JP2019045556A - Monitoring device - Google Patents

Abstract

To make a camera hardly be viewed from a care receiver side, thereby to reduce consciousness of being monitored by the camera.SOLUTION: A plurality of plates, for example, two polarizing plates 21 and 22 are arranged by overlapping with each other at a front of a camera 10 in a state where the polarizers are relatively rotated a predetermined angle, a polarizer unit 20 of which visible light transmittance is 25% or less (preferably 5 to 25%) is arranged. Thereby, the camera 10 is made hardly be viewed from a care receiver side.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a monitoring apparatus for monitoring the condition of a patient (patient) with a camera in, for example, a hospital ward etc. More specifically, the polarizing plate obscures the camera from the side of the patient with a polarizing plate, The present invention relates to a monitoring device which is made not to be conscious.

  Especially in nursing homes etc., the condition of the care recipient requiring constant care is constantly monitored by the camera regardless of day and night, but some carers have a strong awareness of being monitored, and it is unpleasant. There are people who think or feel that the presence of the camera itself is bothersome. Therefore, it is better to hide the surveillance camera so as to be inconspicuous, preferably invisible.

  Although patent document 1 describes placing a polarizing plate in front of a camera, this mainly suppresses reflection in the visible light region to obtain a clear image, and in infrared imaging in a dark place Is to prevent darkening of the image, and the camera may be seen from the subject side.

  Although the polarizing plate used by the invention described in patent document 1 is one, the technique which uses two polarizing plates also exists. For example, Patent Document 2 describes changing the amount of transmitted light by changing the relative rotation angle of two polarizing plates.

  However, Patent Document 2 relates to a technique for controlling the exposure of a camera, and does not make it difficult to view the camera itself in order to reduce awareness of surveillance by the camera.

  Another method of hiding the surveillance camera is to use a magic mirror. However, the magic mirror has low transmittance even in the infrared region, and the photographed image is darkened. As a countermeasure, high-intensity auxiliary light may be used as a lighting device, but it is not preferable from the viewpoint of cost and energy saving.

JP 2015-212742 A Unexamined-Japanese-Patent No. 2006-337658

  Therefore, an object of the present invention is, for example, in a monitoring device that monitors the condition and motion of a cared person (patient) with a camera in a hospital ward etc., the camera can be made less visible from the cared person side by a simple configuration. To reduce their awareness of being monitored by

  In order to solve the above-mentioned subject, the surveillance device of the present invention has sensitivity which can be picturized in visible light field and infrared field, and arranges in the front of the above-mentioned surveillance subject area side of the camera and which picturizes surveillance object area A plurality of polarizing plates each having a polarization characteristic in the visible light region and having no polarization characteristic in the infrared region, both of which are rotated by a predetermined angle relative to each other. It arranges in piles, and it is characterized by the transmissivity in visible light field in the whole of the above-mentioned polarizing plate unit being 25% or less.

  In the present invention, the transmittance of the entire polarizing plate unit in the visible light region is preferably 5 to 25%.

  In order to obtain the transmittance as described above, when the number of polarizing plates is two, the relative rotation angle of the polarization axes is 40 to 65 degrees.

  In addition, an illuminance meter for measuring the illuminance of the monitoring target area, a human sensor for detecting a person in the monitoring target area, and a light emitting unit for emitting auxiliary light of infrared light and / or visible light to the monitoring target area And a control unit configured to control the light emitting unit, wherein the control unit causes the light emission when the illuminance measured by the illuminance meter is equal to or less than a predetermined value, and a person is detected by the human sensor. The aspect which drives a part is also included in this invention.

  According to the present invention, a polarizing plate having a transmissivity of 25% or less (preferably 5 to 25%) is disposed on the front of the camera in a state where a plurality of polarizing plates are relatively rotated by a predetermined angle. By arranging the unit, it is possible to hide the camera from the care receiver side, and the awareness of being monitored by the camera is reduced.

BRIEF DESCRIPTION OF THE DRAWINGS The perspective view which shows typically the monitoring apparatus which concerns on embodiment of this invention. The schematic diagram which shows the combination of two polarizing plates contained in the polarizing plate unit with which the said monitoring apparatus is equipped. The perspective view which shows an example as three polarizing plates contained in the said polarizing plate unit. The circuit diagram which shows an example of the auxiliary | assistant illuminating device with which the said monitoring apparatus is equipped.

  Next, an embodiment of the present invention will be described with reference to FIGS. 1 to 4, but the present invention is not limited to this.

