JPH04192985A - Video interphone - Google Patents

Abstract

PURPOSE:To surely and easily visibly monitor visitors with simple constitution by obtaining the difference between the images when there are no visitors and when there is a visitor, finding the central point of the face region of the visitor from the differential image and macrodisplaying this point. CONSTITUTION:The image in the state of having no visitors is previously stored as a reference image into a reference image memory 23. The difference between the present image and the reference image is obtd. by a differentiating means 24 when the visitor appears. The region changed by the visitor is extracted from the differential image by a binarizing means 26. The center line G of the image of the visitor and the uppermost position M of his head are detected by a means 27 for detecting the center and uppermost part. The central point C of the face is detected by a means 28 for detecting the central point of the face region. The position of the central point is brought to the center of the screen by a reading out control means 29 and the reading out control signal for macrodisplaying the nearby region E over the entire part of the screen is outputted to a present image memory 22. The visitor is macrodisplayed on the screen of a monitor 30 and, therefore, the visitor is surely and easily visibly monitored with the simple constitution.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a television camera that images the faces of visitors at entrances, gates, etc. of ordinary homes, etc., and monitors them inside the house. It concerns intercoms.

[Conventional technology]

This type of TV intercom consists of a slave device with a built-in TV camera that is installed at the entrance or gate of a general home, and a parent device that is installed inside the house and has a built-in monitor. The system uses a television camera to capture the image, sends the image signal to a device, and uses a monitor to confirm whether the person is a family member or a visitor.

In order to capture the image of a visitor standing in front of the entrance on the monitor, such TV intercoms are equipped with a mechanical viewing angle and adjustment function. Since images are taken in the field of view, if the visitor's standing position or height changes, it is not possible to accurately image the visitor.

In order to improve the above-mentioned drawbacks, the direction of the TV camera in the slave device can be changed mechanically under control from the device to obtain the desired field of view, or a wide-angle imaging lens can be used to adjust the imaging field of view in advance. Wide (some settings are set).

[Invention or problem to be solved]

On the other hand, the former method requires complicated mechanical parts and driving parts because it is necessary to mechanically change the angle of the TV camera in two axes, horizontal and vertical, which increases costs and can lead to malfunctions. The disadvantage is that it becomes easier to use and also has a shorter lifespan.

Also, the latter has a small monitor screen, so
The problem is that the visitor's face is displayed small in a part of the screen, making it difficult to confirm whether it is the visitor's face, and that a mechanical mechanism is required to zoom in on the visitor's face, which can cause malfunctions. There was a point.

The present invention has been made in view of the above points, and its purpose is to ensure that visitors can
Moreover, the object is to provide a television intercom that can be easily viewed and monitored.

[Means to solve the problem]

The present invention provides a television intercom comprising a slave device that images a visitor, etc. and outputs a video signal, and a device that captures the video signal output from the slave device via a transmission line and displays it on a monitor. an imaging means for imaging visitors, etc.;
The device includes a video output circuit that outputs a video signal from the imaging device to a transmission line, and the device includes an A/D conversion device that digitizes the video signal transmitted via the transmission line, and an A/D conversion device that digitizes the video signal transmitted via the transmission line. A current image memory that stores the output from the D conversion means as digital image data, a reference image memory that stores a reference image in advance, and a difference means that compares the outputs of the current image memory and the reference image memory and calculates a difference. and a binarization means for binarizing the output of the difference means and cutting out a changing region;
A center/top detection means detects the center line and the top position of the cut out area of change, and a center/top detection means detects the center line and the top position of the cut out area of the face, and detects the face area from the distance between the imaging unit and the visitor, the center line of the area of change, and the position information of the top. A face area center point detection means for determining the center point; a readout control means for generating and outputting an image data readout control signal for enlarging and displaying the face area using the obtained face area center point information; The apparatus is characterized in that it has a D/A conversion means for D/A converting the image data obtained by the image data, and a monitor for displaying the analog image signal outputted from the D/A conversion means on a screen.

