U.S. patent number 4,775,853 [Application Number 06/813,964] was granted by the patent office on 1988-10-04 for device and installation for the instantaneous detection of one or more physical phenomena having a character of risk.
This patent grant is currently assigned to Compagnie Francaise de Protection Electrique Proteg (C.F.P.E. Proteg). Invention is credited to Hector Perez Borruat.
United States Patent |
4,775,853 |
Perez Borruat |
October 4, 1988 |
Device and installation for the instantaneous detection of one or
more physical phenomena having a character of risk
Abstract
A device and installation are provided for the instantaneous and
simultaneous detection, inside and outside, of radiations emitted
in the infrared, visible and ultraviolet spectra by simultaneous
physical phenomena having a character of risk, such as intrusion,
fire, explosion, leaks of dangerous fluids and electric leaks,
disturbances and absence of movement of a regular periodic
phemonenon, said radiations being emitted, directly by the
phenmonena to be monitored at the time when the risk appears or
being caused artifically by directing over an appropriate field of
view, in which take place said phemonena, a source of radiation
comprised in the infrared, visible and ultraviolet, and adapted to
the nature of the phemonena involved, said field of view covered by
the detection device having appropriate horizontal and vertical
dimensions comprising at least one spectral correction filter known
pass band chosen as a function of the nature of the radiation, a
linear or circular polarization filter, a microprism array, and an
image booster. An installation utilizing at least one detection
device is disclosed, where the detection device cooperates with at
least one video data processing unit, at least one video monitor,
each associated to a detection device, a time delay unit, a cyclic
switch, a video tape recorder and a television telephone
transmitter.
Inventors: |
Perez Borruat; Hector (Clichy,
FR) |
Assignee: |
Compagnie Francaise de Protection
Electrique Proteg (C.F.P.E. Proteg) (Saint-Quen,
FR)
|
Family
ID: |
9311011 |
Appl.
No.: |
06/813,964 |
Filed: |
December 27, 1985 |
Foreign Application Priority Data
|
|
|
|
|
Dec 27, 1984 [FR] |
|
|
84 19872 |
|
Current U.S.
Class: |
340/521; 250/226;
250/482.1; 250/504R; 340/565; 348/155; 250/339.05; 348/164 |
Current CPC
Class: |
G08B
13/196 (20130101); G08B 19/00 (20130101); G08B
17/125 (20130101) |
Current International
Class: |
G08B
13/196 (20060101); G08B 13/194 (20060101); G08B
19/00 (20060101); G08B 019/00 (); H04N
007/18 () |
Field of
Search: |
;340/521,506,522,541,565,567,691 ;358/105,108,160,109,113,110
;356/432,434,435
;250/336.1,338,339,341,349,356.1,363R,363S,472.1,482.1,504 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Funkschau, No. 11, Mai 1982, pp. 53-56, Munich, DE; G. Wilhelm et
al.: "Vochnik in Sicherheitsanlagen", pp. 53, 54..
|
Primary Examiner: Crosland; Donnie L.
Attorney, Agent or Firm: Oblon, Fisher, Spivak, McClelland
& Maier
Claims
What is claimed is:
1. A device for the instantaneous and simultaneous detection,
inside and outside of radiations emitted in the infrared, visible
and ultraviolet spectra by simultaneous physical phenomena having a
character of risk, such as intrusion, fire, explosion, leaks of
dangerous fluids and electric leaks, disturbance and absence of
movement of a regular periodic phenomenon, said radiations being
emitted directly by said physical phenomena at the time when said
risk appears or being caused artificially by directing over an
appropriate field of view, in which said phenomena take place, a
source of radiation comprised in the infrared, visible and
ultraviolet spectra and adapted for response to the phenomena
involved, the field of view covered by the detection device having
horizontal and vertical dimensions, wherein said detection device
is formed by a television camera disposed at a distance from said
field and having:
a lens,
a video preamplifier comprising:
a plurality of preamplification stages, each having an input and an
output circuit with loads inserted in each output circuit, and a
negative feedback network connected between an output and an input
of said video preamplifier,
said loads and said negative feedback network being chosen in order
that said video preamplifier generates a response curve which
extends over a band of frequencies appropriate to the spectrum of
said radiations,
a scanning tube connected to said video preamplifier, and
at least one spectral correction filter, chosen as a function of
the nature of said radiations, which is disposed in front of said
lens.
2. Device according to claim 1, further comprising a polarization
filter disposed in front of said at least one spectral correction
filter.
3. Device according to claim 2, wherein said polarization filter is
a linear one.