  As shown in FIG. 1, the monitoring device according to this embodiment includes, as a basic configuration, a camera 10 that captures (captures) an area to be monitored A, and a polarizing plate unit 20.

  The camera 10 is a camera having sensitivity capable of photographing in a visible light region and an infrared region, and a commercially available product can be used. In this embodiment, although the monitoring target area A is a bed on which a cared person wakes up and the periphery thereof, for example, it may be used for an automatic door opening / closing device or a security device, or may be used for vehicle detection. The surveillance camera 10 of this type is often installed at a place where the surveillance target area A can be overlooked by the height of a wall, a ceiling surface, a stand or the like.

  The polarizing plate unit 20 is disposed on the front side of the monitoring target area A of the camera 10. In practice, the polarizing plate unit 20 is housed together with the camera 10 in a housing for housing the camera (not shown) so as to cover the front of the camera 10.

  In this embodiment, the polarizing plate unit 20 includes two polarizing plates 21 and 22. Both the polarizing plates 21 and 22 have polarization characteristics in the visible light region, but do not have polarization characteristics in the infrared region. The polarizing plate may be called a polarizing film or a polarizing sheet or the like.

  Here, visible light refers to light having a wavelength of 360 nm to less than 700 nm, and infrared light (infrared light) refers to light having a wavelength of 700 nm or more, particularly 700 to 940 nm.

  The polarizing plates 21 and 22 are, for example, polarizing plates in which protective layers made of triacetyl cellulose (TAC) are provided on both sides of a stretched film obtained by uniaxially stretching polyvinyl alcohol dyed with iodine or the like. Thus, a commercially available product can be adopted as long as it has polarization characteristics for visible light and has a characteristic of transmitting infrared light.

  The polarizing plate 21 and the polarizing plate 22 are disposed in an overlapping manner, but the other polarizing plate is rotated with respect to the one polarizing plate, and the polarizing axis of the other polarizing plate is made with respect to the polarizing axis of one polarizing plate. By inclining a predetermined angle, the transmittance of the polarizing plate unit 20 to visible light can be changed.

  As an example in FIG. 2, the polarization axis of the polarization plate 22 is inclined 50 degrees (rotated) with respect to the polarization axis of the polarization plate 21, and the polarization plate 21 and the polarization plate 22 are superimposed to form a polarization plate unit 20. An example is shown. In this specification, the angle (50 degrees in the example of FIG. 2) which rotates the polarization axis of the other polarizing plate with respect to the polarization axis of one polarizing plate in this way is referred to as a relative rotation angle.

  As an example, in order to obtain the transmittance when the camera 10 is hidden by the polarizing plate unit 20 and the camera 10 becomes difficult to see when viewed from the monitoring target area A side, the following experiment was performed.

  As the polarizing plates 21 and 22, two Artec (model number: 093493) were prepared. The transmittance was measured by a spectrophotometer U-4100 manufactured by Hitachi High-Tech Fielding. The evaluation was made by naked eye judgment, with the camera clearly visible (no concealment effect) as "x", beginning to be difficult to see (the concealment effect begins to appear) as "Δ", difficult to see (with concealment effect) as "o" .

  The transmittance of 550 nm of the Artec polarizing plate was 51.7%, and the transmittance of 940 nm was 88.0%. One polarizing plate 21 is fixed with its polarization axis horizontal, and the other polarizing plate 22 is fixed at 0 degrees (parallel), 20 degrees, 25 degrees, 30 degrees, 40 degrees, 45 degrees, 50 degrees, 60 degrees, 65 degrees The transmittance at 550 nm and the transmittance at 940 nm were measured by rotating them at 70 degrees and 90 degrees (orthogonal). The results are shown in Table 1 below.

  When the transmittance at 550 nm is 25%, the camera starts to be difficult to see. When the transmittance is smaller than 22%, the concealing effect is sufficiently exerted and the camera becomes difficult to see. Therefore, the transmittance at 550 nm, which does not make the cared person aware of the cared person, is 25% or less.

  When the transmittance at 550 nm is less than 5%, the image becomes dark due to the lack of light, and in the case of a polarizing plate using iodine, a blue leak phenomenon occurs, so the preferred transmittance at 550 nm is 5 to 25. %. This range is 40 to 65 degrees (preferably 45 to 60 degrees) in terms of a relative rotation angle.

  The polarizing plate unit 20 may include three polarizing plates by adding one polarizing plate 23 to the two polarizing plates 21 and 22 in the above embodiment as shown in FIG.

