Patent Publication Number: US-6339376-B1

Title: Automotive cargo space occupant detector

Description:
INCORPORATION BY REFERENCE 
     The disclosure of Japanese Patent Application No. 11-304316 filed on Oct. 26, 1999 including the specification, drawings and abstract is incorporated herein by reference in its entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a moving object detecting apparatus, an abnormality alarm apparatus, and a load-carrying compartment opening control apparatus. 
     2. Description of Related Art 
     Many vehicles have, in addition to a passenger compartment, a trunk compartment (load-carrying compartment) isolated from the passenger compartment. The trunk compartment is provided for placing various kinds of baggage. Although it is recommended that a driver check the inside of the trunk compartment, it is an object of the invention to provide some detection or alarm for telling a driver in case of, for example, an accident where a child or a pet is locked inside the trunk compartment while playing. 
     Various vehicular theft deterrent apparatus have been proposed. For example, Japanese Patent Application Laid-Open No. 6-52449 discloses an apparatus that continually transmits and receives ultrasonic waves using an ultrasonic transmitter-receiver, and detects an invader based on the Doppler effect in the reflected waves from the invader. Various apparatus also exist with regard to systems that detect an invader based on detection of an interruption of an infrared ray. 
     If an apparatus as described above is installed in a trunk compartment, it becomes possible to detect a child, a pet, etc., confined in the trunk compartment. 
     However, the apparatus using the Doppler effect have problems of a complicated system construction and a high cost. Furthermore, a plurality of objects cannot be detected unless Doppler effects are detected after reflected waves from the objects are separated in accordance with the distances of the objects. However, it is difficult to distinguish a plurality of objects and detect a movement of one of the objects. 
     The apparatus using infrared rays also have the following problem. That is, if a piece of baggage or the like is placed near an infrared light emitter portion, no other object can be detected at all. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the invention to provide a moving object detecting apparatus, an abnormality alarm apparatus, and a load-carrying compartment opening control apparatus each capable of reliably detecting a moving object while employing a simple apparatus construction. 
     A moving object detecting apparatus in accordance with one aspect of the invention includes an oscillator circuit that is connected to at least one electrically conductive member and that changes an oscillating frequency based on a change in capacitance of a space near the at least one electrically conductive member, and a frequency change detection circuit that detects a change in the oscillating frequency of the oscillator circuit. Based on a result of detection by the frequency detection circuit, a moving object present in the space near the at least one electrically conductive member can be detected. 
     If a moving object, such as a human, a pet, etc., exists near an electrically conductive member, the capacitance of the space adjacent to the electrically conductive member changes, and the oscillating frequency of the oscillator circuit fluctuates in accordance with movements of the object. Therefore, by detecting fluctuations in the oscillating frequency, a moving object can be detected. 
     An abnormality alarm apparatus in accordance with another aspect of the invention has an alarm device that produces an alarm based on a result of detection by the frequency change detection circuit. For example, the alarm device indicates to a driver that a moving object is detected in the trunk, so that the driver can take a proper action in response to the alarm indication. The alarm may be provided in various forms, such as a sound, a display, etc. 
     In a load-carrying compartment opening control apparatus in accordance with another aspect of the invention, the at least one electrically conductive member of the moving object detecting apparatus is provided in a load-carrying compartment isolated from a passenger compartment of a vehicle. The load-carrying compartment opening control apparatus has an opener that opens an open-close member of the load-carrying compartment when the frequency change detection circuit detects a moving object during a stop of the vehicle. Therefore, if a human, a pet or the like is unintentionally confined in a trunk, the load-carrying compartment opening control apparatus is able to automatically open the load-carrying compartment. 
