and miR-198 inhibition abolished circ_0074032 silencing-mediated effects on PCa cell proliferation, apoptosis, migration and invasion. In addition, miR-198 directly targeted homeobox A1 (HOXA1), and HOXA1 weakened miR-198 mimic-mediated impacts on PCa cell malignant phenotypes. Importantly, circ_0074032 regulated HOXA1 expression by sponging miR-198. Our findings uncovered a novel mechanism by which circ_0074032 promoted PCa progression via elevating HOXA1 expression through acting as a miR-198 sponge, providing a mechanism for circ_0074032 to affect the development of PCa.


Subject(s)
MicroRNAs , Prostatic Neoplasms , Cell Proliferation , Genes, Homeobox , Humans , Male , MicroRNAs/genetics , Prostate , Prostatic Neoplasms/genetics , RNA, Circular
5.
J Cell Mol Med ; 25(22): 10627-10637, 2021 11.
Article in English | MEDLINE | ID: mdl-34697900

ABSTRACT

Prostate cancer is the second most frequent malignancy in men worldwide, and its incidence is increasing. Therefore, it is urgently required to clarify the underlying mechanisms of prostate cancer. Although the long non-coding RNA LINC00115 was identified as an oncogene in several cancers, the expression and function of LINC00115 in prostate cancer have not been explored. Our results showed that LINC00115 was significantly up-regulated in prostate cancer tissues, which was significantly associated with a poor prognosis for prostate cancer patients. Functional studies showed that knockdown LINC00115 inhibited cell proliferation and invasion. In addition, LINC00115 served as a competing endogenous RNA (ceRNA) through sponging miR-212-5p to release Frizzled Family Receptor 5 (FZD5) expression. The expression of miR-212-5p was noticeably low in tumour tissues, and FZD5 expression level was down-regulated with the knockdown of LINC00115. Knockdown LINC00115 inhibited the Wnt/ß-catenin signalling pathway by inhibiting the expression of FZD5. Rescue experiments further showed that LINC00115 inhibits prostate cancer cell proliferation and invasion via targeting miR-212-5p/ FZD5/ Wnt/ß-catenin axis. The present study provided clues that LINC00115 may be a promising novel therapeutic target for prostate cancer patients.


Subject(s)
Frizzled Receptors/genetics , MicroRNAs/genetics , Prostatic Neoplasms/genetics , Prostatic Neoplasms/metabolism , RNA, Long Noncoding/genetics , Wnt Signaling Pathway , Adult , Biomarkers, Tumor , Cell Line, Tumor , Cell Movement , Cell Proliferation , Gene Expression Regulation, Neoplastic , Humans , Male , Middle Aged , Prostatic Neoplasms/mortality , Prostatic Neoplasms/pathology , RNA Interference , Young Adult
6.
Anal Biochem ; 630: 114336, 2021 10 01.
Article in English | MEDLINE | ID: mdl-34400146

ABSTRACT

MicroRNAs (miRNAs) play a significant role in tumorigenesis and tumor development. Exosomal microRNA-141 (miRNA-141, miR-141) has been reported to be overexpressed in prostate cancer (PCa) and has become a potential biomarker for the diagnosis of PCa. Herein, a novel fluorescent biosensor based on toehold-aided cyclic amplification combined with horseradish peroxidase (HRP) enzyme catalysis and magnetic nanoparticles (MNPs) was designed for determination of the exosomes-derived microRNA-141 (miRNA-141, miR-141). The synergy of HRP enzyme catalysis and toehold mediated strand display reaction (TSDR) increase the sensitivity of the method, and the good separation ability of MNPs ensures the specificity of the method. Therefore, under the optimized experimental conditions, the highly sensitive and specific detection of miRNA-141 can be realized, and the detection limit is as low as 10 fM. More importantly, the biosensor successfully determinates the exosomal miR-141 in the plasma of patients with PCa.


