JP2008113088A - Door phone system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a door phone system which has a function of keeping a frame rate constant and enables an answerer to easily confirm an image of a visitor. <P>SOLUTION: A door phone slave device 1 of the present invention has an image compressing unit 18 which compresses image data obtained by photography according to specified image compression parameters, a communication rate detector 21 which detects a communication speed between a door phone master device 100 and the slave device 1, a frame rate computing unit 23 which calculates a frame rate from the communication speed and compressed image data, a frame rate decision unit 24 which decides whether the calculated frame rate is included in a predetermined range of a reference frame rate for keeping the frame rate constant, and an image compression parameter specifying unit 17 which adjusts the image compression parameters so that when it is decided that the calculated frame rate is not within the predetermined range of the reference frame rate, the calculated frame rate is included in the predetermined range of the reference frame rate. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an interphone device with a monitor function that can make a call with a visitor and can visually recognize an image of the visitor with a camera, and particularly relates to a door phone device.

  Conventionally, a door phone slave unit (hereinafter referred to as a slave unit) is provided with a camera, and an image of a visitor is photographed by the camera, and image data obtained by the photographing is obtained by a wired communication means or a wireless communication means. There is a door phone device of a type that transmits to a master device).

  As an example of the door phone device, the slave unit compresses image data captured by the camera and transmits the compressed image data to the master unit, and the master unit decompresses the compressed image data and displays it on the display screen via the display unit. Some are configured to display.

  As a door phone device configured to compress and transmit the image data, Patent Document 1 includes a compression unit that compresses a visitor's image and a character processing unit that writes character information in a character information storage area. A door phone system that can display high-quality character information even if the rate is increased is described.

  Further, in Patent Document 2, it is said that a visitor's video whose change in video is large is compressed at a low compression rate in order to provide a high-quality image, while the video change is small. For an image in front of the camera when there is no visitor, a door phone device is described that compresses at a high compression rate in order to provide a low-quality image.

  Patent Document 3 discloses a method for switching the image compression rate as appropriate according to the convenience of the responder (the person who operates the master unit). If this is used, the responder can easily check the image of the visitor (person who operates the slave unit).

  Patent Document 3 discloses a method of switching the image compression rate in accordance with the image state preferred by the responder among the conflicting frame rate and image quality. The doorphone device described in Patent Document 3 will be briefly described below.

  When the responder of the door phone device looks at the image displayed on the master unit and desires better image quality, he / she presses the “image quality UP” switch, and the responder desires a moving image more than the image quality. Can press the “Speed Up” switch.

  The master unit that has detected the “image quality UP” signal transmits an instruction to lower the image compression rate to the slave unit, and the slave unit reduces the image compression rate and compresses the image in accordance with the instruction from the master unit. Thereby, since the frame rate is lowered, the image quality of the image displayed on the master unit is improved, but the followability to the visitor's movement is inferior to the previous one.

On the other hand, the master unit that has detected the “speed up” switch signal sends an instruction to increase the image compression rate to the slave unit, and the slave unit increases the image compression rate and compresses the image in accordance with the instruction from the master unit. To do. As a result, the frame rate is increased, so that the image displayed on the master unit becomes more animated, but the image quality is inferior to the previous one.
JP 2002-320222 A JP 2004-260462 A JP 2000-216895 A

  By the way, in the door phone device described in Patent Document 3, when the responder desires a moving image, the frame rate can be increased by pressing the “speed UP” switch.

  However, since the frame rate is greatly affected by the communication speed, if the communication speed changes depending on the communication status or the like, the frame rate may also change.

  For example, when a wired line is used as a communication means between the parent device and the child device, the communication speed is likely to be slow, for example, when the line is crowded or when the radio wave condition is bad when using wireless communication.

  Thus, even if the responder desires a moving image and presses the “speed up” switch to increase the frame rate, the frame rate decreases if the communication speed decreases due to the cause as described above. Then, the followability to the visitor's movement is also reduced, and the responder has to press the “speed up” switch again.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a door phone that has a function of keeping a frame rate constant and allows a responder to easily and satisfactorily check a visitor's image. Is to realize the device.

  The door phone slave device of the present invention includes an image pickup device that captures an image of a visitor, compresses image data obtained by the image pickup device, and transmits the compressed image data to the door phone master device using a communication unit. The doorphone slave unit in the doorphone device configured to include the doorphone master unit that decompresses the image data transmitted from the doorphone slave unit and displays the decompressed image data on the display device provided therein, and captures the image by the imaging device Image compression means for compressing the image data acquired by a specific image compression parameter, communication speed detection means for detecting the speed of data communication performed between the doorphone master unit and the doorphone slave unit, and the communication From the communication speed obtained by the speed detecting means and the image data compressed by the image compressing means, a frame rate in the display device of the door phone master unit is obtained. A frame rate calculating means for calculating the frame rate, and determining whether or not the frame rate calculated by the frame rate calculating means is within a predetermined range of a reference frame rate as a reference when the frame rate is kept constant When the frame rate determination means and the frame rate determination means determine that the calculated frame rate is not included in a predetermined range of the reference frame rate, the calculated frame rate is An image compression parameter adjusting unit that adjusts an image compression parameter so as to be included in a predetermined range of the reference frame rate is provided.

  The doorphone slave device control method according to the present invention further includes an imaging device that captures an image of a visitor, compresses image data captured by the imaging device, and transmits the compressed image data to the doorphone master device using a communication unit. And a doorphone slave unit configured to include a doorphone master unit that expands image data transmitted from the doorphone slave unit and displays the data on a display device included in the doorphone slave unit. An image compression step of compressing image data acquired by photographing with the imaging device with a specific image compression parameter, and a speed of data communication performed between the doorphone master unit and the doorphone slave unit are detected. From the communication speed detection step, the communication speed obtained by the communication speed detection step, and the image data compressed by the image compression step, the door A frame rate calculation step for calculating a frame rate in the display device of the main unit, and a frame rate calculated by the frame rate calculation step within a predetermined range of a reference frame rate serving as a reference when the frame rate is kept constant A frame rate determination step for determining whether or not the frame rate is included in the frame rate determination step, and the frame rate determination step in which it is determined that the calculated frame rate is not included in a predetermined range of the reference frame rate Includes an image compression parameter adjustment step of adjusting an image compression parameter so that the calculated frame rate is included within a predetermined range of the reference frame rate.

  According to the above configuration or method, the current frame rate can be calculated using the detected communication speed, and the image compression parameter can be adjusted to match the reference frame rate.

  Thus, the door phone slave of the present invention can keep the frame rate substantially constant at the reference frame rate without being affected by the communication speed.

  As a result, the doorphone slave device of the present invention can perform display in a state in which the followability to the visitor's movement is well maintained, so that the responder can easily check the visitor.

  In addition, the doorphone slave device of the present invention may further include a frame rate setting unit that sets a reference frame rate based on a user instruction transmitted from the doorphone master device.

  According to the above configuration, the responder who is a user can freely change the reference frame rate according to his / her convenience such as when priority is given to image quality or followability to visitors.

  The doorphone slave unit of the present invention further includes image compression parameter storage means for storing a plurality of image compression parameters in accordance with the level of image compression strength, and is calculated by the frame rate calculation means by the frame rate determination means. In the case where it is determined that the calculated frame rate is not included in the predetermined range of the reference frame rate, the image compression parameter adjusting means is configured so that the calculated frame rate is within the predetermined range of the reference frame rate. Is smaller than the image compression parameter storage means, an image compression parameter that makes the degree of image compression stronger than the current image compression parameter is selected, and the image data compressed based on the selected image compression parameter is Sent to the intercom base unit, while the image compression parameter adjustment means, If the calculated frame rate is larger than a predetermined range of the reference frame rate, an image compression parameter that makes the degree of image compression weaker than the current image compression parameter is selected from the image compression parameter storage means. The image data compressed based on the selected image compression parameter is transmitted to the intercom master unit.

