When sun is used as the light source for atmospheric composition detection, it is necessary to image sun for accurate identification and stable tracking. In the course of 180 second of the occultation, the magnitude of sun light intensity through the atmosphere changes greatly. It is nearly 1100 times illumination change between the maximum atmospheric and the minimum atmospheric. And the process of light change is so severe that 2.9 times per second of light change can be reached. Therefore, it is difficult to control the integration time of sun image camera. In this paper, a novel adaptive integration time control method for occultation is presented. In this method, with the distribution of gray value in the image as the reference variable, and the concepts of speed integral PID control, the integration time adaptive control problem of high frequency imaging. The large dynamic range integration time automatic control in the occultation can be achieved.
The novel support structure design of high stability for space borne primary mirror is presented. The structure is supported by a ball head support rod, for statically determinate support of reflector. The ball head assembly includes the supporting rod, nesting, bushing and other important parts. The liner bushing of the resistant material is used to fit for ball head approximated with the reflector material, and then the bad impact of thermal mismatch could be minimized to minimum. In order to ensure that the structure of the support will not be damaged, the glue spots for limitation is added around the reflector, for position stability of reflector. Through analysis and calculation, it can be seen that the novel support structure would not transfer the external stresses to the reflector, and the external stresses usually result from thermal mismatch and assembly misalignment. The novel method is useful for solving the problem of the bad influence form thermal stress and assembly force. In this paper, the supporting structure is introduced and analyzed in detail. The simulation results show that the ball head support reflector works more stably.
For the limitation of detecting materials, the images from the novel un-cooled infrared system based on visible light
readout are blurry and have low contrast. The images also have more noise and larger holes. Especially after
pseudo-color processing, the noise and holes will become much clearer. For the characteristics of images in the
un-cooled IR system, the traditional image processing methods for IR images are not suitable for the image in our
research. Therefore, an advanced one-dimensional triple wavelet analysis in row for infrared images is presented based
on the characteristics of un-cooled infrared system. In this method, the triple wavelet decomposition is made in each row
of image, and detail coefficients and approximation coefficients of each row can be obtained. The detail coefficients in
the first time of wavelet decomposition express the whole details of image containing noise and the edge of object. So
after low-pass filter, the noise in the image can be suppressed. By the wave reconstruction made between the
approximation coefficients in triple wavelet decomposition and the detail coefficients after low-pass filter, each row in
images without noise and holes can be gained. In wavelet reconstruction, a weight being proportional with the filtering
window is multiplied with detail coefficients. The weight can make sure the gray value of whole picture and the contrast
cannot be lower after low-pass filter. The images from un-cooled infrared system are processed in the computer with the
software of MATLAB. The results support that compared with traditional methods the novel method can be more
effective to eliminate the noise and fill holes, and better response to the temperature details of objects.