JPS615689A - Visitor recognizing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to visitor recognition in which visitors outdoors are photographed and recognized by a television camera. Light, shadow□ゎmu. It's small, □Oigao.

It is something.

[Conventional technology]

As shown in Figure 4, a conventional visitor recognition device (1), such as the ZV-118 manufactured by Mitsubishi Electric Corporation, is installed on a wall (3) near the entrance (2) of a home, etc. It consists of a doorbell function with a microphone (4), a speaker (5), and a push button (8) for talking to visitors, a television camera (6) for taking images of visitors, and a light source for taking images (7).

Additionally, inside the room there is a monitor TV that displays images of visitors photographed by a television camera (6), and a device for communicating with visitors. FIG. 5 is a partial cross-sectional view taken along the line -v in FIG. 4, and shows the arrangement of the television camera. In the figure, the main body case (9) houses the television camera body α and the lens part I, and the main body case in front of the lens and the front panel (2) each have an opening tss for imaging, (14)
There is a translucent protective material α9 made of polycarbonate etc. in the opening αJ of the main body case to protect the TV camera.
is installed.

A visitor recognition device configured to be able to confirm a visitor using a television image as described above is commercially available as a doorphone with a television camera or a television doorphone.

By the way, the television camera equipped with a television camera or the television camera used in the television door phone is generally sensitive only to visible light, and the imaging light source is a fluorescent lamp or the like that emits visible light. Furthermore, as in Japanese Patent Application No. 57-198756, which was previously proposed by the inventors, a television camera sensitive to near-infrared light using an infrared-sensitized image pickup tube or a solid-state image pickup device is used as its image pickup device. , A rare gas such as Kr is used as the light source for imaging at several Torr! A visitor recognition device that uses a near-infrared light imaging device that uses a near-infrared light source with a low-pressure rare gas discharge lamp or light bulb equipped with a filter that blocks visible light and transmits near-infrared light. can also be considered. A visitor recognition device that captures images using such a near-infrared light source illuminates with near-infrared light that is invisible to the naked eye, so visitors do not experience any glare.

It has the advantage of causing less discomfort from being imaged.

[Problem that the invention seeks to solve]

A visitor recognition device is usually installed at the entrance of a home or the like where natural light enters, so it can be used from very bright conditions during the day to dark conditions at night. For this reason, there was a problem in that clear and stable images could not be obtained due to the influence of surrounding brightness.

For example, as a means of responding to changes in brightness.

It is possible to add a function to the TV camera section that automatically adjusts the aperture according to the surrounding brightness, but if the back of the visitor is very bright, There is a problem that the image becomes darker and the image becomes unclear. as a way to solve this problem.

One idea is to use a powerful light source that is less affected by surrounding brightness. However, this method is undesirable because it increases the power consumption of the lighting and leads to an increase in the size of the light source. In addition, when using a near-infrared light imaging device,
Since natural light has a wide radiation spectrum distribution from the visible region to the near infrared, there is a problem in that the quality of one image changes depending on whether it is illuminated only with a near infrared light source or when there is natural light. To solve this problem, it is sufficient to use a television camera that is sensitive only to near-infrared light and a light source that has a radiation spectrum distribution that matches the sensitivity of the television camera. However, this requires a very special combination of television camera and light source, making it impractical.

This invention eliminates the above-mentioned conventional problems.

The purpose of the present invention is to provide a visitor recognition device that can obtain a stable image regardless of the influence of surrounding brightness.

[Failure to solve the problem]

The visitor recognition device according to the present invention uses a near-infrared light source as an imaging light source, and transmits the near-infrared light to a television camera unit sensitive to near-infrared light that images the illuminated visitor. It is equipped with a filter that blocks light.

[Operation of the means to solve the problem]' The filter of the present invention transmits near-infrared light and blocks visible light, so it does not reduce the sensitivity to near-infrared radiation, and it does not reduce the sensitivity to near-infrared radiation. The substantial sensitivity to external light is reduced to suppress the influence on the brightness of the surrounding area.

[Embodiment] FIG. 1 is a partial sectional view of a television camera section showing an embodiment of the present invention. In the figure, αυ is a television camera body, and a photoconductive image pickup tube 84113 manufactured by Koshita Denshi Kogyo ■, which is sensitive to near-infrared light, is used. Oe is a filter installed behind the translucent protective member a9, that is, on the lens part αυ side, that blocks visible light and transmits the emitted light from the near-infrared light source.Mitsubishi Rayon NIR-NIR-
80 is used. Further, as a near-infrared light source, an 03A4A1 infrared light emitting diode (LR60RG-D grade) manufactured by Hitachi, Ltd. is used as the imaging light source (7).

Note that other than the above, this device is the same as the conventional device shown in FIGS. 4 and 5.

The operation of this configuration will be explained below with reference to FIG. 2. In Fig. 2, the curve aaη is the photoconductive image pickup tube 841130, the spectral sensitivity characteristic 9 is the curve α, the ladder is the filter 16), the spectral transmittance characteristic O1 is the near-infrared light source (7
) is the spectral sensitivity characteristic when filter 〇〇 is attached to the image pickup tube.

Now, the sensitivity of a television camera to natural light is approximately proportional to the area of the spectral sensitivity characteristic. Therefore, the sensitivity to natural light with the filter is about 115 compared to the case without the filter. On the other hand, the sensitivity of a television camera to a near-infrared light source is only about 20 inches lower than without the filter.