  According to the above configuration, the degree of image compression can be adjusted by gradually changing the degree of image compression, not by changing the degree of image compression suddenly. The frame rate can be gradually brought close to the reference frame rate.

  As a result, it is possible to reduce the risk of image disturbance caused by a sudden change in the frame rate, and the responder can smoothly check the visitors.

  Further, obtaining an image compression parameter that is stronger or weaker than the current image compression parameter can be performed simply by referring to the image compression parameter storage means.

  In the doorphone slave device of the present invention, the image data is compressed based on the image compression parameter adjusted to increase the degree of image compression, and the operation of transmitting the image data to the doorphone master device is continuously performed. And the number of operations in which the image data is compressed based on the image compression parameter adjusted so that the degree of the image compression is weakened and the operation transmitted to the intercom master unit is continuously performed. Each of the image compression units further includes a counting unit for measuring, and when the number of operations measured by the counting unit exceeds a preset upper limit value, the image compression unit performs image adjustment without adjusting the degree of image compression. It is characterized by compressing.

  For example, if the reference frame rate is a value that is much higher than the calculated current frame rate, the degree of image compression is very strong in order to increase the current frame rate and approach the reference frame rate. It is considered necessary to make adjustments. However, if the degree of image compression is increased too much, problems such as image distortion may occur.

  According to the above configuration, since the operation of adjusting the degree of image compression is stopped when a preset upper limit value is exceeded, the operation can be stopped before problems such as the image being disturbed occur.

  As a result, when the reference frame rate is a very high value or a very low value compared to the calculated frame rate, the image is not disturbed rather than keeping the frame rate constant. You can give priority to this.

  Further, the door phone slave unit of the present invention further includes a luminance component extraction unit that extracts only a luminance component from image data obtained by photographing with the imaging device, and the image compression unit is extracted by the luminance component extraction unit. The luminance component thus obtained may be compressed with a specific image compression parameter.

  According to the above configuration, the data size after image compression can be made smaller than the image data size subjected to normal image compression that compresses the color difference component. Accordingly, the amount of data transmitted to the intercom base unit can be reduced while keeping the frame rate constant, which is effective when the communication speed between the handset and the base unit is low.

  Further, according to the above configuration, since image compression is performed using only the luminance component, the image data compressed by the slave unit and transmitted to the master unit is monochrome. Accordingly, even a door phone device including a display device having only a monochrome display function can be displayed without changing other system configurations.

  Further, the image compression means in the door phone slave unit of the present invention may compress image data obtained by photographing with the imaging device by the JPEG method.

  According to the above configuration, the JPEG image data is data that expresses the data of each pixel by the luminance component, the blue color difference, and the red color difference. Therefore, the luminance component can be easily extracted.

  Further, the doorphone master unit of the present invention is a doorphone master unit that communicates with the doorphone slave unit according to the present invention, and a user specifies a reference frame rate as a reference when the frame rate of the display device is kept constant. And a frame rate setting means for setting based on the reference frame rate, and transmitting the reference frame rate set by the frame rate setting means to the intercom slave unit.

  Further, the control method of the doorphone master unit according to the present invention is a control method in the doorphone master unit that communicates with the doorphone slave unit according to the present invention, and serves as a reference when the frame rate of the display device is kept constant. The method includes a frame rate setting step for setting a reference frame rate based on a user instruction, and a step for transmitting the reference frame rate set by the frame rate setting step to the door phone slave unit.

  According to the above configuration or method, the responder who is a user can freely change the reference frame rate according to his / her convenience, such as when priority is given to image quality, or priority is given to followability to visitors. it can.

  The doorphone master unit of the present invention further includes a storage unit that stores a table that stores time and frame rate in association with each other, and a time measuring unit that detects a visit time of a visitor, and the frame rate setting unit includes: From the table, a frame rate corresponding to the time measured by the time measuring means is selected and set as the reference frame rate.

  For example, when the visit time is noon, it is bright and has good visibility, so there is no need to increase the reference frame rate. However, when the visit time is night, it is dark and the visibility is lowered, so the reference frame rate must be increased. it is conceivable that. According to the above configuration, since it is possible to set a convenient reference frame rate according to the detected visit time, the responder can check the visitor's image without feeling stress.

  Further, the doorphone master unit of the present invention includes a storage unit that stores a table that stores the state of the master unit and the frame rate in association with each other, and a master unit mode that detects what state the doorphone master unit is currently in Detecting means, wherein the frame rate setting means selects a frame rate corresponding to the state of the parent device detected by the parent device mode detection means from the table and sets it as a reference frame rate. It is characterized by.

  For example, when the intercom base unit is in the absence setting, the responder plays the recorded image and confirms the visitor, so there is no need to set the reference frame rate high, and the reference frame rate Should be set low.

  Thus, according to the above configuration, a convenient reference frame rate can be set according to each state of the master unit according to the state of the doorphone master unit, so that the responder does not feel stress, Visitor images can be checked.

  Further, the door phone device of the present invention may be configured to include the door phone slave unit configured as described above and the door phone master unit configured as described above.

  According to the above configuration, in order to adjust the strength of the degree of image compression in order for the doorphone slave unit to keep the frame rate constant, the doorphone master unit visits in a state where the followability to the visitor's movement is well maintained. The person's image can be displayed. Thereby, the responder can easily check the visitor.

  The door phone slave unit and the door phone master unit may be realized by a computer. In this case, the door phone slave unit and the door phone master unit are realized by the computer by operating the computer as the respective means. The image compression parameter adjustment program of the slave unit and the door phone master unit, and the computer-readable recording medium on which the program is recorded also fall within the scope of the present invention.

  As described above, the doorphone device of the present invention detects the communication speed and adjusts the frame rate so as to maintain a constant frame rate. Even if the communication speed changes due to the above, it is possible to keep the frame rate substantially constant without being affected by the change.

  As a result, the followability to the movement of the visitor can be kept good, so that the responder using the door phone device of the present invention can easily check the visitor.

  In addition, the responder can arbitrarily change the frame rate that serves as a reference when keeping the frame rate constant. Thus, the responder can freely change the reference frame rate to a frame rate according to the respondent's request such as when priority is given to image quality or followability.

[Embodiment 1]
This embodiment will be specifically described below with reference to the drawings.

  FIG. 4 is a schematic diagram of the overall configuration of the door phone device according to the present embodiment.

  As shown in FIG. 4, the door phone device according to the present embodiment includes a door phone slave unit 1 (hereinafter referred to as a slave unit 1) installed outside a doorway or the like, and a door phone master unit 100 installed indoors ( Hereinafter, it is referred to as parent device 100).

  The handset 1 includes a camera 2 that captures the appearance of a visitor, a speaker 3 for outputting sound to the outside of the handset 1, a microphone 4 for inputting sound to the inside of the handset 1, and a resident And a call switch 5 for calling.

  On the other hand, base unit 100 has a display screen 101 for displaying an image of a visitor, a speaker 102 for outputting voice and a ringing tone to the outside of base unit 100, and a voice for inputting voice into base unit 100. A microphone 103 and an input switch 104 that are used when a home person responds to a call from a visitor or when setting an image adjustment are provided.

  Further, in the door phone device of the present embodiment, wired communication is used as a communication unit between slave unit 1 and master unit 100.

  When there is a visitor, that is, when a change in the call switch 5 is detected, the handset 1 of the present embodiment takes an image of the visitor with the camera 2 and takes the image with the image compression unit 18 described later. The image data is compressed and transmitted to the parent device 100. The master device 100 that has received the image data decompresses the image data by an image decompression unit 112 described later and displays the decompressed image data on the display screen 101.