     The frequency change detection circuit may include a receiver that is disposed apart from the antenna and that receives an electromagnetic wave transmitted from the antenna. A change in the frequency of the electromagnetic wave received by the receiver can be detected. Therefore, frequency fluctuations can be detected by the receiver disposed apart from the antenna. Therefore, it is possible for the system of the invention to use the reception equipment of a different system, for example, a smart entry system or the like. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Preferred embodiments of the invention will be described with reference to the accompanying drawings, wherein like numerals are used to represent like elements and wherein: 
     FIG. 1 is a diagram illustrating a construction of a Colpitts oscillator circuit; 
     FIG. 2 is a diagram illustrating a construction of an oscillator circuit whose frequency fluctuates; 
     FIGS. 3A,  3 B and  3 C are diagrams illustrating frequency fluctuations; 
     FIGS. 4A and 4B are diagrams illustrating a construction of an oscillator circuit for detecting fluctuations in the oscillating frequency with an adjacent space functioning as a capacitor; 
     FIG. 5 is a diagram illustrating a construction for detecting frequency fluctuations; 
     FIG. 6 is a diagram exemplifying a frequency-voltage converting circuit; 
     FIG. 7 is a graph indicating frequency-voltage conversion; 
     FIG. 8 is a diagram illustrating a construction in which a receiver is disposed apart; 
     FIG. 9 is a diagram illustrating operations of a construction wherein the oscillator circuit and the receiver are synchronized; 
     FIG. 10 is a diagram illustrating operations of an asynchronous construction; 
     FIGS. 11 A and  11 B are diagrams illustrating a construction in which a code is superimposed on electromagnetic waves; 
     FIG. 12 is a diagram illustrating a construction that employs a SAW resonator; 
     FIG. 13 is a diagram illustrating a case where an oscillator circuit is disposed in a load-carrying compartment; and 
     FIG. 14 is a diagram illustrating the opening of the load-carrying compartment to a limited extent. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENT(S) 
     FIG. 1 illustrates a construction of a Colpitts oscillator circuit that forms a basic construction of an oscillator circuit in the invention. As shown in FIG. 1, the collector of a transistor Tr 11  is connected to an antenna ANT 11 . A coil L 11  is connected between the collector and the base of the transistor Tr 11 . A capacitor C 11  is connected between the base and the emitter of the transistor Tr 11 . Furthermore, a capacitor C 12  is connected between the collector and the emitter of the transistor Tr 11 . 
     The thus-constructed Colpitts oscillator circuit resonates at a resonance frequency that is determined in accordance with the capacitance of the capacitors C 11 , C 12  and the inductance of the coil L 11 . As for the Colpitts oscillator circuit, the oscillating frequency changes depending on conditions around the antenna ANT 11 . For example, if an electrical conductor exists near the antenna ANT 11  or if a large-size object having a permittivity different from that of the air exists near the antenna ANT 11 , the impedance (capacitance) viewed from the antenna ANT 11  becomes different, so that the oscillating frequency changes. 
     FIG. 2 illustrates a specific oscillator circuit having a construction based on a Colpitts oscillator circuit as shown in FIG.  1 . In the circuit shown in FIG. 2, the collector of a transistor Tr 1  is connected to an antenna ANT 1  via a capacitor C 4 . The collector of the transistor Tr 1  is connected to a power supply via a capacitive tank circuit formed by a coil L 2  and a capacitor C 2  connected in parallel. The base of the transistor Tr 1  is connected to the power supply via a resistor R 1 . The base of the transistor Tr 1  is grounded via a capacitor C 5  and a coil L 1 . The base and the emitter of the transistor Tr 1  are interconnected via a capacitor C 1 . The emitter of the transistor Tr 1  is grounded via a capacitor C 3  and a resistor R 2 . 
     This circuit oscillates if the capacitors C 3 , C 5  are capacitors (pass capacitors) that are low in impedance level so as not to affect the oscillating frequency and if the tank circuit formed by the coil L 2  and the capacitor C 2  is a capacitive tank circuit. The oscillating frequency of the oscillator circuit is basically determined by the components L 1 , C 1 , L 2 , C 2 , and is affected by the value of the capacitor C 4  and the load of the antenna ANT 1 . In an ordinary oscillator circuit, the effect of the antenna ANT 1  on the oscillating frequency is curbed by reducing the capacitance of the capacitor C 4 . In this embodiment, however, the capacitance of the capacitor C 4  is increased so that the antenna ANT 1  couples to the oscillator circuit in an alternating current fashion. 
