CN114136347A - 基于光电容积描记法的活体检测方法及系统 - Google Patents

基于光电容积描记法的活体检测方法及系统 Download PDF

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CN114136347A
CN114136347A CN202111445308.3A CN202111445308A CN114136347A CN 114136347 A CN114136347 A CN 114136347A CN 202111445308 A CN202111445308 A CN 202111445308A CN 114136347 A CN114136347 A CN 114136347A
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崔予红
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Chengdu Weikexin Microelectronics Co ltd
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    • G01D5/58Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using means specified in two or more of groups G01D5/02, G01D5/12, G01D5/26, G01D5/42, and G01D5/48 using optical means, i.e. using infrared, visible or ultraviolet light

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Abstract

本发明公开了基于光电容积描记法的活体检测方法及系统,其系统包括光电检测机构、电容检测机构和微处理器;光电检测机构包括光电二极管和信号放大电路,光电二极管输出端与信号放大电路输入端相连接,信号放大电路输出端与微处理器相连接;电容检测机构为电容式接触传感器电路,电容式接触传感器电路输出端与微处理器相连接;电容式接触传感器电路包括电容式接触传感器和检测电路;电容式接触传感器与放大电路输入端相连接,放大电路输出端与微控制器相连接;光电检测机构通过光电容积描记法进行活体检测。本发明结合PPG信号检测和接近电容检测,可以提高人体接近检测的成功率和识别率,防止非人体表面被识别为人体表面。