  Next, the internal configuration of the slave unit 1 will be described in detail below.

  FIG. 1 is a functional block diagram showing a specific example of the hardware configuration of the door phone slave unit according to the present embodiment.

  As shown in FIG. 1, the door phone slave unit 1 includes a camera unit 2, a speaker unit 3, a microphone unit 4, and a call switch (SW) unit 5 corresponding to the above-described camera and the like. Furthermore, a communication interface 6, a control unit 7, an information storage unit 8, an input unit 9, an image processing unit 10, and an audio processing unit 11 are provided.

  The communication interface 6 is a connection part for communicating with the parent device 100.

  The input unit 9 inputs information from the outside to the child device 1 and includes a call switch (SW) unit 5 and an input detection unit 16. When the input detection unit 16 detects a call signal from the call SW unit 5, the input detection unit 16 outputs the detected call signal to the parent device 100 via the communication control unit 19 described later.

  The voice processing unit 11 processes voices such as voices of visitors and responders (users). Specifically, the voice processing unit 11 A / D-converts a visitor's voice signal input via the microphone unit 4 and transmits the converted signal to the parent device 100 via the communication control unit 19 described later. In addition, the audio processing unit 11 performs D / A conversion on the audio signal from the parent device 100 that is input via the communication control unit 19 described later, and outputs the D / A to the speaker unit 3.

  The information storage unit 8 is a part for storing data and programs, and is a program storage unit 12 for storing programs executed in the control unit 7, and data for storing intermediate data of the programs or data received from the master unit. Storage unit 13.

  The data storage unit 13 is a table in which a sampling ratio and a quantization table (hereinafter referred to as an image compression parameter), which are parameters of a sampling operation and a quantization operation necessary for compressing an image, are associated with a frame rate. And an image compression parameter storage unit 14 (image compression parameter storage means) for storing the frame rate data and a frame rate data storage unit 15 for storing frame rate information necessary for frame rate calculation, which will be described later.

  Here, the frame rate in the present embodiment refers to how many images can be displayed per second.

  In the image compression, first, the luminance resolution is kept as it is, and sampling is performed by thinning out the resolution of the color difference. In order to reduce the ratio of the high frequency component, the data obtained by discrete cosine transform (DCT) is divided by a larger value as the data on the high frequency side is based on the “quantization table”. This quantization makes it possible to compress the amount of data considerably. The sampling ratio means a ratio of thinning out the color difference with respect to the luminance, that is, a band ratio of Y (luminance): Cb (blue color difference): Cr (red color difference).

  For example, when the sampling ratio of the table shown in FIG. 5 is 4: 1: 1, the luminance resolution remains the same, but the color differences Cb and Cr take the average of four pixels, and the resolution is in the vertical and horizontal directions. Both of them mean half. The sampling ratio of 1: 1: 1 means that the color difference is not thinned out at all, and the data amount is not compressed and remains unchanged.

  FIG. 5 is a diagram illustrating an example of the image compression parameter table tabulated.

  As shown in FIG. 5, the image compression parameter storage unit 14 has a frame rate, a sampling ratio used for encoding processing, and data of a quantization table so as to correspond to each other.

  Referring to FIG. 5 more specifically, the frame rate in FIG. 5 is the largest in E and decreases in the order of E> D> C> B> A. That is, the frame rate in the case 1 is the largest, and the frame rate decreases in the order of the case 1> the case 2> the case 3> the case 4> the case 5> the case 6.

  Also, the sampling ratio is the largest in case 1 and decreases in order as the case number increases. In cases 5 and 6, since the sampling ratio is 1: 1: 1, the image data amount is not compressed, and the data amount remains the same.

  The quantization table is also set so that the degree of image compression in case 1 is the strongest.

  From these facts, in FIG. 5, the degree of image compression in the case 1 is the strongest and becomes weaker as the case number increases.

  In the frame rate data storage unit 15, data of a reference frame rate F serving as a reference for keeping the frame rate constant, data of an allowable difference range α (hereinafter, an allowable range) of the reference frame rate F, The data of the repetition upper limit value N is stored.

  Here, the reference frame rate F refers to a frame rate that serves as a reference for a series of operations performed to keep the frame rate constant. The reference frame rate F is set in advance. In the present embodiment, the set reference frame rate F is stored in a frame rate data storage unit 115 (described later) of the parent device 100. Further, the responder arbitrarily changes a reference frame rate F that is set in advance and stored in a frame rate data storage unit 115 (described later) of the parent device 100 via the input SW unit 104 of the parent device 100. Can do.

  In addition, the allowable range α represents a range of allowable difference with respect to the reference frame rate F when the frame rate is kept constant. That is, if the frame rate calculated by the frame rate calculation unit 23 described later is in a range from F−α to F + α (a predetermined range of the reference frame rate), the frame rate is the same value as the reference frame rate. Is considered. And the door phone apparatus in this embodiment does not perform the subsequent frame rate adjustment processing. That is, the constant frame rate in the present embodiment refers to the case where the value of the frame rate is included within a predetermined range of the reference frame rate.

  The repetition upper limit N is an upper limit value of the number of continuous operations (described later) in which an operation for making the frame rate constant is repeated. This is provided on the assumption that the frame rate calculated by the frame rate calculation unit 23 to be described later may not be included in the predetermined range of the reference frame rate no matter how much the image compression parameter is changed. Is.

  The image processing unit 10 includes an image compression parameter specifying unit 17 (an image compression parameter adjusting unit) and an image compression unit 18 (an image compression unit), which process an image captured by the camera unit 2. It has become.

  The image compression parameter specifying unit 17 receives an image from the image compression parameter storage unit 14 based on the frame rate input from the frame rate setting unit 20 (frame rate setting unit) or an instruction input from the frame rate determination unit 24 described later. It has a function of acquiring compression parameters. The acquired image compression parameter is output to the image compression unit 18.

  The image compression unit 18 performs a compression process on the image data captured by the camera unit 2 based on the image compression parameter input from the image compression parameter specifying unit 17.

  Here, the control unit 7 serving as the core of the present embodiment will be described below.

  The control unit 7 includes a communication control unit 19, a frame rate setting unit 20, a communication speed detection unit 21 (communication speed detection means), a frame rate adjustment unit 22, and a counter unit 25. It has a function to keep it constant.

  The communication control unit 19 controls communication means such as a wired LAN or USB (Universal Serial Bus), and bi-directionally communicates images, sounds, and commands with the parent device 100.

  The frame rate setting unit 20 acquires or sets a reference frame rate as a reference for keeping the frame rate constant from the parent device 100.

  The communication speed detector 21 detects a data transmission amount (communication speed) per second between the slave unit 1 and the master unit 100.

  The frame rate adjustment unit 22 calculates a frame rate from the communication speed and the image size compressed by the image compression process, and compresses the image so that the calculated frame rate matches the preset reference frame rate. Has the function of adjusting the rate.

  The frame rate adjustment unit 22 includes a frame rate calculation unit 23 (frame rate calculation unit) and a frame rate determination unit 24 (frame rate determination unit).

  The frame rate calculation unit 23 calculates a frame rate from the communication speed detected by the communication speed detection unit 21 and the image size compressed by the image compression unit 18.

  The frame rate determining unit 24 determines whether or not the frame rate calculated by the frame rate calculating unit 23 is included in a predetermined range of the reference frame rate, and outputs the result to the image compression parameter specifying unit 17. To do.

