Online 3-D laser-scanner is a non-contact measurement system with high speed, high precision and easy operation, which can be used to measure heavy and high-temperature forgings. But the current online laser measurement system is mainly a mobile light indicator, which can only be used in the limited environment and lacks the capability of 3-D accurate measurement. This paper mainly introduces the structure of the online high-speed real-time 3-D measurement for heavy high-temperature forgings of Academy of Opto-Electronics (AOE), Chinese Academy of Sciences. Combining TOF pulse distance measurement with hybrid scan mode, the system can scan and acquire point cloud data of an area of 20m×10m with a 75°×40° field of view at the distance of 20m. The entire scanning time is less than 5 seconds with an accuracy of 8mm, which can meet the online dimensional measurement requirements of heavy high-temperature forgings.
A 16-channal front-end preamplifier array has been design in a 0.18um CMOS process for pulse Laser ranging radar receiver. This front-end preamplifier array incorporates transimpedance amplifiers(TIAs) and differential voltage post-amplifier(PAMP),band gap reference and other interface circuits. In the circuit design, the regulated cascade (RGC) input stage, Cherry-Hooper and active inductor peaking were employed to enhance the bandwidth. And in the layout design, by applying the layout isolation structure combined with P+ guard-ring(PGR), N+ guard-ring(NGR),and deep-n-well(DNW) for amplifier array, the crosstalk and the substrate noise coupling was reduced effectively. The simulations show that a single channel receiver front-end preamplifier achieves 95 dBΩ transimpedance gain and 600MHz bandwidth for 3 PF photodiode capacitance. The total power of 16-channel front-end amplifier array is about 800mW for 1.8V supply.
Hyperspectral Lidar using supercontinuum laser as light source, applying spectroscopic technology gets backscattered reflectance of different wavelengths, and can acquire both the geometry and spectral information on the target. In the vegetation detection by using Hyperspectral Lidar, through refusing 3d and spectral data, we can get the physical structure and biochemical parameter such as vegetation index, chlorophyll content. This paper constructs a simulating scene including an atmosphere, vegetation and ground surface, simulates spectral waveform of different input conditions such as varying ground reflectance, sloped versus flat ground, and comparisons of "leaf-on" and "leaf-off" conditions. First, using fractal method, the vegetation model was established. Second, applying Monte Carlo method, the laser between vegetation was traced. Third, using the PROSPECT model, established the vegetation spectral reflectance model. Last, by combining of the above three models, built hyperspectral Lidar vegetation detection model, and carry out simulation model under a variety of conditions supply.
An integrated multi-channel receiver for a pulsed time-of-flight (TOF) laser rangefinder has been designed in this paper. The receiver chip as an important component of the laser radar device has been implemented in a 0.18um CMOS process. It consists of sixteen channels and every channel includes preamplifier, amplifier stages, high-pass filter and a timing discriminator which contains a timing comparator and a noise comparator. Each signal paths is independent of other channels. Based on the simulations, the bandwidth and transimpedance of the amplifier channel are 652MHz, 99dBΩ. Under the simulation condition of TT corner and 27℃, the propagation delay of the discriminator is 2.15ns and the propagation delay dispersion is 223ps. The power consumption during continuous measurement is 810mW, and the operating temperature range of the device is -10~60℃.
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