DE8912983U1 - Arrangement for room monitoring - Google Patents

Description

.:. .:38·&bgr;.·&idiagr;7^&ogr; de &ogr;&igr; Siemens Aktiengesellschaft

Arrangement for room monitoring 5

The invention relates to a further development of the arrangement for room monitoring defined in the preamble of claim 1, which - at least for ultrasound - in principle already provides

- DE-C2-29 38 969

Such room surveillance is generally used to trigger an alarm of any kind in the event of a break-in, e.g. activating a siren and/or other devices such as hidden cameras.

The invention was initially developed for monitoring the interior of vehicles, preferably with ultrasonic pulses without using the Doppler effect, for which it is particularly well suited. However, it turned out that the invention also suitable for monitoring with light pulses, e.g. infrared pulses, both with and without using the Doppler effect. It also turned out that the invention is even suitable for monitoring any other interior and exterior spaces, not just for vehicle interiors, So overall it is quite versatile.

The concrete structure of the known arrangement, and also its operation, are - despite the achieved sensitivity and despite the achieved security against false alarms - already relatively low effort. A generally relatively large memory is used to store a large number of received actual profiles. By means of an appropriate evaluation using a microprocessor, irrelevant, especially periodic, data from the stored actual profiles can be reliably removed. see, echo changes are automatically recognized as such, as long as such echo changes are typical for a rotating fan or for the swinging of clock pendulums, but completely untypical for a break in the over-

01 Q)J

\.*2:.. ,:. .:J&8'G.'i7ßO de &ogr;&igr; awake room. The echo changes recognized as "harmless", i.e. corresponding changes in the room and the air no longer trigger a false alarm. The known arrangement therefore works according to an adaptive process because it automatically adapts to changes in the room and the air that are recognized as "harmless". False alarms were therefore prevented with a relatively high level of hardware and software effort.

The object of the invention, namely

- to offer a particularly simple solution in terms of structure and operation,

in an adaptive manner, namely by constantly automatically adapting the stored target profile, to avoid false alarms, especially those false alarms that caused by those echo changes which arise from air streaks and air temperature changes and are therefore atypical for a break-in, namely to be able to avoid such false alarms despite the comparatively very simple structure of the invention, and

- nevertheless being able to quickly and with a high degree of sensitivity immediately detect the echo changes typical of a break-in with a high degree of probability, is achieved by the arrangement defined in claim 1.

The additional measures mentioned in the subclaims allow additional advantages to be achieved. Among other things, the measures according to the protection claim allow

2, to detect even slow echo changes caused by very slow movements of an intruder. even if air streaks (body heat and warm exhaled air from the burglar!) already caused echo changes,

3, to make the sensitivity of the arrangement particularly high for detecting echo changes typical of burglars, and still not triggering a false alarm when only weak air movements (sluggish air streaks) occur,

4, to adjust the sensitivity of the arrangement so that no false alarm is triggered in the event of strong, uneven air movements,

01 02

·..?.:.. .:. .:s8'G.'i7tfo de &ogr;&igr; 5, the sensitivity of the arrangement from case to case to the

needs, and
6, a particularly elegant, simple and space-saving solution to

offer.
5

The invention and its further developments are explained further using the examples shown in the figures, which can be any acoustic or optical arrangements for monitoring any interior or exterior space, with or without the use of the double effect. Figures

1 an example of a flow chart for the operation of a microprocessor, which calculates intermediate values, each of which lies in the middle between the previously stored target individual values and the actual individual values, as well as

2a, 2b, 2c a sequence of consecutively stored target echo profiles, which are continuously changed due to air streaks, and

2a ¹ , 2b ¹ , 2c ¹ consecutively received IST echo profiles. 20

The invention therefore relates to an arrangement for space monitoring which operates according to a radar-like pulse-echo method, with or without using the Doppler effect. Ultrasound pulses or infrared light pulses can be used as pulses, for example, because it has been shown that both acoustic and optical pulses are influenced by air streaks if the actual profiles are measured with sufficient accuracy, the target profiles are stored with sufficient accuracy and the actual profile measured in each case is compared with the target profile with sufficient accuracy. As is usual with radar-like devices, the invention contains a receiver in addition to the transmitter, which receives actual profiles of echoes in the pause between the transmission of two switching pulses. These ACTUAL profiles each represent a temporal sequence of instantaneous analog ACTUAL individual signals of the echo, whereby this sequence triggers a sequence of corresponding signals in the receiver, which in turn - depending on whether a more analog or more digital method is used - represent analog or digital ACTUAL individual values that can be expressed in numbers.

