1、S. Lee et al.: A Pyroelectric Infrared Sensor-based Indoor Location-Aware System for the Smart HomeA Pyroelectric Infrared Sensor-based Indoor Location-Aware System for the Smart HomeSuk Lee, Member, IEEE, Kyoung Nam Ha, Kyung Chang Lee, Member, IEEEAbstract Smart home is expected to offer various i
2、ntelligent services by recognizing residents along with their life style and feelings. One of the key issues for realizing the smart home is how to detect the locations of residents. Currently, the research effort is focused on two approaches: terminal-based and non-terminal-based methods. The termi
3、nal -based method employs a type of device that should be carried by the resident while the non-terminal-based method requires no such device. This paper presents a novel non-terminal-based approach using an array of pyroelectric infrared sensors (PIR sensors) that can detect residents. The feasibil
4、ity of the system is evaluated experimentally on a test bed.Index Terms smart home, location-based service, pyroelectric infrared sensor (PIR sensor), location-recognition algorithmI. INTRODUCTIONThere is a growing interest in smart home as a way to offer a convenient, comfortable, and safe resident
5、ial environment 1, 2. In general, the smart home aims to offer appropriate intelligent services to actively assist in the residents life such as housework, amusement, rest, and sleep. Hence, in order to enhance the residents convenience and safety, devices such as home appliances, multimedia applian
6、ces, and internet appliances should be connected via ahome network system, as shown in Fig. 1, and they should be controlled or monitored remotely using a television (TV) or personal digital assistant (PDA) 3, 4. Fig. 1. Architecture of the home network system for smart homeEspecially, attention has
7、 been focused on location-based services as a way to offer high-quality intelligent services, while considering human factors such as pattern of living, health, and feelings of a resident 5-7. That is, if the smart home can recognize the residents pattern of living or health, then home appliances sh
8、ould be able to anticipate the residents needs and offer appropriate intelligent service more actively. For example, in a passive service environment, the resident controls the operation of the HVAC (heating, ventilating, and air conditioning) system, while the smart home would control the temperatu
9、re and humidity of a room according to the residents condition. Various indoor location-aware systems have been developed to recognize the residents location in the smart home or smart office. In general, indoor location-aware systems have been classified into three types according to the measuremen
10、t technology: triangulation, scene analysis, and proximity methods 8. The triangulation method uses multiple distances from multiple known points. Examples include Active Badges 9, Active Bats 10, and Easy Living 11, which use infrared sensors, ultrasonic sensors, and vision sensors, respectively. T
11、he scene analysis method examines a view from a particular vantage point. Representative examples of the scene analysis method are MotionStar 12, which uses a DC magnetic tracker, and RADAR 13, which uses IEEE 802.11 wireless local area network (LAN). Finally, the proximity method measures nearness
12、to a known set of points. An example of the proximity method is Smart Floor 14, which uses pressure sensors.Alternatively, indoor location-aware systems can be classified according to the need for a terminal that should be carried by the resident. Terminal-based methods, such as Active Bats, do not
13、recognize the residents location directly, but perceive the location of a device carried by the resident, such as an infrared transceiver or radio frequency identification (RFID) tag. Therefore, it is impossible to recognize the residents location if he or she is not carrying the device. In contrast
14、, non-terminal methods such as Easy Living and Smart Floor can find the residents location without such devices. However, Easy Living can be regarded to invade the residents privacy while the Smart Floor has difficulty with extendibility and maintenance.This paper presents a non-terminal based locat