  In this case, if the total transmittance of the three polarizing plates 21, 22, and 23 (the transmittance as the polarizing plate unit 20) is 5 to 25%, the breakdown of the relative rotation angle (polarizing plate 21 and polarizing plate 22 The relative rotation angle of the polarizing plate 22 and the polarizing plate 23 is not particularly limited, but as an example, the relative rotating angle between the polarizing plate 21 and the polarizing plate 22 is 10 degrees, and the polarizing plate 22 and the polarizing plate 23 The transmittance was 21.2% when the relative rotation angle between them was 40 degrees (total of 50 degrees).

  By the way, by using a plurality of polarizing plates stacked as described above including the case of photographing in a dark place, the light amount of visible light decreases, and in dimly lit areas, the light amount at the time of photographing may be insufficient. is there. Therefore, the monitoring device according to this embodiment includes the auxiliary lighting device 30 shown in FIG.

  The auxiliary lighting device 30 includes a light emitting unit 31 and a control unit 32 that controls the light emitting unit 31. In this embodiment, the light emitting unit 31 is provided with a plurality of infrared light emitting diodes 311. Instead of the infrared light emitting diode 311, a visible light source may be used. The infrared light emitting diode 311 and the visible light source may be used in combination.

  The control unit 32 includes an illuminance meter 321 that measures the illuminance of the monitoring target area A, a human sensor 322 that detects a person in the monitoring target area A, and switches SW1 and SW2. As the illuminance meter 321, CdS (cadmium sulfide), a CMOS sensor or a photodiode may be used. For the human sensor 322, a pyroelectric element may be used. Preferably, an electronic switch such as a FET is used as the switches SW1 and SW2.

  One end of the light emitting unit 31 on the anode side is connected to the in-device power supply DRV via the switch SW1, and the other end on the cathode side of the light emitting unit 31 is connected to the ground in the device via the switch SW2. The illuminance meter 321 is connected to the base of the switch SW1 (FET), and the human sensor 322 is connected to the base of the switch SW2 (FET).

  According to this, when the environment of the monitoring target area A is dark with a predetermined illuminance or less (for example, 100 lx or lower) and a person exists in the monitoring target area A, both the switches SW1 and SW2 are turned on (conductive). Thus, the light emitting unit 31 is supplied with power, and the light emitting unit 31 is turned on to emit infrared light toward the monitoring target area A.

  As described above, according to the present invention, a plurality of polarizing plates are arranged in a relatively rotated state relative to each other in front of the camera 10, and the visible light transmittance is 25% or less. By disposing the polarizing plate unit 20 preferably having a ratio of 5 to 25% (40 to 65 degrees in terms of the relative rotation angle of the polarizing plate), the camera 10 can be made difficult to see from the care receiver side. Awareness of being monitored by

  Also, when the environment of the monitoring target area A is dark with a predetermined illumination intensity or less (for example, 100 lx or lower) and a person exists in the monitoring target area A, infrared light and / or Alternatively, since visible light is emitted, reliable monitoring can be performed even in a dark place.

DESCRIPTION OF SYMBOLS 10 Camera for monitoring 20 Polarizing plate unit 21, 22, 23 Polarizing plate 30 Auxiliary illumination apparatus 31 Light emission part 311 Infrared light emitting diode 32 Control part 321 Illuminance meter 322 Human sensor SW1, SW2 switch

Claims (4)

The camera has a sensitivity capable of photographing in a visible light region and an infrared region, and includes a camera for photographing a monitoring target area, and a polarizing plate unit disposed in front of the monitoring target area of the camera.
In the above polarizing plate unit, a plurality of polarizing plates having polarization characteristics in the visible light region and not having the polarization characteristics in the infrared region are overlapped and disposed in a relatively rotated state by a predetermined angle, A monitoring device characterized in that the transmittance in the visible light region of the entire plate unit is 25% or less.   2. The monitoring device according to claim 1, wherein the transmittance of the entire polarizing plate unit in the visible light region is 5 to 25%.   The monitoring device according to claim 1 or 2, wherein the number of the polarizing plates is two, and the relative rotation angle of the polarization axes is 40 to 65 degrees.   An illuminometer for measuring the illuminance of the monitoring target area, a human sensor for detecting a person in the monitoring target area, a light emitting unit for irradiating the monitoring target area with infrared and / or visible auxiliary light, and The light emitting unit further includes a control unit that controls the light emitting unit when the illuminance measured by the illuminance meter is equal to or less than a predetermined value and a person is detected by the human sensor. The monitoring device according to any one of claims 1 to 3, wherein the monitoring device is driven.

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