     Various kinds of objects can exist near the antenna ANTI of the above-described circuit. If an object exists near the antenna ANTI, the load on the electromagnetic waves radiated from the antenna ANT 1  changes, so that the frequency of the oscillator circuit changes. Basically, the presence of an object near the antenna ANT 1  changes the capacitance viewed from the antenna ANT 1 , so that the oscillating frequency changes. In particular, when the object moves, the oscillating frequency fluctuates. 
     FIG. 3A indicates the spectrum of the oscillating frequency in a case where no object that affects the antenna ANT 1  exists near the antenna ANT 1 , that is, where there is no particular load and no load fluctuation. As indicated, the circuit oscillates at a stable frequency f 0  that is determined based on the values of the various elements. 
     FIG. 3B indicates the spectrum of the oscillating frequency when a moving object (e.g., a human) that affects the antenna ANT 1  exists near the antenna, that is, where there is a load fluctuation. In this case, the frequency changes as indicated by a solid line, a broken line, and a one-dot chain line due to the load fluctuation. If the moving object continues moving, the oscillating frequency moves back and forth, for example, between f L , f M , and f H . As a result, the frequency fluctuates as if it is frequency-modulated. 
     FIG. 3C indicates an oscillating frequency spectrum when an object that affects the antenna ANT 1  exists near the antenna ANT 1  but the object does not move. If the oscillating frequency with no object existing near the antenna ANT 1  is f 0 , the presence of the object changes the oscillating frequency to f′. However, since the object does not move, the oscillating frequency becomes stable at f′. Therefore, if a piece of baggage or the like that affects the antenna ANT 1  is placed in the trunk compartment, the oscillating frequency does not fluctuate since baggage or the like do not move without an external force. 
     Thus, the presence of a moving object can be detected based on whether there is a fluctuation in the oscillating frequency. 
     Therefore, if the antenna ANT 1  is disposed in a trunk compartment, it becomes possible to detect a moving object within the trunk compartment. It is preferable that the determination as to whether the oscillating frequency fluctuates be conducted during a stop of the vehicle (at a vehicle speed of 0) since during running, a piece of baggage or the like may be moved. 
     As for the antenna ANT 1 , a loop antenna (magnetic field detection type), a pattern antenna formed on a printed circuit board, etc., are preferable because they allow cost reductions. 
     As indicated in FIG. 4A, a pair of electrically conductive plates  10 ,  12  are connected to an oscillator circuit  14 . In this manner, a space of interest between the conductive plates  10 ,  12  in which the detection of an object is desired can be incorporated into the oscillator circuit in the form of a large-size capacitor. If a human body or the like moves within the space, the capacitance changes, so that the oscillating frequency correspondingly changes. Therefore, by detecting a fluctuation in the oscillating frequency of the oscillator circuit  14 , a moving object can be detected. 
     As the oscillator circuit  14 , the circuit shown in FIG. 1 or  2  may be used. In that case, one of the conductive plates  10 ,  12  is used as the antenna ANT 1  or ANT 11 , and the other conductive plate is grounded. 
     As a result, an oscillating frequency is determined based on a capacitance C 0  as indicated in FIG. 4A, where no object exists in the space of interest. If a moving object (human body) exists in the space, in which the detection is desired, as indicated in FIG. 4B, the capacitance of a capacitor formed by the conductive plates  10 ,  12  and the space of detection changes. When the human body moves, the capacitance of the capacitor fluctuates, so that the oscillating frequency fluctuates. Therefore, by detecting a fluctuation in the oscillating frequency, the presence of a moving object within the space of interest can be detected. 