01 03

'..&Aacgr;:.. .:.88i.G 1.160..BE Ol A memory is installed in the receiver, e.g. a RAM, which in turn digitally stores a target profile of the echo in the form of a sequence of target individual values. An analog or digital comparator circuit compares the target individual values of the target profile stored in the memory with the actual individual values of the actual profile just received, whereby this comparator circuit only triggers an alarm if the difference between at least one of the target individual values and the corresponding actual individual value of the profile exceeds a threshold value, i.e. a tolerance.

The calculation circuit causes the adaptive behavior of the invention. This series circuit calculates, at least as long as no alarm condition is triggered, a new target profile with Using the last received ACTUAL profile. The new DESIRED profile is formed from intermediate values, which in turn lie between the previously stored DESIRED individual values and the corresponding, last received ACTUAL individual values. In the invention, the immediately most recently received stored target profile is updated in an adaptive manner immediately after receiving a new actual profile, at least as long as no alarm condition is triggered. Because the invention only stores the one, updated target profile and possibly temporarily - namely until the calculation of the relevant new target input individual values of the new DESIRED profile - must store the last received ACTUAL profile in whole or in part, the memory requirement of the invention is particularly small and the comparator circuit and the computing circuit can perform their respective functions quickly and easily, via This despite the particularly small hardware and software expenditure.

As already mentioned, the invention is particularly suitable for automatically eliminating the disruptive influence of air streaks, so that no more false alarms are triggered by air streaks. This is important for the operational safety of acoustic and optical echo methods, especially ultrasonic echo methods.

01 04

bE oi safety of the arrangement, very important for practice. Such air streaks are caused in particular by temperature differences in the room to be monitored, often not only by solar radiation, but also by electrical devices such as Radios and the like, which give off waste heat. Even in a vehicle that has just been parked, some parts of the walls of the vehicle interior near the engine and exhaust are still very hot for a relatively long time; these heated parts of the walls cause air streaks over long periods of time, which often flow irregularly and therefore cause echo changes (often even very non-periodic). Nevertheless, even the interior of such a vehicle that has just been parked should be monitored with high sensitivity for break-ins.

[ 15 According to the invention, highly sensitive monitoring is even possible automatically in an adaptive and simple way by constantly updating the target profile stored in the memory immediately using the updated with the latest received ACTUAL profile. This avoids the threshold value - i.e. the maximum permissible difference between the ACTUAL individual values and the DESIRED individual values at which no alarm condition is triggered - having to be made extremely large to avoid false alarms, which would severely impair the sensitivity of the system, i.e. its ability to quickly detect a break-in.

The invention allows the sensitivity of the arrangement to be made very high and yet a relatively modest amount of hardware and software is used. Because air streaks only slowly spread or change, and because the pulse sequence emitted by the transmitter, e.g. the ultrasound transmitter, usually has a high pulse frequency in comparison to the slowness of the air streak change, the change from the previous ACTUAL echo profile to the following ACTUAL echo profile is only small (as long as no break occurs that causes a rapid change in at least one of the ACTUAL individual signals of the ACTUAL echo profile), - even if eventually in the course of longer

01 05

'..&dgr;.:.. ,188!G &Pgr;6&Oacgr; .DE Ol time, the changes in the ACTUAL echoes add up to considerable values. In the invention, the DESIRED profile stored in the memory follows the respective ACTUAL profile so quickly that the threshold value, i.e. the permissible maximum difference between the individual values compared by the comparator circuit, can be made particularly small, despite the relatively small hardware and software expenditure involved in the invention.