Subject(s)
Biosensing Techniques , Exosomes/chemistry , Horseradish Peroxidase/metabolism , Magnetite Nanoparticles/chemistry , MicroRNAs/blood , Prostatic Neoplasms/diagnosis , Biocatalysis , Exosomes/metabolism , Humans , Male , MicroRNAs/metabolism , PC-3 Cells , Prostatic Neoplasms/blood , Prostatic Neoplasms/metabolism , Tumor Cells, Cultured
7.
J Xray Sci Technol ; 28(2): 357-367, 2020.
Article in English | MEDLINE | ID: mdl-32039882

ABSTRACT

INTRODUCTION: To report the management and outcome of one case of pediatric patient sustaining high-grade blunt renal trauma. We present and discuss the clinical characteristics and radiologic features of the patient. PATIENTS AND METHODS: A 10 years old child was admitted for serious blunt renal trauma formed a huge urinoma in the right renal after injury gradually in 2018. We treated the patient with synchronous percutaneous nephrostomy drainage and retrograde ureteral catheterization. A retrospective review was performed of this case, including the clinical features, imaging studies and short-term follow-up. A literature review was also performed to highlight the principals of diagnosis and treatment of severe blunt renal trauma in children. RESULTS: After drainage, the symptoms of abdominal distension gradually disappeared, and the physical examination shows that the abdomen gradually reduced to normal. The huge urinoma was cured by synchronous drainge. No complications occurred in short-term follow-up. COMMENTS: The choice of surgical treatment is based on the degree and location of renal trauma. Grade IV injuries are a heterogeneous group and management should be tailored to the patient, especially among pediatric patients. Persistent urinary extravasation and/or symptomatic urinoma is a common complication of high-grade renal trauma, which will be amenable to ureteral stent placement or percutaneous drainage. For huge urinoma, synchronous percutaneous nephrostomy drainage and retrograde ureteral catheterization can relieve symptoms quickly.


Subject(s)
Kidney/diagnostic imaging , Kidney/injuries , Nephrostomy, Percutaneous/methods , Tomography, X-Ray Computed/methods , Child , Humans , Male , Wounds, Nonpenetrating
8.
J Xray Sci Technol ; 28(1): 125-135, 2020.
Article in English | MEDLINE | ID: mdl-31796723

ABSTRACT

PURPOSETo evaluate therapeutic efficacy of two minimally invasive surgical methods in managing acute ureteral obstruction and severe infection caused by upper urinary tract calculi (UUTC).PATIENTS AND METHODSData of 47 patients diagnosed with acute upper urinary tract obstruction and severe infection caused by ureteral calculus using X-ray CT between September 2014 and January 2019 were retrospectively analyzed. All patients were treated with immediate renal drainage and, after infection and ureteral obstruction were relieved, UUTC removal. Renal drainage was performed by ultrasound-guided percutaneous nephrostomy and retrograde ureteral catheterization was performed using cystoscopy. Kidney and ureteral stones were removed; renal function and the urinary tract were examined by X-ray during follow-up.RESULTSPercutaneous nephrostomy was performed in 29 patients in a critical condition including intolerance to surgery, high-grade hydronephrosis, or failure of retrograde ureteric stent placement. In other 18 patients diagnosed with small stones (≤10 mm) and low-grade hydronephrosis, indwelling double-J ureteral stents were temporally installed by a cystoscope. Acute infection and ureteral obstruction were relieved; white blood cell counts returned to normal values within 3 to 7 days after drainage in all patients. In the second-stage treatment, percutaneous nephrolithotomy (PCNL), ureteroscopic lithotripsy, extracorporeal shock wave lithotripsy and nephrectomy were performed in 24, 10, 8 and 5 patients, respectively. No patients developed severe complication after stone removal surgery. All patients were followed up for 3 months to 4.5 years. Renal function was significantly recovered; 17/29 (59%) patients with elevated serum creatinine returned to normal and serum creatinine in 12/29 (41%) patients improved significantly after drainage, with a pre-operation level of 285±169µM vs 203±91µM post-operation (P = 0.014). Five patients were lost during follow-up.CONCLUSIONThis study demonstrated an optimal approach for relieving upper urinary tract obstruction and acute infection in which percutaneous nephrostomy drainage is preferred for patients with severe pyonephrosis, large stones (>10 mm) with high-grade hydronephrosis, steinstrasse, or failure in retrograde ureteric stent placement, while retrograde ureteral catheterization using cystoscopy is suitable for patients diagnosed with small stones (≤10 mm) and low-grade hydronephrosis.