     In this embodiment, a fluctuation in the oscillating frequency of the oscillator circuit  14  is detected. To that end, a frequency fluctuation detecting portion  16  is connected to the oscillator circuit  14  as shown in FIG. 5, and it is detected by the frequency fluctuation detecting portion  16  whether there is a fluctuation in the oscillating frequency of the oscillator circuit  14 . The result of detection is supplied to a determining portion  18  that determines whether there is a moving object based on whether there is a frequency fluctuation. 
     In FIG. 5, an antenna  20  is connected to the oscillator circuit  14 . The antenna  20  corresponds to the antenna ANT 11  in FIG. 1, the antenna ANT 1  in FIG. 2, and the conductive plates  10 ,  12  in FIG.  4 . 
     Furthermore, the frequency fluctuation detecting portion  16  is preferably formed by a frequency-voltage converting circuit. A preferable frequency-voltage converting circuit is, for example, a quadrature detector circuit shown in FIG.  6 . 
     The frequency fluctuation detecting portion  16  shown in FIG. 6 is equipped with the oscillator circuit  14 . The oscillator circuit  14  is connected to a multiplier  30  via a capacitor C 21  for cutting direct currents. The multiplier  30  is also supplied with an output from the capacitor C 21  via a π/2-phase shifter  32 . Therefore, the multiplier  30  multiplies two outputs from the oscillator circuit  14  that are shifted π/2 in phase from each other. 
     The π/2-phase shifter  32  has a capacitor  22 , a resistor R 21 , a capacitor C 23 , and a coil L 21 . The capacitor  22  is connected at one end thereof to a connecting portion between the capacitor C 21  and one input end of the multiplier  30 . The other end of the capacitor  22  is connected to another input end of the multiplier  30 . Another end side of the multiplier  30  is connected to the resistor R 21 , the capacitor C 23 , and the coil L 2 . The end side of the multiplier  30  is grounded via the resistor R 21 . 
     The output of the multiplier  30  is connected to a voltmeter  36  via a low-pass filter (LPF)  34 . As the output of the voltmeter  36 , voltage that increases with decreases in the oscillating frequency of the oscillator circuit  14  as indicated in FIG. 7 is provided. Therefore, by detecting a fluctuation in the value of output voltage of the voltmeter, the presence of a moving object can be detected. As indicated by a broken line in FIG. 7, if the resistance of the resistor R 21  is reduced, a relatively flat conversion characteristic is obtained although the sensitivity to fluctuations in the frequency decreases (Q decreases). Therefore, it is preferable to achieve an appropriate characteristic by adjusting the resistor R 21 . 
     Thus, the circuit shown in FIG. 6 is able to detect a change in the oscillating frequency of the oscillator circuit  14  while employing a simple circuit construction. Therefore, the cost of the entire circuit can be reduced. 
     If a phase-locked loop (PLL) circuit is used as a frequency-voltage converting circuit, a frequency change can be detected with a higher precision. 
     In the above-described embodiment, the frequency fluctuation detecting portion  16  is directly connected to the oscillator circuit  14  as shown in FIG. 5, and the output of the oscillator circuit  14  is directly supplied to the frequency fluctuation detecting portion  16 . However, it is also preferable that electromagnetic waves radiated from the antenna  20  be received, and a fluctuation in the frequency of the received electromagnetic waves be detected for the aforementioned determination. 
     That is, as shown in FIG. 8, an antenna  40  for receiving electromagnetic waves transmitted from the antenna  20  is provided apart from the antenna  20 . For example, the antenna  20  is provided in a trunk compartment of a vehicle, and the antenna  40  is provided in the passenger compartment. The antenna  40  is connected to a receiver  42 , in which the reception processing of the electromagnetic waves received by the antenna  40  is performed. The receiver  42  is connected to a control portion  44 . The control portion  44  detects a fluctuation in the frequency of the received signal, and determines whether there is a moving object. 
     This construction makes it possible to share the antenna  40 , the receiver  42 , and the control portion  44  with an apparatus that performs a different function. For example, in a smart entry system, a communication is conducted between a portable device carried by a driver and a vehicle-side device. When the vehicle-side device recognizes that the present communication is a communication with a pre-registered portable device, the system performs a control such as cancellation of an immobilizer or the like. If such a system is installed in a vehicle, a device for the above-described communication is disposed in the passenger compartment (e.g., near a front panel). This device may be used as a combination of the antenna  40 , the receiver  42  and the control portion  44  shown in FIG.  8 . 
