JP2009261007A - Intercom system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an intercom system in which an intercom master unit can surely and automatically record an expanded visitor's face by magnifying a face part in an image taken by a door phone slave unit without any manual operations. <P>SOLUTION: In the intercom system, when a door phone slave unit 20 is operated, a video image processing section 25, which acts as an image processing means for an image taken with a camera part 24, performs an image processing operation so as to: detect the position of a visitor's face from the taken image; expand the detected face part; and send it to the master unit 1 to be recorded. Specifically, the master unit 1 can surely and automatically record an expanded visitor's face by magnifying a face part in an image taken with the door phone slave unit 20 without any manual operations. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an interphone system that records and reproduces an image of a visitor imaged by a doorphone slave installed outdoors using an interphone master installed indoors.

  As an interphone system of this type, as shown in FIG. 13, it is possible to make a call between a doorphone slave unit 60 with a camera installed at an outdoor entrance and a doorphone slave unit 60 installed indoors. There is provided an interphone system including an interphone master 50 that displays an image captured by a camera of the slave unit 60 on a display device such as a liquid crystal display and records the image (see Patent Document 1). That is, when a visitor presses the call button 61 of the doorphone slave unit 60, a call signal is transmitted to the interphone master unit 50, and the interphone master unit 50 that receives this call signal sounds a ringing tone as well as the doorphone slave unit 60. The camera is activated to image a visitor, and this captured image is displayed on the screen 51 of the display device. When the call button 52 of the intercom base unit 50 is pressed, a communication path is formed with the door phone slave unit 60, and a call can be made with a visitor while watching the other party on the display device screen. Furthermore, the interphone base unit 50 can record an image of a visitor who is talking.

  Here, since the camera of the doorphone slave unit 60 uses a lens having a relatively short focal length so that the appearance of the visitor can be reliably imaged, the face of the visitor displayed on the screen of the display device. Tend to be smaller. Therefore, in the conventional example described in Patent Document 1, the intercom base unit 50 has a function of displaying the range S selected on the screen of the display device in an enlarged manner on the entire screen. The user can move the selection range on the screen to place the visitor's face within the selection range, and then operate the zoom button 54 to enlarge the selection range to display and record the entire screen. It has become.

  In addition, this type of intercom system has a function of automatically recording an image captured by the camera of the doorphone slave unit 60 by the interphone master unit 50 that has detected the calling signal from the doorphone slave unit 60 (answering function). In the absence recording, since the person cannot operate the cross key button 53 to move the selection range, for example, the center of the screen that is expected to have a high probability corresponding to the position of the visitor's face is used. The video was automatically enlarged and recorded.

JP-A-5-236478

  However, the visitor's face position does not necessarily match the center of the screen, and if an enlarged image of the center of the screen that does not match the face position is recorded, the visitor's range of view is narrower than the original image. On the contrary, there is a possibility that the face of the visitor cannot be identified.

  The present invention has been made in view of the above circumstances, and its purpose is to reliably and automatically display an image obtained by enlarging the position of a visitor's face from an image captured by a door phone slave unit without human operation. It is intended to provide an intercom system capable of recording with an interphone master unit.

  In order to achieve the above object, the invention of claim 1 is provided with an image pickup means for picking up an image of a visitor and is installed outdoors and imaged by an image pickup means of the doorphone set installed indoors. In an interphone system configured with an interphone master unit that records images and reproduces the recorded images and is capable of making a call with a door phone slave unit, the interphone master unit includes image storage means for storing images, A display means for displaying an image; and an image control means for reading out the image stored in the image storage means and displaying the image on the display means. The image pickup means captures the image on either the doorphone slave unit or the interphone master unit. Image processing means for detecting the position of the face of the visitor in the image by performing image processing on the image and expanding the image of the detected face position; An image pickup control means for detecting the visit of the visitor and operating the image pickup means, and when the image pickup control means operates the image pickup means, the image processing means is operated to enlarge an image of the visitor's face. It is stored in the image storage means of the intercom base unit.

  According to the first aspect of the present invention, when the image pickup control means operates the image pickup means, the image processing means performs image processing on the image picked up by the image pickup means, whereby the position of the visitor's face in the image is obtained. And the image processing means stores an image in which the position of the face detected from the images taken by the imaging means is enlarged in the image storage means of the interphone master unit, so that the door phone can be operated without human operation. An image obtained by enlarging the position of the visitor's face from an image captured by the slave unit can be surely and automatically recorded by the interphone master unit.