Subject(s)
Minimally Invasive Surgical Procedures/methods , Nephrostomy, Percutaneous/methods , Ureteral Obstruction/etiology , Ureteral Obstruction/surgery , Urinary Calculi/complications , Urinary Tract Infections/etiology , Acute Disease , Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Tomography Scanners, X-Ray Computed , Treatment Outcome , Ureteral Obstruction/diagnostic imaging , Urinary Calculi/diagnostic imaging , Urinary Calculi/therapy , Urinary Tract/diagnostic imaging , Urinary Tract/surgery , Urinary Tract Infections/diagnostic imaging , Urinary Tract Infections/therapy , Young Adult
9.
J Xray Sci Technol ; 27(6): 1155-1167, 2019.
Article in English | MEDLINE | ID: mdl-31476195

ABSTRACT

BACKGROUND: Calyceal diverticula outpouchings that occur rarely in the upper collecting system of the kidney and is often difficult to detect. In this study, we present two cases of calyceal diverticula and discuss their clinical characteristics and radiologic features. PATIENTS AND METHODS: In the presented two cases, we applied several imaging examinations, including delayed intravenous pyelography, retrograde pyelography and axial computerized tomographic (CT) scanning of the kidneys with and without contrast. Serum creatinine levels in fluid withdrawn from the diverticula were found to be significantly higher than the simultaneous serum creatinine levels. Intravenous injection of methylene blue through a ureteral catheter was also aided in the diagnosis. Calyceal diverticulum neck dilatation was performed through a percutaneous nephroscope.ResultsThe two cases were diagnosed preoperatively and the operation was successful performed. The nephrostomy tube was removed seven days after surgery without complications. CT scans of the kidney after six months showed that the size of the calyceal diverticulum of two patients were considerably smaller than pre-surgery. There were no reports of pain in the lumbar region or other discomfort. COMMENTS: Diagnosis of calyceal diverticulum mainly depend on a variety of imaging examinations, including the delayed intravenous pyelography, retrograde pyelography, and kidney CT plain scan plus enhanced scan. If the patient cannot be diagnosed by above methods, cyst fluid can be aspirated percutaneously to measure the preoperative creatinine level. If it is significantly higher than the serum creatinine level, the cyst fluid is considered urine, which can assist in the diagnosis of calyceal diverticulum. A ureteral catheter should also be inserted before operation namely, intravenous injection of methylene blue through a ureteral catheter is helpful for diagnosis. The choice of surgical treatment is based on the size and location of calyceal diverticulum and clinical manifestations.


Subject(s)
Diverticulum/diagnosis , Kidney Calices/pathology , Kidney Diseases, Cystic/diagnosis , Adult , Creatinine/metabolism , Diverticulum/diagnostic imaging , Diverticulum/metabolism , Diverticulum/surgery , Female , Humans , Kidney Calices/diagnostic imaging , Kidney Calices/metabolism , Kidney Calices/surgery , Kidney Diseases, Cystic/diagnostic imaging , Kidney Diseases, Cystic/pathology , Kidney Diseases, Cystic/surgery , Male , Multimodal Imaging , Nephrolithotomy, Percutaneous , Nephrostomy, Percutaneous , Tomography, X-Ray Computed , Treatment Outcome , Urography
10.
Ann Clin Biochem ; 54(1): 76-85, 2017 Jan.
Article in English | MEDLINE | ID: mdl-27126269

ABSTRACT

Objective The purpose of this study was to explore serum miR-135a-5p expression in colorectal cancer and examine the potential usefulness of this molecule as a biomarker for diagnosis in colorectal cancer. Methods Serum samples were collected from 60 patients with primary colorectal cancer, 40 patients with colorectal polyps and 50 healthy controls. Serum miR-135a-5p expression levels were detected by reverse transcription quantitative real-time quantitative polymerase chain reaction. Serum carcinoembryonic antigen and carbohydrate antigen 199 concentrations were detected by MODULAR ANALYTICS E170. Results The relative expression level of serum miR-135a-5p in colorectal cancer patients, colorectal polyps patients and healthy controls was 2.451 (1.107, 4.413), 0.946 (0.401, 1.942) and 0.949 (0.194, 1.415), respectively, indicating that it was significantly higher in colorectal cancer patients than that in the other two groups ( U = 351.0, 313.0, both P < 0.001). Additionally, it was significantly correlated with different degrees of tumour differentiation ( U = 215.0, P = 0.029) and different tumour stages ( U = 202.0, P = 0.013). There was no significant correlation between the relative expression of serum miR-135a-5p and carcinoembryonic antigen ( r2 = 0.023, P = 0.293) or carbohydrate antigen 199 ( r2 = 0.067, P = 0.068) in colorectal cancer patients. Compared with colorectal polyps group, AUCROC of serum miR-135a-5p in colorectal cancer group was 0.832 with 95% CI 0.73-0.93; compared with healthy control group, AUCROC was 0.875 with 95% CI 0.80-0.95. Conclusion Serum miR-135a-5p expression in colorectal cancer patients was higher than that in patients with colorectal polyps and healthy controls, suggesting that serum miR-135a-5p may prove to be an important biomarker for auxiliary diagnosis of colorectal cancer.