4. Device according to claim 2, wherein said polarization filter is
a circular one.
5. Device according to claim 1, further comprising an array of
microprisms, said microprisms being cut so as to have a number of
microprisms adapted for diffraction of said physical phenomena
taking place in said field and disposed between said lens and said
at least one spectral correction filter.
6. Device according to claim 1, further comprising an image booster
coupled to the lens of the camera having a focal length which is
chosen as a function of the distance existing between said camera
and said field as well as a function of the horizontal and vertical
dimensions of the field covered by the detection device.
7. Device according to claim 1, further comprising a polarization
filter disposed in front of said at least one spectral correction
filter and an array of microprisms, said microprisms being cut so
as to have a number of microprisms adapted for diffraction of said
physical phenomena taking place in said field and disposed between
said lens and said at least one spectral correction filter.
8. Device according to claim 1, further comprising a polarization
filter disposed in front of said at least one spectral correction
filter, an array of microprisms, said microprisms being cut so as
to have a number of microprisms adapted for diffraction of said
physical phenomena taking place in said field and disposed between
said lens and said at least one spectral correction filter, and an
image booster coupled to the lens of the camera having a focal
length which is chosen as a function of the distance existing
between said camera and said field as well as a function of the
horizontal and vertical dimensions of the field covered by the
detection device.
9. Device according to claim 1, further comprising an array of
microprisms, cut so as to have a number of microprisms adapted for
diffraction of said physical phenomena taking place in said field
and disposed between said lens and said at least one spectral
correction filter and an image booster coupled to the lens of the
camera having a focal length which is chosen as a function of the
distance existing between said camera and said field as well as the
function of the horizontal and vertical dimensions of the field
covered by the detection device.
10. A device for the instantaneous and simultaneous detection,
inside and outside, of radiations emitted in the infrared, visible
and ultraviolet spectra by simultaneous physical phenomena having a
character of risk, such as intrusion, fire, explosion, leaks of
dangerous fluids and electric leaks, disturbance and absence of
movement of a regular periodic phenomenon, said radiations being
emitted directly by said physical phenomena at the time when said
risk appears or being caused artificially by directing over an
appropriate field of view, in which said phenomena take place, a
source of radiation comprised in the infrared, visible and
ultraviolet spectra and adapted for response to the phenomena
involved, the field of view covered by the detection device having
appropriate horizontal and vertical dimensions, wherein said
detection device is formed by a television camera disposed at an
appropriate distance from said field, and having:
a lens,
a video preamplifier comprising:
a plurality of preamplification stages, each having an input and an
output circuit with loads inserted in each output circuit, and a
negative feedback network connected between an output and an input
of said video preamplifier,
said loads and said negative feedback network being chosen in order
that said video preamplifier generates a response curve which
extends over a band of frequencies appropriate to the spectrum of
said radiations,
a scanning tube connected to said video preamplifier,
at least one spectral correction filter, chosen as a function of
the nature of said radiations, which is disposed in front of said
lens,
a polarization filter disposed in front of said at least one
spectral correction filter,
an array of microprisms, cut so as to have a number of microprisms
adapted for diffraction of said physical phenomena taking place in
said field and disposed between said lens and said at least one
spectral correction filter,
an image booster coupled to the lens of the camera having a focal
length which is chosen as a function of the distance existing
between said camera and said field as well as a function of the
horizontal and vertical dimensions of the field covered by the
detection device.
