JP7196209B2 - Communication device, control method and program - Google Patents

Description

The present invention relates to a communication device capable of communicating with an external device.

2. Description of the Related Art In recent years, with the advancement of communication functions of communication devices such as digital cameras and mobile phones, content is being transmitted and received between communication devices.

Japanese Patent Application Laid-Open No. 2002-200000 discloses that a server-client system such as HTTP is used, and a digital camera acts as a server to realize remote photographing.

JP 2013-073506 A

When a user is provided with a remote control function using an HTTP server/client system, the remote-controlled digital camera serves as the server, and the remote-controlling side serves as the client. Remote control is realized by implementing a program for controlling the digital camera in the client device. In this case, a combination of a URL for remote controlling a digital camera and an executable HTTP method may be published as a communication API (Application Programming Interface), thereby reducing the client's program implementation load. The client, which is the counterpart machine, implements a program for realizing remote control based on the published API specifications. In order to further reduce this implementation load, it is conceivable to prepare an API using chunk transmission. However, chunk transmission is a transmission method that repeatedly transmits an HTTP response body after returning an HTTP response header. Therefore, if the data to be transmitted cannot be prepared during the transmission of the HTTP response body, the digital camera cannot notify the error using the HTTP response header. On the other hand, if error information is included in the HTTP response body in order to notify the error, processing for analyzing the error information is required in the counterpart machine, increasing the implementation load of developing the counterpart application.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to further reduce the implementation load when developing a counterpart application for controlling a communication device.

One communication apparatus according to the present invention includes generation means for generating a live -view image, operation means, communication means, and when the live-view image is generated by the generation means, an external device is generated via the communication means. When a second request is received from the device, a process of generating a response from the live view image generated by the generating means, and transmitting the generated response as a response corresponding to the second request via the communication means transmitting the live view image to the external device, and if the live view image is not generated by the generating means and the second request is received from the external device via the communication means, an error is generated. performing a process of generating a response including information for notification, and a process of transmitting the generated response as a response corresponding to the second request to the external device via the communication means; a process of generating a response from the live view image generated by the generating means when a first request is received from the external device via the communication device, and the generated response as a response corresponding to the first request; transmitting to the external device via means, generating a response from the live view image generated by the generating means, and using the generated response as a response corresponding to the first request. If the live view image is not generated while the process of transmitting to the external device via the communication means is repeated, a predetermined image is used instead of the live view image that was not generated by the generating means. A control means for controlling to perform a process of generating a response and a process of transmitting the generated response to the external device via the communication means as a response corresponding to the first request .

According to the present invention, it is possible to further reduce the implementation load when developing a counterpart application for controlling a communication device.

1A and 1B are diagrams showing a block configuration, a front surface, and a rear surface of a digital camera according to a first embodiment; FIG. 1 is a block diagram showing the configuration of a smart device according to the first embodiment; FIG. 1 is a block diagram showing a system configuration according to a first embodiment; FIG. 3 is a diagram showing the basic configuration of a communication API in the first embodiment; FIG. 4A and 4B are diagrams for explaining an API for acquiring a through image of a digital camera according to the first embodiment; FIG. FIG. 10 is an example of a sequence diagram when executing an API for acquiring through-the-lens images one frame at a time according to the first embodiment; FIG. 10 is an example of a sequence diagram when executing an API for acquiring a through image of a digital camera by chunk transmission according to the first embodiment; 4 is a flow chart showing an example of the operation of the digital camera 100 according to the first embodiment; 4 is a flow chart showing an example of the operation of the smart device 200 according to the first embodiment; (a) is an example of a UI diagram of the smart device 200 during live view for acquiring through-the-lens images one frame at a time according to the first embodiment. (b) is an example of a UI diagram of the smart device 200 when an error occurs in the digital camera 100 during live view for acquiring through-the-lens images frame by frame according to the first embodiment. (a) is an example of a UI diagram of the smart device 200 during live view in chunk transmission using the first embodiment. (b) is an example of a UI diagram of the smart device 200 when an error occurs in the digital camera 100 during live view in chunk transmission using the first embodiment. (c) is an example of a UI diagram of the smart device 200 when an error occurs in the digital camera 100 during live view in chunk transmission without using the first embodiment. 4 is a flow chart showing an example of the operation of the digital camera 100 when acquiring through-the-lens images one frame at a time according to the first embodiment. FIG. 10 is an example of a flowchart of a smart device when acquiring through images one frame at a time according to the first embodiment; FIG. 4 is a flowchart showing an example of the operation of the digital camera 100 in chunk transmission that does not use the first embodiment; FIG. 10 is a flow chart showing an example of operation of the smart device 200 in chunk transmission without using the first embodiment; FIG. 4 is a flow chart showing an example of the operation of the digital camera 100 in chunk transmission using the first embodiment; 4 is a flow chart showing an example of operation of the smart device 200 in chunk transmission using the first embodiment;