  The counter unit 25 (counting unit) has a function of counting C1 and C2, which are the number of continuous operations described later. C1 is an operation in which image data captured by the camera unit 2 is compressed based on an image compression parameter adjusted to increase the degree of image compression, and the compressed image data is transmitted to the parent device 100 Is the number of continuous operations when this operation is performed continuously. C2 is the compression of the image data captured by the camera unit 2 based on the image compression parameter adjusted so that the degree of image compression is weakened, and the compressed image data is transmitted to the parent device 100. If the operation is one operation, it means the number of continuous operations when this operation is performed continuously.

  When the counter unit 25 receives the initialization instruction signal from the frame rate setting unit 20, the counter unit 25 sets the counts of C1 and C2 to zero.

  Next, the internal configuration of base unit 100 will be described.

  FIG. 2 is a functional block diagram showing a specific example of the hardware configuration of the doorphone master unit according to the present embodiment.

  As shown in FIG. 2, base unit 100 includes display unit 101, speaker unit 102, microphone unit 103, and input switch (SW) unit 104 corresponding to the display screen described above. Furthermore, a communication interface 105, a control unit 106, an information storage unit 107, an input unit 108, an image processing unit 109, and an audio processing unit 110 are provided.

  The communication interface 105 is a connection part for communicating with the child device 1.

  The input unit 108 inputs a response signal and a reference frame rate change signal from the outside to the base unit 100, and includes an input SW unit 104 and an input detection unit 111.

  The image processing unit 109 processes the image data transmitted from the slave unit 1 and outputs the processed image data to the display unit 101, and includes an image expansion unit 112. Specifically, image data compressed by the image compression unit 18 of the slave unit 1 is input to the image processing unit 109 via the communication control unit 113. Then, the image processing unit 109 expands the image data compressed by the image expansion unit 112 and outputs the expanded image data to the display unit 101.

  The voice processing unit 110 processes voices such as voices of responders and visitors. Specifically, the voice processing unit 110 performs A / D conversion on the voice signal of the responder input through the microphone unit 103 and transmits the converted signal to the slave unit 1 through the communication control unit 113 described later. In addition, the audio processing unit 110 performs D / A conversion on the audio signal from the child device 1 input via the communication control unit 113 described later, and outputs the D / A to the speaker unit 102.

  The information storage unit 107 is a part that stores data and programs, and includes a frame rate data storage unit 115 that stores a preset reference frame rate F.

  The control unit 106 includes a communication control unit 113 for controlling communication means and bi-directionally communicating images, sounds, and commands with the child device 1, and a frame rate setting unit 114 for setting a reference frame rate F.

  The communication control unit 113 of the parent device 100 outputs a call signal from the child device 1 to the image processing unit 109 and the audio processing unit 110 and also to the frame rate setting unit 114. The voice processing unit 110 to which the call signal is input outputs the call sound to the outside via the speaker unit 102. Further, the image processing unit 109 also starts displaying an image photographed by the slave unit 1 via the display unit 101.

  When the frame rate setting unit 114 receives the call signal from the child device 1 via the communication control unit 113, the frame rate setting unit 114 acquires a preset reference frame rate F from the frame rate data storage unit 115. The frame rate setting unit 114 that has acquired the reference frame rate F outputs the reference frame rate F to the communication control unit 113 in order to transmit the reference frame rate F to the child device 1. Then, the communication control unit 113 transmits the reference frame rate F to the child device 1.

  Next, the operation performed by the door phone apparatus according to the present embodiment to keep the frame rate constant will be described with reference to FIG.

  FIG. 3 is a flowchart showing a series of operations for keeping the frame rate performed at the doorphone slave unit 1 constant.

  First, upon receiving an input detection signal from the input detection unit 16, the communication control unit 19 provided in the control unit 7 is stored in the frame rate data storage unit 115 of the parent device 100 via the communication control unit 113. A reference frame rate F is acquired (S1).

  The communication control unit 19 that has acquired the reference frame rate F outputs the acquired data of the reference frame rate F to the frame rate setting unit 20.

  The frame rate setting unit 20 outputs the data of the reference frame rate F acquired in S1 to the frame rate data storage unit 15 and also outputs it to the image compression parameter specifying unit 17. Further, when the frame rate setting unit 20 acquires the data of the reference frame rate F, the frame rate setting unit 20 outputs an instruction signal for initializing the count to the counter unit 25. In response to the initialization instruction signal, the counter unit 25 sets both the counts of C1 and C2 to zero (S2).

  The image compression parameter specifying unit 17 that has acquired the reference frame rate F corresponds to the input reference frame rate F from the image compression parameter table shown in FIG. 5 stored in the image compression parameter storage unit 14. The image compression parameter is acquired (S3).

  Then, the image compression parameter specifying unit 17 outputs the parameters acquired from the image compression parameter storage unit 14 to the image compression unit 18.

  Here, a method in which the image compression parameter specifying unit 17 acquires the image compression parameter from the image compression parameter storage unit 14 will be specifically described below with reference to FIG.

  First, the image compression parameter specifying unit 17 applies the reference frame rate F acquired in S1 to the table stored in the image compression parameter storage unit 14 shown in FIG. 5 and determines which sampling ratio and quantization table to use. decide.

  For example, if the acquired reference frame rate F is greater than or equal to C and less than D, it corresponds to the case 3 of the table. Therefore, the image compression parameter specifying unit 17 sets the sampling ratio of 4: 2: 2 and the quantization table c. The parameter is determined to be used for sampling and quantization, and the data is acquired. Then, the image compression parameter specifying unit 17 outputs the image compression parameter of case 3 to the image compression unit 18.

  Based on the image compression parameter input from the image compression parameter specifying unit 17, the image compression unit 18 captures the image by the camera unit 2 and compresses the acquired image data (S4). Then, the image compression unit 18 outputs the compressed image data to the frame rate calculation unit 23.

  By the way, the communication speed detection unit 21 measures the amount of data transmitted from the parent device 100 within a certain fixed time, and divides the transmitted data amount by the certain time, whereby the current parent device 100. -The communication speed between the subunit | mobile_units 1 is detected (S5). Then, the communication speed detection unit 21 outputs the detected communication speed to the frame rate calculation unit 23.

  The frame rate calculation unit 23 calculates the frame rate M using the communication speed data input from the communication speed detection unit 21 and the image data after image compression processing input from the image compression unit 18 (S6). Specifically, the frame rate calculation unit 23 calculates the frame rate by dividing the communication speed by the amount of image data per frame. Then, the frame rate calculation unit 23 outputs the data of the calculated frame rate M to the frame rate determination unit 24.

  The frame rate determination unit 24 that has acquired the frame rate M first acquires data of the reference frame rate F, the allowable range α, and the repetition upper limit value N from the frame rate data storage unit 15. Then, the frame rate determination unit 24 obtains predetermined ranges F + α and F−α of the reference frame rate from the acquired reference frame rate F and the allowable range α, and the calculated frame rate M is the reference frame rate. In the predetermined range (between F−α ≦ M ≦ F + α) (S7, S12).

  Below, the determination method of said S7 and S12 which the frame rate determination part 24 performs is demonstrated concretely.

  The frame rate determination unit 24 first determines whether or not the frame rate M is smaller than F-α, which is the minimum value in the predetermined range of the reference frame rate (S7).

  Specifically, when it is determined that the frame rate M is smaller than the F-α, that is, when YES in S7 of FIG. 3, the frame rate M is within a predetermined range of the reference frame rate. It is judged not to be included.

  In this case, the frame rate determination unit 24 next acquires data of the current value of C1 from the counter unit 25, and determines whether or not the value of C1 is equal to or less than the acquired repetition upper limit value N (S8). ).

  If it is determined that the value of C1 is repeatedly less than or equal to the upper limit value N, that is, if YES in S8 of FIG. 3, the frame rate determination unit 24 outputs an instruction signal for increasing the degree of image compression. In addition to outputting to the parameter specifying unit 17 (S9), the counter unit 25 outputs an instruction signal for increasing the value of C1 by 1 and an instruction signal for initializing C2.

