JP2847597B2 - Infrared monitoring system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intruder monitoring system using infrared rays, and more particularly to an infrared monitoring system capable of reliably detecting an intruder even when there is a large disturbance in environmental temperature.

Various types of intruder detection systems used in security systems are already known. Among them, an infrared monitoring system that detects an intruder by processing an image with an infrared camera is excellent in that it has high secrecy from an intruder and high reliability in detecting an intruder.

In such an infrared monitoring system, it is desired that an intruder can be reliably detected even when there is a large disturbance in the background environmental temperature such as when the infrared monitoring system is installed outdoors.

[0004]

2. Description of the Related Art FIG. 4 shows an entire configuration of a conventional infrared monitoring system to which the present invention is applied.
11 _{1 to} 11 _n are infrared / visible composite cameras provided corresponding to the plurality of channels CH _{1 to} CH _n , which are distributed in the guard area and are assigned to respective monitoring areas. Images are captured by an infrared camera and a visible light camera. 12 A ₁ to 12 _n is a controller provided in correspondence with each camera, performs required control such as a temperature measurement range setting for each camera.

[0005] 13 _{1 to} 13 _n and 14 _{1 to} 14 _n are:
A transmission unit and a reception unit of a transmission system provided corresponding to each camera, and transmit information from each camera provided at a remote place. 15 is a video switch, and outputs the switching signal of each camera from the receiving unit 14 ₁ to 14 _n.

Reference numeral 16 denotes a TV monitor which displays an image from the visible light camera selected by the video switch 15. Reference numeral 17 denotes an image processing unit which performs image processing for detecting an intruder in each monitoring area based on a video signal of the infrared camera selected by the video switch 15.

Reference numeral 18 denotes a data processing unit which performs processing such as determination of an intruder and generation of an alarm based on the processing result of the image processing unit 17. Reference numeral 19 denotes an alarm device, which issues a required alarm when the data processing unit 18 determines that an alarm has occurred. Reference numeral 20 denotes a display for setting various alarm conditions in the data processing section 18 and displaying when an alarm occurs. Reference numeral 21 denotes a printer, which performs necessary recording when an alarm is generated in the data processing unit 18.

The data processing section 18 controls the video switch 15 to periodically switch the camera of each channel to perform monitoring, and controls the controller of each camera to measure the temperature of the infrared camera. , Control for instructing the number of gradations and the like at the time of image display.

FIG. 5 shows the basic concept of intruder detection in the infrared surveillance system.
By performing a difference operation with the reference image indicating the background,
Indicates that an intruder is to be detected.

In the input image, if the background temperature is t ₁ , the intruder temperature is t _2, and the difference temperature between them is t ₃ , the difference between the input image and the reference image equal to the background temperature is obtained. image showing the intruder by the temperature t ₃ is obtained.

Is the background temperature t₁ = 20 ° C, intruder temperature
t_Two = 30 ° C, differential temperature t _Three = 10 ° C
Indicates that an intruder is displayed, and indicates the background temperature t.₁ =
0 ° C, intruder temperature t_Two = 30 ° C, differential temperature t
_Three = 30 ° C indicates that an intruder is displayed,
Is the background temperature t₁ = 50 ° C, intruder temperature t_Two = 30 °
At C, the difference temperature t_Three = -20 degrees Celsius intruders
It is displayed.

It is effective in detecting an intruder to determine the temperature measurement range of the infrared camera in the infrared monitoring system so as to follow a range determined by the minimum temperature and the maximum temperature of the measured background temperature. In this case, since the temperature measurement value has an error within the temperature resolution value ΔT as a system, the temperature measurement range needs to be set with a margin by this error.

FIG. 6 shows the setting of the background temperature and the temperature measurement range of the infrared camera. As shown in the figure, the lower limit value T _MIN of the temperature measurement range of the infrared camera is lower than the minimum background temperature T _BMIN by the system temperature resolution ΔT, and the upper limit value T _MAX is lower than the maximum background temperature T _BMAX. The temperature resolution is increased by ΔT. The value of ΔT is
Temperature resolution value α corresponding to one gradation of image of infrared camera
More usually, it is a considerably large value.

Thus, the intruder temperature, which is an unspecified temperature,
Degree is the minimum temperature value T of the background_BMINEven if lower,
Is the maximum temperature T of the background_BMAXTemperature measurement even if higher
Detection can be performed as being within the range. this
Sets the lower limit of the temperature measurement range for infrared cameras.
Value T_MINThe lower object temperature is T_MINAnd the upper limit set value T
_MAXThe higher object temperature is T_MAXDisplay on the scale
This is because it has an over function.

By doing so, the intruder detection process can be performed within the minimum necessary temperature measurement range, that is, with the minimum necessary temperature resolution value, while eliminating the influence of environmental temperature fluctuations. .