11. An installation for the instantaneous and simultaneous
detection, inside and outside, of radiations emitted in the
infrared, visible and ultraviolet spectra by simultaneous physical
phenomena having a character of risk, such as intrusion, fire
explosion, leaks of dangerous fluids and electric leaks,
disturbance and absence of a movement of a regular periodic
phenomenon, said radiations being emitted directly by said physical
phenomena at the time when said risk appears or being caused
artificially by directing over an appropriate field of view, in
which said phenomena take place, a source of radiation comprised in
the infrared, visible and ultraviolet spectra and adapted for
response to the phenomena involved, said field of view covered by
the detection device having appropriate horizontal and vertical
dimensions, said installation comprising in combination:
at least one detection device formed by a television camera
disposed at an appropriate distance from said field and having:
a lens,
a video preamplifier comprising:
a plurality of preamplification stages, each having an input and an
output circuit with loads inserted in each output circuit, and a
negative feedback network connected between an output and an input
of said video preamplifier,
said loads and said negative feedback network being chosen in order
that said video preamplifier generates a response curve which
extends over a band of frequencies appropriate to the spectrum of
said radiations,
a scanning tube connected to said video preamplifier,
at least one spectral correction filter, chosen as a function of
the nature of said radiations, which is disposed in front of said
lens,
a polarization filter disposed in front of said at least one
spectral correction filter,
an array of microprisms, cut so as to have a number of microprisms
adapted for diffraction of said physical phenomena taking place in
said field and disposed between said lens and said at least one
spectral correction filter,
an image booster coupled to the lens of the camera having a focal
length which is chosen as a function of the distance existing
between said camera and said field as well as a function of the
horizontal and vertical dimensions of the field covered by the
detection device,
at least one video data processing unit producing an alarm signal
in response to the detection of said phenomena having a character
of risk and comprising an analog digital converter associated with
a microcomputer equipped with a video-graphic interface,
at least one video monitor, each associated with a detection device
by means of said video data processing unit.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a device and an installation for
the instantaneous and multipurpose detection, inside and/or
outside, of physical phenomena having a character of risk and being
as varied as intrusion and/or fire and/or explosion and/or leaks
(of fluids and/or "electric" ones) and/or else the disturbance or
absence of a movement or of a regular or periodic phenomenon, taken
separately or together and possibly simultaneously.
2. Description of the Prior Art
In the particular case of fire detection, different types of
detectors are used at the present time which are able to measure
the presence of one or other of the following physical
phenomena:
combustion aerosols,
combustion gases,
visible smoke,
flames,
temperature threshold,
rapid temperature rise.
From the point of view of the physical phenomenon detected, fire
detectors are distinguished as indicated below:
ionic detectors, which allow combustion aerosols to be detected and
which are responsive to the variations of the properties of an
artificially ionized atmosphere;
optical smoke detectors, responsive to the presence of visible
smoke, which are of the so called:
opacity type (responsive to the attenuation of light due to the
presence of smoke), and
diffusion type (using the diffusion effect of the light due to the
smoke);
optical flame detectors, which use the energy radiated by the
flames (for reasons of stability and selectivity, the visible
radiation of the flame is not used but rather the infrared or
ultraviolet radiation);
heat detectors, whose sensitive element measures:
a preset temperature threshold (temperature threshold detector),
or
the rate at which the temperature rises (thermovelocimetric
detectors).
In addition, so called special detectors are known, more
particularly:
ember detectors, which are specifically used for detecting the
unmodulated infrared radiation characteristic of ember fires;
acoustic detectors, which measure the bursting noise of a
bulbcontaining a gas which, under the effect of the pressure
increase due to the heat, causes the bulb to "burst";
laser detectors, which provide a linear check of the variation
present, on reception, in a coherent photon beam emitted by an
appropriate source and caused by the convection movement due to the
seats of the fire, and
surface effect detectors, which in their basic principle are used
as dangerous gas detectors.
In so far as fire detection is concerned using said means, they
have a certain number of drawbacks, more particularly:
in so far as ionic detectors are concerned, they are slow and are
never used outside because they are influenced by air currents;
furthermore, they may cause untimely alarms (i.e. without real
danger) too frequently;
in so far as optical smoke detectors are concerned:
the operation of opacity type detectors is greatly disturbed in
dusty atmospheres and they react with a certain delay for smoke
emissions of low opacity, whereas
diffusion type detectors have difficulty in detecting black smoke
because of their poor reflecting power;
furthermore, diffusion type detectors are too slow and are never
used outside;
in so far as flame detectors are concerned (infrared or ultraviolet
detectors), although they may be used outside and although they are
rapid, the corresponding detection area (or surveyed area) is very
much reduced; in addition, they are sensitive to atmospheric
phenomena (more especially to the illumination due to lightning and
the sun) and the object being monitored must be fixed: in addition,
outside protection requires a certain number of requirements to be
complied with which make it complicated and expensive;
in so far as heat detectors are concerned, they are slow and are
never used outside;
in so far as the so called special detectors are concerned,
ember detectors, which may be used possibly outside as well, are at
present still in the experimental application stage,
acoustic detectors, when they are used outside, are disturbed by
the surrounding noise,
laser detectors provide detection along an axis and not of a
volume, so that their outside use, more particularly, requires a
large number of this type of device to be used (which are at
present economically valid essentially for protecting large inside
areas, for example supermarkets, and
surface effect detectors, which have solved the problem of the
monitoring range, have a sensitive element subject to chemical
drifting and, furthermore, they are expensive.