When the arrangement is started, e.g. immediately after the vehicle is parked and the inventive burglar alarm system is switched on, a first ACTUAL profile is received by sending at least one single pulse, e.g. an ultrasonic pulse, which can be immediately stored in the memory as a DESIRED profile, whereby the arrangement can be automatically switched on when the vehicle is parked, e.g. when the vehicle doors are closed using the central locking system.

In principle, however, it is also possible to install a delay element in the arrangement in such a way that initially several pulses sent out, several ACTUAL profiles received - and even first several DESIRED profiles are determined one after the other before the arrangement is enabled to trigger an alarm state. Compare this with the upper, first loop in the flow chart according to Figure 1, which shows such an initial operation of the arrangement , whereby only after this first loop has been run through several times (only) the subsequent lower loops of the flow chart are run through regularly as continuous operation.

In continuous operation, after a transmission pulse is sent, the ACTUAL echo, broken down into a sequence of digital words, is read into the comparator circuit and compared with the corresponding TARGET individual values of the TARGET profile/TARGET curve stored in the memory. This comparison triggers either an alarm condition if at least one of the ACTUAL individual values deviates significantly from the corresponding TARGET individual value (the relevant threshold value can be

01 06

'..'7·:.. /..88!.G 1.7.60.ÖE 01 may be specified) - or this comparison causes the "old", previously stored TARGET individual value, e.g.3. according to the example shown in Figure 1, to be simply added to the "new", corresponding ACTUAL individual value just received, whereby according to this example, half of this sum then results in the new TARGET individual value to be stored in the memory. Then the next ACTUAL individual value is compared with the next TARGET individual value, which is symbolized in Figure 1 by the flow diagram stage "n+1". As soon as the entire echo profile of the room to be monitored has been sufficiently compared and all new TARGET individual values of the new TARGET profile to be stored have been calculated, a new pulse is sent out, which is symbolized in Figure 1 by "n=1".

The diagrams shown in Figures 2a to 2c ¹ illustrate the gradual change in the TARGET echo profile when only air streaks and no intruder affect the ACTUAL profile. These figures show TARGET and ACTUAL echo profiles, where the abscissa corresponds to the time between two transmission pulses and the ordinate to the analog value of the strength of the echo. Depending on the measurement method selected, the "strength" of the echo corresponds to the amplitude of the individual echo values and/or - when using the Doppler effect - the frequency change or the phase change of the individual echo values. - For the sake of simplicity, it was assumed here that echo segments that are irrelevant or disruptive to the reliability of the arrangement were only masked out at the beginning and end of the echoes; in principle, however, time segments within the profiles shown could also be masked out, e.g. time segments that correspond to a (sometimes rotating) fan.

At time t0, for example, the DESIRED echo profile shown in Figure 2a is stored in memory. Then, i.e. at time t0 + ^t, the ACTUAL echo profile shown in Figure 2a ¹ is received, whereupon the computer calculates the DESIRED echo profile shown in Figure 2b, namely as intermediate values between the DESIRED echo profile according to Figure 2a and the ACTUAL echo profile according to Figure 2a ¹ .

01 07

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Subsequently, namely at time t0 + 2 £t, the ACTUAL echo profile shown in Figure 2b ¹ is received, in which the first echo maximum has increased and the second echo maximum has decreased. At the same time, the microprocessor calculates a new DESIRED echo profile according to Figure 2c as the mean value between the individual values of the DESIRED echo profile according to Figure 2b and the ACTUAL echo profile according to Figure 2b ¹ .

If an echo profile is recorded after this, i.e. at time to + 3 ^t,

If a signal as shown in Figure 2c ¹ is received, in which the first echo maximum has increased even further and the second echo maximum has decreased even further, a new target echo profile would be formed in a corresponding manner by forming intermediate values between the profiles according to Figures 2c and 2c ¹ , which is then stored.

It has already been emphasized that in the example shown in Figure 1, the intermediate values newly calculated by the Rschenschaltung are exactly in the middle between the previously stored target values and the corresponding ACTUAL individual values. This is often sufficient to detect a break-in: In this case, relatively slow echo changes caused by the burglar's slow movements generally trigger an alarm. Above all, the burglar, e.g. due to his body heat and because of the warm air exhaled by him, air streaks or even relatively strong air eddies are formed, which in themselves cause more or less significant echo changes - at least with regard to individual ACTUAL individual values - so that the arrangement according to the invention at the latest with the smallest additional The burglar’s physical movements quickly trigger an alarm.