However, when there is an unnecessary temperature source having a temperature significantly higher than the maximum background temperature in the monitoring area, the unnecessary temperature source follows the range defined by the minimum and maximum temperatures of the measured background temperature. When the temperature measurement range of the infrared camera is determined, the temperature measurement range is widened and the temperature resolution value is increased. Therefore, it is necessary to eliminate the influence of the unnecessary temperature source.

FIG. 7 conceptually shows the relationship between the intruder temperature and the unnecessary temperature source. In the figure, A indicates the temperature of the intruder (human), and the temperature T measured with the fluctuation of the environmental temperature changes, and the skin exposed portion is generally higher than the clothing portion. The maximum temperature _Tm is almost constant. On the other hand, B indicates the temperature of the unnecessary temperature source, such as the reflected light of sunlight, which is the maximum temperature T _m of the intruder.
Significantly higher.

FIGS. 8A and 8B conceptually explain the rejection of environmental disturbance on the monitor screen. FIG. 8A shows a shape mask, and FIG. 8B shows a temperature mask. In the figure, the hatched portions are mask portions.

Generally, the following can be considered as factors that cause disturbance on the monitoring screen. Unwanted background in the monitoring area Unwanted temperature source generated in the monitoring area

In FIG. 8A, reference numeral 25 denotes a monitoring area, and reference numeral 26 denotes an unnecessary background, for example, outside the site of the monitoring area. Reference numeral 27 denotes a shape mask set on the screen in such a case, which is set according to the shape of the unnecessary background, thereby removing the influence of the unnecessary background on the monitoring area, and performing image processing and data processing. The amount can be reduced.

In FIG. 8A, reference numeral 28 denotes an unnecessary temperature source in the monitoring area. Such unnecessary temperature sources include, for example, reflected light of sunlight from the water surface existing in the monitoring area, vehicle headlights, illumination lights, and other equipment.

Since the generation of such an unnecessary temperature source is generally unspecified in terms of area and time, it cannot be eliminated by the shape mask as described above. Therefore, in the conventional system, a temperature mask is provided and a certain temperature range is masked in image processing, thereby eliminating the temperature range.

In FIG. 8B, reference numeral 29 denotes a temperature mask, and the lower limit temperature T _M of the temperature mask is set equal to the temperature T _H ° C of the unnecessary temperature source 28 so that the unnecessary temperature source 2
8 has been shown to eliminate the effects.

[0024]

In order to eliminate unnecessary temperature sources using a temperature mask in the above-described image processing, it is necessary to perform processing such as extracting absolute value information after a difference calculation, which complicates the processing. A reduction in processing speed is inevitable. As described above, the conventional infrared monitoring system has a problem in that it is difficult to simply and reliably eliminate an unnecessary temperature source.

An object of the present invention is to solve such a problem of the prior art. In an infrared monitoring system which sets a temperature measurement range of an infrared camera following environmental temperature fluctuations, It is an object of the present invention to provide an infrared monitoring system capable of easily and reliably removing the influence of an unnecessary temperature source from monitoring information of an infrared camera, thereby preventing a malfunction based on the unnecessary temperature source.

[0026]

The present invention will be described with reference to FIG.
(1) An infrared camera 1 for obtaining a temperature distribution by imaging a monitoring area, and a temperature change area detecting means 2 for detecting a temperature change area having a temperature different from the temperature of the background area in the image of the infrared camera 1 When, and a temperature measurement range setting means 3 for setting to follow the range determined temperature measurement range of the infrared camera 1 at the minimum and maximum temperatures of the background area, to process information of the temperature variation region, the in infrared monitoring system for detecting a detection member, temperature measuring range setting means 3, the maximum temperature of the background region, pre-set the body to be detected
When boss was higher than the highest temperatures, the upper limit of the temperature measurement range is set higher than the maximum temperature of the object to be detected by the system temperature resolution value, minimum temperature of the background area, the <br/> best detected body is lower than the temperature sets the lower limit of the temperature measurement range than the lowest temperature of the background region only system temperature resolution value lower the minimum temperature of the background area, plus the system temperature resolution value to the maximum temperature of the object to be detected when higher value, the lower limit of the temperature measurement range, the minimum temperature resolution value of the infrared camera than the upper limit value circuit which sets as low a value obtained by multiplying the number of gradations
Have.

(2) Further, in the present invention, in (1), a review updating means 4 for updating the setting of the temperature measurement range of the infrared camera 1 at regular intervals is provided.

[0028]

[Action] Figure 2 shows the relationship between the set temperature measurement range of the background temperature and the infrared camera in the present invention, (a) is a minimum value of the background temperature, the detected body, i.e., pre intruders
Indicates lower than the maximum temperature T _m of the set, (b) the minimum value of the background temperature, the detected body, i.e., shows the higher than the highest temperature T _m of a intruder.