Description

基于光电容积描记法的活体检测方法及系统
技术领域
本发明涉及接近传感器领域,尤其涉及基于光电容积描记法的活体检测方法及系统。
背景技术
接近传感器又称无触点接近传感器,是理想的电子开关量传感器。当金属检测体接近传感器的感应区域,开关就能无接触,无压力、无火花、迅速发出电气指令,准确反应出运动机构的位置和行程,即使用于一般的行程控制,其定位精度、操作频率、使用寿命、安装调整的方便性和对恶劣环境的适用能力,是一般机械式行程开关所不能相比的。接近传感器具有使用寿命长、工作可靠、重复定位精度高、无机械磨损、无火花、无噪音、抗振能力强等特点。因此到目前为止,接近传感器的应用范围日益广泛,其自身的发展和创新的速度也是极其迅速。
目前市场上的绝大多数接近传感器产品,电路式接近传感器大多采用电容式原理,在有导体接近时改变电容参数,从而进行接近检测。光电式接近传感器则是通过感应收光量的强弱来判断接近关系。
光电开关(光电传感器)是光电接近开关的简称,它是利用被检测
物对光束的遮挡或反射,由同步回路选通电路,从面检测物体。物体不限于金属,所有能反射光线的物体均可被检测。光电开关将输入电流在发射器上转换为光信号射出,接收器再根据接收到的光线的强弱或有无对目标物体进行探测。
电容式接近传感器亦属于一种具有开关量输出的位置传感器,它的测量头通常是构成电容器的一个极板,而另一个极板是物体的本身,当物体移向接近开关时,物体和接近开关的介电常数发生变化,使得和测量头相连的电路状态也随之发生变化,由此便可控制开关的接通和关断。
现有技术中,在可穿戴设备(如蓝牙耳机、运动手环等)存在单一的光电式传感器或电容式接近传感器进行佩戴检测,但由于电容式接近传感器会在靠近非人体的导体表面时同样产生接近识别,故使用单一的电容式检测电路对是否为活体佩戴存在误差。
而由于应用环境的多样性及运动导致的佩戴变化,会导致光电传感器与人体皮肤产生相对位移,光电信号中夹杂着运动产生的噪声,并且光电式接近传感器不区分人体和非人体表面,接近时均有反应,进而影响检测的准确性。
光电容积描记法(photo plethysmo graphy,PPG)通过可穿戴设备中的光发射器发出特定波长的光并入射到皮肤组织中,经过皮肤组织的反射、散射以及吸收之后,一部分光可以从皮肤表面出射并被可穿戴设备中的光接收器接收,在此过程中,由于皮下组织的血液容积随心脏律动呈搏动性变化,使光接收器接收到的光强也随之呈搏动性变化,故可以对人体独有的ppg信号进行精确反应,但现有佩戴式电子器件却鲜少装载有运用光电容积描记法的接近检测电路。同时光电容积描记法采用光电传感器,故运用光电容积描记法的接近检测电路同样存在光电传感器在活体检测方面的缺陷。
发明内容
本发明的目的在于解决解决现有接近传感器领域活体检测难度高,复杂度大,成功率低等不足,提供了基于光电容积描记法的活体检测方法及系统。
本发明的目的是通过以下技术方案来实现的:
基于光电容积描记法的活体检测系统方法,包括以下具体步骤:
根据人体可能的信号频率,在频域将信号划分为两部分,一部分为人体ppg信号频段,另一部分为非人体ppg信号频段;
通过光电二极管获取被测物体反射的光电信号,并将光电信号传输至信号放大电路进行放大处理;
将信号放大电路处理后的光电信号传输至微处理器;
根据PPG信号所处频段进行初步判定,判断接近的被测物体是否为人体;
电容式接触传感器通过检测导体接近或远离时电容量,将电容量信号传输给信号检测电路;
电容量信号经信号检测电路处理后,传输给微控制器进行二次判定;
微处理器结合光电检测机构和电容检测机构检测结果,得到最终判定。
所述人体ppg信号频段为0.5hz-3hz范围内,超出0.5hz-3hz范围即为非人体ppg信号频段。
所述最终判定具体包括:
当光电检测机构判定检测到活体表面,电容式接触传感器同时检测到导体时,微处理器判定为接近物体为活体;
当光电检测机构判定检测到活体表面,电容式接触传感器检测到为非导体时,微处理器判定为接近物体为非活体;
当光电检测机构判定检测到非活体表面,电容式接触传感器检测到为导体时,微处理器判定为接近物体为非活体;
当光电检测机构判定检测到非活体表面,电容式接触传感器检测到为非导体时,微处理器判定为接近物体为非活体。
基于光电容积描记法的活体检测系统,包括光电检测机构、电容检测机构和微处理器;所述光电检测机构包括发光激光管、光电二极管和信号放大电路,光电二极管输出端与信号放大电路输入端相连接,信号放大电路输出端与微处理器相连接,发光激光管与微处理器相连接;所述电容检测机构为电容式接触传感器电路,电容式接触传感器电路输出端与微处理器相连接。
所述光电检测机构通过光电容积描记法进行活体检测。
