Design And Implementation Of CIS Linear Array Image Scanning Software System

With the continuous development of social informatization,the digital management of paper documents is the development trend of administrative offices and various counter businesses.In the fields of finance,education,and consumption,flatbed scanners and high-speed cameras are common image scanning devices.Such devices cost more and take up more office space.The contact image sensor(CIS)has the advantages of short imaging focal length,compact structure and low cost,and is suitable for collecting surface images of objects such as paper paper document and textiles.The CIS image scanning system can be integrated into devices such as printers and folding machines,adding image scanning functions to such devices,thereby reducing the overall cost and volume of office equipment.However,the existing CIS image scanning systems transfer the original image data to a personal computer through a printer or other equipment.Since the processor mounted on the printer or other equipment usually does not have the ability to quickly transmit and process a large amount of image data,the existing CIS image scanning system is hard to efficiently complete large-format image scanning,and the speed and stability of the image scanning process are low.In addition,CIS scanned image quality is easily affected by factors such as light source exposure time,photosensitive unit characteristics,mechanical transmission structure,and self-preservation method.Existing CIS image scanning systems are poor in improving image quality and efficiency in response to these factors.This paper analyzes the needs of CIS image scanning system.In view of the key issues of slow image scanning speed,poor imaging quality and high hardware cost of existing CIS image scanning equipment,the image scanning software is designed based on the image acquisition hardware module with FPGA and ARM as the core.The overall scheme of the system fully utilizes the advantages of parallel computing performance of FPGA and the flexibility and portability of ARM to improve the efficiency of the system while reducing the overall cost;for the existing image scanning system,the original image data is transferred to the personal computer through external devices such as printers,resulting in low scanning speed.The ARM is used as the data transmission center and the USB host device driver and USB slave device driver are designed and implemented in it,which completes the high-speed and stable transmission of a large amount of data between the image scanning system and the rest of the equipment;in response to the problem that the existing image scanning system is difficult to efficiently complete large-format image scanning,a digital video interface device driver is designed and implemented,and the efficient reception and caching of image data by ARM is accomplished through technologies such as memory mapping,which provide solutions for compression and other image processing algorithms;in order to make the color balanced and the brightness moderated in the CIS scanned image,the adaptive adjustment method of the image brightness is designed according to the feedback control theory,which solves the problem that the brightness of the CIS scanned image is uneven and the color cannot be truly presented;in order to eliminate the streak noise caused by the characteristics of the CIS photosensitive unit in the scanned image,a point-by-point correction scheme and correction algorithm were designed,and the algorithm was optimized using ARM's Neon extended instruction technology to solve the problem that the image correction of the traditional CIS image scanning system is poor in results and low in efficiency;In order to reduce the influence of factors such as mechanical transmission structure and self-preservation method on the image quality,the image background processing algorithm is designed by extracting the background and adjusting the brightness component of the image,eliminating the shadows and creases in the CIS scanned image.The experimental results show that the image scanning system designed based on the above scheme can realize the rapid acquisition and transmission of images with multiple resolutions and multiple wavelength spectra.Compared with the original image output by CIS,the quality of the scanned image processed by this system has been significantly improved.The products developed based on the research results of this paper have been commercialized and mass produced,used in many large enterprises such as the Agricultural Bank of China.The functions and performance of this system have been tested.