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments described below are examples of means for implementing the present invention, and may be appropriately modified or changed according to the configuration of the apparatus to which the present invention is applied and various conditions. Moreover, it is also possible to combine each embodiment suitably.

[First embodiment]
<Configuration of Digital Camera 100>
FIG. 1A is a block diagram showing a configuration example of a digital camera 100, which is an example of a communication device to which this embodiment is applied. Note that although a digital camera will be described here as an example of a communication device, the communication device is not limited to this. For example, the communication device may be a portable media player, a so-called tablet device, or an information processing device such as a personal computer.

The control unit 101 controls each unit of the digital camera 100 according to the input signals and programs described later. Note that instead of the control unit 101 controlling the entire apparatus, a plurality of pieces of hardware may share processing to control the entire apparatus.

The imaging unit 102 includes, for example, an optical lens unit, an optical system for controlling diaphragm, zoom, focus, etc., and an imaging element for converting light (image) introduced through the optical lens unit into an electrical image signal. Configured. As an imaging device, a CMOS (Complementary Metal Oxide Semiconductor) or a CCD (Charge Coupled Device) is generally used. Under the control of the control unit 101, the imaging unit 102 converts subject light imaged by the lens included in the imaging unit 102 into an electrical signal by the imaging element, performs noise reduction processing, etc., and converts the digital data into an image. Output as data. In the digital camera 100 of this embodiment, image data is encoded by the control unit 101 and recorded as a file on the recording medium 110 according to the DCF (Design Rule for Camera File system) standard.

The non-volatile memory 103 is an electrically erasable/recordable non-volatile memory, and stores a later-described program and the like executed by the control unit 101 . The working memory 104 is used as a buffer memory for temporarily holding image data captured by the imaging unit 102, an image display memory for the display unit 106, a work area for the control unit 101, and the like.

The operation unit 105 is used by the user to receive instructions for the digital camera 100 from the user. The operation unit 105 includes, for example, a power button for the user to turn on/off the power of the digital camera 100, a release switch for instructing shooting, and a playback button for instructing playback of image data. Furthermore, it includes an operation member such as a dedicated connection button for starting communication with an external device via a communication unit 111, which will be described later. The operation unit 105 also includes a touch panel formed in the display unit 106 to be described later. The release switch has SW1 and SW2 for detecting the depressed state in two stages. When the release switch is in a so-called half-pressed state, SW1 is turned on. This accepts instructions for preparing for shooting such as AF (autofocus) processing, AE (auto exposure) processing, AWB (auto white balance) processing, and EF (flash pre-emission) processing. Further, when the release switch is in a so-called full-press state, SW2 is turned on. Thus, an instruction for photographing is accepted.

A display unit 106 displays a viewfinder image at the time of photographing, displays photographed image data, displays characters for interactive operation, and the like. Note that the display unit 106 does not necessarily have to be built into the digital camera 100 . The digital camera 100 can be connected to an internal or external display unit 106 as long as it has at least a display control function for controlling display on the display unit 106 . Note that the operation unit 105 and the display unit 106 constitute a user interface of the digital camera.