15、ion-aware system that uses an array of pyroelectric infrared (PIR) sensors 15, 16. The PIR sensors on the ceiling detect the presence of a resident and are laid out so that detection areas of adjacent sensors overlap. By combining the outputs of multiple PIR sensors, the system is able to locate a r
16、esident with a reasonable degree of accuracy. This system has inherent advantage of non-terminal based methods whileavoiding privacy and extendibility, maintenance issues. In order to demonstrate its efficacy, an experimental test bed has been constructed, and the proposed system has been evaluated
17、experimentally under various experimental conditions. This paper is organized into four sections, including this introduction. Section II presents the architecture of the PIR sensor-based indoor location-aware system (PILAS), and the location-recognition algorithm. Section III describes a resident-d
18、etection method using PIR sensors, and evaluates the performance of the system under various conditions using an experimental test bed. Finally, a summary and theconclusions are presented in Section IV.II. ARCHITECTURE OF THE PIR SENSOR-BASED INDOORLOCATION-AWARE SYSTEMA. Framework of the smart home
19、Given the indoor environment of the smart home, an indoor location-aware system must satisfy the following requirements. First, the location-aware system should be implemented at arelatively low cost because many sensors have to be installed in rooms of different sizes to detect the resident in the
20、smart home. Second, sensor installation must be flexible because the shape of each room is different and there are obstacles such as home appliances and furniture, which prevent the normal operation of sensors. The third requirement is that the sensors for the location-aware system have to be robust
21、 to noise, and should not be affected by their surroundings. This is because the smart home can make use of various wireless communication methods such as wireless LAN or radio-frequency (RF) systems, which produce electromagnetic noise, or there may be significant changes in light or temperature th
22、at can affect sensor performance. Finally, it is desirable that the systems accuracy is adjustable according to room types.Among many systems that satisfy the requirement, the PIR sensor-based system has not attracted much attention even though the system has several advantages. The PIR sensors,whic
23、h have been used to turn on a light when it detects human movement, are less expensive than many other sensors. In addition, because PIR sensors detect the infrared wavelengthemitted from humans between 9.410.4 m, they are reasonably robust to their surroundings, in terms of temperature, humidity, a
24、nd electromagnetic noise. Moreover, it ispossible to control the location accuracy of the system by adjusting the sensing radius of a PIR sensor, and PIR sensors are easily installed on the ceiling, where they are not affected by the structure of a room or any obstacles. Figure 2 shows the framework
25、 for the PILAS in a smart home that offers location-based intelligent services to a resident. Within this framework, various devices are connected via a home network system, including PIR sensors, room terminals, a smart home server, and home appliances. Here, each room is regarded as a cell, and th
26、e appropriate number of PIR sensors is installed on the ceiling of each cell to provide sufficient location accuracy for the location-based services. Each PIR sensor attempts to detect the resident at a constant period, and transmits its sensing information to a room terminal via the home network sy
27、stem. Fig. 2. Framework of smart home for the PILAS.Consequently, the room terminal recognizes the residents location by integrating the sensor information received from all of the sensors belonging to one cell, and transmits the residents location to the smart home server that controls the home app