  According to a second aspect of the present invention, in the first aspect of the invention, the image processing means is provided in a door phone sub unit.

  According to the present invention, an image obtained by enlarging the position of a visitor's face from an image captured by a door phone slave unit can be reliably and automatically recorded by an interphone master unit without being operated by a person.

1 is a system configuration diagram of Embodiment 1. FIG. It is a block diagram same as the above. It is a circuit block diagram of the image | video process part of the door phone sub unit in the same as the above. It is a figure for operation | movement description of a video processing part in the same as the above, Comprising: (a) is an image figure of the template image for face detection, (b) is an image figure of the gradient direction image of the template image for face detection, (c) is a face detection It is a shape feature explanatory view of a template image. FIG. 6 is a captured image diagram for explaining the operation of the video processing unit in the first to fifth embodiments. It is a figure for operation | movement description of a video processing part in the same as the above, Comprising: (a) is an image figure of the gradation gradient direction image of a captured image, (b) is a figure characteristic explanatory drawing of a captured image. It is explanatory drawing of the Sobel filter used for the same as the above. It is explanatory drawing of the vote result of a reference point candidate point same as the above. It is a top view of the intercom main unit by which the enlarged image same as the above was displayed. It is a figure for operation | movement description of the image | video process part in the same as the above, Comprising: (a) is an image figure of the template image for face detection, (b) is an image figure of the gradation gradient direction image of the template image for face detection, (c) is a detection object. It is an image figure of the captured image which imaged the face of. (A) is a block diagram of the face detection means used in Embodiments 2 and 3, and (b) is an explanatory diagram of the relationship between the face size and the vote value in the face size detection of the face detection means of the above. (A) is the block diagram of the face detection means used for Embodiment 4, 5, (b) is the image figure of the picked-up image which imaged the face of the detection object same as the above, (c) is the face rotation angle in the face rotation detection same as the above. It is relationship explanatory drawing with a vote value. It is a system configuration diagram of a conventional example.

(Embodiment 1)
Hereinafter, embodiments of the present invention will be described with reference to the drawings. The intercom system according to the present embodiment includes an intercom master unit 20 installed at a front door or the like outside a dwelling unit and an interphone master unit (hereinafter referred to as “master unit”) that is installed inside the dwelling unit and makes a call between the doorphone sub unit 20. 1). Here, the door phone slave unit 20 is connected to the base unit 1 by two pairs of signal lines L1 including a two-wire communication line and a two-wire control line.

  1 and 2 show a system configuration diagram and a block diagram of this embodiment, respectively.

  The door phone sub unit 20 receives a voltage applied to the call line by the base unit 1 to create an internal operating power source, and performs a two-to-four line conversion between the internal call path and the call line; A voice input / output unit 22 having a microphone and a speaker, a voice processing unit 23 for amplifying a voice signal inputted from the microphone, amplifying a voice signal sent from the master unit 1 through a call line, and the like, A camera unit 24 that has such an individual image sensor and an optical system such as a lens and images a visitor, and a microcomputer as main components, and image processing (described later) on a video signal output from the camera unit 24 ) And frequency-modulating the video signal after image processing, and a switch that is turned on when the visitor presses the call button 28 (see FIG. 1). A display element (light-emitting diode) is supplied with power via the control unit 26 during a call with the operation unit 26 that sends a call signal by changing the line voltage of the call line when it is turned on. ) Is lit. Here, the video signal (hereinafter referred to as “FM video signal”) frequency-modulated to the audio signal (baseband signal) output from the audio processing unit 23 is multiplexed by the power receiving unit 21 and is transmitted through the communication line to the master unit. Sent to 1.

  Main unit 1 applies a DC voltage to a telephone line to supply power to door phone slave unit 20, and also feeds power unit 2 that separates multiplexed audio signals and FM video signals, and a microcomputer. Main unit control unit 3 as a component, audio input / output unit 4 having a microphone and a speaker, an audio signal input from audio input / output unit 4 and an audio signal from doorphone slave unit 20 separated by power supply unit 2 And a voice processing unit having a function of a voice switch for switching the call direction (master unit 1 → door phone slave unit 20 or master unit 1 ← door phone slave unit 20) by attenuating the voice signal having the lower signal level 5, a display unit 6 composed of a liquid crystal display (LCD), and a video processing unit 7 that demodulates the FM video signal sent from the intercom 20 and outputs the video signal to the display unit 6 to display the video. There are a call switch that is turned on by operation of the call button 11 (see FIG. 1) and a monitor switch that is turned on by operation of the monitor button 12 (see FIG. 1). The main unit operation unit 8 to be output to the control unit 3, the recording unit 9 that demodulates the FM video signal sent from the door phone slave unit 20, converts it into a digital signal and stores (records) it, and the commercial power supply And a power supply unit 10 for creating an operating power supply. In the recording unit 9, the FM video signal is demodulated and converted into a digital signal, but may be converted into a digital signal without being demodulated, or may be stored as an analog signal after being demodulated. It doesn't matter if you do.