In short, and generally, still limited to the particular case of
fire detection, the traditional systems rely on the analysis of
physical phenomena (more particularly optical, thermal, mechanical
phenomena) and chemical phenomena using detectors which are very
specialized in their functions and whose design compels use thereof
almost exclusively inside, in that no detector lends itself to
outside use without enormous constraints which greatly limit the
real use of some of them to rare specific cases and which
completely prohibit the other applications.
Furthermore, to the knowledge of the applicant, there exists at
present no single system which is capable of detecting outside as
well as inside, not only the different manifestations of a fire,
but at the same time other physical phenomena as well having a
character of risk , such as intrusion, and/or leaks (of fluids and
"electric" ones) and/or explosion, for example, as well as a priori
any character of disturbance or absence in the regular movement of
a system which may have dangerous or, in any case, undesirable
consequences for the correct operation of the system.
SUMMARY OF THE INVENTION
The purpose of the present invention is therefore to provide a
system for the instantaneous detection, inside and/or outside, of
physical phenomena having a character of risk and being as varied
as intrusion and/or fire and/or explosion and/or leaks (of fluids
and/or "electric" ones) and/or else the disturbance and/or absence
of a regular or periodic movement, taken individually or jointly
and possible simultaneously.
Within the scope of this invention by intrusion is to be understood
not only the presence of persons in a static field, but also the
presence of any foreign body in the field of action of a priori any
dynamic system, such as an automated industrial production line or
similar.
The present invention provides then a device for the instantaneous
and multipurpose detection, inside and/or outside, of physical
phenomena having a character of risk and being as varied as
intrusion and/or fire and/or explosion and/or leaks (of fluids
and/or "electric" ones) and/or else the disturbance and/or absence
of a movement or of a regular or periodic phenomenon, taken
separately or jointly and possibly simultaneously, which detection
device is characterized in that it is formed by a television camera
with wide spectrum, namely extending simultaneously to the near
infrared, to the visible and the ultraviolet spectra, or of reduced
spectral sensitivity, namely limited to the infrared spectrum
and/or visible or ultraviolet and/or visible spectra, which camera
is equipped with:
at least one spectral correction filter with known pass band chosen
as a function of the nature of the radiation, infrared and/or
visible and/or ultraviolet, which is emitted directly by the
phenomenon or phenomena to be monitored at the time when the risk
appears or which is caused artificially by directing over the field
to be monitored a source of radiation, infrared and/or visible
and/or ultraviolet , appropriate to the nature of the phenomenon
concerned, and, possibly, as well with:
a linear or circular polarization filter,
and/or a microprism array, cut so as to have the number of
microprisms appropriate to the field or to the desired angle of
coverage,
and/or an image booster, of the first or of the second order or of
a higher order, which is coupled to the lens of the camera, the
focal length of this latter being chosen as a function of the
distance existing between the position of the camera and the zone
to be monitored as well as the function of the horizontal and
vertical dimension of the area covered, at a given distance, by the
detection; the values of the load resistors and of the negative
feedback networks of the conventional type video preamplifier of
the camera being modified so as to have a preamplifier whose
response curve extends over a frequency range appropriate to each
desired application, which amplifier receives the signal from a
scanning tube, it too conventional, following the lens of the
camera possibly equipped with said image booster.
The present invention also provides an installation for the
instantaneous and multipurpose detection in said sense, which
comprises in combination:
one or more detection devices conforming to the preceding
arrangements, disposed appropriately in one or more inside and/or
outside zones to be protected,
one or more video information processing units, known per se,
comprising more particularly an analog/digital converter possibly
associated with a microcomputer equipped with its video-graphic
interface, the different detection devices being spaced apart
between one or more of said processing units, which give an alarm
signal,
one or more video monitors, each associated with a detection
device, and possibly, the units for using the video signal thus
processed which are indicated hereafter:
a time delay unit, known per se, which receives the alarms given by
the video information processing units so as to trigger an
automatic telephone transmitter, it too known per se,
and/or a cyclic switch and a video tape recorder with time stamp,
known per se, associated with each video information processing
unit,
and/or a television telephone transmitter, known per se,
broadcasting the video information processed to a distant
monitoring station and capable of calling an alarm reception
station, it too known per se, through the normal telephone
network.
BRIEF DESCRIPTION OF THE DRAWINGS
Besides the above mentioned arrangements, the invention comprises
further arrangements which will be clear from the following
description.
The invention will be better understood from the complement of
description which follows which refers to the accompanying
drawings, in which:
FIG. 1 illustrates the general diagram comprising the essential
components of the detection system of the invention,
FIG. 2 illustrates a conventional electronic diagram of the video
preamplification block shown in FIG. 1 with the indication of the
resistance and capacity parameters which are likely to be changed
as a function of the desired response,
FIGS. 3A-3C to 8A-C show schematically different examples given by
way of nonlimitative applications of the invention.
