Fiber optic assemblies which are more flexible, highly efficient, high reliability, small mass and volume have been used in several spaceborne laser altimeter systems for laser sample, laser monitor, echo signal receiver and altimeter calibration. Moreover, application procedure and verification plan of commercial fiber optic assemblies used in spaceborne laser altimeter system is proposed. It is useful for fiber optic assembly’s development and qualification.
Hand gesture recognition has recently grown as a powerful technical means in human-machine interaction field for control the appliances such as in home automation. However, the accuracy recognition of diverse hand gestures is still in the early stage for real-world application. In this paper, we present a new gesture recognition framework which is capable of classifying ten different hand gestures based on the input signals from surface electromyography (sEMG) sensors. The multi-channel signals of a hand motion are simultaneously captured and transmitted to a PC via Bluetooth wireless protocol. The proposed recognition framework composes of three main steps: gesture sequence segmentation, feature extraction by sparse autoencoder, and deep neural network (DNN) based classification. The advantage of the proposed approach is the automated abstract feature extraction based on sparse autoencoder method. Combined with the DNN classification technique, we could achieve a better recognition performance tested on the dataset consisting of ten types of hand gestures compared with other classification methods.
In order to satisfy the application requirements of spaceborne three dimensional imaging lidar , a prototype of nonscanning multi-channel lidar based on receiver field of view segmentation was designed and developed. High repetition frequency micro-pulse lasers, optics fiber array and Geiger-mode APD, combination with time-correlated single photon counting technology, were adopted to achieve multi-channel detection. Ranging experiments were carried out outdoors. In low echo photon condition, target photon counting showed time correlated and noise photon counting were random. Detection probability and range precision versus threshold were described and range precision increased from 0.44 to 0.11 when threshold increased from 4 to 8.
Solid laser pumped by semiconductor laser has the large value in the area of space laser technology, because of the advantages of high efficiency, small volume and long life. As the indispensable component of laser, laser power is also very important. Combined with ZY3(02) laser altimeter project, a high voltage(0～300V), high current(0～80A), long pulse width(0～230us) and high precision temperature semiconductor laser power is developed. IGBT is applied in the driving circuit as the switch to provide a current pulse for LD. The heating or cooling capacity of TEC is controlled by PID compensation circuit quickly adjusts the duty cycle of the UC1637 PWM signal, to realize the high accuracy controlling of LD working temperature. The tests in the external ambient temperature of 5°C, 20°C, 30°C show that the LD current pulse is stable and the stability of LD working temperature up to ±0.1°C around the set point temperature, which ensure the highly stable operation of DPL.