Subject(s)
Biomarkers, Tumor/genetics , Colonic Polyps/diagnosis , Colorectal Neoplasms/diagnosis , Gene Expression Regulation, Neoplastic , MicroRNAs/genetics , Adult , Aged , Aged, 80 and over , Antigens, Tumor-Associated, Carbohydrate/blood , Antigens, Tumor-Associated, Carbohydrate/genetics , Biomarkers, Tumor/blood , Carcinoembryonic Antigen/blood , Carcinoembryonic Antigen/genetics , Case-Control Studies , Colonic Polyps/blood , Colonic Polyps/genetics , Colonic Polyps/pathology , Colorectal Neoplasms/blood , Colorectal Neoplasms/genetics , Colorectal Neoplasms/pathology , Diagnosis, Differential , Female , Humans , Male , MicroRNAs/blood , Middle Aged , Neoplasm Grading , Neoplasm Staging , Real-Time Polymerase Chain Reaction , Sensitivity and Specificity
11.
Guang Pu Xue Yu Guang Pu Fen Xi ; 36(2): 502-10, 2016 Feb.
Article in Chinese | MEDLINE | ID: mdl-27209758

ABSTRACT

Sensitive band positions, models and the principles of soil dispersion detected by hyperspectral remote sensing were firstly discussed according to the results of soil dispersive hyperspectral remote sensing experiment. Results showed that, (1) signals and noises could be separated by Fourier transformation. A finely mineral identification system was developed to remove spectral noises and provide highly accurate data for establishing soil dispersive model; (2) Soil dispersive hyperspectral remote sensing model established by the multiple linear regression method was good at soil dispersion forecasting for the high correlation between sensitive bands and the soil dispersions. (3) According to mineral spectra, soil minerals and their absorbed irons were reflected by sensitive bands which revealed reasons causing soils to be dispersive. Sodium was the closest iron correlated with soil dispersion. The secondary was calcite, montmorillonite and illite. However, the correlation between soil dispersion and chlorite, kaolinite, PH value, quartz, potassium feldspar, plagioclase was weak. The main reason was probably that sodium was low in ionic valence, small ionic radius and strong hydration forces; calcite was high water soluble and illite was weak binding forces between two layers under high pH value.

12.
Guang Pu Xue Yu Guang Pu Fen Xi ; 35(6): 1700-4, 2015 Jun.
Article in Chinese | MEDLINE | ID: mdl-26601393

ABSTRACT

To improve the accuracy of mineral content extraction by linear decomposition model, a method was established, which took rock spectra with wavelength from 350 to 2 500 nm as the data source, identified minerals based on spectral matching methods, applied Hapke model to transform spectral reflectance into single scattering albedo and resolved single scattering albedo to get mineral content. In this method, sectional noise filtering and regional mineral spectra library were added to improve the identifying accuracy. Based on the analysis on the fifth Baogutu rock body, compared with XRD results, accuracies of quartz, feldspar class and altered minerals identification were 75%, 100% and 92.2% separately. Accuracy of the content extraction of feldspar class, hornblende and altered minerals were 80.5%, 64%, 92.36% separately. This method added mineralogy symbiotic relationship into mineral identification to ensure the reliability, proposed the idea of sectional noise filtering to avoid the influence of filtering algorithm, applied the single scattering albedo to avoid the complex nonlinearly calculations to improve the accuracy theoretically. This method has a certain guiding significance for the work such as rapid analysis of alteration information.

13.
Guang Pu Xue Yu Guang Pu Fen Xi ; 32(8): 2065-9, 2012 Aug.
Article in Chinese | MEDLINE | ID: mdl-23156753

ABSTRACT

Aiming at the low accuracy of mineral identification with hyperspectral data, the present article established regional spectra library on the basis of the study area geological background, and presented a pretreatment method that filters the original spectra by section. First, continuum based fast Fourier transform was used to filter the noise among 2000-2200, 2250-2300 and 2350-2500 nm. Then apply the rapid quantificational identification model with regional spectrum library was used to dispose the processed spectra. The highest effective rate of the result is 80%, and the highest accuracy rate is 67%. Compared with the identification result of original spectra, the average accuracy rate was upgraded by 17.7%, and the average effective rate was upgraded by 5.1%. Compared with the identification result of all-filtered spectra, the average accuracy rate was upgraded by 5.8%, while the average effective rate was upgraded by 39.8%. This method, which could guarantee that the identification result contains the most correct minerals and the fewest error ones, promoted mineral identification accuracy. The result with higher accuracy is significant to rapid mineral extraction work in field.

