Research Of Tachograph Imaging System Based On OV4689

The vehicle driving recorder is installed on the vehicle and can not only store and record the safety state information related to vehicle operation such as vehicle speed,mileage,and time,but also directly establish the connection between the driver and the vehicle information center,prevent dangerous behaviors such as driver fatigue and vehicle speeding.In this concept,the good image quality of the driving recorder directly determines the driver's driving experience for assisted driving,and further guarantees the safety of driving.At present,the vehicle-mounted driving recorders using CCD image sensors at home and abroad occupy a large market,but the cost of the CCD image sensors is high,and the image quality is generally achieved.Compared with CMOS image sensors,the advantages are poor.In addition,common optical lenses are commonly used in driving recorders currently on the market.This kind of lens imaging has a visual dead angle,which increases unsafe factors.Therefore,ultra-wide-angle cameras based on CMOS image sensors have become the optimal choice for driving recorders.In order to improve the image effect of the driving recorder,this paper proposes a more optimized program.The driving recorder imaging system using the OV4689 image sensor not only has the characteristics of high-definition and high-resolution,but also ensures stability in the complex electromagnetic environment inside the vehicle and runs without image quality problems.In the design of the project,firstly,the CMOS image sensor OV4689 and the matched super-wide angle fisheye lens were selected.The working principle of the CMOS image sensor,the characteristic parameters of the OV4689,and the parameter matching design of the fisheye lens were explained in detail;Secondly,the hardware circuit design of the system is highlighted,mainly including the schematic diagram and PCB design of image sensor peripheral circuit,power supply circuit,clock circuit,etc.Introduce circuit analysis method,electric dipole model,and slim straight antenna model to rectify EMC protection analysis;Then,according to the needs of image configuration adjustment,a simple explanation of the software configuration and processing algorithms of the system is provided;Finally,through the image quality testing and related reliability experiments,gets the achieve compliance test results.The finally designed driving recorder imaging system can not only have high-definition image effects,but also can operate normally and stably under the conditions of a variety of electromagnetic environments,complicated circuits,and strong interference within the automobile.