作者：敖子逸1, 杨建2, 万清3, 周伟1, 袁婷萱1, 范浩1
作者单位：1. 成都理工大学核技术与自动化工程学院，四川 成都 610059;
2. 中国测试技术研究院，四川 成都 610021;
3. 四川中测辐射科技有限公司，四川 成都 610052
关键词：x光机焦点;狭缝法;焦点测量;fpga;线阵ccd
摘要：
x光机的焦点尺寸是影响x射线成像质量的关键因素之一，针对x光机焦点尺寸测量方法繁琐、测量效率低等问题，文章提出一种以fpga为核心控制芯片，狭缝法为测量原理的x光机焦点测量仪系统设计方案，通过线阵ccd传感器采集狭缝成像后的焦点信息，随后进行模数转换，并采用usb2.0传输方式将数据传输至上位机进行处理和计算。文章重点讨论线阵ccd、a/d转换和usb传输的驱动与时序设计，以及焦点尺寸的计算方法，该系统具有高精度、实时性低延迟的特点。实验结果表明，在对x光机大、小焦点尺寸各进行10次测量后，测量重复性分别为0.2808%和0.4779%，示值误差均在±0.15 mm范围内，这证明了该系统能够实现对x光机焦点尺寸的精准测量。
design of focus measuring instrument system of x-ray machine based on fpga
ao ziyi1, yang jian2, wan qing3, zhou wei1, yuan tingxuan1, fan hao1
1. college of nuclear technology and automation engineering, chengdu university of technology, chengdu 610059, china;
2. national institute of measurement and testing technology, chengdu 610021, china;
3. sichuan zhongce radiation technology co., ltd., chengdu 610052, china
abstract: the focal size of x-ray machine is one of the key factors affecting the quality of x-ray imaging. aiming at the problems of cumbersome measurement method and low measurement efficiency of x-ray machine focus size, this paper proposes a design scheme of x-ray machine focus measuring instrument system based on fpga as the core control chip and slit method as the measurement principle. the focus information after slit imaging is collected by linear ccd sensor. then the analog-to-digital conversion is carried out, and the data is transferred to the upper bit computer by usb2.0 transmission mode for processing and calculation. this paper mainly discusses the driving and timing design of linear array ccd, a/d conversion and usb transmission, and the calculation method of focus size. the system has the characteristics of high precision, real-time. the experimental results show that after 10 measurements of the large and small focal dimensions of the x-ray machine, the measurement repeatability is 0.2808% and 0.4779% respectively, and the indicating errors are within the range of ±0.15 mm, which proves that the system can achieve accurate measurement of the focal dimensions of the x-ray machine.
keywords: x-ray machine focus;slit method;focus measurement;fpga;linear ccd
2024, 50(8):137-143 收稿日期: 2023-09-26;收到修改稿日期: 2024-01-31
基金项目: 国家自然科学基金项目（11975060）
作者简介: 敖子逸（2000-），男，四川乐山市人，硕士研究生，专业方向为核仪器开发。
参考文献
[1] 严翔. x射线的产生机理及应用 [j]. 科技信息, 2012(9): 178.
yan x. the producing mechanism of x-ray and application [j]. science & technology information, 2012(9): 178.
[2] 韩放达, 肖永顺, 常铭, 等. x射线源焦点尺寸测量方法和标准综述[j]. 中国体视学与图像分析, 2014, 19(4): 321-329.
han f d, xiao y s, chang m, et al. review of measurement methods and standards of focal[j]. chinese journal of stereology and image analysis, 2014, 19(4): 321-329.
[3] medical electrical equipme-nt - x-ray tube assemblies for medical diagnosis - focal spot dimensi-ons and related characteristics: iec 60336—2020[s]. 2020.
[4] 冯晓艳, 胡彦君, 吴嘉伟, 等. 基于fpga的微型光谱仪ccd系统设计[j]. 仪表技术与传感器, 2021(9): 29-32.
feng x y, hu y j, wu j w, et al. design of micro-spectrometer ccd system based on fpga[j]. instrument technique and sensor, 2021(9): 29-32.
[5] 杨程, 李俊, 李长武, 等. 基于fpga的压电式加速度计自动化校准系统研究[j]. 中国测试, 2022, 48(s2): 171-174.
yang c, li j, li c w, et al. automatic calibration system of piezoelectric accelerometer based on fpga[j]. china measurement & test, 2022, 48(s2): 171-174.
[6] 何小英, 谷鹏羊, 吴爱平, 等. 基于fpga的微电阻率扫描成像测井仪极板检测装置设计[j]. 中国测试, 2023, 49(2): 133-138.
he x y, gu p y, wu a p, et al. design of plate detection device of micro-conductivity imaging logging tool based on fpga[j]. china measurement & test, 2023, 49(2): 133-138.
[7] 李明豫, 田璐, 范杰, 等. 狭缝法测量诊断x光机焦点研究[j]. 中国测试, 2015, 41(11): 31-34.
li m y, tian l, fan j, et al. studies on measurement of diagnosis x-ray apparatus focus using slot method[j]. china measurement & test, 2015, 41(11): 31-34.
[8] 万清, 赖万昌, 郑永明, 等. 基于面阵ccd的医用x光机焦点检测研究[j]. 中国测试, 2015, 41(3): 130-33.
wan q, lai w c, zheng y m, et al. focus research of medical x-ray machine based on plane array ccd detection[j]. china measurement & test, 2015, 41(3): 130-33.
[9] 王越, 王亚南, 江南. 狭缝法实时测量x射线机焦点的研究[j]. 中国医疗器械信息, 2017, 23(19): 26-28.
wang y, wang y n, jiang n, et al. study on real-time measurement of focus of x-ray apparatus by slit method[j]. china medical device information, 2017, 23(19): 26-28.
[10] 盖立俊. x、γ射线增感屏性能的monte carlo模拟研究[d]. 哈尔滨: 黑龙江大学, 2015.
ge l j. monte carlo simulation of the performance of x - and γ-ray intensifier screens[d]. harbin: heilongjiang university, 2015.
[11] 程瑶, 甘婷源. 线阵ccd输出特性测量系统设计[j]. 仪表技术与传感器, 2019(5): 85-90.
cheng y, gan t y. design of line array ccd output characteristic measurement system[j]. instrument technique and sensor, 2019(5): 85-90.
[12] 韦凯, 张铆, 黄旭东. 基于usb接口的fpga在线升级方法研究[j]. 电子设计工程, 2019, 27(15): 99-102.
wei k, zhang m, huang x d, et al. research online upgrade method of the fpga based on usb interface[j]. electronic design engineering, 2019, 27(15): 99-102.
[13] 实时焦点测量仪校准规范: jjf 1688—2018[s]. 北京: 中国质检出版社, 2018.
calibration specification for real-time focus meters: jjf 1688—2018[s]. beijing: quality inspection press of china, 2018.