[0029] In the case of FIG. 2 (a), as shown, the minimum value of the background temperature and the maximum value T _BMIN, T _{BM AX} is, T _BMIN <
T _m , T _BMAX > T _m , and in this case, the lower limit and the upper limit T _MIN, T of the temperature measurement range of the infrared camera.
_MAX is defined as follows. T _MAX = T _m + ΔT (1) T _MIN = T _BMIN −ΔT (2) where ΔT is the system temperature resolution.

In the case of FIG. 2B, as shown in FIG.
The minimum and maximum values T _{BMIN and} T _BMAX of the background temperature are T _BMIN >
T _m + ΔT, T _BMAX > T _m + ΔT, and in this case, the lower limit value and the upper limit value T of the temperature measurement range of the infrared camera.
_MIN, the T _MAX, determined in the following manner. _{T MAX = T m + ΔT ...} (3) T MIN = T MAX -α m n ... (4) where alpha _m, the minimum temperature resolution value of the infrared camera, n represents a number of gradations of the infrared camera image.

[0031] By doing so, a temperature higher than the highest temperature T _m of a intruder unwanted temperature source is fixed to the upper limit value T _MAX of the temperature measurement range of the infrared camera. Also, T
higher than the _m background temperature is also fixed to the T _MAX. That is,
The temperature difference between the unnecessary temperature source and the background temperature is zero. this is,
In the case of an infrared camera, the lower limit set value T of the temperature measurement range
Temperature of lower than _MIN object to T _MIN, the upper limit set value T
_This is because an object having a temperature higher than _MAX has a scale-over function of displaying the temperature at TMAX.

This makes it possible to automatically eliminate a disturbance factor due to generation of an unnecessary temperature source from the system without requiring additional processing such as image processing. The setting of the temperature measurement range of the infrared camera is controlled to be updated at regular time intervals.

In the infrared monitoring system of the present invention,
By doing so, an unnecessary temperature source is generated,
The erroneous operation of intruder detection can be easily and reliably eliminated.

[0034]

FIG. 3 shows an embodiment of the present invention, and illustrates a processing method in the infrared monitoring system of the present invention by way of a flowchart, wherein 25 indicates an infrared camera, and 26 indicates an infrared camera. Reference numeral 27 denotes processing of the data processing unit, reference numeral 27 denotes processing of temperature setting control of the infrared camera in the controller, and a system software table 29 for controlling the whole is provided. Thus, control for each unit and setting of parameters are performed.

The image processing section samples the infrared image from the infrared camera 25 at a predetermined sampling cycle by the frame sampling shown in FIG.
Create an image frame. 32 for image frames
The portions outside the guard area in the image frame are removed by the mask generation shown in FIG.

Then, a difference operation is performed between the previous image frame and the current image frame as shown in FIG.
The temperature change area with respect to the background area is extracted, and 2 shown in FIG.
The binarization is performed to binarize the temperature change region and the background region.

Further, in the histogram calculation shown in 35, the temperature change area is divided into a predetermined number of gradations to form a histogram for obtaining the number of pixels for each gradation, and the temperature measurement range is converted to each gradation above a predetermined threshold value. An area having a number of pixels equal to or greater than a predetermined threshold is extracted.

Further, in the projection calculation shown in 36, the temperature change region extracted in the histogram calculation 35 is
The process of detecting the intruder by calculating the aspect ratio of the shape on the screen, and the highest temperature region (face portion) of the temperature change region extracted by the histogram calculation 35
And the process of detecting the intruder by obtaining the relative position occupied by, that is, the temperature center of gravity.

The processing in the image processing section is repeatedly performed for each image frame. In the data processing unit, the projection calculation 3
When the values of the aspect ratio and the temperature barycenter obtained in step 6 exceed predetermined threshold values, processing for determining an intruder is performed.

In the warning process shown in FIG. 38, when the intruder is determined in the determination process 37, a predetermined alarm is generated in the alarm device, an abnormality is displayed on the display, and the record is printed out by the printer. I do.

As an intermittent process, histogram calculation is performed to obtain the number of pixels for each gradation obtained by dividing the temperature measurement range into a predetermined number of gradations in the background region by the histogram calculation shown in 35, and shown in 39. By calculating the background temperature range,
The minimum temperature having the minimum number of pixels determines the minimum value T _BMIN of the background temperature, and the maximum temperature having the minimum number of pixels determines the maximum value T _BMAX of the background temperature.