14.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 28(4): 804-9, 2011 Aug.
Article in Chinese | MEDLINE | ID: mdl-21936385

ABSTRACT

Since there is a clinical need for the tissue-engineered vascular graft (TEVG), fabricating the vascular scaffold individually appears to be necessary. In this work, we have developed the traditional tubular scaffold and branch vascular scaffold utilizing low-temperature deposition manufacturing (LDM) technology. Then different tubular scaffolds were fabricated by changing the processing parameters, and the morphological properties of the scaffolds were assessed. The scaffolds reproduced the structure of 3D vascular model accurately. Wall thickness of the scaffold increased with the increase of velocity ratio (V(L)/V(s)) and nozzle temperature, and both the micropore size and wall roughness were positively correlated with the nozzle temperature. However, the porosity was barely affected by the nozzle temperature. This approach, fabricating vascular scaffold with special structure and appearance features via LDM technology, is potential for the individual fabrication of vascular scaffold.


Subject(s)
Blood Vessel Prosthesis , Computer-Aided Design , Tissue Engineering/methods , Tissue Scaffolds , Biocompatible Materials/chemistry , Cold Temperature , Humans , Lactic Acid/chemistry , Polyesters , Polymers/chemistry
15.
Guang Pu Xue Yu Guang Pu Fen Xi ; 31(7): 2003-6, 2011 Jul.
Article in Chinese | MEDLINE | ID: mdl-21942070

ABSTRACT

Spectral difference is an important aspect for extracting shadows of buildings. Based on the analysis of the relationship between the building heights and the shadows in ALOS Images, the paper presents the principle and the method for building heights estimation in a city from the shadows of an image, and works out a feasible approach to determining shadow zones in a panchromatic ALOS Images. It has also contributed a standard process for extracting buildings distribution information of different heights in a city from the shadows in a panchromatic ALOS Images. A result with about 87.6% accuracy has been achieved while applying this technique to Tianjin City, which has demonstrated prospective applications of satellite remote sensing to urban purposes.

16.
Guang Pu Xue Yu Guang Pu Fen Xi ; 31(5): 1366-70, 2011 May.
Article in Chinese | MEDLINE | ID: mdl-21800602

ABSTRACT

The rapid identification of the minerals in the field is crucial in the remote sensing geology study and mineral exploration. The characteristic spectrum linear inversion modeling is able to obtain the mineral information quickly in the field study. However, the authors found that there was significant difference among the results of the model using the different kinds of spectra of the same sample. The present paper mainly studied the continuum based fast Fourier transform processing (CFFT) method and the characteristic spectrum linear inversion modeling (CSLM). On one hand, the authors obtained the optimal preferences of the CFFT method when applying it to rock samples: setting the CFFT low-pass frequency to 150 Hz. On the other hand, through the evaluation and study of the results of CSLM using different spectra, the authors found that the ASD spectra which were denoised in the CFFT method could provide better results when using them to extract the mineral information in the field.

17.
Guang Pu Xue Yu Guang Pu Fen Xi ; 30(9): 2433-7, 2010 Sep.
Article in Chinese | MEDLINE | ID: mdl-21105412

ABSTRACT

Hyperspectral characteristics analysis of ground features is the basis for applications of high-resolution imaging technology to ground target identification and ground features classification. Based on morphological multi-scale Top-Hat transformation, a novel spectral absorption enhancing algorithms was put forward, which enhanced spectral absorption features while maintaining shape features of the absorption peak bands. Eleven reflectance spectra of different mineral groups were chosen from the mineral spectral library of the United States Geological Survey (USGS), and we used a K-means clustering analysis on both the absorption-enhanced spectra and the original reflectance spectra. Results showed that, firstly, clustering groups of the absorption-enhanced spectra (AES) had better similarity within the same clustering group, and greater difference between different groups, furthermore, they were more consistent with the geological background of these minerals compared with clustering result of the original spectra (OS). Secondly, while all the original spectra were re-sampled to their ASTER spectra and the AES clustering result was displayed in the form of ASTER spectra of the minerals, we could easily describe both the representative spectral feature of each clustering group, and the typical spectral differences between every two groups. These fully demonstrate that the absorption-enhanced spectra have enhanced absorption features of the mineral spectra, and improved the separability of hyper-spectra. Accordingly, feature analysis based on absorption enhanced spectra can be used as reference for information extracting based on multi-spectral remote sensing image data, and it is a very useful method of hyperspectral analysis.

