Mao Zhihua

Optimum segmentation of simple objects in high-resolution remote sensing imagery in coastal areas

The optimum segmentation of ground objects in a landscape is essential for interpretation of high-resolution remotely sensed imagery and detection of objects; and it is also a technical foundation to efficiently use spatial information in remote sensing imagery. Landscapes are complex system composed of a large number of heterogeneous components. There are many explicit homogeneous image objects that have similar spectral character and yet differ from surrounding objects in high-resolution remote sensing imagery. Thereby, a new concept of Distinctive Feature of fractal is put forward and used in deriving Distinctive Feature curve of fractal evolution in multiscale segmentation. Through distinguishing the extremum condition of Distinctive Feature curve and the inclusion relationship of fractals in multiscale representation the Scalar Order is built. This can help to determinate the optimum scale in image segmentation for simple-objects, and the potential meaningful image-object fitting the intrinsic scale of the dominant landscape object can be obtained. Based on the application in high-resolution remote sensing imagery in coastal areas, a satisfactory result was acquired.

Simulation and analysis of UV-A radiance reaching the passive satellite sensors over case-I and case-II waters

An at-sensor radiance simulation environment based on the atmosphere-ocean coupled model OSOAA for case-I and case-II waters is set up for evaluation of arbitrary combinations of sensors. Simulated results show that the 385 nm and 355 nm channels are sensitive to chlorophyll when it is less than 2.5 mg/m, sensitive to suspended sediment when it is less than 2.5 mg/L, and sensitive to CDOM when aCDOM is less than 0.08 m −1. The quantification of dynamic range for TOA (top of atmosphere) radiances should help to design the forthcoming ultraviolet ocean-color satellite sensors, e.g. the UVI (UltraViolet Imager) on HY-1/C (HaiYang-1/C) of China, as well as correctly exploit the satellite data acquired by the future ultraviolet satellite sensors.An at-sensor radiance simualtion environment based on the atmosphere-ocean coupled model OSOAA for case-I and case-II waters is set up for evaluation of arbitrary combinations of sensors. Simulated results show that the 385 nm and 355 nm channels are sensitive to chlorophyll when it is less than 2.5 mg/m3 , sensitive to suspended sediment when it is less than 2.5 mg/L, and sensitive to CDOM when aCDOM is less than 0.08 m−1. The quantification of dynamic range for TOA (top of atmosphere) radiances should help to design the forthcoming ultraviolet ocean-color satellite sensors, e.g. the UVI (UltraViolet Imager) on HY-1/C (HaiYang-1/C) of China, as well as correctly exploit the satellite data aquired by the future ultraviolet satellite sensors.