所述电容式接触传感器电路包括电容式接触传感器和检测电路;电容式接触传感器与放大电路输入端相连接,放大电路输出端与微控制器相连接;电容式接触传感器中一个电极为金属板,另一个电极为导体接近物。
本发明的有益效果:
本发明结合光电信号检测和接近电容检测,可以提高人体接近检测的成功率和识别率,防止非人体表面被识别为人体表面。
附图说明
为了更清楚地说明本发明实施例或现有技术中的技术方案,下面将对实施例或现有技术描述中所需要使用的附图作简单地介绍,显而易见地,下面描述中的附图仅仅是本发明的一些实施例,对于本领域普通技术人员来讲,在不付出创造性劳动的前提下,还可以根据这些附图示出的结构获得其他的附图。
图1是本发明的结构框图。
具体实施方式
应当理解,此处所描述的具体实施例仅用以解释本发明,并不用于限定本发明。
下面将结合本发明实施例中的附图,对本发明实施例中的技术方案进行清楚、完整地描述,显然,所描述的实施例仅是本发明的一部分实施例,而不是全部的实施例。基于本发明中的实施例,本领域普通技术人员在没有作出创造性劳动前提下所获得的所有其他实施例,都属于本发明保护的范围。
基于光电容积描记法的活体检测系统方法,包括以下具体步骤:
根据人体可能的信号频率,在频域将信号划分为两部分,一部分为人体ppg信号频段,另一部分为非人体ppg信号频段;
通过光电二极管获取被测物体反射的光电信号,并将光电信号传输至信号放大电路进行放大处理;
将信号放大电路处理后的光电信号传输至微处理器;
根据PPG信号所处频段进行初步判定,判断接近的被测物体是否为人体;
电容式接触传感器通过检测导体接近或远离时电容量,将电容量信号传输给信号检测电路;
电容量信号经信号检测电路处理后,传输给微控制器进行二次判定;
微处理器结合光电检测机构和电容检测机构检测结果,得到最终判定。
所述人体ppg信号频段为0.5hz-3hz范围内,超出0.5hz-3hz范围即为非人体ppg信号频段。
3.根据权利要求1所述的基于光电容积描记法的活体检测系统方法,其特征在于,所述最终判定具体包括:
当光电检测机构判定检测到活体表面,电容式接触传感器同时检测到导体时,微处理器判定为接近物体为活体;
当光电检测机构判定检测到活体表面,电容式接触传感器检测到为非导体时,微处理器判定为接近物体为非活体;
当光电检测机构判定检测到非活体表面,电容式接触传感器检测到为导体时,微处理器判定为接近物体为非活体;
当光电检测机构判定检测到非活体表面,电容式接触传感器检测到为非导体时,微处理器判定为接近物体为非活体。
基于光电容积描记法的活体检测系统,包括光电检测机构、电容检测机构和微处理器;所述光电检测机构包括发光激光管、光电二极管和信号放大电路,光电二极管输出端与信号放大电路输入端相连接,信号放大电路输出端与微处理器相连接,发光激光管与微处理器相连接;所述电容检测机构为电容式接触传感器电路,电容式接触传感器电路输出端与微处理器相连接。
所述光电检测机构通过光电容积描记法进行活体检测。
所述电容式接触传感器电路包括电容式接触传感器和检测电路;电容式接触传感器与放大电路输入端相连接,放大电路输出端与微控制器相连接;电容式接触传感器中一个电极为金属板,另一个电极为导体接近物。如图1所示,本实施例包括光电二极管、光电信号放大电路、电容式接近传感器电极、电容检测电路、微控制器。光电二极管及光电信号放大电路可接收人体的ppg信号,再将信号传递给微控制器,根据预设阈值进行人体ppg信号识别。电容式接近传感器电极及电容检测电路,则可对接近的导体物质进行电容响应,帮助对ppg信号的错误识别进行纠正。
所述光电二极管为一般的光电二极管,所述的信号放大电路具有一般意义上较高的信号幅度增益能力。首先测得光电二极管获取的光电信号,根据人体可能的信号频率划分在频域将信号划分为两部分,一部分为人体ppg信号频段(0.5hz-3hz),一部分为非人体ppg信号频段(3hz-∞)。其次,检测人体ppg信号频段的能量大小,若大于实验所获得的阈值,则判断为接近人体,若小于,则认为所接触表面为非人体表面。
一套电容式接近传感器电路,所述的电容式接近传感器电路包含一片金属充当电容极板,电容的另一极板为导体接近物。当有导体接近或远离时,电容检测电路可检测到电容量的改变。当光电二极管靠近果皮或橡胶表面导致所接收的信号幅度过强导致出现误判时,电容式接近传感器电路可以帮助纠正。
本发明可以提高光电传感器活体检测成功率正确率。
以上显示和描述了本发明的基本原理和主要特征和本发明的优点。本行业的技术人员应该了解,本发明不受上述实施例的限制,上述实施例和说明书中描述的只是说明本发明的原理,在不脱离本发明精神和范围的前提下,本发明还会有各种变化和改进,这些变化和改进都落入要求保护的本发明范围内。本发明要求保护的范围由所附的权利要求书及其等效物界定。