[Effect]

In the TV intercom of the present invention, the difference between the reference image when there are no visitors and the current image when there are actually visitors is used to determine the amount of change in the number of visitors, etc., and the face of the visitor is calculated from the difference image. The center point of the area is determined and the image is enlarged to a predetermined size around this point.

〔Example〕

An embodiment of the present invention will be described based on the drawings. Figure 1 shows
FIG. 1 is a block diagram showing an embodiment of the present invention. 1 is a slave device installed at the entrance, gate, etc. of a general household, and is used to photograph visitors and output the video signal. The child organ l is
It includes an imaging means 11 for taking an image of a visitor, and a video output circuit 12 for transmitting a video signal output from the imaging means 11 from a slave device 1 to a device 2 to be described later. Video output circuit 1
2 includes a balancing circuit if, for example, a simple pair of wires such as a telephone line is used as a transmission line and the video signal and power source are superimposed. The imaging means 11 is set to have a wide angle to absorb variations such as the position and height of the visitor standing in front of the child device 1, and it is preferable to use a CCD imaging device from the viewpoint of cost and stability.

Reference numeral 3 denotes a transmission line such as a coaxial cable or a telephone line, which transmits the video signal output from the slave device 1 to the device 2.

Reference numeral 2 denotes a device installed in the house, which takes in a video signal inputted from slave device 1 via transmission line 3 and monitors the video. The device 2 is an A/D conversion means 2
1. Current image memory 22, reference image memory 23, difference means 24, D/A conversion means 25, binarization means 26, center/top detection means 27, face area center point detection means 28, readout control means 29, and It includes a monitor 30. A
The A/D conversion means 21 A/D converts the video signal inputted from the slave device 1 via the transmission line 3, and obtains, for example, digital image data of 8 bits per pixel. The current image memory 22 temporarily stores the image data of the current image, and the reference image memory 23 stores in advance the image data of the image when there are no visitors. The memory size of the image memories 22 and 23 is, for example, 51
It is 2x512 or 256x256. The reference image is updated at regular intervals, for example, because the entire background changes between day and night. At that time, 1
When compared with the previous reference image, if the difference is small, update it as a new reference image and store it in the reference image memory 23, or if the difference with the previous reference image is large, use the imaging means There's a high possibility that someone was just passing by in front of 11, so I'll try not to update it. The difference means 24 takes the difference between the image data of the current image memory 22 and the reference image memory 23. The current image memory 22 and the reference image memory 23 are read out at the same time, and the portion where the brightness changes due to the visitor is extracted. Since the difference value is the difference between corresponding pixels of the reference image and the current image, it naturally takes a positive or negative value, or here, the difference in absolute value is calculated. The binarization means 26 binarizes the difference value obtained by the difference means 24 using a predetermined threshold value, thereby extracting a region changed by the visitor. The center/top detection means 27 includes 2
The center and the top of the visitor in the X-axis direction are determined using the binarized image data indicating the change area outputted from the value converting means 26. Here, we first find the center of gravity of the changing region, that is, the X
determining the center of the visitor by calculating the average value of the coordinates, and further determining the top position of the changing area;
In other words, the topmost part of the visitor's face can be determined by finding the pixel with the largest value of the X coordinate of all the pixels constituting the area. The face area center point detection means 28 is for finding the center point of the visitor's face area. In other words, assuming the size L of the visitor's face (for example, 30 cm), the distance between the visitor and the imaging means 11 determined by the distance sensor 4, which will be described later, and the focal length d of the imaging means are used to determine the size of the image on the screen. The face size X in can be found by d-D/L, and the center point of the face can also be found. The readout control means 29 outputs a readout control signal for reading out the current image to the current image memory 22 so that a predetermined size centered on the center point of the face is enlarged and displayed on the entire screen. The D/A conversion means 25 performs D/A conversion on the image data read from the current image memory 22 and converts it into an analog video signal. The monitor 30 displays the video signal from the D/A conversion means 25.

