JP2000244900A - Television interphone - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a television interphone which can confirm a person photographed by a photographing camera of a slave set without deteriorating the monitor visibility of a master set. SOLUTION: This interphone includes an image pickup means 31 which photographs an object such as a visitor, a projection means 33 which radiates the light on the object, a lighting control means 34 which performs the turn-on/off control of the means 33 when the object is photographed by the mens 31, an image memory/differential means 35 which stores the image photographed by the means 31 and then performs the differential processing when the means 33 is turned on and off and a photometry means 36 which calculates the luminance level of an area that is acquired via the differential processing. Then a slave set 3 is added to correct the calculated luminance level so as to feed the luminance level back to the means 31 and to photograph a differential area at a desired luminance level together with a master set 7 which displays the object image that undergone the feedback control on a monitor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television capable of monitoring the face or figure of a monitoring target such as a visitor in an ordinary house or apartment house with an image pickup camera and confirming the image on a monitor installed in the house. It concerns intercoms.

[0002]

2. Description of the Related Art In a conventional television intercom, a CC with an electronic shutter and an automatic gain control (AGC) function is provided in a slave unit.
An image pickup device such as a D camera is provided, and feedback control is performed so that the average luminance of the screen is constant. As a result, even when the illumination state for imaging the subject changes, the image of the monitoring target displayed on the monitor can be imaged so as not to cause loss of white or black.

[0003]

However, in the conventional television intercom, control is performed based on the average luminance of the entire screen. Therefore, for example, when a person stands in front of the imaging unit with the retrograde state as the background, the ratio of the area occupied by the background on the screen is large,
As the average brightness, the brightness level of the background is dominant, and feedback control is performed at that brightness level, and the brightness level of the face and body of the visitor being monitored is relatively lowered and darkened, resulting in poor visibility. Had.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to reduce the visibility of a person imaged by an imaging camera of a child device on a monitor of a parent device. It is an object of the present invention to provide a TV intercom that allows the user to check without any trouble.

[0005]

According to the first aspect of the present invention,
Image capturing means for capturing an image of a monitoring target such as a visitor, light emitting means for irradiating light to the monitoring target, lighting control means for controlling turning on / off of the light emitting means when capturing the monitoring target by the image capturing means, An image memory / difference unit that stores a video imaged by the imaging unit when the light emitting unit is turned on and off and performs a difference process, and a photometry unit that calculates a luminance level of an area obtained by the difference process. And a master unit that corrects the difference level so that the difference area is imaged at a desired brightness level by feeding back the brightness level to the imaging unit, and a master unit that displays an image of the monitoring target that is feedback-controlled on the monitor. It is characterized by the following.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a television interphone according to an embodiment of the present invention will be described in detail with reference to FIGS. FIG. 1 is a schematic configuration diagram of a television intercom. FIG. 2 is an explanatory diagram showing a time change of the photometric signal and the infrared light emitting diode signal. FIGS. 3A and 3B are explanatory diagrams showing a process of extracting a site of interest. FIG. 3A shows an image before processing, FIG. 3B shows an image when an infrared light emitting diode is turned on, and FIG. The image when the outside light emitting diode is turned off is shown, and (d) shows the extracted target part (person area)
And (e) shows an image of which brightness is controlled in the person area.

[0007] TV intercom 1 according to the present embodiment
In, the deterioration of the visibility caused by using the average luminance of the entire screen for the control of the screen luminance is controlled based on the luminance level of a target portion of the screen (for example, a face or a body of a visitor). In this way, the target portion can always be monitored with appropriate luminance.

In a conventional TV door phone, a light emitting means (for example, an infrared light emitting diode) is turned on in order to eliminate insufficient lighting at night, and a relatively short distance (about 5 km from the camera).
It is common to illuminate a visitor (assuming 0 cm). However, in the TV door phone of the present embodiment, an attention site is extracted using the reflected light. Specifically, the infrared light emitting diode is turned on for a certain one frame period, and the infrared light emitting diode is turned off in the next one frame. This is to obtain a pair of images that do not exist, and extract the region of the attention site from the comparison.