The recording medium 110 can record files of image data output from the imaging unit 102 . The recording medium 110 may be configured to be detachable from the digital camera 100 or may be built in the digital camera 100 . In other words, the digital camera 100 should at least have means for accessing the recording medium 110 .

The communication unit 111 is an interface for connecting with an external device. The digital camera 100 of this embodiment can exchange data with an external device via the communication unit 111 . For example, image data generated by the imaging unit 102 can be transmitted to an external device via the communication unit 111 . In this embodiment, the communication unit 111 includes an interface for communicating with an external device via a so-called wireless LAN that conforms to the IEEE802.11 standard. The control unit 101 realizes wireless communication with an external device by controlling the communication unit 111 . Note that the communication method is not limited to a wireless LAN, and may include, for example, an infrared communication method, a Bluetooth (registered trademark) communication method, a wireless communication method such as Wireless USB, and the like. Furthermore, a wired connection such as a USB cable, HDMI (registered trademark), IEEE1394, or Ethernet may be employed.

The short-range communication unit 112 includes, for example, an antenna for wireless communication, a modulation/demodulation circuit for processing wireless signals, and a communication controller. The short-range communication unit 112 outputs a modulated radio signal from an antenna and demodulates a radio signal received by the antenna to perform short-range communication according to the ISO/IEC 18092 standard (so-called NFC: Near Field Communication). come true. In addition, it realizes short-range wireless communication according to wireless communication methods such as an infrared communication method, Bluetooth (registered trademark) communication method, and Wireless USB. The short-range communication unit 112 of this embodiment is arranged on the side of the digital camera 100 .

In this embodiment, the smart device 200 (to be described later) is connected to the smart device 200 by starting communication from the communication unit. Also, the communication unit 111 of the digital camera 100 in this embodiment has an AP mode that operates as an access point in infrastructure mode and a CL mode that operates as a client in infrastructure mode. By operating the communication unit 111 in the CL mode, the digital camera 100 in this embodiment can operate as a CL device in the infrastructure mode. When the digital camera 100 operates as a CL device, it can participate in a network formed by AP devices by connecting to peripheral AP devices. By operating the communication unit 111 in the AP mode, the digital camera 100 according to the present embodiment can operate as a simple AP with more limited functions (hereinafter referred to as a simple AP), although it is a type of AP. is also possible. When the digital camera 100 operates as a simple AP, the digital camera 100 itself forms a network. Devices around the digital camera 100 can recognize the digital camera 100 as an AP device and participate in the network formed by the digital camera 100 . As described above, the program for operating the digital camera 100 is held in the nonvolatile memory 103, and the user operates the operation unit 105 to select AP mode or CL mode.

Although the digital camera 100 in this embodiment is a kind of AP, it is a simple AP that does not have a gateway function for transferring data received from a CL device to an Internet provider or the like. Therefore, even if data is received from another device participating in the network formed by itself, it cannot be transferred to a network such as the Internet.

Next, the appearance of the digital camera 100 will be described. 1(b) and 1(c) are diagrams showing an example of the front and back of the external appearance of the digital camera 100. FIG. A release switch 105a, a playback button 105b, a direction key 105c, and a touch panel 105d are operation members included in the operation unit 105 described above. In addition, an image obtained as a result of imaging by the imaging unit 102 is displayed on the display unit 106 . The configuration of the digital camera 100 according to the embodiment has been described above.

<Internal Configuration of Smart Device 200>
FIG. 2 is a block diagram showing an example configuration of a smart device 200, which is an example of an information processing apparatus that communicates with the digital camera 100 of this embodiment. A smart device means a mobile terminal such as a smart phone or a tablet device. Also, although a smart device is described here as an example of an information processing apparatus, the information processing apparatus is not limited to this. For example, the information processing device may be a digital camera, printer, television, or personal computer with a wireless function.

The control unit 201 controls each unit of the smart device 200 according to input signals and programs described later. Note that instead of the control unit 201 controlling the entire apparatus, a plurality of pieces of hardware may share processing to control the entire apparatus.

