Qin Qiming

NIR-red spectral space based new method for soil moisture monitoring

Drought is a complex natural disaster that occurs frequently. Soil moisture has been the main issue in remote monitoring of drought events as the most direct and important variable describing the drought. Spatio-temporal distribution and variation of soil moisture evidently affect surface evapotranspiration, agricultural water demand, etc. In this paper, a new simple method for soil moisture monitoring is developed using near-infrared versus red (NIR-red) spectral reflectance space. First, NIR-red spectral reflectance space is established using atmospheric and geometric corrected ETM+ data, which is manifested by a triangle shape, in which different surface covers have similar spatial distribution rules. Next, the model of soil moisture monitoring by remote sensing (SMMRS) is developed on the basis of the distribution characteristics of soil moisture in the NIR-red spectral reflectance space. Then, the SMMRS model is validated by comparison with field measured soil moisture data at different depths. The results showed that satellite estimated soil moisture by SMMRS is highly accordant with field measured data at 5 cm soil depth and average soil moisture at 0–20 cm soil depths, correlation coefficients are 0.80 and 0.87, respectively. This paper concludes that, being simple and effective, the SMMRS model has great potential to estimate surface moisture conditions.

A study on recognition characterization of passive super low frequency electromagnetic exploring curves of goaf

It is found that the abandoned mine goaves, because of the different fillers, exist in below types: goaves filled with air, filled with water, and congested by falling coal bed roof after investigation. According to the goaf types and characteristics of different fillings in goaves by super low frequency (SLF) electromagnetic exploring, the SLF electromagnetic exploring curves may be classified into three major categories: the characteristic curve of air filled goaf, the characteristic curve of water filled goaf, and the characteristic curve of coal bed roof backfilled goaf. Based on the analysis above, we established the recognition characterization of passive super low frequency electromagnetic exploring spectrum curves with respect to goaves, and accordingly obtained the information of goaves.

A comparative study on snow cover monitoring of different spatial resolution remote sensing images

A comparative research of snow cover is conducted, which is aimed to investigate the effect of spatial scale variation and the differences of different spatial resolution remote sensing images, by using moderate-resolution imaging spectroradiometer (MODIS) data and the satellite-B (HJ-1B) data of the small satellite constellation for environment and disaster monitoring and forecasting of China. Results show that: (1) the scaling-change within certain limits has little impact on snow cover mapping; (2) high spatial resolution image gives a better description of the detailed information of snow cover area; (3) the differences of snow cover between low spatial resolution and high resolution images are due to the different snow cover type.

CART-Based Rare Habitat Information Extraction For Landsat ETM+ Image

In the paper, The DT classifier adopted was CART(Classification and Regression Trees) to obtain a habitat of interest to Paeonia sinjiangensis, existing as fragments on the southern coteau of the Altay mountain located Xinjiang autonomous region of China. In the paper, decision tree classifier allows for the integration of remotely sensed data with other sources of georeferenced information such as land use data, spatial texture, and digital elevation models (DEMs) to obtain greater classification accuracy. TM reflectance data acquired in 2001 were required to completely cover Altay mountain area. Several ancillary datasets were used as inputs into the decision tree classification. These datasets include land use, city boundaries, vegetation types and digital elevation models. Logical decision rules, discovered from samples through CART integrating spectral textural and the spatial distribution character, then are used with the above various datasets to assign class values to each pixel. Finally, In contrast with CART, a standard maximum likelihood decision rule implemented by a discriminant analysis. Results on study of Paeonia sinjiangensis ground extraction from ETM imagery show that the classification results of CART was significantly better than that of Common DT classification. And this organizational methodology for classification is feasible and reliable if taking advantage of ancillary data and image analyst for classification.

DSM Generation of Buildings based on Corresponding Object Constraint

Common methods for DEM generation are based on collinearity equation, and rational function. Either of them require registered stereo pair as input. In order to register each point precisely, this paper proposes a corresponding image object constrained registration method based on object oriented image segmentation. Compared with current methods, the proposed method provides one geometric image transform (GIT) function for each pair of building roof because one GIT could fit well for just one roof. Object oriented segmentation not only helps us set the effective area for each GIT, but also provide us enough feature points from the boundary of a segmented building points to fit the coefficients of its GIT. The result by applying the proposed method on IKONOS stereo pair demonstrates the feasibility of generating building DSM with acceptable accuracy.