     In the above-described apparatus, the control portion  44  sends a control signal to the oscillator circuit  14 , and controls the operation of the oscillator circuit  14 . That is, the control portion  44  controls the timing of oscillation of the oscillator circuit  14 , and performs the reception processing synchronously with the oscillation timing. Therefore, the control portion  44  is able to recognize that the received electromagnetic waves are transmitted from the antenna  20 , so that stable processing can be performed. 
     For example, as indicated in FIG. 9, the receiver  42  is periodically turned on for a predetermined time, and during the on-period, electromagnetic waves are transmitted from the antenna  20 . The control portion  44  performs a process of detecting a frequency fluctuation only during the period when the electromagnetic waves are transmitted from the antenna  20 . If any electromagnetic wave is received outside the period, the control portion  44  invalidates the received electromagnetic wave. For example, if the control portion  44  turns on and receives electromagnetic waves when the antenna  20  is not transmitting electromagnetic waves, the control portion  44  determines that the received electromagnetic waves are from an unauthorized oscillation source, and invalidates the electromagnetic waves. 
     Thus, if an oscillation from the antenna  20  is performed synchronously with the frequency fluctuation detecting process, reception of an inauthentic oscillation can be recognized and invalidated. Therefore, even if an inauthentic oscillation is similar in frequency and frequency fluctuation to a signal of detection of a movement of a human body, the inauthentic oscillation can be invalidated. 
     As indicated above, it is preferable that the electromagnetic waves used for the communications in the passenger compartment by the smart entry system and the electromagnetic waves used for transmission from the antenna  20  be in the same frequency band (e.g., a 300-MHz band). If the apparatus of the embodiment and the smart entry system share the aforementioned device, it is advisable to perform the detection of a movement of a human body at a timing when the communication of the smart entry system is not performed (time sharing). 
     The occasion of confinement in the trunk compartment or the like is predictable to some extent. Therefore, the rate of performing the detection of a moving object may be increased, for example, immediately after the trunk lid is closed. It is also possible to combine the above-described detection means with other detection means, for example, a microphone or the like, and to perform the detection of a moving object when an abnormal noise is detected. 
     Furthermore, it is preferable to superimpose a code on the oscillating frequency in the oscillator circuit  14 . For example, if vehicles equipped with similar systems exist adjacent to each other, it may be conceivable based on the nature of electromagnetic waves that electromagnetic waves from the adjacent vehicle are received. Owing to the aforementioned synchronization within each system, the probability of coincidence in timing between two systems is considered to be low. However, there is a possibility of such timing coincidence. If such coincidence occurs, normal detection cannot be performed. 
     Therefore, a serial number specific to each vehicle is superimposed as a code on the electromagnetic waves to be transmitted from the antenna  20 . As a result, the electromagnetic waves transmitted from the oscillator circuit  14  are modulated with the code. Thus, since the signal from the oscillator circuit  14  is modulated with the code (the serial number of the vehicle in which the detecting apparatus is installed), it becomes possible to determine whether a received signal is a signal transmitted within the vehicle in which the detecting apparatus is installed. 
     With this construction, the detecting apparatus can extract only the information regarding itself, so that it becomes unnecessary to synchronize the transmission of electromagnetic waves from the oscillator circuit  14 . For example, as indicated in FIG. 10, the receiver  42  is activated for reception every 200 msec, and the oscillator circuit  14  is activated every 60 seconds to transmit electromagnetic waves for about 400 msec. Thus, although the transmission and the reception are asynchronous, the receiver  42  is able to receive electromagnetic waves from the oscillator circuit  14  without fail. Since the electromagnetic waves from the oscillator circuit  14  are coded, the electromagnetic waves are not affected by interference with other electromagnetic waves, so that highly reliable detection can be performed. 