Normally, a general video signal has 525 scanning lines, and if we assume that the vertical size of the image memory 22 is 256 lines, there are only 1/2 scanning lines, so one screen can be read out by reading the same content twice. Form. That is, in the vertical direction,
If the same content is displayed across two interlaced fields, will the same data be lined up on two lines?
As a result, the image is displayed enlarged to fill the entire screen.Next, the operation of the above embodiment will be explained. Figure 2 (a)
), an image with no visitors present is stored in the reference image memory 23 as a reference image. Figure 2 (b
), when a visitor appears, the difference means 24 calculates the difference between the current image and the reference image, and the difference image is converted into a binarized image by the binarization means 2.
In step 6, as shown in FIG. 2(C), areas changed by the visitor are extracted. Next, the center/top detecting means 27 detects the center line G of the visitor's image and the top position M of the head, as shown in FIG. , as shown in Figure 2(e),
The center point C of the visitor's face is detected. Based on the information on the center point C, the readout control means 29 brings the position of the center point C to the center of the screen, and then spreads the area E near the center point position, that is, the vicinity of the visitor, over the entire screen. A readout control signal for enlarged display is output to the current image memory 22. The current image data read out according to this readout control signal is converted into a video signal by the D/A conversion means 25, and then enlarged and displayed on the screen of the monitor 30 by the visitor, as shown in FIG. 2(f). It will be done.

The distance sensor 4 determines the distance between the imaging means 11 and the visitor, and sends distance data to the face area center point detection means 28.

Note that in this embodiment, distance data from the distance sensor 4 is used when determining the center point of the face area, but a preset value may be used as the distance data.

〔Effect of the invention〕

As described above, the television intercom of the present invention has the following features:
By taking the difference between the reference image when there are no visitors and the current image when there are actually visitors, the amount of change in the number of visitors, etc. is determined, and the center point of the visitor's face area is determined from the difference image. Since the display is enlarged to a predetermined size with a dot as the center, it is possible to provide a television intercom that can be easily viewed and monitored by visitors with a simple configuration.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIGS. 2 and 3 are operation explanatory diagrams of the same. ■-Slave device 2-Sensitive device 3 Transmission line 4-Distance sensor 1m-Imaging means 12-Video output circuit 21-A/D conversion means 2
2 Current image memory 23--Reference image memory 24-Difference means 25-D/A conversion means 26-Binarization means 27-
Center/top detection means 28 - face area center point detection means 29 - readout control means 30 - monitor Fig. 2 (C)' (d) 1

Claims (1)

[Claims] (1) A television intercom consisting of a slave unit that images a visitor and outputs a video signal, and a master unit that captures the video signal output from the slave unit via a transmission line and displays it on a monitor, the slave unit being , a video output circuit that outputs a video signal from the imaging device to a transmission line; and a video output circuit that outputs a video signal from the imaging device to a transmission line, and the parent device digitizes the video signal transmitted via the transmission line. A/D conversion means for
A current image memory that stores the output from the D conversion means as digital image data, a reference image memory that stores a reference image in advance, and a difference means that compares the outputs of the current image memory and the reference image memory and calculates a difference. , a binarization means for binarizing the output of the difference means and cutting out a changed area, a center/top detection means for detecting a center line and a top position of the cut out changing area, the imaging means and a visitor. face area center point detecting means that calculates the center point of the face area from the distance between the two areas, the center line of the changing area, the top position information, etc.; and the facial area center point detection means that enlarges and displays the face area using the obtained face area center point information. a readout control means for generating and outputting a readout control signal for image data, a D/A conversion means for D/A converting the read image data, and an analog image signal output from the D/A conversion means. A television intercom characterized by having a monitor that displays on a screen.