But breaking windows and similar abrupt burglary actions also trigger abrupt echo changes - at least with regard to individual values - which generally trigger an alarm sufficiently reliably with such intermediate value formations.

The sensitivity of the arrangement according to the invention can be

01 08

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',JBB'C'nSO DE Ol in particular by giving different weightings to the target and actual profiles when calculating the new target profile to be saved:

If you want to make the system even more sensitive, so that even faster movements of air streaks, especially for example, the breath of a burglar, even if the burglar is otherwise calm, trigger an alarm, then you can increase the sensitivity of the invented n accordance with the invention, the intermediate values determined by the calculation circuit are closer to the previously stored TARGET individual values than to the newly received ACTUAL individual values. For example, see in Figure 1 the program step "results in new target value", the Multiply the previously stored TARGET individual value "old" by a relatively large importance factor, e.g. by two or five, and add to it the corresponding ACTUAL individual value "new", and then divide this sum by a corresponding value, e.g. by three or six, in order to to calculate an intermediate value that is closer to the previously stored target individual value "old" than to the corresponding actual individual value "new". The sensitivity of the arrangement according to the invention can be increased by intermediate values calculated in this way, i.e. by weighting the actual and TARGET individual values can even be increased so much that only very weak air movements do not trigger an alarm, but slightly stronger air movements do trigger an alarm - depending on the extent to which the intermediate value is closer to the previously stored TARGET individual value than to the newly received ACTUAL individual worth it.

If necessary, the sensitivity of the arrangement according to the invention can also be reduced by different weighting, namely so that even with strong, uneven air movements no (false) alarm is triggered, e.g. in order to be able to classify the air flow from fans, possibly also the uneven swinging of plant leaves in moving air, as a "harmless" cause of echo changes - even if

01 09

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JK 1 possibly at the expense of the reliability with which a previous

t A slow-moving burglar can still be recognized

The calculation circuit can also be replaced by other weighting of the ACTUAL and TARGET individual values such intermediate

t; 5 values can be calculated, each of which is closer to the actual individual

'0 values than the previously stored target individual values

For this purpose, one can, for example, use the program step "results

f new setpoint", see Figure 1, the ACTUAL individual value "new" with

'k a relatively high importance factor, e.g. two or five,

Multiply £ 10, plus the previously stored corresponding

&iacgr; Add the target individual value "old", then divide this sum by the

&idiagr; corresponding value, e.g. then by three or six,

■ divide to form the intermediate value.

t 15 The sensitivity of the arrangement according to the invention can therefore be adjusted within very wide limits, and with very little effort. Above all, the sensitivity can be increased to such an extent that only weak air streaks that spread very slowly do not trigger an alarm.

The invention also allows the sensitivity to be changed from case to case. For example, the sensitivity can be set relatively low for a certain period of time - namely by setting a corresponding intermediate value. calculation - and for a further, different period of time a very high sensitivity - also by means of appropriate intermediate value calculation. In this way, it is possible, for example, to monitor a room to be monitored as long as it is heated and illuminated by (heat-emitting) light bulbs with a relatively small sensitivity; however, as soon as this room is no longer heated and no longer lit, it can be monitored with high sensitivity. For example, a switch can be attached to the arrangement which influences the programming of the microprocessor in such a way that the intermediate value in the one switch position is calculated differently than in the other

Switch position. For example, the intermediate value in one switch position will be more or less close to, or exactly in the middle between, the ACTUAL and DESIRED individual values, but in the other switch position it will be relatively close to the respective

01 10

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·88*&'17£0 DE Ol DESIRED individual value or relatively close to the respective ACTUAL individual value. Depending on the set sensitivity of the arrangement, the DESIRED profile can therefore change adaptively quickly or only slowly.
5