     If the oscillator circuit transmits coded electromagnetic waves, it is preferable that the bit rate of the code be different from the frequency changes caused by moving objects such as a human body and the like. 
     That is, if a frequency fluctuation caused by an object moving near the oscillator circuit  14  is similar to the change in the frequency of the oscillator circuit  14  caused by modulation with the code, the reception of the frequency fluctuation is substantially no different from the reception of electromagnetic waves modulated with a different code. Thus, the detection becomes impossible. 
     Therefore, it is preferable that the bit rate of the code be sufficiently greater than the frequency of frequency fluctuations caused by movements of a human body, as exemplified in FIG.  11 A. As a result, frequency fluctuations caused by movements of a human body can be obtained after the code is removed. Since the movements of a human body include considerably low-speed movements, it is preferable that the bit rate of the code be sufficiently increased so as to differ from the frequency fluctuations caused by movements of a human body. 
     In this case, as shown in FIG. 11B, after detection (frequency-voltage conversion (f-V conversion)) is performed in a detector circuit  50  within the receiver  42 , a signal of the detection is supplied to both a low-pass filter  52  and a high-pass filter (or band-pass filter)  54 . Thus, the low-pass filter  52  provides a low-frequency signal, and the high-pass filter  54  provides a high-frequency signal. The outputs from the low-pass filter  52  and the high-pass filter  54  are supplied to comparators  56 ,  58 , respectively, and are thereby binarized. Therefore, two kinds of modulation signals of different frequencies, that is, the code and movements of a human body, can be separated. Thus, the sets of information regarding the code and movements of a human body can be correctly recognized. 
     Although the code is simply superimposed on the electromagnetic waves from the oscillator circuit  14  in the above description, it is also possible to generate a PN code based on the aforementioned code, and to perform spectrum diffusion using the PN code. Therefore, if reverse diffusion is performed at the receiver  42 , electromagnetic waves regarding the vehicle in which the detecting apparatus is installed can be obtained. 
     Furthermore, the foregoing embodiment employs an LC oscillator circuit as shown in FIG. 2, as the oscillator circuit  14 . However, the oscillator circuit  14  may be a different type of circuit. For example, various resonating elements may be used in the oscillator circuit, so that the precision of the oscillating frequency can be improved. 
     As the resonating elements, it is conceivable to use a ceramic oscillator, a quartz oscillator, a SAW resonator, a dielectric resonator, a pattern on a printed circuit board, etc. In general, as the resonator value Q is increased, the frequency stability increases and the frequency fluctuation width decreases. However, the frequency fluctuation width with respect to load fluctuation can be adjusted by decreasing the value Q through the use of a resistor, adding an extension coil, etc. 
     FIG. 12 exemplifies an oscillator circuit employing a SAW resonator. A SAW resonator  60  is connected to the base of a transistor Tr 1  via a coil L 31 . The collector of the transistor Tr 1  is connected to a power supply via a coil L 32 . The base of the transistor Tr 1  is connected to the power supply via a resistor R 31 , and is connected to a ground via a resistor R 32 . The base and the emitter of the transistor Tr 1  are interconnected via a capacitor C 1 . The emitter of the transistor Tr 1  is grounded via a capacitor C 3  and a resistor R 2 . An antenna ANT 1  is connected to the collector of the transistor Tr 1  via a capacitor C 4 . The other end of the SAW resonator  60  is grounded via a capacitor C 31 . 
     In this circuit, the oscillating frequency is substantially determined by the value of the SAW resonator  60 . Since the precision of the oscillating frequency of the SAW resonator  60  is far better than that of the LC arrangement, this circuit greatly facilitates the adjustment of the oscillating frequency and the like, and is able to make an adjustment-free circuit. 