  Moreover, in this embodiment, the camera subunit 40 is connected to the main unit 1 by the signal line L2 separately from the door phone subunit 20. The camera slave unit 40 receives a voltage applied to the signal line L2 by the base unit 1 and creates an internal operation power source, a voice input unit 42 having a microphone, and a voice signal input from the microphone. An audio processing unit 43 that performs amplification, a camera unit 44 that has an individual imaging device such as a CCD and an optical system such as a lens, and a microcomputer as a main component and outputs from the camera unit 44 The image processing unit 45 performs image processing (to be described later) on the image signal to be processed and frequency-modulates the image signal after image processing, and detects the heat rays radiated from the human body with a pyroelectric element. A human sensor 46 that senses the presence or absence of a person, and a display 47 that turns on a display element (light emitting diode) when the human sensor 46 senses a visitor. .

  Next, basic operations of the base unit 1, the door phone slave unit 20, and the camera slave unit 40 will be described.

  First, when a visitor presses the call button 28 of the door phone cordless handset 20, the operation unit 26 transmits a call signal from the power receiving unit 21 to the base unit 1 through the telephone line, and the video processing unit 25 and the camera unit 24 further. The video of the visitor that is activated and imaged by the camera unit 24 is transmitted from the power receiving unit 21 to the base unit 1 via the telephone line. In the base unit 1, the base unit control unit 3 that has detected the calling signal controls the voice processing unit 5 to ring the ringing sound from the speakers of the voice input / output unit 4, and the FM transmitted from the doorphone slave unit 20. The video signal is demodulated by the video processing unit 7 and the video of the visitor is displayed on the display unit 6. When the housekeeper presses the call button 11 of the base unit 1, an operation signal is output from the base unit operation unit 8, and the base unit control unit 3 that receives this operation signal is connected to the voice processing unit 5 and the voice input / output unit 4. A call path is formed between the call lines, and a call with the door phone slave unit 20 becomes possible. When the monitor button 12 is pressed and an operation signal is output from the base unit operation unit 8, the base unit control unit 3 that has received this operation signal is sent from the power supply unit 2 to the door phone sub unit 20 through the call line. Since the camera unit 24 and the video processing unit 25 of the door phone slave unit 20 are activated and the video imaged by the camera unit 24 is sent to the base unit 1, the camera unit 24 of the door phone slave unit 20 is displayed on the display unit 6. The image captured with is displayed. That is, in the doorphone sub unit 20, when the call button 28 of the operation unit 26 is pressed, the visitor is detected and the imaging unit (the camera unit 24 and the video processing unit 25) is operated. Thus, the operation unit 26 corresponds to an imaging control unit.

  In addition, when a visitor or a suspicious person enters the sensing area, the motion sensor unit 46 of the camera slave unit 40 senses the presence of a person and the video processing unit 25 and the camera unit 24 are activated and the camera unit 24 takes an image. The user's video is transmitted from the power receiving unit 21 to the base unit 1 via the call line, and the voice input unit 42 and the voice processing unit 43 are activated and the voice input to the voice input unit 42 is also transmitted from the power receiving unit 21. It is transmitted to the base unit 1 via the line. In the base unit 1, the base unit control unit 3 controls the audio processing unit 5 to output the sound transmitted from the camera sub unit 40 from the speakers of the audio input / output unit 4 and is transmitted from the camera sub unit 40. The received FM video signal is demodulated by the video processing unit 7 and the video of the visitor or suspicious person is displayed on the display unit 6. That is, in the camera slave unit 40, the human sensor unit 46 detects a visitor and operates the imaging means (camera unit 44 and video processing unit 45), and the human sensor unit 46 controls the imaging. Corresponds to means. Note that a speaker may be provided in the audio input unit 42 of the camera slave unit 40, and the sound transmitted from the parent device 1 may be output from the speaker, thereby threatening the suspicious person.