Claims (6)

1.基于光电容积描记法的活体检测系统方法,其特征在于,包括以下具体步骤:
根据人体可能的信号频率,在频域将信号划分为两部分,一部分为人体ppg信号频段,另一部分为非人体ppg信号频段;
通过光电二极管获取被测物体反射的光电信号,并将光电信号传输至信号放大电路进行放大处理;
将信号放大电路处理后的光电信号传输至微处理器;
根据信号所处频段进行初步判定,判断接近的被测物体是否为人体;
电容式接触传感器通过检测导体接近或远离时电容量,将电容量信号传输给信号检测电路;
电容量信号经信号检测电路处理后,传输给微控制器进行二次判定;
微处理器结合光电检测机构和电容检测机构检测结果,得到最终判定。
2.根据权利要求1所述的基于光电容积描记法的活体检测系统方法,其特征在于,所述人体ppg信号频段为0.5hz-3hz范围内,超出0.5hz-3hz范围即为非人体ppg信号频段。
3.根据权利要求1所述的基于光电容积描记法的活体检测系统方法,其特征在于,所述最终判定具体包括:
当光电检测机构判定检测到活体表面,电容式接触传感器同时检测到导体时,微处理器判定为接近物体为活体;
当光电检测机构判定检测到活体表面,电容式接触传感器检测到为非导体时,微处理器判定为接近物体为非活体;
当光电检测机构判定检测到非活体表面,电容式接触传感器检测到为导体时,微处理器判定为接近物体为非活体;
当光电检测机构判定检测到非活体表面,电容式接触传感器检测到为非导体时,微处理器判定为接近物体为非活体。
4.根据权利要求1-3任意一项所述方法的基于光电容积描记法的活体检测系统,其特征在于,包括光电检测机构、电容检测机构和微处理器;所述光电检测机构包括发光激光管、光电二极管和信号放大电路,光电二极管输出端与信号放大电路输入端相连接,信号放大电路输出端与微处理器相连接,发光激光管与微处理器相连接;所述电容检测机构为电容式接触传感器电路,电容式接触传感器电路输出端与微处理器相连接。
5.根据权利要求4所述的基于光电容积描记法的活体检测系统,其特征在于,所述光电检测机构通过光电容积描记法进行活体检测。
6.根据权利要求4所述的基于光电容积描记法的活体检测系统,其特征在于,所述电容式接触传感器电路包括电容式接触传感器和检测电路;电容式接触传感器与放大电路输入端相连接,放大电路输出端与微控制器相连接;电容式接触传感器中一个电极为金属板,另一个电极为导体接近物。
CN202111445308.3A 2021-11-30 2021-11-30 基于光电容积描记法的活体检测方法及系统 Pending CN114136347A (zh)

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Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070147667A1 (en) * 2005-12-26 2007-06-28 Sharp Kabushiki Kaisha Biometrics information processing device and method
WO2017025573A1 (en) * 2015-08-10 2017-02-16 Yoti Ltd Liveness detection
CN106691425A (zh) * 2016-12-30 2017-05-24 北京工业大学 一种运动手环的腕部心率监测方法
CN109350031A (zh) * 2018-12-07 2019-02-19 深圳先进技术研究院 一种光电容积脉搏波信号特征点检测方法及装置
CN110169764A (zh) * 2019-05-06 2019-08-27 上海理工大学 一种lms自适应滤波ppg信号心率提取方法
CN110506299A (zh) * 2018-11-02 2019-11-26 深圳市汇顶科技股份有限公司 活体识别的装置和门锁
US20200212723A1 (en) * 2018-12-27 2020-07-02 Automotive Research & Testing Center Method of foreign object detection and foreign object detection device
CN111563454A (zh) * 2020-05-08 2020-08-21 浙江大学 一种双重活体验证的手部静脉识别方法及装置
CN211856927U (zh) * 2020-09-11 2020-11-03 深圳市汇顶科技股份有限公司 活体接近检测装置、电子设备
US20210251567A1 (en) * 2020-02-19 2021-08-19 Faceheart Inc. Device and method for liveness detection

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070147667A1 (en) * 2005-12-26 2007-06-28 Sharp Kabushiki Kaisha Biometrics information processing device and method
WO2017025573A1 (en) * 2015-08-10 2017-02-16 Yoti Ltd Liveness detection
CN106691425A (zh) * 2016-12-30 2017-05-24 北京工业大学 一种运动手环的腕部心率监测方法
CN110506299A (zh) * 2018-11-02 2019-11-26 深圳市汇顶科技股份有限公司 活体识别的装置和门锁
CN109350031A (zh) * 2018-12-07 2019-02-19 深圳先进技术研究院 一种光电容积脉搏波信号特征点检测方法及装置
US20200212723A1 (en) * 2018-12-27 2020-07-02 Automotive Research & Testing Center Method of foreign object detection and foreign object detection device
CN110169764A (zh) * 2019-05-06 2019-08-27 上海理工大学 一种lms自适应滤波ppg信号心率提取方法
US20210251567A1 (en) * 2020-02-19 2021-08-19 Faceheart Inc. Device and method for liveness detection
CN111563454A (zh) * 2020-05-08 2020-08-21 浙江大学 一种双重活体验证的手部静脉识别方法及装置
CN211856927U (zh) * 2020-09-11 2020-11-03 深圳市汇顶科技股份有限公司 活体接近检测装置、电子设备

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