Rotating Mirror Camera Synchronization With The Speed Sensor Active Components

High speed rotating mirror camera can precisely record the time and space information of transient process. It is mainly used to research the real-time modality changes and displacements of objects. Considerable interests have been attracted into the synchronous and velocity sensor of high speed camera. A new speed-measuring method by opto-electrical techniques, which combines complex programmable logic devices (CPLD) and microcomputer units (MCU), has been proposed to implement the programmable and real-time monitoring. In this system, CAN(Controller Area Network) bus is used for transferring the data. The whole system works rapidly, stably and accurately, and is also untouched, well controllable and repeatable. Related research has been seldom reported in national and abroad, and the system gets high application value.In this dissertation, efforts have been made intensively to improve the performances of the synchronous and velocity sensor of high speed rotating mirror camera. The main works and creative ideas are about the subassemblies of the synchronous and velocity sensor, which are displayed as follows:1. An opto-electronic detecting system has been developed to meet the demands of high speed synchronous and velocity sensor. The rotating mirror's time information is transformed into optical signals, and then into electrical signals by photo detectors. Standard TTL pulse signals are obtained by using amplifying and reshaping circuits, through which highly accurate time intervals and synchronous signals can be gained.2. Considering the disadvantages of interference and noise among pulse signals in the receiving module, CPLD and MCU technologies were applied to implement real-time control, noise filtering and programmable time-delay of TTL pulse. As a result, the signals have been optimized to fulfill the requests of time-interval measurement, and the precision of the system has also been improved.3. In the original system, the semiconductor laser was designed to work without specific environment, so that the laser beam was sent out unstably. In order to optimize the working environment, a stable constant current source circuit for laser driving has been designed in this dissertation. The controllable constant current input has been implemented by MCU and a D/A converter. A protecting and a slow starting circuit for the constant current source have also been designed to have low noise and high stabilization.4. A detecting circuit of laser power has been designed in the active region for real-time monitoring of the working laser. Obtained current and power values are converted using the ADC function of high speed MCU, and the converted data is transferred to the main controlling system through the CAN bus. Then the controlling system adjusts the input value of the constant current source according to the actual status. of The current and power values of the laser are implemented synchronously monitoring by this detecting circuit so that the whole sending module gets dynamic balance. As a result, a quasi-invariable laser output can be obtained, and the reliability and stability of the system is enhanced consequently.