     The above-described moving object detecting apparatus is suitably applicable to a trunk emergency cancellation system. For example, it is preferable to dispose an oscillator circuit and an antenna in a lower central portion of a trunk compartment as shown in FIG.  13 . The oscillator circuit and the antenna may be disposed at any location. However, it is preferable to dispose the oscillator circuit and the antenna at lower central locations in the trunk where external influences are less, for the following two reasons: (i) substantially consistent detection over the entire trunk space is possible; (ii) malfunction due to an external influence is unlikely. 
     Upon recognizing the presence of a moving object in the trunk based on fluctuations in the oscillating frequency during a stop of the vehicle, the system opens the trunk regardless of the use of a key or, instead of opening the trunk, produces an alarm to indicate the possibility of confinement in the trunk to a person outside. 
     Therefore, should a child or the like enter a trunk and be confined therein, the confinement can be easily detected. If a piece of baggage is placed in the trunk and, due to the effect of the load on the oscillator circuit, the frequency changes, the frequency change is a mere deviation from one frequency to another, and can be distinguished from frequency fluctuations in response to movements of a moving object. 
     If a detector using an infrared beam or the like is employed, the system becomes inoperable when a piece of baggage or the like covers the light-emitting portion or the light-receiving portion. However, electromagnetic waves propagate around such a blocking object, and therefore allow detection even in such a situation. 
     As the opening of the trunk, it is also preferable to open the trunk in a manner different from the normal manner of opening the trunk, that is, open (half-open) the trunk to a limited extent of, for example, about 10 cm, as shown in FIG.  14 . 
     Confinement in a trunk can happen in various situations, for example, a situation where a child mischievously enters the trunk and is confined, a situation where a pet enters the trunk when it is open, and a person closes the trunk lid without knowing that the pet is inside the trunk, etc. If the trunk lid remains completely closed in such a situation, the temperature in the trunk may become high under a hot sun, or sound or voice passage may be impeded. If the trunk lid is fully open upon detection of a moving object in the trunk, there may arise problems of easiness to steal from the trunk, rain falling into the trunk when raining, etc. 
     These problems can be resolved by opening the trunk to about 10 cm through operation of the trunk emergency cancellation system. 
     The system requires an authorized key in order to normally open the trunk. This construction makes a system that is capable of performing required operations at the time of an emergency and is immune to theft or the like. 
     Furthermore, it is preferable that the trunk emergency cancellation system operate in different manners depending on the state of the vehicle. That is, when the vehicle is at a stop or the engine is off, the system performs a control of opening the trunk based on the detection. During running of the vehicle, during which it is considered that a driver is in the vehicle, the system notifies the driver of the detection in the manner of alarm or information. It is dangerous to open the trunk upon detection of confinement during running of the vehicle. Furthermore, it is conceivable that a piece of baggage or the like may move in the trunk due to accelerations of the vehicle or the like. Therefore, it is preferable that the system outputs information regarding the detection but does not open the trunk during driving. If the driver suspects or determines that there is a confinement based on the information, the person can stop the vehicle at a safe location, and can check the trunk. 
     As is apparent from the foregoing description, the invention is able to detect a moving object by using electromagnetic waves. Therefore, it becomes possible to detect confinement of a human, a pet or the like in a trunk, and to perform operations, such as producing an alarm, opening the trunk, etc. 
     It should be understood that the circuits shown in FIGS. 1,  2 ,  4 - 6 ,  8 ,  11   b  and  12  can be implemented as portions of a suitable programmed general purpose computer. Alternatively, each of the circuits shown in FIGS. 1,  2 ,  4 - 6 ,  8 ,  11   b  and  12  can be implemented as physically distinct hardware circuits within an ASIC, or using a FPGA, a PDL a PLA or a PAL, or using discrete logic elements or discrete circuit elements. In general, any device on which resides a finite state machine capable of implementing the figures shown may be used to implement the processor functions of this invention. The particular form each of the circuits shown in FIGS. 1,  2 ,  4 - 6 ,  8 ,  11   b  and  12  will take is a design choice and will be obvious and predictable to those skilled in the art. 
     While the invention has been described with reference to specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, the preferred embodiments of the invention as set forth herein are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the invention.