The imaging unit 202 converts subject light imaged by a lens included in the imaging unit 202 into an electrical signal, performs noise reduction processing and the like, and outputs digital data as image data. After the captured image data is stored in the buffer memory, the control unit 201 performs predetermined calculation and encoding processing, and records the data as a file on the recording medium 210 .

The nonvolatile memory 203 is an electrically erasable/recordable nonvolatile memory. The nonvolatile memory 203 stores an OS (operating system), which is basic software executed by the control unit 201, and applications that cooperate with the OS to realize applied functions. In this embodiment, the nonvolatile memory 203 also stores an application (hereinafter referred to as an application) for communicating with the digital camera 100 .

The work memory 204 is used as an image display memory for the display unit 206, a work area for the control unit 201, and the like. The operation unit 205 is used to receive instructions for the smart device 200 from the user. The operation unit 205 includes, for example, a power button for the user to turn on/off the power of the smart device 200 and an operation member such as a touch panel formed on the display unit 206 . A display unit 206 displays image data, displays characters for interactive operations, and the like. Note that the display unit 206 does not necessarily have to be included in the smart device 200 . The smart device 200 can be connected to the display unit 206 and has at least a display control function for controlling display on the display unit 206 . Note that the operation unit 205 and the display unit 206 constitute the user interface of the smart device 200 .

The recording medium 210 can record image data output from the imaging unit 202 . The recording medium 210 may be configured to be detachable from the smart device 200 or may be built into the smart device 200 . In other words, the smart device 200 should have at least means for accessing the recording medium 210 .

A communication unit 211 is an interface for connecting with an external device. The smart device 200 of this embodiment can exchange data with the digital camera 100 via the communication unit 211 . In this embodiment, the communication unit 211 is an antenna, and the control unit 101 can be connected to the digital camera 100 via the antenna. The connection with the digital camera 100 may be made directly or through an access point. A protocol for communicating data is, for example, HTTP (Hyper Text Transfer Protocol). In addition, PTP/IP (Picture Transfer Protocol over Internet Protocol) through wireless LAN can also be used. Communication with the digital camera 100 is not limited to this. For example, the communication unit 211 can include an infrared communication module, a Bluetooth (registered trademark) communication module, a wireless communication module such as WirelessUSB. Furthermore, a wired connection such as a USB cable, HDMI, IEEE1394, or Ethernet may be employed.

The short-range wireless communication unit 212 is a communication unit for realizing non-contact short-range communication with other devices. The short-range wireless communication unit 212 includes an antenna for wireless communication, a modulation/demodulation circuit for processing wireless signals, and a communication controller. The short-range wireless communication unit 212 realizes non-contact short-range communication by outputting a modulated wireless signal from an antenna and demodulating a wireless signal received by the antenna. Here, contactless communication according to the ISO/IEC 18092 standard (so-called NFC) is realized. Upon receiving a data read request from another device, the short-range wireless communication unit 212 outputs response data based on the data stored in the nonvolatile memory 203 .

The public network communication unit 213 is an interface used for public wireless communication. The smart device 200 can communicate with other devices via the public network communication unit 213 . At this time, the control unit 201 performs voice signal input and output via the microphone 214 and the speaker 215, thereby realizing a call. In this embodiment, the public network communication unit 213 is an antenna, and the control unit 101 can connect to the public network via the antenna. It should be noted that the communication unit 211 and the public network communication unit 213 can be shared by one antenna. The smart device 200 according to the embodiment has been described above.

<System configuration>
FIG. 3 is a diagram showing a system configuration for controlling the digital camera 100 by the smart device 200 using the communication API of the digital camera 100 through the network.

There are three types of system configurations for controlling the digital camera 100 using the communication API.

First, as shown in communication 301, the configuration is such that the digital camera 100 and smart device 200A are connected via peer-to-peer. At this time, the digital camera 100 becomes a Wi-Fi access point and constructs a LAN (Local Area Network). The smart device 200A becomes a Wi-Fi client and joins the LAN constructed by the digital camera 100. FIG. In this embodiment, an example in which the communication 301 is connected by Wi-Fi is given, but a wired connection such as Ethernet may be used.