  Next, image processing in the video processing units 25 and 45 of the door phone slave unit 20 and the camera slave unit 40, which is the gist of the present invention, will be described. However, since the image processing performed by the two video processing units 25 and 45 is quite common, only the video processing unit 25 of the doorphone slave unit 20 will be described below.

  When the camera unit 24 and the video processing unit 25 are activated by pressing the call button 28 as described above, the video processing unit 25 detects the position of the visitor's face in the image captured by the camera unit 24 ( Hereinafter, image processing (hereinafter referred to as “zoom processing”) for enlarging the image of the detected face position is performed.

  First, the face position detection process will be described. FIG. 3 is a block diagram showing a configuration for performing the face position detection process of the video processing unit 25. An image input unit 251 that captures a captured image from the camera unit 24 by A / D conversion, and a face detection template in advance. The stored face detection template image storage means 252 and the face detection template image A and image input means 251 stored in the face detection template image storage means 252 as shown in FIG. The density gradient direction extracting means 253 for extracting the density gradient direction images A ′ and B ′ (see FIGS. 4B and 4A) of the captured image B as shown in FIG. 5, and the extracted density gradient The density gradient direction image storage unit 254 that stores the direction images A ′ and B ′, and the density gradient direction image A ′ of the face detection template image A stored in the density gradient direction image storage unit 254 The distance L between the reference point O and each reference coordinate point (hereinafter referred to as reference point) R, and the line connecting the reference point O and each reference point R intersects the horizontal axis (X axis) passing through the reference point R Shape feature extraction means 255 for extracting information on the angle α to be performed, shape feature storage means 256 for separating and storing the extracted information for each value θ in the density gradient direction of the face detection template image A, and density gradient Based on the density gradient direction value θ at each reference point R ′ of the density gradient direction image B ′ of the captured image B stored in the direction image storage unit 254 and the shape feature information stored in the shape feature storage unit 256. The voting means 257 for voting the reference point candidate points in the density gradient direction image B ′, and the face detecting means 258 for detecting the position of the face based on the voting result obtained by the voting means 257. The

  The operation of each means will be described below.

  First, the density gradient direction extracting means 253 is used for face detection, which is captured by the camera unit 24 and stored in the captured image B and face detection template image storage means 252 shown in FIG. 5A input by the image input means 251. The density gradient direction images B ′ and A ′ are extracted from the template image A. 4B shows the density gradient direction image A ′ of the face detection template image A, and FIG. 6A shows the density gradient direction image B ′ of the captured image B. When extracting these density gradient direction images A ′ and B ′, as shown in FIG. 5, a 3 × 3 x-direction Sobel filter 12x and a y-direction Sobel filter 12y are applied to all pixels included in the input grayscale image. The differential value dx in the horizontal axis (X-axis) direction and the differential value dy in the vertical axis (Y-axis) direction in each image are obtained from (Formula 1) and (Formula 2).

dx = (c + 2f + i) − (a + 2d + g) (Formula 1)
dy = (g + 2h + i) − (a + 2b + c) (Formula 2)
(A to h indicate the values a to d and f to h of the target pixel e and eight pixels in the vicinity of the target pixel e as shown in FIG. 7.) At this time, the differential direction value θ Is represented by the following (formula 3).

θ = tan ⁻¹ (dy / dx) (Equation 3)
Here, the density gradient direction images A ′ and B ′ are images having the density gradient direction value θ as a pixel value, and this image is stored in the density gradient direction image means 254.

  The shape feature extraction unit 255 first calculates the center of gravity in the density gradient direction image B of the face detection template image A stored in the density gradient direction image storage unit 254 and sets it as the reference point O. The distance L between the reference point O and the reference point R shown in FIG. 4C and the angle α between the line connecting the reference point O and the reference point R and the horizontal axis β passing through the reference point R are calculated. The shape feature storage unit 256 stores the feature information of the face detection template image A for each angle between the density gradient direction γ and the line β, that is, for each density gradient direction value θ. As shown in FIG. 4A, the face detection template image A used in the present embodiment is created in a form including an average human face characteristic part (eyes, eyebrows, nose, mouth, etc.). Is adopted. The shape feature of the face detection template image A may be stored in the shape feature storage unit 256 in advance.

