基于增益调制的激光成像准确度研究

The Accuracy Research on Gain Modulation Laser Imaging

微通道板电压与增益对数理论上呈线性关系,为了更接近实际情况,根据已知的微通道板电压与增益对数的函数关系选取一组线性数据点,并在其基础上加一组随机数作为波动,得到新的电压与增益对数的关系,获得指数拟合公式,用于还原目标的距离信息.对成像准确度进行理论分析,结果表明成像准确度与系统信噪比和增益调制函数有关,且信噪比越高,距离准确度越高.测量了微通道板增益与电压的关系曲线,在不同电压条件下照射同一距离同一目标得到回波图像,利用不同电压下回波图像灰度值之比得到相对增益之比.分别在恒定增益和调制增益下,对距离成像系统60m的目标进行成像,利用增益曲线对所得的图像进行处理,准确还原出目标的距离信息,准确度达到分米量级.

The relationship of the gain logarithm and voltage of microchannel plate is linear in theory. In order to be closer to the actual situation, according to the known function between the voltage and logarithmic gain of microchannel plate, a set of linear data points added random numbers were selected, and the new relationship of the voltage and logarithmic gain was obtained which can be used to restore the target distance information. The analysis results of imaging accuracy show that the imaging accuracy is related to the system＇s signal noise ratio and gain modulation function, the higher signal noise ratio is, the higher the distance accuracy is. The relationship between the gain and the voltage of microchannel plate was measured. The echo images in different voltages conditions were obtained by illuminating the same target at the same distance, the gray value ratio of the echo images under different voltages was used to get the ratio of relative gain. Respectively under the condition of constant gain and modulation gain, the target which was 60 m far from the imaging system was imaged. By using the gain curve, the obtained images were processed and the distance information of target accurately was restored, the distance accuracy could reach decimeter magnitude.