The Design Of Potato Grading Machine Image Acquisition System Based On Trinocular Cameras

This subject is designed and implemented based on the requirements of potato rapid non-destructive testing and classification equipment for potato image collection.The image acquisition system design of trinocular camera is completed based on machine vision technology.The content mainly includes the following four parts.(1)According to the needs of the project in order to obtain the complete appearance image of the potato under motion,three cameras are used to collect synchronously from the top,left and right sides of the potato to be tested,and a set of reasonable synchronous acquisition system scheme is designed.,And select the appropriate image acquisition unit,including light source,industrial camera,industrial lens,etc.(2)The STM32F103R6 Microcontroller is used as a signal controller to trigger the camera to work synchronously in the image acquisition system.However,the high-level voltage value of the PWM signal generated by STM32 fails to meet the voltage requirement of the camera using LineO interface for external triggering.This paper uses LM358 to design a level of in-phase voltage amplifying circuit to double the high-level voltage value of the PWM signal to generate an external trigger signal for the simultaneous exposure of three cameras in the external trigger mode.(3)The supporting software of the camera can not realize the function of three cameras collecting at the same time,so on the basis of the software package and development documents provided by the software,the C++language is used for secondary design and development on the Visual Studio 2013 platform.Realize the synchronous acquisition of three cameras and synchronous storage of images,and complete the overall design of the image acquisition system.(4)After completing the design of the image acquisition system,test the performance of the system.It was measured that the three cameras of the image acquisition system can work stably at the acquisition frame rate of 12 frames per second,and meet the needs of the project team at the acquisition rate of 5 frames per second.When the system performs a long-time acquisition at 5 frames per second,the system basically completes the image storage within 50 ms.The test proves that the synchronization performance of the system is good and stable.Meet the design requirements of the project team for the image acquisition system.The design of the image acquisition system is the core link of the rapid non-destructive grading inspection system for potatoes developed by the project team.The success of the design of the image acquisition system largely determines the success or failure of the entire system.It has an important influence on the realization of the function of potato rapid nondestructive testing and grading system.