Passive microwave remote sensing was firstly applied to detect the moon by Chang'E-1 satellite with a four channel
microwave radiometer. Its primary goal is to detect the thickness of lunar regolith and to assess the content of 3He. There
are remained theoretical problems to be systematically solved, which include to research the microwave radiation
transfer properties and to establish the suitable model to inverse lunar regolith depth. Considering the variation of these
factors influencing on the brightness temperature, a new multi-layer microwave transfer model to inverse the depth of
lunar regolith is presented. The physical factors among top lunar regolith influencing the brightness temperature change
sharply with the thickness, so the top lunar regolith is divided subtly. On the contrary, the deep lunar regolith where the
factors vary slowly with the thickness is divided roughly. Then, by applying the fluctuation dissipation theorem, the
brightness temperatures obtained from four frequency channels (3.0GHz, 7.8GHz, 19.35GHz, 37GHz) are simulated
based on the multi-layer model at different locations on the moon and at different times of a lunar day. In comparison the
calculated results with other models, it indicates that the proposed model has better stability and less calculation.
In this paper, a 1-D bar code is used to implement image measurement of object displacement. The bar code is etched or printed on a rod to be a coded scale with bar widths modulated by a sinusoidal function and so the rod has unique phase at each position. During the measurement, an imaging sensor collects image of partial code elements of the whole scale. The displacement can be obtained from phase analysis of collected bars. The phase is calculated via Fourier transform with elimination of windowing effect for the collected image is actually a rectangular windowed signal. If the digital frequency of bar code is high enough and there is enough bars on photosurface, the calculated phase fluctuation caused by noise introduced by bar width detection can be small enough so that the calculated value can be amended to be the ideal one and thus the measuring error is mainly determined by positioning precision of bar center on the photosurface. Under the conditions described in the paper, our experimental results show that the maximum of displacement measuring error is 0.036mm and the standard deviation 0.024mm, which indicates the feasibility of this method and good application prospect of it.
A special man-made 2-D bar code ruler is applied to the CCD image measurement of 2-D micro-displacement of close quarters object in this paper. The bar code ruler is a set of concentric annulus in which the widths of them are based on cosine rule. In measuring process, the ruler is attached to the object, moving with it, and the relatively fixed CCD collects the image data of the bar code before and after the movement. From analysis of phase shifts of those image data, we can get the measuring results. Besides that the measurement precision is affected by quantization, the size of pixels and interspaces between pixels, there are other factors which can cause distorted image data and in turn result in errors in results. By comparison of the decussating form and the concentric annular form of the bar code, we can see that though not all the image data of the whole annulus make contribution to the calculation of phase shifts, the latter form plays a great role in practical application for it ensures the precondition which makes it possible to get correct measurement and detect the distorted image data.
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