  Upon receiving the signal from the frame rate determination unit 24, the counter unit 25 increases the count number C1 by 1 to C1 + 1, and initializes the value of C2, that is, C2 = 0. (S10).

  The image compression parameter specifying unit 17 to which an instruction signal for increasing the degree of image compression is input from the frame rate determination unit 24 (S9), and sampling is performed so that the degree of image compression is increased by one step from the image compression parameter storage unit 14. The ratio and quantization table image compression parameters are acquired (S3). Then, the image data compressed using the acquired image compression parameter is transmitted to the parent device 100 via the communication control unit 19 (S4, S18).

  For example, when it is assumed that the previous image compression (S4) was performed based on the data of case 3 in the table of the image compression parameter storage unit 14 shown in FIG. The image compression parameter specifying unit 17 to which the strengthening instruction signal is input acquires the image compression parameter of the case 2 whose degree of image compression is one step stronger than the case 3 (S3).

  Then, the image compression unit 18 acquires the image compression parameter from the image compression parameter specifying unit 17, and performs image compression based on the image compression parameter (S4). The compressed image data is transmitted to the master unit (S18).

  If it is determined in S8 that the value of C1 is repeatedly larger than the upper limit N, image compression is performed using the current image compression parameter (S4) and transmitted to the parent device (S18).

  On the other hand, if it is determined in S7 that the frame rate M is larger than the F-α, that is, if NO in S7 of FIG. Is greater than F + α which is the maximum value in the predetermined range of the reference frame rate (S12).

  At this time, the frame rate determination unit 24 outputs to the counter unit 25 an instruction signal for initializing the value of C1. Upon receiving the initialization instruction signal, the counter unit 25 initializes the value of C1, that is, sets C1 = 0 (S11).

  If the frame rate determination unit 24 determines that the frame rate M is greater than the F + α, that is, if YES in S12 of FIG. 3, the frame rate M is within a predetermined range of the reference frame rate. It is judged not to be included.

  In this case, the frame rate determination unit 24 next acquires data of the current value of C2 from the counter unit 25, and determines whether the value of C2 is equal to or less than the repetition upper limit value N (S13).

  If it is determined that the value of C2 is repeatedly less than or equal to the upper limit value N, that is, if YES in S13 of FIG. 3, the frame rate determining unit 24 outputs an instruction signal for reducing the degree of image compression as an image compression parameter. In addition to outputting to the specifying unit 17 (S14), an instruction signal to increase the value of C2 by 1 is output to the counter unit 25. Upon receiving the instruction signal to increase the value of C2 by 1, the counter unit 25 increases the value of C2 by 1 to C2 + 1 (S15).

  When an instruction signal for weakening the degree of image compression is input (S14), the image compression parameter specifying unit 17 sets an image compression parameter that reduces the degree of image compression by one step from the image compression parameter storage unit 14. Obtain (S3).

  For example, when it is assumed that the previous image compression (S4) was performed based on the data of case 2 in the table of the image compression parameter storage unit 14 shown in FIG. 5, an instruction signal for reducing the degree of image compression is obtained. The input image compression parameter specifying unit 17 acquires the image compression parameter of Case 3 whose degree of image compression is one step weaker than that of Case 2 (S3).

  Then, the image compression unit 18 performs image compression based on the image compression parameter acquired in S3 from the image compression parameter specifying unit 17 (S4). The compressed image data is transmitted to the master unit (S18).

  If it is determined in S13 that the value of C2 is repeatedly larger than the upper limit value N, image compression is performed using the current image compression parameter (S4) and transmitted to the parent device (S18).

  On the other hand, if it is determined in S12 that the frame rate M is smaller than F + α, that is, if NO in S12 of FIG. 3, the frame rate M is within a predetermined range of the reference frame rate (F -Α ≦ M ≦ F + α), the frame rate determination unit 24 outputs the signal compression level to the signal image compression parameter specifying unit 17 instructing to maintain the current level (S16). At this time, the frame rate determination unit 24 outputs an instruction signal for initializing the value of C2 to the counter unit 25. Upon receiving the initialization instruction signal, the counter unit 25 initializes the value of C2, that is, sets C2 = 0 (S17).

  Then, the image compression unit 18 performs image compression based on the same parameter as the previous image compression parameter acquired from the image compression parameter specifying unit 17 (S4). The compressed image data is transmitted to the master unit (S18).

  The control unit 7 performs the above-described series of operations (S1 to S18) until the value of the frame rate M calculated by the frame rate calculation unit 23 is included within a predetermined range of the reference frame rate, or , C1 or C2 is repeated until the upper limit value N is repeated.

  When the control unit 7 receives an instruction signal for changing the reference frame rate F from the base unit 100 regardless of the current operation from S1 to S18, the frame rate setting unit 20 A new reference frame rate F corresponding to the instruction signal is set. The frame rate setting unit 20 then outputs the newly set reference frame rate data to the frame rate data storage unit 15 and outputs an instruction signal for initializing C1 and C2 to the counter unit 25.

  The frame rate data storage unit 15 updates the stored reference frame rate F data to the newly set reference frame rate data, and the counter unit 25 sets the values of C1 and C2 to zero.

  Thus, the operation for keeping the frame rate constant after the change of the reference frame rate F is performed using the reference frame rate F after the change, and C1 and C2 are also counted from 0.

  By performing the above series of operations, the intercom apparatus according to the present embodiment can keep the frame rate between handset 1 and base unit 100 substantially constant near the reference frame rate.

  Also, for example, when the reference frame rate is a value that is much higher than the calculated current frame rate, in order to increase the current frame rate and approach the reference frame rate, the degree of image compression is extremely However, if the degree of image compression is increased too much, problems such as image distortion may occur.

  On the other hand, by providing the repeated upper limit value N and the counter unit 25, the series of operations are stopped when a preset upper limit value is exceeded, so that the operation before the problem such as the image is disturbed occurs. Can be stopped.

  As a result, when the reference frame rate is a very high value or a very low value compared to the calculated frame rate, the image is not disturbed rather than keeping the frame rate constant. You can give priority to this.

  In this embodiment, since the communication speed is detected and the frame rate adjustment of the above series of operations is performed, the frame rate is kept constant without being affected even when the communication speed changes due to the congestion of the line. It becomes possible to keep.

  As a result, the door phone device according to the present embodiment can keep good followability to the visitor's movement, so that the responder can easily check the visitor without feeling stress.

  In the door phone device of the present embodiment, the responder can arbitrarily set the reference frame rate F.

  Specifically, base unit 100 includes an input SW 104 such as a frame rate UP switch or a frame rate DOWN switch, and further includes a frame rate data storage unit 115 that stores data of a plurality of frame rates in advance.

  If the responder presses the frame rate UP switch, the input detection unit 111 detects the frame rate UP instruction signal and outputs the detected signal to the frame rate setting unit 114. Then, based on the acquired frame rate UP instruction signal, the frame rate setting unit 114 acquires data of a frame rate that is one rank higher than the currently set reference frame rate from the frame rate data storage unit 115, and uses it as a reference Set as frame rate F. Then, the frame rate setting unit 114 transmits the set reference frame rate F to the child device 1 via the communication control unit 113. The subsequent operation of processing for making the frame rate constant in the slave unit 1 is as shown in FIG.

  Master unit 100 also performs the same operation as the above operation when the responder presses the frame rate DOWN switch, but frame rate setting unit 114 is currently set from frame rate data storage unit 115. Data having a frame rate one rank lower than the existing reference frame rate F is acquired and set as the reference frame rate F.

  In addition, as a method for the responder to arbitrarily set the reference frame rate, a method may be considered in which base unit 100 directly inputs a frame rate value that the responder wants to set, such as 45 frames per second.