It should however be understood that these drawings and the
corresponding descriptive parts are given solely by way of
illustration of the subject of the invention, of which they are in
no way a limitation.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Within the scope of the present invention, the video technique is
used for the simultaneous and instantaneous detection, inside
and/or outside, of various physical phenomena having a risk
character, such as:
intrusion,
and/or fire,
and/or explosion,
and/or leaks (of fluids and/or "electric" ones).
It should be emphasized in this connection that, although it is
true that limitatively to the specific field of the detection of
intrusion at the present time the video technique is also used
(particulally in a closed circuit), with television cameras and
video monitors spaced apart appropriately, however, to the
knowledge of the applicant, cameras have never been used either for
fire detection or for the detection of the other phenomena having a
character of risk which have been mentioned above.
In so far as the acquisition of information is concerned by using
television cameras, the use of professional high definition and
high sensitivity cameras is indispensable.
Depending on the nature of the risk or of the risks to be detected,
cameras are used with reduced spectral response namely "infrared"
or "ultraviolet" cameras, or else wide spectrum cameras.
In so far as intrusion detection is concerned, this may be provided
obviously just as well with reduced spectrum as with wide spectrum
cameras, the choice being made depending on the environmental
characteristics and on the other risks contemplated.
Now, the photosensitive surface of a camera has a specific spectral
response curve which, however, in no case is naturally adapted to a
given environment and to a given risk or a given combination of
risks. It is therefore necessary to modify the spectral response of
the type of camera chosen by adding one or more filters with known
passband (for example the filters 1a and 1b of FIG. 1) so as to
obtain the overall spectral response of the camera always adapted
to the environmental characteristics and to the risks contemplated;
more precisely, the passband of the spectral correction filter or
filters is chosen depending on the nature (infrared or ultraviolet
of the radiation which will be emitted at the time when the
monitored risk will appear.
Furthermore, in some cases, the performances of the detection
system of the invention may be substantially improved by adding an
optical linear or circular polarization device 2, so as to
attenuate or eliminate certain reflections and generally to
increase the contrast and, consequently, the sensitivity of the
detection system (cf. FIG. 1).
Moreover, considering the well known phenomenon of attenuation of
the sensitivity as a function of the distance between the
phenomenon to be detected and the detection device, another optical
device should be provided formed by an array of microprisms 3 in an
appropriate number, in order to artificially increase the volume of
a seat of a fire more particularly: thus, any light point is
diffracted (the microprisms in fact act like an optical amplifier,
by diffraction), which eliminates the disadvantage of degressive
sensitivity (cf. again FIG. 1).
The video signal (which is obtained from television cameras whose
lens 4, made from a good quality optical glass or from quartz, may
be coupled to an image booster 5, namely to a light amplifier and
more particularly of the first or of the second order, and whose
spectral response and sensitivity have been modified as mentioned
above, and which is analyzed in a tube 6 (in particular a scanning
tube "Newvicon ER") driving a video preamplifier 7 (cf. FIG.
1).
Now, the standard values of the load resistors, as well as of the
negative feedback networks of this preamplifier, must be changed so
that the response curve of the video preamplifier is appropriate to
each of the applications envisaged; these are modifications which
are within the scope of a man skilled in the art: for this reason,
in FIG. 2 the elements of the standard circuit of a type (moreover
not limitative) of conventional video amplifier have been
surrounded with broken lines, whose values are likely to be
modified in said direction.
After having been preamplified, the video signal is processed in a
standard type electronic assembly 8 forming an integral part of the
traditional equipment of a video 9 camera (cf. FIG. 1).
In so far as the video signal thus obtained is concerned, it is fed
to a video information processing unit (cf FIG. 1), namely to:
an analog/digital converter converting a certain number of bits, in
particular 2.sup.6 =64 or 2.sup.8 =256. In this case, a subsystem
generates the horizontal and vertical addresses (1024 or 4096,
respectively, depending on said number of bits). The digital
information which is stored bit by bit is compared with a program
loaded in an EPROM store and, if the video voltage varies at one or
more addresses, a comparator gives a usable alarm signal, and
possibly also to:
a microcomputer equipped with its corresponding video-graphic
interface: in this case, the system obviously has great software
flexibility and an appreciably greater memory capacity.