Instead of such a switch, or in addition to such a switch, you can also choose an adaptive automatic switching of the computing unit to change the sensitivity of the arrangement: You can store the maximum difference of individual values between the DESIRED profile and the ACTUAL profile in the above-mentioned memory, or in an additional other memory, for a longer period of time, e.g. for the duration of 100 received echoes, in the form of a protocol. If the stored sequence of measured maximum differences shows that at least the last stored maximum differences are far below the threshold value that triggers an alarm, then you can increase the sensitivity of the arrangement automatically by having the computing circuit then form intermediate values in the future that are closer to the DESIRED profile than before. Conversely, if the last stored measured maximum differences between individual values of the target profile and the actual profile approach that threshold value very strongly, but only very slowly, the computing unit can calculate intermediate values in the future that approach the actual profile more closely than before. Through the adaptive change in the sensitivity of the arrangement according to the invention described above using protocols that record the consequences of the measured maximum differences of individual values between the target profile and the actual profile (with particularly low memory requirements!) and allow automatic adaptive weighting of the target and actual profiles, the sensitivity of the arrangement can be automatically and adaptively adjusted, namely by adaptively adjusting the importance factor, to always be just large enough so that air streaks that have arisen naturally no longer trigger a false alarm and that changes in the situation caused by a break-in are quickly and with particularly high reliability. - Of course, you can also set the threshold value for yourself - in addition to the adaptive change in weighting or on its own, exclusively for

01 11

V 12- .:.8g.G 1.7.60.J3E - change; however, one often does not make sufficient use of the opportunity offered by the inventive ongoing adaptive slow change of the target profile.

A particularly elegant, simple and space-saving solution for the arrangement according to the invention is achieved by additionally installing an analog-digital converter in it, by means of which the received analog ACTUAL individual signals are converted into digital ACTUAL individual values, whereby the comparator circuit and the arithmetic circuit are implemented by an appropriately programmed microprocessor, which in turn compares or calculates the individual values that then form digital words.

01

Claims (1)

'..'IS.. .:.8S.G L760..DE Ol Protection claims 1. Arrangement for room monitoring, which works according to a radar-like pulse-echo method, e.g. with ultrasonic pulses or infrared light pulses, contains a receiver that receives an actual profile of echoes in the pause between the transmission of two pulses, e.g. sound pulses, which represents the temporal sequence of instantaneous actual individual signals of the echo and in the Receiver triggers a sequence of corresponding signals, which in turn correspond to analog or digital actual values, in the receiver contains a memory - e.g. a RAM - which digitally stores a target profile of the echo in the form of a sequence - stores a sequence of individual target values, - contains a calculation circuit that calculates the target profile using one or more of the - preferably most recently - received actual profiles, as well as an analog or digital comparator circuit which compares the stored target individual values of the target profile with the actual individual values of the actual profile and only triggers an alarm state if there is a significant difference between at least one of the target individual values and the corresponding actual individual value, e.g. arrangement for monitoring the interior of a motor vehicle, characterized in that the calculation circuit - at least as long as no alarm condition is triggered - calculates a new target profile, which in turn only consists of intermediate values between the last stored TARGET profile and the newly received ACTUAL profile, whereby the intermediate values lie between the previously stored TARGET individual values of the TARGET profile and the corresponding ACTUAL individual values of the ACTUAL profile. 2. Arrangement according to claim 1,
characterized in that 03 01 l<f .^8iG &Idigr;76&Oacgr; DE Ol /|; - the intermediate values are in the middle between the previously stored target individual values and the actual individual values. 3. Arrangement according to claim 1, characterized in that the intermediate values are each closer to the previously stored TARGET individual values than to the ACTUAL individual values. ix. Arrangement according to claim 1, characterized in that the intermediate values are closer to the ACTUAL individual values than to the previously stored TARGET individual values. 5. Arrangement according to one or more of the protection claims 2 to 4, characterized in that the calculation circuit can be switched so that, depending on requirements, it calculates intermediate values that lie to varying degrees between the TARGET individual values and the ACTUAL individual values. 6. Arrangement according to one of the preceding protection claims, characterized in that - it contains an analog-digital converter which converts the received analog ACTUAL individual signals into ACTUAL individual values, which each form digital words, and the comparator circuit and the arithmetic circuit are implemented by an appropriately programmed microprocessor, which compares or calculates the individual values forming the digital words. 03 02