TVDI based crop yield prediction model for stressed surfaces

In the agriculture research field, the main object of drought monitoring is to gain the soil moisture, furthermore to confirm the loss of drought. Soil moisture is one of the most important factors affecting the crop especially for the drought area. Besides, the terrain of farmland also affects the soil moisture and the variety of crop. This paper will indicate the effects of the two factors above and the relationship between them. Agriculture drought research group of PKU has used TVDI (Temperature Vegetation Dryness Index) to evaluate the soil moisture in order to establish a model to predict crop yield, which has been used in the real task of meteorology and agriculture department. Using a special software system established by the research group, the TVDI could be conveniently calculated and the result accords with the real situation very well when we use it to compare with the local observation data.

The Research of Aerial RS Real-time Image Compression and Transmission Based on DSP

Aerial Remote Sensing (Aerial RS) image compression & transmission on-board system, not only is the core of Aerial RS supervising, but also the key technology about the security of data obtainment. The requirement of Aerial RS is stricter on the data quality and security. If we transmit the images through some special channels while the images are obtained during the task of Aerial RS, the control center on the ground could acquire the status of the whole Aerial RS system. Besides, it could also backup the images immediately. Image compression & transmission system is the important bridge between the Aerial RS system on-board and the control center. The research group of Aerial RS data processing in Peking University, integrates all the necessary technologies including compression algorithm & hardware, integration of function modules, protocol of data packing & unpacking. The research group has developed an efficient compression method that has been optimized both in software structures and hardware architecture. Considering with the narrow space on the airplane, the research group has designed the compression & transmission function module which is installed on the motherboard of the Aerial RS control system. The compression program is compiled in the Code Composer Studio (CCS) development environment, and then the result file compiled is burned into the DSP chip on the module. This paper also introduces an efficient protocol designed by the research group, which can ensure the accuracy of the transmission. It ensures the control center can rebuild & unpack the packages correctly, and avoid fatal errors caused by some false frames and packages during the transmission. This data compression & transmission system, which has been tested in certain different places in China, has achieved the purpose expected.

Hyperspectral remote sensing for coal-bed methane exploration

Based on the theory of coal-bed methane(CBM) geology, the micro-seeps of hydrocarbon cause geochemical alterations in rocks and soil. In this study, the hyperspectral instrument, Hyperion, was used to detect the alterations and hydrocarbons on the land surface of CBM reservoirs. Our study area is in the Qinshui Basin, China. Utilizing Hyperion datasets, the endmember spectra of specific minerals were extracted and the carbonate was mapped by the Spectral Angle Mapper (SAM) algorithm and the hydrocarbons in soil were detected by the Normalized Hydrocarbon Index (NHI). Because the vegetation endmembers in this study can produce similar absorption feature at 1730nm, the distribution of the vegetation was obtained by SAM. The results show that the carbonate and hydrocarbons concentrated in Jincheng Coal Mining Area. This approach, using the hyperspectral datasets, is advantageous for CBM exploration.

The application of dyadic wavelet in the RS building image edge detection

In the edge detection of RS building image, the useful detail losing and the spurious edge often appear. To solve the problem, we used the dyadic wavelet to detect the edge of surface features by combining the edge detecting with the multi-resolution analyzing of the wavelet transform. Via the dyadic wavelet decomposing, we obtained the RS building image of a certain appropriate scale, and figured out the edge data of the plane and the upright directions respectively, then worked out the grads vector module of the surface features, at last by tracing them we got the edge data of the buildings therefore built the RS image which obtained the checked edge. This method can depress the effect of noise and examine exactly the edge data of the building object by rule and line. With an experiment of RS building image, we certificated the feasibility of the application of dyadic wavelet in the RS building image edge detection.

Retrieving land surface component temperatures using ATSR-2 data

The retrieval of component temperatures from mixed pixel over vegetable-soil system is more valuable than the retrieving of average temperature. However, there are two essential mechanisms such as component thermal radiation and atmosphere correction must be newly considered. A good mathematic scheme should also be employed, which can make use of the ATSR-2 information in order to separate component temperatures. This paper is an attempt for the above topics. We bring forward more appropriate atmosphere parameters and retrieve them by resolving a system of nonlinear equations, which also includes vegetable and soil temperature as unknown variables. To resolve it, Broydens method is adopted. We use the ATSR-2 imagery on a pilot field in Shunyi county on April 16, 2001 to validate our method, and errors of 2 degC and 1 degC are achieved for soil temperature and vegetable temperature respectively.