Whereas, with the analog/digital converter, the variation in space
of the phenomenon or phenomena to be monitored can be positioned,
the use of a microcomputer allows the recognition of form to be
obtained (image analysis) because of the increase of the fineness
of analysis (matrix of more than 100.000 picture elements or
"pixels").
Since the design of the detection system of the invention is
semi-automatic, that involves the interpretation or use by human
beings of the information supplied by the system, namely video
images and signals localizing anomalies, available more
particularly on monitors and/or video tape recorders.
Furthermore, since the applications are almost always related to
safety measures, optimum efficiency is obtained - after human
interpretation - by an intervention which may be localized or
remote (transmission of the information by radio or telephone
line).
In what follows different examples are given by way of non
limitative applications illustrating the principles which are at
the basis of the present invention. In each example the following
are used:
a lens formed by a good quality optical glass (with good
reproduction) up to the near infrared (more particularly the
apochromatic system, "ED" or similar) long telephoto lens, whose
focal length is chosen as a function of the desired horizontal and
vertical coverage for a given distance between the camera and the
possible risk to be detected, and
a scanning tube, formed for example by the "Newvicon ER" type, the
standard values of the load resistors and of the negative feedback
networks of the video preamplifier of the camera being modified so
as to obtain a response curve in a frequency range appropriate to
each application.
In each example, the initial response curve of the camera, modified
for the desired purpose, is represented by curve a.
In the different examples which follow the lens may cooperate
with:
an image booster, which may be of the first or second order or of a
higher order,
and/or a microprism array, cut so as to have the number of
microprisms appropriate to the contemplated application (the number
of microprisms decreases with the angle of coverage),
and/or a polarizing filter, which may be linear or circular,
and/or at least one filter for the spectral correction of the
initial response curve of the camera (it is a question for example
of restricted Wratten filters).
EXAMPLE NO. 1--REDUCED ANGLE VOLUMETRIC PROTECTION
The general diagram is illustrated in FIG. 3A-3C and refers to the
coverage of a probable intrusion and/or fire and/or explosion risk
situated at a distance of 500 m from the camera (and even more, the
maximum coverage distance depending essentially on the real
performances of the different basic components of a camera, namely
the lens, the scanning tube, the video preamplifier as well as
accessory components which may possibly cooperate, in accordance
with the invention, with this basic equipment, namely the image
booster and filters)
In this case, the following may be used:
a circular polarizing filter 2b,
two spectral correction filters 1'c and 1"c for obtaining the
corrected spectral response curve b which is limited in the values
of linear infrared spectrum (the response is limited to 50% between
750 and 850 nm, whereas the response is absolute between 700 and
900 nm ),
a microprism array 3a cut so as to have 100.000 microprisms,
a lens 4a whose focal length is situated between 100 and 250 mm,
which provides, in correspondance with the ends of this range of
focal length values and at a distance of 500 m:
a horizontal coverage of 55 m and vertical coverage of 42 m for 100
mm of focal length, and
a horizontal coverage of 22 m and a vertical coverage of 16 m for
250 mm of focal length,
an image booster 5 of the first order, the video preamplifier 7a
being adjusted so as to have a response curve up to 4 MHz.
EXAMPLE NO. 2--SEMI-REDUCED ANGLE VOLUMETRIC PROTECTION
The general diagram is illustrated in FIG. 4A-4C and refers to the
coverage of a possible intrusion and/or fire and/or explosion risk
situated at a maximum distance from the camera of about 200 m.
In this case, the following are used:
a linear polarizing filter 2a,
a spectral correction filter 1d for obtaining the corrected
spectral response curve c which is limited to be astride the
infrared and visible spectra, namely between the values of the near
infrared spectrum and orange of the visible spectrum (the response
is limited to 50% between 650 and 770 nm, whereas the response is
absolute between 600 and 820 nm),
an array of microprism 3b cut so as to have 250.000
microprisms,
a lens 4b whose focal length is between 75 and 100 mm (average
telephoto lens), which provides in correspondance with the ends of
this range of focal length values and at the distance of 200 m:
a horizontal coverage of 30 m and a vertical coverage of 22 m, for
75 mm of focal length, and
horizontal coverage of 22 m and vertical coverage of 16 m, for 100
mm of focal length, the video preamplifier 7b being adjusted so as
to have a response curve up to 6 MHz.
The absence of image booster will be noted in this example and in
the following examples.
EXAMPLE NO. 3--WIDE ANGLE VOLUMETRIC PROTECTION
The general diagram is illustrated in FIG. 5A-5C and refers to the
coverage of a possible risk of intrusion and/or fire and/or
explosion situated at a maximum distance from the camera of about
100 m.