  According to the above configuration, the responder can arbitrarily set the frame rate. Therefore, when priority is given to good image quality, the frame rate can be set low, and good follow-up to visitor movement can be achieved. If priority is given, the frame rate can be set high. Thereby, the convenience of the door phone device in the present embodiment is improved.

  Further, since the door phone device of the present embodiment has a function of making the frame rate constant, even when the reference frame rate F is changed, the frame rate can be kept constant at the changed reference frame rate.

  Therefore, the responder can easily check the visitor without feeling stress.

  In addition, the door phone device in the present embodiment is configured to include the counter unit 25 in order to repeatedly set the upper limit value N in the operation (S1 to S18) for keeping the frame rate constant, but the present invention is not limited to this. The upper limit value N may not be provided, and the counter unit 25 may not be provided accordingly.

In the door phone device according to the present embodiment, wired communication is used as the communication means between the parent device and the child device. However, the door phone device of the present invention is not limited to this, and other communication means may be used. The door phone device of the present invention may be, for example, a door phone device using radio as the communication means, or both wired and wireless as the communication means, and the communication speed detecting unit 21 may perform wired according to the communication speed. In addition, the door phone device may be configured to switch between radios.
[Embodiment 2]
This embodiment is different from the door phone device of the first embodiment in the configuration of a part of the control unit 201 of the parent device 200, but the other configurations are the same. Therefore, the same configurations as those of the first embodiment in the present embodiment are denoted by the same reference numerals as those of the first embodiment, and the description thereof is omitted.

  FIG. 6 is a functional block diagram showing a specific example of the hardware configuration of the doorphone master device according to the present embodiment.

  Base unit 200 of the present embodiment has a function of automatically setting an optimal reference frame rate for each mode state of the base unit.

  Frame rate data storage section 203 in the present embodiment stores data of an optimal frame rate for each mode state of the parent device in advance.

  Hereinafter, the internal configuration of the control unit 201 in the parent device 200 will be described.

  The control unit 201 includes a communication control unit 113, a frame rate setting unit 114, and a parent device mode detection unit 202 (parent device mode detection means).

  The base unit mode detection unit 202 detects what mode state the base unit 200 is currently in. The mode state of base unit 200 is, for example, a state where the responder is set to be away when the responder is away (absence setting state), a state where the responder is responding to the visitor (response state), etc. Can be considered.

  The communication control unit 113 that has received the call signal from the handset 1 outputs the call signal to the image processing unit 109 and the sound processing unit 110 and also to the base unit mode detection unit 202.

  When a call signal from handset 1 is input, base unit mode detection unit 202 detects the current mode state of base unit 200, and displays mode information including the current base unit mode state as a frame rate setting unit. To 114.

  When the mode information is input from the parent mode detection unit 202, the frame rate setting unit 114 obtains an optimal frame rate corresponding to the current mode of the parent unit included in the mode information from the frame rate data storage unit 115. Acquire and set the reference frame rate.

  Then, the frame rate setting unit 114 transmits the set reference frame rate to the child device 1 via the communication control unit 113.

  Since the operation for making the frame rate constant in the slave unit 1 that has acquired the reference frame rate is the same as that in the first embodiment, the description thereof is omitted in this embodiment.

  Here, as a specific example, the processing operation of the parent device 200 when the parent device is in the response state will be described below.

  The communication control unit 113 that has received the call signal from the child device 1 outputs the call signal to the image processing unit 109, the sound processing unit 110, and the parent device mode detection unit 202.

  The base unit mode detection unit 202 to which the call signal is input first detects the state of the base unit as a pre-response mode and outputs the mode information to the frame rate setting unit 114. When base unit 200 is in the pre-response mode, the door phone device of the present embodiment is required to improve the image quality in order to make it easier for visitors to check. Therefore, it is preferable that the door phone device according to the present embodiment has a low degree of image compression, that is, a frame rate as low as possible.

  Then, the frame rate setting unit 114 acquires a low frame rate corresponding to the pre-response mode from the frame rate data storage unit 203, and sets the acquired frame rate as a reference frame rate.

  Further, when a response button (input SW unit 104) is pressed by a responder who has heard the ringing tone, the base unit mode detection unit 202 receives a response detection that is issued when the response button is pressed via the input detection unit 111. A signal is input. Upon receiving the response detection signal, base unit mode detection unit 202 detects the mode of base unit 200 as a response mode and outputs the mode information to frame rate setting unit 114.

  When the parent device 200 is in the response mode, since the voice is exchanged between the visitor and the responder, the voice processing unit 110 operates and the load on the system becomes heavy. Therefore, it is preferable to increase the frame rate, that is, to increase the degree of image compression to reduce the image size after compression.

  This is because in the door phone device of the present embodiment, if the image size after image compression is reduced, the load of Huffman decoding at the time of decoding becomes light, so the load on the image decompression unit 112 becomes light and the system performance is improved. It is because it can be made.

  Then, the frame rate setting unit 114 acquires a high frame rate corresponding to the response mode from the frame rate data storage unit 203, and sets the acquired frame rate as a reference frame rate.

  In the door phone device of the present embodiment, as described above, if the frame rate is increased after the response, that is, the degree of image compression is increased, there is a possibility that the image quality deteriorates. However, since the responder confirms the visitor once before the response, it is considered that there is no need to sufficiently confirm the visitor after the response. Thus, after responding, the responder can respond to the visitor without feeling stress by improving the system performance rather than suppressing the deterioration of the visibility accompanying the deterioration of the image quality.

  Further, when the parent device is in the absence setting state, the image processing unit 109 of the parent device 200 may include an image storage unit 204 as shown in FIG. As a result, the door phone device of the present embodiment can store the visitor image transmitted from the child device 1 when the parent device 200 is in the absence mode, and the responder returns to the parent device after returning home. The accumulated image can be displayed on the display unit 101 by pressing the input SW unit 104 of the machine.

  In this case, since the responder reproduces the recorded image and confirms the visitor, it is not necessary to set the reference frame rate high.

  Therefore, the frame rate setting unit 114 that has acquired the mode information detected by the base unit mode detection unit 202 as the absence mode, acquires the optimum frame rate for the absence setting mode from the frame rate data storage unit 203, and the reference frame rate Set as.

According to the above configuration, the door phone device according to the present embodiment can automatically set an optimal reference frame rate according to each mode state of the parent device, and therefore the influence of a change in the mode state of the parent device. It is hard to receive. Further, in the door phone device of the present embodiment, the frame rate can be kept constant in the vicinity of the reference frame rate according to the mode state of the parent device. Thereby, the responder can check the image of the visitor without feeling stress.
[Embodiment 3]
The present embodiment is different from the door phone device of the first embodiment in the configuration of a part of the control unit 301 of the base unit 300, but the other configurations are the same. Therefore, the same configurations as those of the first embodiment in the present embodiment are denoted by the same reference numerals as those of the first embodiment, and the description thereof is omitted.

  FIG. 7 is a functional block diagram showing a specific example of the hardware configuration of the doorphone master device according to the present embodiment.

  Base device 300 of the present embodiment has a function of automatically setting an optimal reference frame rate according to the visit time of the visitor.

  The frame rate data storage unit 303 in the present embodiment stores in advance a table of time and data of an optimal frame rate corresponding to the time.

  Hereinafter, an internal configuration of control unit 301 in base unit 300 will be described.

  The control unit 301 includes a communication control unit 113, a frame rate setting unit 114, and a time measuring unit 302 (time measuring means).

  The time measuring unit 302 has a function of specifying a time when a visitor has visited.

  The timer unit 302 receives a call signal, which is generated when a visitor presses the call SW unit 5, via the communication control unit 113. The time measuring unit 302 specifies the time when the call signal is input, and outputs the specified time information to the frame rate setting unit 114 as the visit time of the visitor.

