Mr. Zhenghai Wang Profile

Zhenghai Wang

at China Univ of Geosciences

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Publications (2)

Proceedings Article | 10 November 2008 Paper

A classification model of Hyperion image base on SAM combined decision tree

Zhenghai Wang, Guangdao Hu, YongZhang Zhou, Xin Liu

Proceedings Volume 7146, 71461W (2008) https://doi.org/10.1117/12.813161

KEYWORDS: Data modeling, Image classification, Atmospheric corrections, Spectrometers, Remote sensing, Atmospheric modeling, Calibration, Vegetation, Data acquisition, Reflectivity

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Monitoring the Earth using imaging spectrometers has necessitated more accurate analyses and new applications to remote sensing. A very high dimensional input space requires an exponentially large amount of data to adequately and reliably represent the classes in that space. On the other hand, with increase in the input dimensionality the hypothesis space grows exponentially, which makes the classification performance highly unreliable. Traditional classification algorithms Classification of hyperspectral images is challenging. New algorithms have to be developed for hyperspectral data classification. The Spectral Angle Mapper (SAM) is a physically-based spectral classification that uses an ndimensional angle to match pixels to reference spectra. The algorithm determines the spectral similarity between two spectra by calculating the angle between the spectra, treating them as vectors in a space with dimensionality equal to the number of bands. The key and difficulty is that we should artificial defining the threshold of SAM. The classification precision depends on the rationality of the threshold of SAM. In order to resolve this problem, this paper proposes a new automatic classification model of remote sensing image using SAM combined with decision tree. It can automatic choose the appropriate threshold of SAM and improve the classify precision of SAM base on the analyze of field spectrum. The test area located in Heqing Yunnan was imaged by EO_1 Hyperion imaging spectrometer using 224 bands in visual and near infrared. The area included limestone areas, rock fields, soil and forests. The area was classified into four different vegetation and soil types. The results show that this method choose the appropriate threshold of SAM and eliminates the disturbance and influence of unwanted objects effectively, so as to improve the classification precision. Compared with the likelihood classification by field survey data, the classification precision of this model heightens 9.9%.

Proceedings Article | 28 October 2006 Paper

Alteration/minerals information extraction from EO-1 Hyperion data

Zhenghai Wang, Guangdao Hu

Proceedings Volume 6419, 64190A (2006) https://doi.org/10.1117/12.712704

KEYWORDS: Associative arrays, Minerals, Atmospheric corrections, Short wave infrared radiation, Feature extraction, Calibration, Satellites, Imaging systems, Sensors, Atmospheric modeling

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