In this case, the following are used:
a linear polarizing filter 2a,
a spectral correction filter 1e for obtaining the corrected
spectral response curve d which is limited astride the infrared and
visible spectra, namely between the values of the near infrared
spectum and green of the visible spectrum (the response is limited
to 50% between 510 and 800 mm, whereas the response is absolute
between 450 and 900 mm),
an array of microprisms 3c cut so as to have 500.000
microprisms,
a lens 4c whose focal length is that of a super wide angle, more
especially of 5.5 mm, to which value corresponds a horizontal
coverage of 200 m and a vertical coverage of 150 m at the distance
of 100 m, the video preamplifier 7c being adjusted so as to have a
response curve up to 10 MHz.
EXAMPLE NO. 4
The general diagram is illustrated in FIG. 6A-6C and refers more
particularly to the coverage of a possible risk of gas leak and/or
fire and/or intrusion and/or explosion, situated at a maximum
distance from the camera of about 100 m.
It is assumed that the gas is stored in the liquid state: then the
leak is of course accompanied by a rapid change to the gaseous
state. Now, this change of state, which occurs from the moment when
the liquid gas comes into contact with the atmosphere, causes in
this latter a sudden modification of the temperature and of its
transparency properties.
In this case, the following are used:
a spectral correction filter 1f for obtaining the corrected
spectral response curve which is limited astride the infrared and
visible spectra, namely between the values of the near infrared
spectrum and blue of the visible spectrum (the response is limited
to 50% between 540 and 830 nm, whereas the response is absolute
between 420 and 950 nm),
a lens 4d whose focal length is 120 mm, for which a horizontal
coverage of 9 m and a vertical coverage of 6.6 m is obtained at a
distance of 100 m, the video preamplifier 7b being adjusted so as
to have a response curve up to 6 MHz.
EXAMPLE NO. 5
The general diagram is illustrated in FIG. 7A-7C and refers more
particularly to the coverage of a probable risk of leak of certain
vapors and/or fire and/or intrusion and/or explosion, situated at a
maximum distance from the camera of about 100 m.
It should be emphasized that, starting with elements initially in
the liquid state, detection is provided by illuminating the
position at which the leak in question is likely to occur with
sometimes visible and sometimes infrared lighting, depending on the
chemical nature of the vapors monitored. Now, in the case of
visible illumination, modification of the transparency of air is
used, whereas with infrared illumination, this same transparency is
used and the appearance of the luminescence phenomenon.
In this case, the following are used:
a filter 1d giving the same spectral correction defined by curve c
in example 2, and
a lens 4d having the same characteristics as those given in example
4,
the video preamplifier 7'a being adjusted so as to have a response
up to 2 or 4 MHz.
Within the scope of the present invention, "electric leak" may also
be detected in a damaged insulator before the "flash", that is to
say that the permanent leak current in a damaged insulator may be
detected before its intensity results in a conventional electric
arc; the corona effect may even be predicted (in combination with
the simultaneous detection of intrusion and/or fire and/or
explosion and/or fluid leak).
For this, advantage is taken of the fact that the radiations
emitted in this type of situation are ultraviolet radiations and so
a specific spectral response camera is used whose photosensitive
surface has a spectral sensitivity covering a part of the visible
spectrum (from blue) up to the UV.sub.1 or UV.sub.2 range of the
ultraviolet spectrum.
As in the applications with infrared cameras, in this case also the
spectral response curve of an "ultraviolet" camera must be modified
(still as a function of the environmental characteristics and of
the other possible risks contemplated), by using filters with known
pass band restricted to be astride the visible spectrum and the
ultraviolet spectrum, namely between blue of the visible spectrum
and the UV.sub.1 or UV.sub.2 range of the ultraviolet spectrum.
Furthermore, with "ultraviolet" cameras polarization filters and
microprism arrays may also need to be used; however, these
devices--as well as the lenses--must be made from quartz, taking
into account the very high degree of attenuation of optical glasses
in the ultraviolet radiation range.
The following example illustrates a possible application using an
"ultraviolet" camera.
EXAMPLE NO. 6
The general diagram is shown in FIG. 8A-8C and refers to the
coverage of a probable risk of "electric" leak and/or intrusion
and/or fire and/or explosion situated at a maximum distance from
the camera of about 100 m.