  Table 1 shows the shape features stored in the shape feature storage means 256, and is in a table format in which the angle α and the distance L are entered for each density gradient direction value θ of each reference point.

  The voting unit 257 stores the density gradient direction value θ of the density gradient direction image B ′ of the captured image B shown in FIG. 6A stored in the density gradient direction image storage unit 254 and the shape feature storage unit 256. Using the shape feature of the face detection template image A, a reference reference point candidate point is obtained from the following (Equation 4) and (Equation 5), and the vote is voted for that point. Then, the face detection means 258 detects the peak of the vote value from the voting result shown in FIG. 8A, determines the reference point O ′ (o′x, o′y), and determines the position of the face. FIG. 8B shows the relationship with the voting value of the segment range shown in FIG.

ox ′ = L × cos (α) + r′x (Formula 4)
oy ′ = L × cos (α) + r′y (Formula 5)
As described above, according to the face position detection process of the present embodiment, even if the size of the body and the face detection template image may match, the values of the respective density gradient directions are different. Votes are less likely to concentrate, the body is not erroneously detected, and there is an advantage that image processing means (video processing units 25 and 45) that are resistant to fluctuations in illumination can be realized by using density gradient direction images.

  When the face position is detected as described above, a well-known zoom process for enlarging the image in the range including the face position to the size of the original captured image is performed, and the zoomed image is converted to D / A. It is converted and transmitted from the video processing unit 25 to the parent device 1 through the power receiving unit 21 through the telephone line. Then, the master unit 1 can display an image in which the range S including the visitor's face is enlarged as shown in FIG. 9 on the display unit 6, or the visitor's face is enlarged at the time of absence recording. The recorded image is automatically recorded in the recording unit 9. In the present embodiment, the door phone slave unit 20 and the camera slave unit 40 always enlarge the face part of the visitor. For example, when the master unit 1 is set to be an answering machine, The face position detection process and the zoom process may be performed when a zoom operation button (not shown) provided on the operation unit 8 of the machine 1 is pressed.

  By the way, in the face position detection process, instead of the face detection template image A stored in the face detection template image storage means 252, as shown in FIG. A created template image may be used. That is, since the template image of the average contour of the face is used, the eye, the eyebrows, the nose, the mouth, and the like indicating the facial features are not correctly imaged as in backlight, as shown in FIG. The position of the face in the image B can be detected correctly. FIG. 10B shows the density gradient direction image A ′ extracted by the density gradient direction extraction means 253 from the face detection template image A shown in FIG.

(Embodiment 2)
This embodiment is characterized by face position detection processing in the video processing units 25 and 45 of the door phone slave unit 20 and the camera slave unit 40, and other configurations and operations are the same as those in the first embodiment, and are illustrated and described. Is omitted.

  Since the basic configuration of the video processing unit 25 (also common to the video processing unit 45) is the same as that of the first embodiment shown in FIG. 3, reference is made to FIG. The video processing unit 25 according to this embodiment is characterized in that a face size detecting unit 258a is provided in the face detecting unit 258 as shown in FIG.

  The face size detecting means 258a performs voting by the voting means 257 while changing the size of the face detection template image, and as shown in FIG. Therefore, it is means for detecting the size that maximizes the value as the face size.

  As described above, this embodiment has an advantage that the face can be detected even if the size of the face is not constant.

(Embodiment 3)
This embodiment is characterized by face position detection processing in the video processing units 25 and 45 of the door phone slave unit 20 and the camera slave unit 40, and other configurations and operations are the same as those in the first embodiment, and are illustrated and described. Is omitted.

  In the second embodiment, the face size is detected by changing the size of the face detection template image. However, the present embodiment detects the face size by changing the distance information in the shape feature described above. There is a feature. The basic configuration of the video processing unit 25 (also common to the video processing unit 45) is the same as the configuration of the first embodiment shown in FIG. 3, so refer to FIG. Similarly, face size detecting means 258a (see FIG. 11A) is provided.