[0009] Television intercom 1 according to the present embodiment.
As shown in FIG. 1, a slave unit 3, a signal transmission system 5 for transmitting an image signal, and a monitor (not shown) for displaying an image
And a parent device 7 having

The slave unit is an image pickup means 31 such as a CCD camera.
A synchronizing signal generating means 32 for supplying a synchronizing signal to the imaging means 31;
A synchronous lighting control means 34 for controlling the lighting of the infrared light emitting diode 33 in accordance with the synchronization signal; and a video signal from the imaging means 31 which is digitized and stored. An image memory / difference means 35 for performing a difference process from a video signal; a photometric means 36 for calculating a luminance level of the video signal in accordance with the output thereof; Multiplexes audio signals and the like emitted by the
And a multiplexing means 37 for sending to the master unit 7 via

The synchronizing signal generating means 32 generates a synchronizing signal for the imaging means 31 by self-running. This synchronization signal is supplied to the image pickup means 31 and also to the synchronous lighting control means 34. The synchronous lighting control means 34 creates a photometric signal for extracting a target part.
As shown in FIG. 2, the synchronous lighting control means 34 generates a photometric signal over two frame periods, in which the infrared light emitting diode 33 is turned on for one frame period, and the infrared light emitting diode 33 is emitted for the next one frame. The light emitting diode 33 is controlled to be turned off, and the light metering means 36 is notified of the light metering period. This photometry is for the TV door phone 1
Are started at the time of starting image display or periodically during image display.

As shown in FIG. 2, one frame corresponds to two frames.
Since it is composed of fields, the two-frame period of the photometric signal is a four-field period. In this embodiment,
Although the lighting / light-off period is set to one frame, the lighting / light-off period is not limited to this, and half of the field processing can be simply performed.

The image pickup means 31 used here is a fixed image pickup element such as a CCD camera, which generates a video signal in synchronization with an external synchronization signal and performs feedback control in response to an external input. Controls the electronic shutter, performs automatic gain control (AGC), and controls the luminance in imaging.

The image memory / difference means 35 is
The video signal from 1 is digitized, one frame is stored, a difference from the next one frame is made, and an image having a large difference is set to "1" by comparing with a predetermined threshold value, and the others are set to "0". Output. This binarized image is input to the next-stage photometric unit 36 as a photometric pattern. The photometric means 36 digitizes the video signal and, when the above-described photometric pattern is input during the photometric period from the synchronous lighting control means 34, stores the video signal data of the pixel “1” and simultaneously stores the data of the pixel “1”. The average luminance of the target portion is calculated from the sum of the number of pixels for one screen, and the information is fed back to the imaging unit 31. Thereby, in the imaging means 31,
The control is performed so that the luminance of the target portion becomes appropriate (for example, the median value).

The above processing will be described with reference to FIG. FIG. 3A shows an image before processing. As shown in this image, in the TV door phone 1, when a person is standing in front of the child unit 3, when the sun is present in the background, or when the background is irradiated with sunlight, the brightness of the background is increased. In many cases is much higher than the brightness of the face. In such a case, the bright background is dominant in the normal imaging means 31, and the visitor's face is often overblown due to lack of its dynamic range.

With respect to such an image, in the television door phone 1 according to the present embodiment, the infrared light emitting diode 33 is turned on and off in units of frames, and a region of interest is extracted. FIG.
FIG. 3B is an example of an image when the infrared light emitting diode 33 is turned off, and the region of the person is dark as in FIG. Next, the difference processing is performed on the images when the infrared light emitting diode 33 is turned on and off as shown in FIGS. 3B and 3C, and the binarization processing is performed using a preset threshold value. As a result, it is possible to extract a target part (person area) as shown in FIG. Of course, strictly speaking, the reflectance of the face, clothes, and the like is not constant in the region of the person, so it is actually difficult to completely extract all the desired regions as shown in FIG. However, it is possible to extract a region of a desired desired region of interest. The average brightness of only the region extracted in this way is calculated by the photometry means 36 and fed back to the imaging means 31 so that the brightness of the target portion, that is, the brightness of the person is properly controlled as shown in FIG. It will be done. In the above-described control, a bright background (clouds in the bright sky or the sun) may cause overexposure. However, in view of the purpose of the TV door phone 1, even if a bright background such as the sky becomes difficult to see, it is considered that there is no problem in use.