In this case, the following are used:
a spectral correction filter 1h for correcting the spectral
response curve a.sub.1 of the camera so as to obtain the corrected
curve f which is limited astride the upper part of the visible
spectrum and the ultraviolet spectrum (the response is limited to
50% between 136 and 393 nm, whereas the response is absolute
between 58 and 450 nm),
a microprism array 3c cut so as to have 500.000 microprisms,
a lens 4e whose focal lens is 100 mm, to which value corresponds a
horizontal coverage of 11 m and a vertical coverage of 8 m, at the
distance of 100 m,
an image booster 5a of the second order, the video preamplifier 7c
being adjusted so as to have a response curve up to 10 MHz.
It goes without saying that in all the above examples, when among
the possible risks to be monitored there exists also a risk of
explosion, the positioning of the camera must be calculated as a
function of the potential power of the explosion and, in the case
where this power cannot be estimated with sufficient accuracy, it
is obvious that the minimum distance of the camera will correspond
substantially to the maximum distance indicated in each of the
above examples and, in general, to the maximum distance to be
respected in the different real situations.
Furthermore, it is also possible to take particular protection
measures consisting more particularly in using antiexplosion or
armoured caissons or else concrete casemates, etc.
Generally, the system of the invention may be applied in any
environment (including environments as hostile as those formed for
example by sea depths and blast furnaces where very high pressures
and temperatures reign, respectively) on condition that adequate
means are provided for suitably isolating the data acquisition
elements.
The very wide range of applications which may be envisaged within
the scope of the present invention is such that its original
character is demonstrated without any ambiguity, more especially in
that, to the knowledge of the applicant, there exists up to the
present time no system capable of predicting in particular the
formation of an electric arc or of the corona effect, with the
technical and economic advantages which that implies.
Although the examples refer, for the sake of simplicity, to the use
of a single camera, the detection installations constructed using
the system of the present invention may comprise a very large
number of cameras.
In the general case, it is therefore a question of sharing the
cameras between a number (substantially less) of video information
processing units (for example one, two or more) which, in the most
simple case, give the alarm and send back images to each of the
video monitors associated with the cameras effectively used.
This basic configuration may be improved by adding a time delay
unit, known per se, (and not shown), which receives the alarms
given by the data processing units so as to trigger off an
automatic telephone transmitter, it too known per se, in the case
of absence or immobilization (aggression) of the guardian or
guardians, after a certain (programmed) time has elapsed. When the
guardians are present and able to use the detected signals, they
have the programmed lapse of time for cancelling out the telephone
transmission using a digital keyboard with which said timing unit
is equipped.
To the basic configuration of the detection installation thus
modified may also be added a cyclic switch and a video tape
recorder with time clock (not shown because these devices are all
known per se) and this for each group of cameras (and so of
monitors) connected to a data processing unit: in a normal
situation, the different cameras of each group are scanned
cyclically and the images are recorded, by the corresponding video
tape recorder, as a succession of fixed images. In an alarm
situation, the data processing unit couples the camera which
detected the calamity to the video tape recorder and begins to
record in real time.
In the case where the monitoring post is relatively distant from
the position of the cameras, a television telephone transmitter,
known per se, (and not shown), transmits the processed video
information and the video information to said monitoring station,
said telephone transmitter being able to call an alarm reception
station (known per se) using the normal telephone network.
It goes without saying that in the basic starting configuration may
also be included a loud speaker network which, in an abnormal
situation, may broadcast a sound message (manually or
automatically) in the protected zone or zones.
(The devices situated downstream with respect to the video data
processing units are generally designated in FIG. 1 by UE, which
designation refers to the "Units of Exploitation".
Furthermore, it is clear that the position of the different cameras
depends, for one or more outside and/or inside zones to be
protected, on the field of vision and on the environmental
constraints (more particularly in so far as the outside is
concerned), namely on the existence of optical disturbances
consisting for example of the presence of mercury vapor lighting
and/or fog and/or moving objects, etc.
It must be once more emphasized that the applications indicated in
the present description have no limitative character, since other
applications may be envisaged without for all that departing from
the scope and spirit of the invention, in that the detection system
of the invention may be used not only for detecting phenomena,
possibly simultaneous, such as intrusion and/or fire, and/or
explosion and/or leaks (of fluids and "electric" ones), but also in
all cases where the disturbance or absence of a movement must be
detected which, in a normal situation, is regular or periodic (in
this connection, it is easy to envisage applications in the medical
field as well, for example).
As follows from the foregoing the invention is in no way limited to
those of its embodiments and modes of application which have been
described more explicitly; it embraces, on the contrary, all
variants thereof which may cccur to a technician skilled in the
matter, without departing from the scope and spirit of the present
invention.
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