18.
Guang Pu Xue Yu Guang Pu Fen Xi ; 30(5): 1315-9, 2010 May.
Article in Chinese | MEDLINE | ID: mdl-20672625

ABSTRACT

Rapid identification of minerals is the key point for enhancing the efficiency of mineral exploration by remote sensing, mineral mapping by remote sensing and many geological investigations. Because of the limitation of technology and other aspects, the amount of models and software concerning rapid identification of minerals is very small. Since 1990s the development in spectrometers and computers has made it possible to apply near infrared spectrum technology to identify minerals. Two models have emerged. Model I is based on analyzing the position of absorption bands, while Model II is founded on waveform matching. In the present paper, characteristic spectrum linear inversion modeling was built. Validated by the data gained from end-members of USGS mineral spectrum library by mixing randomly, this model with the accuracy being approximately 100% is much better than Model I and II. Used to analyze the 23 samples selected in Baogutu area in Xinjiang, the model we built with the accuracy of 64.6% is superior to Model I (the accuracy is 33.8%) and Model II (the accuracy is 8.1%). Though the accuracy of our model is not as high as that of identification by microscope at present, using our model is much more effective and convenient, and there also will be less artificial error and smaller workload. The good performance of our model in the mineral exploration work by remote sensing in Baogutu area in Xinjiang shows wide popularizing prospects.

19.
Guang Pu Xue Yu Guang Pu Fen Xi ; 30(5): 1320-3, 2010 May.
Article in Chinese | MEDLINE | ID: mdl-20672626

ABSTRACT

In order to explore the feasibility of studying the geochemical anomaly of copper element by using remote sensing method, the correlation between Cu and other elements and the correlation between Cu and reflectance spectra were analyzed based on the element contents and the reflectance spectra of rock samples. It was found that Fe is most highly correlated with Cu, followed by Ti and As. The relationship between the Cu content and the reflectance spectra is of a negative correlation, and the higher the Cu content, the stronger the correlation. Furthermore, based on the reflectance spectra, the partial least squares regression of the Cu, Fe, Ti and As content was carried out respectively. The result shows that Ti gets the highest accuracy, followed by Fe. The worst is for As. Although the accuracy of the Cu model is not too high, it is feasible to establish an indirect model of copper anomaly on the basis of Fe model because of the strong correlation between them. In order to improve the accuracy of the model, some transformations for the reflectance spectra were performed and many spectral indices were acquired. Based on the spectral indices, the partial least squares regression of Fe was carried out. The accuracy of the regression model increased greatly. The highest correlation coefficient of the regression model is 0.687 6 for the calibration samples and it is 0.595 9 for the validation samples.

20.
Guang Pu Xue Yu Guang Pu Fen Xi ; 30(3): 644-8, 2010 Mar.
Article in Chinese | MEDLINE | ID: mdl-20496678

ABSTRACT

The present study introduced the generalized morphological filter into the denoising of visible and near infrared spectra for the first time, and provided a new method for denoising the reflectance spectra by combining mathematical morphology methods with the wavelet packet transformation. The authors used vegetable spectra from USGS spectral library as the reference spectra, and obtained the noised spectra by adding noises with different signal-to-noise ratios to the referenced spectra. The results were evaluated by signal-to-noise ratio (SNR), root mean squared error (RMSE), normalized correlation coefficient (NCC) and smoothness ratio (SR) of the denoised spectra. The authors' results showed that both the thresholding on wavelet packet decomposition best bases method and the generalized morphological filter method could maintain the spectral shape and the spectral smoothness after denoising. The generalized morphological filter method can remove larger amplitude random noise whereas the continuous small amplitude random noise could not be removed well. Hence, the denoised spectra were not smooth. Nevertheless, the denoised spectra using the thresholding on the best base groups of wavelet packet decomposition method were smooth, but the larger amplitude noise could not be removed completely. The authors' method by combining the two methods has the merits of the two methods but removing their defects. The results showed that both large and small amplitude noise could be removed completely, meanwhile the normalized correlation coefficient (NCC) and smoothness ratio (SR) were improved, which indicated that the authors' method is superior to other methods in denoising visible and near infrared spectra.

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