28、liances to offer location-based intelligent services to the resident.Within this framework, the smart home server has the following functions. 1) The virtual map generator makes a virtual map of the smart home (generating a virtual map), and writes the location information of the resident, which is
29、received from a room terminal, on the virtual map (writing the residents location). Then, it makes a moving trajectory of the resident by connecting the successive locations of the resident (tracking the residents movement). 2) The home appliance controller transmits control commands to home applian
30、ces via the home network system to provide intelligent services to the resident. 3) The moving pattern predictor saves the current movement trajectory of the resident, the current action of home appliances, and parameters reflecting the current home environment such as the time, temperature, humidit
31、y, and illumination. After storing sufficient information, it may be possible to offer human-oriented intelligent services in which the home appliances spontaneously provide services to satisfy human needs. For example, if the smart home server “knows” that the resident normally wakes up at 7:00 A.M
32、. and takes a shower, it may be possible to turn on the lamps and some music. In addition, the temperature of the shower water can be set automatically for the resident.S. Lee 等人:基于热释电红外传感器的智能家居室内感应定位系统基于热释电红外传感器的智能家居室内感应定位系统Suk Lee,电机及电子学工程师联合会会员Kyoung Nam Ha, Kyung Chang Lee,电机及电子学工程师联合会会员摘要智能家居,是
33、一种可以通过识别具有不同生活习惯和感觉的住户来提供各种不同的智能服务。而实现这样的功能其中最关键的问题之一就是如何确定住户的位置。目前,研究工作只要集中于两种方法:终端方式和非终端方式。终端方式需要一种住户随身携带的设备,而非终端方式则不需要这样的设备。本文提出一种使用可以探测到住户的热释电红外传感器(红外传感器)的新的非终端方式。该系统的可行性已经通过了测试平台的实验性评估。索引词智能家居,定位服务,热释电红外传感器(红外传感器),定位识别算法I. 简介现在由于人人都想有一个方便,舒适,安全的居住环境,因此大家对于智能家居表现的越来越感兴趣1 2。一般来说,智能家居旨在提供合适的智能服务来积
34、极促进住户更好的生活,比如家务劳动,娱乐,休息和睡眠。因此,为了提高住户的便捷和安全,像家用电器,多媒体设备和互联网设备应通过家庭网络系统连接在一起,如图1所示。并且它们应通过电视或个人数字助理(PDA)来控制或远程监控3 4。图1 智能家居的家庭网络体系结构尤其要注意的是,作为一种提供高质量的智能服务,目标应集中于定位服务,同时考虑人为因素,比如住户的生活方式,健康状况和居住感受57。也就是说,如果智能家居能识别住户的生活方式或健康状况,那么家用电器应该能预见住户的需要,并能更主动的提供适合的智能服务。例如,在一个被动的服务环境下,需要住户控制供热通风与空气调节系统(供暖,通风和空调),而智
35、能家居将根据住户情况自动调节房间的温湿度。智能家居或智能办公室的各种室内感应定位系统的已经研发到能够识别住户的位置。一般来说,室内定位感应系统根据测量技术分为三种类型:三角测量,场景分析和接近方法8。三角测量法是通过多个已知点来计算位置距离。运用三角测量法的例子包括Active Badges9,Active Bats10和Easy Living11,它们分别运用了红外传感器,超声波传感器和视觉传感器来实现的。场景解析法是检测一个场景内的特定着眼点。场景解析法的典型例子是使用直流磁力跟踪器的MotiveStar12,和使用无线局域网络LAN标准IEEE 802,11的RADAR13。接近法则是以
36、一组已知点中最接近的点近似作为定位点。接近法的例子有使用压力传感器的Smart Floor14。另外,室内感应定位系统可以根据是否需要住户随身携带一种设备来分类。终端方式,例如Active Bats,不需要直接找到住户位置,但是可以感应到住户随身携带的设备位置,例如红外收发器或者射频识别技术(RFID)标签。因此,如果住户没有随声携带终端设备,那就不可能找到他。相反的,非终端方式如Easy Living和Smart Floor则不需要这种设备就能找到住户位置。然而,人们认为Easy Living侵犯了住户隐私,Smart Floor则是扩展和维护都比较困难。本文提出一种使用阵列热释电红外(PI
37、R)传感器实现的基于非终端方式的室内感应定位系统15 16。红外传感器固定在天花板上,并使相邻的传感器的感应范围有重叠。当它感应到一名住户时,通过多个红外传感器的综合,能够比较准确的确定住户的位置。该系统不仅具有非终端方式的特有优点,还避免了侵犯隐私,扩展性不佳和维护困难的问题。为了证明其有效性,已经在实验平台上通过了各种不同测试环境下的实验性评估。包括此简介,本文共分为四个部分,第二部分介绍基于红外传感器的室内定位感应系统架构(PILAS)以及定位识别算法。第三部分介绍了基于红外传感器的住户检测法和在实验测试平台上的不同环境下评估系统的表现。最后一部分为总结和结论。II. 基于热释电红外传感
38、器的室内感应定位系统架构A智能家居的结构鉴于智能家居的室内环境,室内感应定位系统必须满足一下条件。第一,由于需要在各种大小不同的房间里安装大量传感器来感知智能家居中的住户,因此定位感应系统需保持较低的成本。第二,传感器的安装必须是灵活可变的,因为各个房间的形状结构不同,并且还有各样阻碍传感器正常工作的家电和家具。第三,要求定位感应系统使用的传感器能够抵御很强的噪声,这是因为智能家居能利用各种无线传输技术,比如无线局域网,射频系统,它们都会产生电磁噪声,并且光或温度的巨大变化也会影响传感器的正常工作。最后该系统的精度可以,根据房间类型作出最合适的调节。尽管基于热释电红外传感器的这个系统有诸多的优
39、点,但在众多满足要求的产品中并不能吸引人们更多的关注。它已应用于感应灯(当它感应到人体移动时使灯自动打开),并且成本低于许多其他种类的感应器。另外,由于热释电红外传感器感应的是人体发出的9.410.4微米波长的红外线,从温度、湿度和电磁噪声来说,这种波长相对周围环境较为明显。而且,它可以通过调整感应半径来控制定位精度,并容易安装在天花板上,这样就不会受到房间结构和障碍物的影响。图2显示的是为住户提供基于位置的智能服务的PILAS智能家居框架。在这个框架下,包括热释电红外传感器、房屋终端、智能家居服务器和家用电器在内的各种设备通过家庭网络系统连接在一起。每个房间被视为一个单元,并在每个单元的天花
40、板上安装适当数量的传感器,为定位服务提供足够的定位精度。每个红外传感器周期性的感应住户位置,然后将感应信息通过家庭网络系统传输到房屋终端。因此,房屋终端通过集合来自同一个单元的传感器信息来确定住户的位置,再将住户位置传输到智能家居服务器,服务器就会控制家用电器为住户提供基于位置的定位服务。图2 PILAS智能家居框架在这个框架内,智能家居服务器具有以下功能:(1)虚拟地图发生器为智能家居提供虚拟地图(生成虚拟地图),并在虚拟地图中标出由房屋终端提供的住户位置信息(标注住户位置)。然后,它通过连接住户的连续定位点来绘制住户的运动轨迹(追踪住户运动)。(2)家电控制器通过家庭网络系统发送控制命令给家用电器为住户提供智能服务。(3)运动模式预测器保存当前的住户运动轨迹、家电的动作和反映居家环境的参数,比如时间、温度、湿度、光照度。储存足够的信息后,它可能会使家电主动提供满足人们需要的人性化的智能服务。例如,如果智能家居服务器“知道”住户通常在早上7点醒来,之后要淋浴,它也许就会在那一时间打开灯并播放音乐。另外,住户的淋浴水温也会被自动记录。. .此处忽略!