  Thus, the face size detection means 258a (FIG. 11A) of the present embodiment changes the distance information by changing the magnification s with respect to the distance L in the shape feature, and the voting means 257 causes the density gradient direction image storage means. The density gradient direction value θ of the density gradient direction image B ′ of the captured image B shown in FIG. 6A stored in the H.254 and the shape feature of the face detection template image A stored in the shape feature storage unit 256. Is used to obtain a reference point candidate point according to the following (formula 6) and (formula 7), and vote for that point in the voting space. Then, as shown in FIG. 11B, since the peak of the vote value is obtained from the vote result for each face size, the size with the maximum value is detected as the face size.

ox ′ = s × L × cos (α) + r′x (Formula 6)
oy ′ = s × L × cos (α) + r′y (Expression 7)
s: magnification of distance (Embodiment 4)
This embodiment is characterized by face position detection processing in the video processing units 25 and 45 of the door phone slave unit 20 and the camera slave unit 40, and other configurations and operations are the same as those in the first embodiment, and are illustrated and described. Is omitted. The basic configuration of the video processing unit 25 (also common to the video processing unit 45) is the same as that of the first embodiment shown in FIG.

  Then, as shown in FIG. 12A, the video processing unit 25 (also common to the video processing unit 45) in the present embodiment includes a face size detection unit 258a (the face size of the second and third embodiments) in the face detection unit 258. Any of the detection means 258a may be provided) and the face rotation angle output means 258b may be provided.

  On the other hand, the face rotation angle extraction means 258b is for corresponding to the picked-up image B captured with the face tilted as shown in FIG. 12B, and the voting means while rotating the face detection template image A. By voting by 257, as shown in FIG. 12C, a peak of the voting value is obtained from the voting result for each rotation angle. Therefore, the rotation angle that maximizes the value is extracted as the rotation angle of the face. Means.

  This embodiment has an advantage that the face can be detected even if the rotation angle of the face is not constant.

(Embodiment 5)
Although the face rotation angle extraction means 258b in the fourth embodiment rotates the face detection template image A, the face rotation angle detection means 258b in the present embodiment converts angle information in the shape feature described above. There is a feature in point. Since the basic configuration of the image processing apparatus according to the present embodiment is the same as that of the first embodiment shown in FIG. 1, refer to FIG. 3, and in the face detection unit 258 as in the fourth embodiment, for example, the embodiment 3 is provided with a face rotation angle output means 258b in addition to the face size detection means 258a used in FIG. 3 (see FIG. 12A).
Thus, the face rotation angle extraction unit 258b of the present embodiment changes the angle information in the shape feature described above, and the density of the density gradient direction image stored in the density gradient direction image storage unit 254 by the voting unit 257. Gradient direction value θ (when rotation angle is φ and density gradient direction of captured image B is θ ′, θ = θ′−φ) and face detection template image stored in shape feature storage means 7 Using the shape feature of A, a reference point candidate point is obtained from (Equation 8) and (Equation 9) below, and a vote is given to that point in the voting space. Then, as shown in FIG. 12C, since the peak of the vote value is obtained from the vote result for each rotation angle, the rotation angle at which the maximum value is obtained is detected as the face rotation angle.

ox ′ = L × cos (α + φ) + r′x (Expression 8)
oy ′ = L × cos (α + φ) + r′y (Equation 9)
φ: Rotation angle (change the angle information by changing the value of this rotation angle)
In the first to fifth embodiments, the image processing means for performing the face position detection process and the zoom process is configured by the video processing units 25 and 45 of the doorphone slave unit 20 and the camera slave unit 40. The image processing means may be configured by the unit 3. The base unit 1 may be configured to include imaging control means for activating the camera units 24 and 44 and the video processing units 25 and 45 of the door phone slave unit 20 and the camera slave unit 40.

DESCRIPTION OF SYMBOLS 1 Intercom main unit 20 Door phone subunit 24 Camera part 25 Image processing part 40 Camera subunit 44 Camera part 45 Image processing part

Claims (2)

Door phone slave installed outdoors with imaging means for imaging a visitor, and images recorded by the imaging means of the door phone slave installed indoors as well as playing back recorded images and door phone slaves In the intercom system composed of the interphone master unit that can talk with
The intercom base unit includes an image storage unit that stores an image, a display unit that displays an image, and an image control unit that reads an image stored in the image storage unit and displays the image on the display unit.
An image of the detected face position is detected by performing image processing on the image picked up by the image pickup means on either the door phone slave unit or the interphone master unit, thereby detecting the position of the face of the visitor in the image. Image processing means for enlarging the image, and imaging control means for operating the imaging means upon detecting the visit of a visitor,
An interphone system characterized in that when the image pickup control means operates the image pickup means, an image processing means is operated and an image obtained by enlarging the position of the visitor's face is stored in the image storage means of the interphone base unit.   2. The intercom system according to claim 1, wherein the image processing means is provided in a door phone slave unit.