In the above description, the case where the background is brighter than the person is assumed. On the contrary, even when the background is dark and the part of the person is bright, the reflection of the infrared light-emitting diode 33 is also considered. It goes without saying that the same control function can be realized as long as there is a luminance difference in the light.

In this case, the infrared light emitting diode 33 is used for extracting the target portion. However, the infrared light emitting diode 33 is mounted on the general TV door phone 1 and a light emitting means is newly added. This is because the infrared light emitting diode 3
Light sources other than 3 may be used.

Further, here, an external synchronization type which operates in synchronization with an external synchronization signal is used as the imaging means 31, but an internal synchronization type which generates a synchronization signal by itself and operates at that timing may be used. , Can be used as long as the synchronization signal is output to the outside. In this case, since the synchronization signal from the imaging unit 31 is directly input to the synchronous lighting control unit 34, the synchronization signal generation unit 32 is not required and a simple configuration can be achieved.

[0020]

As described above, according to the first aspect of the present invention, the image pickup means for picking up an object to be monitored such as a visitor, the light projecting means for irradiating light to the object to be monitored, and the image pickup means A lighting control unit for controlling turning on / off of a light projecting unit when capturing an image of a monitoring target; an image memory / difference unit for storing a video imaged by the imaging unit when the light emitting unit is turned on and off, and performing a difference process; A sub-unit that includes a photometric unit that calculates the luminance level of the region obtained by the difference processing, and that corrects the difference region so as to be imaged at a desired luminance level by feeding back the obtained luminance level to the imaging unit; The main unit that displays the image of the monitored object under feedback control is displayed on the monitor. Target image Is extracted as a target part, and feedback control is performed on the imaging means based on the luminance level of the monitoring target, so that a person imaged by the imaging camera of the child device is not deteriorated in visibility on the monitor of the parent device. There is an effect that it is possible to provide a TV interphone that enables confirmation.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a television intercom.

FIG. 2 is an explanatory diagram showing a time change of a photometric signal and an infrared light emitting diode signal.

FIGS. 3A and 3B are explanatory diagrams showing a process of extracting a target portion, wherein FIG. 3A shows an image before processing, FIG. 3B shows an image when an infrared light emitting diode is turned on, and FIG. An image when the infrared light emitting diode is turned off is shown, (d) shows an extracted target part (person area), and (e) shows an image of which brightness is controlled in the person area.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 TV interphone 3 Remote device 5 Signal transmission means 7 Master device 31 Imaging means 32 Synchronization signal generation means 33 Infrared light emitting diode (light projection means) 34 Synchronous lighting control means 35 Image memory / difference means 36 Photometry means 37 Multiplexing means

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[Procedure amendment]

[Submission date] March 25, 1999 (1999.3.2
5)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0003

[Correction method] Change

[Correction contents]

[0003]

However, in the conventional television intercom, control is performed based on the average luminance of the entire screen. Thus, for example, when a person stands in front of the image pickup means opposite the light state as the background, because the ratio of the area occupied by the background in the screen is large,
As the average brightness, the brightness level of the background is dominant, and feedback control is performed at that brightness level, and the brightness level of the face and body of the visitor being monitored is relatively lowered and darkened, resulting in poor visibility. Had.

Claims (1)

[Claims] 1. An image capturing means for capturing an image of a monitoring target such as a visitor, a light projecting means for irradiating light to the monitoring target, and turning on / off of the light emitting means when the monitoring target is imaged by the image capturing means. Lighting control means, image memory / difference means for storing a video taken by the imaging means when the light emitting means is turned on and off, and performing difference processing, and photometric means for calculating a luminance level of an area obtained by the difference processing A slave unit that feeds back the obtained luminance level to the imaging unit and corrects the difference area so that the difference area is imaged at a desired luminance level, and a master unit that displays a video of the feedback-controlled monitoring target on the monitor. A television intercom, characterized in that it consists of: