Geiger APD Array Lidar High-speed Imaging Circuit

As the concept of environmental protection is more and more accepted by countries all over the world,wind energy,as a kind of abundant clean energy,has made considerable progress in recent years.At present,the image detection of fans is usually based on infrared images and visible light images,but due to its imaging characteristics,the three-dimensional information of the target cannot be obtained well.According to its imaging principle,lidar can more accurately capture the three-dimensional information of the target,bringing new ideas and detection methods for wind turbine detection.Geiger APD area array lidar has the advantages of high frame rate,long detection range,high detection accuracy,and small size.At the same time,there is also the disadvantage of low signal-to-noise ratio of the original range image obtained by lidar.In order to meet the requirements of real-time acquisition and processing of high frame rate and high resolution data for fault detection,this paper has completed the multi-frame accumulation imaging of the original range image of the laser based on FPGA: the large-capacity cache can meet the requirements of high resolution and high frame rate.The requirements for image buffering;the real-time performance of the output result is improved through the high-parallel imaging circuit;the image size and the number of accumulated frames for multi-frame accumulation imaging are configurable.Lidar imaging circuit is mainly divided into two parts: high-speed image buffer and imaging circuit.Due to the characteristics of multi-frame accumulation imaging,the high-speed image cache circuit requires a cache solution with higher data bandwidth and larger capacity.This article designs an efficient DDR3 access strategy based on the access characteristics of DDR3 and the characteristics of image cache.Under the condition of large capacity,a high cache speed is realized;the imaging circuit needs to process high frame rate and high resolution image sequences,so it has higher requirements for computing power.This paper designs an imaging circuit with a small resource occupation.Under the premise of certain logic resources,a high degree of parallelism can be achieved,and the computing power of the scheme and the real-time performance of imaging results can be improved through the parallel mode of multiple imaging circuits.According to the above scheme,the design and verification of the laser radar high-speed imaging circuit have been completed.Under the condition that the image size is 256×256 and the cumulative number of frames is 400,imaging can be completed in 20 ms.Compared with the pure software operation based on DSP,the speedup ratio is 313.