In recent years, although the government has carried out some serious investigation and effort to shut down the indigenous coke-production, it has not achieved effective control. There are still a lot of problems and the situation is still severe. One of the important measures towards to solving the problem is to improve the monitoring level. As the big producing province, southeast of Shanxi in China was chosen as the study area for this paper. Against the background of the Landsat5 data of this area in 1999 and 2004, the information about indigenous coke-production was extracted through TM751 and TM721 band compositions technology. The results showed that TM7 channel was the most sensitive to indigenous coke-production, where the reflectance value manifested the “peak” configuration as a flag of the indigenous coke-production. TM5 channel was the second most-sensitive to coke-production. According to the spectral profiles, TM7 and TM5 critical values of indigenous coke-production were given. The higher the coke-making temperature, the nearer the band was to TM5 channel. TM751 band compositions can be used to interpret indigenous coke-production over 90% accuracy identified by the ground check. During 5 years, the quantity of indigenous coke-production, distributed mainly on the plain in districts of population concentration, increased by 10 times and the indigenous coke-production had caused serious pollution to the environment. Some control strategy was proposed in the last paper. These findings contributed to the scientific foundation for accurately monitoring the dynamics of indigenous coke-production at large scale, and offered a kind of brand-new, quick technological method in monitoring indigenous coke-production.
Several vegetation canopies have a two-layer structure. In forests a moss or lichen layer is on ground surface under grass layer. In field crops a thin weed layer on ground under crop canopy is rather common. Both, optical and structural parameters of these two layers may be rather different and if we use homogeneous canopy reflectance (CR) models for the calculation of the directional reflectance of such canopies using mean (weighted mean) values of phytometrical and optical parameters we may have systematic errors in reflectance values. In this article, based on the two-layer canopy reflectance model ACRM, canopy reflectance angular distributions with wavelength 820 nm and 1 600 nm are simulated under the influence of LAI (leaf area index), Cw (water content)and N (a structural parameter). Research results indicate that the hot spot effect can be simulated precisely. The sensitivity of canopy reflectance angular distributing to LAI is less than to LAI-Cw and LAI-N. Reflectance angular distribution at 1 600 nm wavelength is strongly related to LAI and Cw while reflectance at 820nm is appreciable larger than the one at 1 600 nm under LAI and N effect. Besides, using information contained in near-infrared (820 nm)and short-wave infrared (1 600 nm) canopy reflectance we proposed a soil-adjusted water index which is employed to retrieve the canopy water content is also greatly influenced by canopy structure. Canopy structure is worth considering in the process of model selection henceforth.
In the research of hyper-spectral remote sensing, we need combine field spectra and image spectra to analyze. The correct collection of field spectra and pre-process of two kinds of spectra are often ignored by us, for there is little relationship between them and information analysis. In fact, before analysis directly, the raw data gotten from field or from remote sensing need format-change and de-noise etc. Though there are many books about spectra analysis now, none of them introduce how to collect spectra or spectra pre-process. Many persons who just begin to deal with hyper-spectral always feel confused. The author of this article has taken part in many projects about field spectra collection and airborne remote sensing, pre-processed a lot of field and image spectra in these years. This article introduces the author's experience and methods summarized from experiments from three aspects: ①how to collect field spectra correctly; ②how to pre-process field spectra; ③how to pre-process remote sensing images with field spectra. In this paper, the field spectra are collected by ASD --FR2500 and images are OMIS images. Data from other spectral apparatus and remote sensors can be dealt with analogously.
Geometric correction is a very important step in remote sensing image processing. The collection of ground control point can greatly influence the accuracy and efficiency of that process. This article compares the advantages and disadvantages among several methods of collecting Ground Control Point through the practice of geometric correction of SPOT5.The article also summarizes and explores the methods on how to process the remote sensing images based on digital raster graphic.
High range resolution(HRR) is an important aspect of the development of Synthetic Aperture Radar. High resolution in range is in proportion to the bandwidth of transmitted signal. In the application of space bore SAR, the increase of system instantaneous bandwidth will cause much difficult in generating, transmission and receiving of the signal for the limitation of hardware. So generation of wide bandwidth signals in current hardware level, and improvement of range resolution with no increasing of system instantaneous bandwidth by employing new waveforms have significant meaning and high practical value. The synthetic bandwidth technique employed stepped chirp is one effective method with such characteristic. The principle of the method is introduced, and simulation of synthetic bandwidth is carried out. The hardware circuit of the generation of stepped chirp based on FPGA is Presented. The experimental result of the generator output on the medium frequency is acquired, and then the combination of 3 sub |pulse with 30 MHz bandwidth to one 90 MHz bandwidth signal is implemented, which show that high range resolution by means of synthetic bandwidth generated by stepped chirp is correct, effective and practical.