This makes the paper less susceptible to the effects of surrounding brightness.

In addition, the actual spectral sensitivity wavelength range becomes narrower.

Stable images can be obtained regardless of day or night. Also, it is K because it is less affected by external light such as natural light.

There is no need to use a powerful light source, and it becomes possible to use a light source with a lower output than conventional ones. This makes it possible to use light-emitting diodes, which have been difficult to use in the past despite their small size and long life.

For example, in the example shown in FIG. 4, the number of required light emitting diode chips may be 1/4 of that without a filter.

Fig. 3 is a characteristic diagram of another embodiment. In this embodiment, the TV camera body αα is equipped with Hitachi's new MO8 type solid-state image sensor HE97211, and the filter Oe is equipped with only a part of the near-infrared region. Corning's infrared filter 087-69 which shows selective high transmittance.

In addition, the imaging light source (7) is a newly manufactured Hitachi G.A.I.
An A s infrared light emitting diode HE8811 is used. Note that the other configurations are similar to the above embodiment shown in FIG.

In this figure, curve 1 (A) is the spectral sensitivity characteristic of the MO8 type solid-state sensor. Curve 9 +211 is the spectral transmittance characteristic of the filter S7-69, and @ is the radiation spectrum of the photographic light source HE8811.
11 vector distribution, @ is the spectral sensitivity characteristic when a filter is attached to the image sensor. As shown in FIG. 3, when the spectral sensitivity characteristics of the television camera are sufficiently extended toward longer wavelengths than the emission wavelength of the near-infrared light source.

It not only blocks short wavelengths, that is, visible light.

A filter that also blocks long wavelengths and selectively transmits the radiation spectrum of the light source is effective. In addition, in this invention, the sensitivity of the television camera is regulated by the filter, so it is not only possible to use a television camera that is specially sensitive to near-infrared light.
It is possible to use a general solid-state image pickup device, such as a MOS type or COD, which has sensitivity even outside the near range.

In addition, in Fig. 1, filter +141 is the lens part (11).
However, due to appearance issues, it may be installed so as to cover areas other than the television camera section at the same time.

For example, it is also possible to install a filter so as to block the front of the television camera and the near-infrared light source at the same time.

Furthermore, it is clear from the principle that the filter can be installed anywhere in front of the photoelectric conversion section of the television camera, without being limited to the main body case.

Further, in this invention, an example in which a light emitting diode is used as a near-infrared light source has been described, but the present invention is not limited to this.
It goes without saying that other near-infrared light sources, such as near-infrared rare gas discharge lamps that emit light from rare gases such as argon and krypton, can be used in the same way.

However, if a light emitting diode is used as a near-infrared light source, like a near-infrared rare gas discharge lamp, it will cause noise to the communication device and television camera, which are comprised of a microphone (4) and speaker (5) installed in the device. There is no need to worry about it, and unlike near-infrared light sources with filters attached to incandescent light bulbs, there are no problems with heat treatment as they do not require high temperatures.

Furthermore, if a filter that blocks visible light and transmits near-infrared light has selective transmission characteristics that almost matches the emission light region of the near-infrared light source.

Furthermore, it is possible to provide a visitor recognition device that is not easily affected by surrounding brightness and can stably obtain a nine-sided image.

〔Effect of the invention〕

As explained above, according to the present invention, in a visitor recognition device consisting of a television camera sensitive to near-infrared, a near-infrared light source, and a telephone device, visible light is blocked in the television camera section, and the near-infrared light source emits radiation. By installing a filter that transmits light, it is possible to obtain a stable image that is less affected by the surrounding brightness, does not require a special TV camera, and reduces the light output of the near-infrared light source. can do.

[Brief explanation of drawings]

FIG. 1 is a partially enlarged sectional view showing an embodiment of the television camera section which is the main part of the present invention, FIG. 2 is a spectral characteristic diagram of that embodiment, and FIG. 3 is a spectral characteristic diagram of another embodiment. Figure 4 is a schematic front view showing a conventional visitor recognition device, and Figure 5 is its V.
-V is an enlarged partial sectional view. In the figure, (4) is a microphone, (5) is a speaker, (6) is a TV camera, (7) is an imaging light source (near infrared light source), and i8
1 is a push button, aα is the television camera body, and αl) is a lens part. a9 is a transparent protective member, and 06) is a filter. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (5)

[Claims] (1) It has a television camera unit sensitive to near-infrared light and an imaging light source that emits near-infrared light, and illuminates visitors with near-infrared light emitted from the near-infrared imaging light source. A visitor recognition device that recognizes visitors by taking an image with a television camera, characterized in that the television camera section is provided with a filter that blocks visible light and transmits near-infrared light. (2) Visitor recognition according to claim 1, characterized in that the filter provided in the television camera section blocks visible light and selectively transmits radiation emitted from a near-infrared light source. Device. (3) The visitor recognition device according to claim 1 or 2, wherein the television camera is comprised of a solid-state image sensor. (4) The visitor recognition device according to any one of claims 1 to 3, wherein the near-infrared light source is a light emitting diode. (5) The visitor recognition device according to any one of claims 1 to 3, wherein the near-infrared light source is a rare gas discharge lamp.