  The frame rate setting unit 114 to which the time information is input acquires the frame rate corresponding to the time from the frame rate data storage unit 303, and sets the acquired frame rate as a reference frame rate. Then, the frame rate setting unit 114 transmits the set reference frame rate to the child device 1 via the communication control unit 113.

  For example, when the visit time is daytime, the outside is bright and the visibility for visitors is relatively good. On the other hand, when the visit time is night, the outside is dark and the visibility for the visitor is lower than in the daytime. For this reason, it is preferable that the door phone device of the present embodiment reduces the degree of image compression in order to provide good image quality when the visit time is nighttime. Therefore, the frame rate data storage unit 303 stores data of a low reference frame rate F as a frame rate corresponding to night time, and data of a high reference frame rate F as a frame rate corresponding to daytime time. ing.

  Since the operation for making the frame rate constant in the slave unit 1 that has acquired the reference frame rate F is the same as that in the first embodiment, the description thereof is omitted in this embodiment.

  According to the above configuration, since an optimal reference frame rate can be set according to the visit time of the visitor, it is less susceptible to the influence of the background of the visitor such as day and night. In the door phone device of the present embodiment, the frame rate can be kept constant in the vicinity of the reference frame rate set according to the visit time of the visitor. Thereby, the responder can check the image of the visitor without feeling stress.

  Moreover, although this Embodiment is a structure provided with the time measuring part 302 in a doorphone main | base station, this invention is not restricted to this, You may provide a time measuring part in a doorphone child machine.

  Further, the image processing unit 10 of the handset 1 of the door phone device in the first to third embodiments may include the luminance component extraction unit 30.

  In the above configuration, the camera unit 2 outputs the captured image data of the visitor to the luminance component extraction unit 30. The luminance component extraction unit 30 extracts only luminance component data from the input image data of the visitor and outputs the extracted data to the image compression unit 18.

  The image compression unit 18 compresses only the luminance component data input from the luminance component extraction unit 30 with the image compression parameter acquired from the image compression parameter specifying unit 17. Then, the image compression unit 18 outputs the compressed luminance component data to the frame rate calculation unit 23 when the frame rate is not constant, and transmits it to the parent device 100 via the communication control unit 19 when the frame rate is constant.

  The image expansion unit 112 of the parent device 100 expands the luminance component data compressed and transmitted by the child device 1. Then, the image processing unit 109 outputs the expanded luminance component data to the display unit 101.

  Specific examples of the image compression method include, for example, the JPEG method according to ITU-T (International Telecommunication Union-Telecommunication sector) recommendation used for compression and expansion of color images.

  Usually, a JPEG image is represented by a color space representation of Y (luminance), Cr (Chrominance red), and Cb (Chrominance blue), and compression processing is performed based on this data.

  According to the above configuration, the intercom apparatus according to the first to third embodiments can make the data size after image compression smaller than the image data size subjected to normal image compression that compresses the color difference component. As a result, the amount of data transmitted to the parent device 100 can be reduced while keeping the frame rate constant, so that the communication speed when using wireless communication as a communication means between the child device 1 and the parent device 100 decreases. It is effective when

  Further, according to the above configuration, since the image is compressed using only the Y component (luminance component), the image data compressed by the slave unit 1 and transmitted to the master unit 100 is binary (monochrome). As a result, the door phone devices of the first to third embodiments can display without changing the other system configuration even when the display unit 101 has only a monochrome display function.

  In the image compression, the JPEG method is used. However, the present invention is not limited to this, and the MPEG method may be used. When the MPEG system is used, the door phone apparatus according to the first to third embodiments can reproduce a visitor's image as a stream instead of frame-by-frame.

  In the first embodiment, as a method for acquiring the image compression parameter in S3 of FIG. 3, the image corresponding to the reference frame rate is obtained by associating the reference frame rate with the image compression parameter table stored in the information storage unit. Although a method for acquiring compression parameters is used, the image compression parameter acquisition method of the present invention is not limited to this, and other methods may be used.

  Further, in the first embodiment, the door phone cordless handset 1 includes the communication speed detection unit 21, the frame rate calculation unit 23, the frame rate determination unit 24, and the frame rate data storage unit 15 for keeping the frame rate constant. However, the present invention is not limited to this, and the above-described configuration may be provided in the master unit.

  In the second embodiment, the case where the state of the parent device is the absence setting state or the response state has been described. However, the present invention is not limited to this, and the door phone device of the present invention detects another state of the parent device. It is also possible to set an optimum frame rate according to the state as the reference frame rate.

  In the second embodiment, the parent device has a function of detecting the state of the parent device. However, the present invention is not limited to this, and the child device may have a function of detecting the state of the parent device. In this case, the state of the master unit is transmitted from the communication control unit of the master unit to the communication control unit of the slave unit by a command, and is interpreted by the control unit of the slave unit.

  Moreover, although the door phone apparatus in Embodiment 3 is configured to include a timekeeping unit in the parent device, the present invention is not limited thereto, and may be configured to include the timekeeping unit in the child device. According to this, the time measuring unit specifies the time when the call signal is input from the input detection unit of the child device as the visit time of the visitor, and the time information together with the call signal via the communication control unit 19. Transmit to. The frame rate setting unit 114 that has acquired the time information sets a reference frame rate corresponding to the time.

  Finally, in particular, the frame rate setting unit 20, the communication speed detecting unit 21, the frame rate calculating unit 23, the frame rate determining unit 24, the image compression parameter specifying unit 17, the image compressing unit 18, and the like of each block of the intercom 1 The frame rate setting unit 114 of the doorphone master unit 100 may be configured by hardware logic, or may be realized by software using a CPU as follows.

  That is, the doorphone slave unit 1 and the doorphone master unit 100 include a CPU (central processing unit) that executes instructions of a control program for realizing each function, a ROM (read only memory) that stores the program, and a RAM that expands the program. (Random access memory), a storage device (recording medium) such as a memory for storing the program and various data. The object of the present invention is to enable the computer to read the program code (execution format program, intermediate code program, source program) of the control program for the doorphone slave unit 1 and the doorphone master unit 100, which is software that implements the functions described above. This can also be achieved by supplying the recorded recording medium to the doorphone slave unit 1 and the doorphone master unit 100, and the computer (or CPU or MPU) reads and executes the program code recorded on the recording medium. .

  Examples of the recording medium include tapes such as magnetic tapes and cassette tapes, magnetic disks such as floppy (registered trademark) disks / hard disks, and disks including optical disks such as CD-ROM / MO / MD / DVD / CD-R. Card system such as IC card, IC card (including memory card) / optical card, or semiconductor memory system such as mask ROM / EPROM / EEPROM / flash ROM.

  Further, the doorphone slave unit 1 and the doorphone master unit 100 may be configured to be connectable to a communication network, and the program code may be supplied via the communication network. The communication network is not particularly limited. For example, the Internet, intranet, extranet, LAN, ISDN, VAN, CATV communication network, virtual private network, telephone line network, mobile communication network, satellite communication. A net or the like is available. Also, the transmission medium constituting the communication network is not particularly limited. For example, even in the case of wired such as IEEE 1394, USB, power line carrier, cable TV line, telephone line, ADSL line, etc., infrared rays such as IrDA and remote control, Bluetooth ( (Registered trademark), 802.11 wireless, HDR, mobile phone network, satellite line, terrestrial digital network, and the like can also be used. The present invention can also be realized in the form of a computer data signal embedded in a carrier wave in which the program code is embodied by electronic transmission.

