Abstract: ]In order to realize the automatic line inspection of the car,a CCD camera is used to identify the runway of different colors,and the black line is selected in the test.The CCD has 128×1 pixels and can collect 128 linear array data at a time.it can be converted to 128 8-bit binary numbers,which are output through A/D interface and connected with STM32 microprocessor.The software is used to collect and process the data.The median algorithm is used to find the edges on both sides of the black line and determine the center of the black line.The offset between the center of the car and the center of the black line is calculated to control whether the car turns left,right or straight.The encoder is used to measure the speed of the wheels and the speed PID algorithm is used to control the driving of the car in order to realize the automatic line patrol.The test results show that the CCD line-patrolling intelligent vehicle can realize the function of automatic line-patrolling.It can not only automatically track black lines,but also track lines of other colors,which improves the speed of the cars line-patrolling.It provides a new method and a new idea for the automatic line-following car.

Key words: Charge Coupled Device(CCD), Auto Tracking, Smart car, Speed PID