[0042] Then, the background temperature evaluation shown in 40 evaluates whether the maximum value T _BMAX of the background temperature is significantly greater than the maximum temperature T _m of a intruder, when T _BMAX was sufficiently large is the 41 in T _MAX settings shown, the upper limit T _MAX temperature measurement range of the infrared camera, defined as T _MAX = T _m + ΔT.

Next, in the calculation of T _MIN, α shown in 42, when the minimum value T _BMIN of the background temperature is T _BMIN <T _m , the lower limit value T _MIN of the temperature measurement range of the infrared camera is set to one gradation. The temperature resolution value α is defined as T _MIN = T _BMIN −ΔT α = (T _MAX −T _MIN ) / n. Here, n is the number of gradations of the image.

The minimum value T _BMIN of the background temperature is equal to T _BMIN
> When the T _m + [Delta] T, the lower limit value T _MIN of the temperature measurement range of the infrared camera, defined as _{T MIN = T MAX -α m n} . Here, α _m is the minimum temperature resolution value of the infrared camera.

[0045] In the temperature setting control 28, the controller for the infrared camera 25, T _{MA X} set 41, T _MIN,
The infrared camera 25 performs a process of setting the upper limit value and the lower limit value of the temperature measurement range obtained by the α calculation 42 and the temperature resolution value α or α _{m of} one gradation. Perform measurement.

Further, the process of background temperature range calculation 39 to T _MIN, α calculation 42 is executed at each update time designated from the system software table 29 by the review update shown in 43, and the temperature is updated in the temperature setting control 28. The settings in the infrared camera 25 are made based on these parameters. This is because changes in background temperature etc. are relatively slow,
This is because the setting may be changed every certain time.

[0047]

As described above, according to the present invention, in the infrared surveillance system, the temperature measurement range of the infrared camera is changed in accordance with the change of the background environmental temperature, and the temperature range is significantly changed based on the unnecessary temperature source. For high background temperatures, the upper limit of the temperature measurement range is set to a value that allows a certain margin to the intruder's maximum temperature, preventing malfunctions due to unnecessary temperature sources in the monitoring area. Thus, the process of correctly detecting only the intruder can be easily and reliably executed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a basic configuration of the present invention.

[Figure 2] A graph showing the relationship between the set temperature measurement range of the background temperature and the infrared camera in the present invention, (a) shows the case where the minimum value of the background temperature is lower than the maximum temperature T _m of a intruders , (B) shows that the minimum value of the background temperature is the maximum temperature T of the intruder.
_{Shows the} case where it is higher than _m

FIG. 3 is a diagram showing one embodiment of the present invention.

FIG. 4 is a diagram showing an entire configuration of a conventional infrared monitoring system to which the present invention is applied.

FIG. 5 is a diagram showing a basic concept of intruder detection in the infrared monitoring system.

FIG. 6 is a diagram showing a background temperature and setting of a temperature measurement range of an infrared camera.

FIG. 7 is a diagram conceptually showing a relationship between an intruder temperature and an unnecessary temperature source.

FIGS. 8A and 8B are diagrams conceptually illustrating environmental disturbance elimination on a monitoring screen, wherein FIG. 8A shows a shape mask and FIG. 8B shows a temperature mask.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Infrared camera 2 Temperature change area detection means 3 Temperature measurement range setting means 4 Review and update means

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01J 5/48 G01V 9/04 G08B 13/196 H04N 5/33

Claims (2)

(57) [Claims] 1. A infrared camera (1) for obtaining the temperature distribution by imaging a monitoring region, the temperature change area detection for detecting a temperature change area having a temperature different from the temperature of the background region in the image of the infrared camera (1) Means (2); and a temperature measurement range setting means (3) for setting a temperature measurement range of the infrared camera (1) so as to follow a range defined by a minimum temperature and a maximum temperature of a background area; In the infrared monitoring system for processing the information of the area to detect the object to be detected, the temperature measurement range setting means (3) may be configured such that when a maximum temperature of the background area is higher than a preset maximum temperature of the object to be detected. , wherein the upper limit of the temperature measurement range is set higher than the uppermost <br/> high temperature of the detection object only system temperature resolution value, the highest minimum temperature the body to be detected of the <br/> background area Below the temperature Sets the lower limit of the temperature measurement range only system temperature resolution values than the minimum temperature of the background area low,
When the minimum temperature of the background area is higher than a value obtained by adding a system temperature resolution value to the maximum temperature of the object to be detected, the lower limit value of the temperature measurement range is reduced to the minimum temperature resolution value of the infrared camera from the upper limit value. An infrared surveillance system, characterized in that the system is configured to set a value lower by a value multiplied by a tone number. 2. A claim 1, wherein the infrared monitoring system, the setting of the temperature measurement range of the infrared camera (1), characterized in that a revised update means for updating at regular time intervals (4) Infrared monitoring system.