It is a functional block diagram which shows the specific example of the hardware constitutions of the door phone cordless handset in this embodiment. It is a functional block diagram which shows the specific example of the hardware constitutions of the door phone main unit in this embodiment. It is the flowchart figure which showed a series of operation | movement for keeping a frame rate constant. It is a schematic diagram of the whole structure of the door phone apparatus which concerns on this embodiment. It is a figure which shows an example of the image compression parameter table stored in an image compression parameter storage part. It is a functional block diagram which shows the specific example of the hardware constitutions of the door phone main unit in this embodiment. It is a functional block diagram which shows the specific example of the hardware constitutions of the door phone main unit in this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Door phone cordless handset 100, 200, 300 Door phone master phone 2 Camera part 3, 102 Speaker part 4, 103 Microphone part 5, 104 Input switch (SW) part 6, 105 Communication interface 7, 106, 201, 301 Control part 8, Reference Signs List 107 Information storage unit 9, 108 Input unit 10, 109 Image processing unit 11, 110 Audio processing unit 12 Program storage unit 13 Data storage unit 14 Image compression parameter storage unit (image compression parameter storage means)
15, 115, 203, 303 Frame rate data storage unit 16, 111 Input detection unit 17 Image compression parameter specifying unit (image compression parameter adjusting means)
18 Image compression unit 19, 113 Communication control unit 20, 114 Frame rate setting unit (frame rate setting means)
21 Communication speed detection unit (communication speed detection means)
22 Frame rate adjustment unit (frame rate adjustment means)
23 Frame rate calculation unit (frame rate calculation means)
24 Frame rate determination unit (frame rate determination means)
25 Counter section (counting means)
202 Base unit mode detection unit (base unit mode detection means)
302 Timekeeping section (timekeeping means)

Claims (16)

An image capturing device for capturing an image of a visitor, a door phone slave unit that compresses image data obtained by capturing with the image capturing device and transmits the compressed image data to the door phone master unit, and the door phone slave unit that is transmitted from the door phone slave unit The doorphone slave unit in a doorphone device configured to include a doorphone master unit that decompresses image data and displays the image data on a display device included in the image data,
Image compression means for compressing image data acquired by photographing with the imaging device with specific image compression parameters;
A communication speed detecting means for detecting a speed of data communication performed between the doorphone master unit and the doorphone slave unit;
A frame rate calculating means for calculating a frame rate in the display device of the doorphone master unit from the communication speed obtained by the communication speed detecting means and the image data compressed by the image compressing means;
Frame rate determination means for determining whether or not the frame rate calculated by the frame rate calculation means is included within a predetermined range of a reference frame rate that is a reference when the frame rate is kept constant;
When the frame rate determination means determines that the calculated frame rate is not included in a predetermined range of the reference frame rate, the calculated frame rate is determined to be a predetermined value of the reference frame rate. An intercom slave unit comprising image compression parameter adjustment means for adjusting an image compression parameter so as to be included in the range.   The doorphone slave unit according to claim 1, further comprising a frame rate setting unit that sets a reference frame rate based on a user instruction transmitted from the doorphone master unit. Image compression parameter storage means for storing a plurality of image compression parameters in accordance with the level of image compression strength;
In the case where it is determined by the frame rate determination means that the frame rate calculated by the frame rate calculation means is not included in a predetermined range of the reference frame rate,
When the calculated frame rate is smaller than a predetermined range of the reference frame rate, the image compression parameter adjustment unit sets the degree of image compression from the image compression parameter storage unit to the current image compression parameter. The image compression parameter to be strengthened is selected, and the image data compressed based on the selected image compression parameter is transmitted to the doorphone master unit,
On the other hand, when the calculated frame rate is larger than a predetermined range of the reference frame rate, the image compression parameter adjustment unit is configured to perform image compression from the image compression parameter storage unit more than the current image compression parameter. 3. The door phone slave unit according to claim 1, wherein an image compression parameter for reducing the degree is selected, and image data compressed based on the selected image compression parameter is transmitted to the door phone master unit. . The number of operations in which the image data is compressed based on an image compression parameter adjusted to increase the degree of image compression, and the operation transmitted to the intercom master unit is continuously performed,
Counting means for measuring the number of operations in which the image data is compressed based on an image compression parameter adjusted so that the degree of image compression is weak and the operations transmitted to the intercom master unit are continuously performed. Further comprising
The image compressing unit compresses an image without adjusting the degree of image compression when the number of operations measured by the counting unit exceeds a preset upper limit value. Item 4. A door phone slave unit according to item 3. A luminance component extracting means for extracting only the luminance component from the image data obtained by photographing with the imaging device;
5. The door phone slave unit according to claim 1, wherein the image compression unit compresses the luminance component extracted by the luminance component extraction unit with a specific image compression parameter. 6.   6. The door phone slave device according to claim 5, wherein the image compression unit compresses image data obtained by photographing with the imaging device by a JPEG method. A door phone parent device that communicates with the door phone child device according to any one of claims 1 to 6,
A frame rate setting unit configured to set a reference frame rate as a reference when the frame rate in the display device is kept constant based on a user's instruction; and the reference frame rate set by the frame rate setting unit is A door phone master unit that transmits to a door phone slave unit. A storage unit that stores a table that stores the time and the frame rate in association with each other; and a timing unit that detects a visit time of the visitor.
8. The doorphone parent according to claim 7, wherein the frame rate setting means selects a frame rate corresponding to the time counted by the timing means from the table and sets it as the reference frame rate. Machine. A storage unit that stores a table that stores the state of the parent device and the frame rate in association with each other; and a parent device mode detection unit that detects what state the doorphone parent device is currently in,
8. The frame rate setting means selects a frame rate corresponding to the state of the parent device detected by the parent device mode detection means from the table and sets it as a reference frame rate. Or the door phone main unit of 8. An image capturing device for capturing an image of a visitor, a door phone slave unit that compresses image data obtained by capturing with the image capturing device and transmits the compressed image data to the door phone master unit, and the door phone slave unit that is transmitted from the door phone slave unit A method for controlling the doorphone slave unit of the doorphone device configured to include the doorphone master unit that decompresses the image data and displays the image data on a display device included in the image data,
An image compression step of compressing image data acquired by photographing with the imaging device with specific image compression parameters;
A communication speed detection step for detecting a speed of data communication performed between the doorphone master unit and the doorphone slave unit;
A frame rate calculation step of calculating a frame rate in the display device of the doorphone master unit from the communication speed obtained by the communication speed detection step and the image data compressed by the image compression step;
A frame rate determination step for determining whether or not the frame rate calculated by the frame rate calculation step is included in a predetermined range of a reference frame rate that serves as a reference when the frame rate is kept constant;
In the frame rate determining step, when it is determined that the calculated frame rate is not included in a predetermined range of the reference frame rate, the calculated frame rate is determined to be a predetermined value of the reference frame rate. An image compression parameter adjustment step of adjusting an image compression parameter so as to be included in the range. A control method in a door phone parent device that communicates with the door phone child device according to any one of claims 1 to 6,
A frame rate setting step for setting a reference frame rate, which is a reference in the case of keeping the frame rate constant in the display device, based on a user instruction;
Transmitting the reference frame rate set in the frame rate setting step to the door phone slave unit.   The door phone apparatus of the structure containing the door phone subunit | mobile_unit of any one of Claims 1-6, and the door phone main | base station of any one of Claims 7-9.   An image compression parameter adjustment program for operating the doorphone slave device according to any one of claims 1 to 6, wherein the computer functions as each of the above-described means.   A computer-readable recording medium on which the image compression parameter adjustment program according to claim 13 is recorded.   A reference frame rate setting program for operating the intercom master unit according to any one of claims 7 to 9, wherein the reference frame rate setting program causes a computer to function as each of the above means.   A computer-readable recording medium on which the frame rate setting program according to claim 15 is recorded.

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