Next, as shown by a network router 302 and communications 303 and 304, the digital camera 100 and smart device 200A are connected via the network router 302. FIG. At this time, the network router becomes a Wi-Fi access point and constructs a LAN. The digital camera 100 and smart device 200A become Wi-Fi clients and join the LAN constructed by the network router 302 . In this embodiment, an example in which the communications 303 and 304 are connected by Wi-Fi was given, but a wired connection such as Ethernet may also be used.

Finally, as shown by a network router 302, communication 303, and public line 305, the smart device 200B is connected to the digital camera 100 via the public line 305. FIG. In the two system configurations described above, connections are made within the same LAN. On the other hand, in this configuration, the smart device 200B can communicate with the digital camera 100 from a remote location outside the LAN through the Internet by using, for example, VPN (Virtual Private Network). In addition, since VPN is a well-known technique, description is omitted here.

In the three types of system configurations described above, the smart device 200 can use the communication API of the digital camera 100 .

<Basic Configuration of Communication API Published by Digital Camera 100>
4 and 5 are diagrams showing the configuration of a communication API for controlling the digital camera 100 from an external device such as the smart device 200. FIG.

The digital camera 100 publishes a communication API for controlling the digital camera 100 from external devices such as the smart device 200 . By accepting a request using this API, the digital camera 100 of this embodiment can transmit device information recorded in the nonvolatile memory 103 and content files stored in the recording medium 110 or the like via the communication unit 111. Send to external device. A content file is an image file generated by the digital camera 100 and stored in the recording medium 110 or the nonvolatile memory 103. In this embodiment, it refers to a captured still image file or moving image file.

A program corresponding to this communication API is stored in the nonvolatile memory 103 in advance. When communication with the external device is established via the communication unit 111, the control unit 101 develops a program corresponding to the communication API in the working memory 104 and waits for a request using the communication API from the external device. When the control unit 101 detects a request using a communication API from an external device, it executes processing according to the type of communication API and returns the result as a response to the external device. A program corresponding to the communication API is executed on the communication protocol defined by the digital camera 100, and the external device communicates with the digital camera 100 using the defined communication protocol and requests using the communication API. In this embodiment, a program corresponding to this communication API is executed on HTTP (Hyper Text Transfer Protocol). That is, the digital camera 100 functions as an HTTP server. That is, in the present embodiment, a case where a communication API is implemented as a Web API will be described as an example.

Note that the communication protocol is not limited to HTTP, and other protocols may be used. Further, since the HTTP protocol itself is widely used, its explanation is omitted here.

A method of executing a program corresponding to the communication API in HTTP is realized by the following procedure.

First, the external device describes necessary instruction information according to the specifications of the communication API to be accessed in the HTTP request body as text data for the URL published as the communication API. Then, it transmits to the digital camera 100 using one of the four HTTP methods of GET (obtain), POST (generate), PUT (update), and DELETE (delete).

The digital camera 100 that receives this performs processing based on the contents of the URL, HTTP method, and instruction information in the HTTP request body, adds the result to the HTTP response body together with the HTTP response header, and returns it to the external device. It is realized by the above procedure. It is assumed that the HTTP response header contains the HTTP status code.

In the communication API, the data described in the HTTP request body and HTTP response body are expressed in JSON (Javascript (registered trademark) Object Notation), which is one of the data description languages. For each communication API, JSON syntax specifications are defined according to their respective functions, and the digital camera 100 and smart device 200 perform request instructions and response analysis according to these specifications.

Although JSON is used in this embodiment, XML (Extensible Markup Language) may be used, or text data or binary data defined in a unique format may be used.

Next, the configuration of the communication API will be described in detail.

In the following description, to simplify the description, not only the interface itself but also the service corresponding to the communication API and the program that implements it will be simply referred to as the API or the communication API. That is, executing a program that implements a service corresponding to an API is described as executing the API, and requesting execution of the corresponding service via the API is described as requesting the API.

FIG. 4 is a diagram for explaining the basic configuration of the communication API.

First, the HTTP method used in the communication API in this embodiment will be described. HTTP methods used in the communication API in this embodiment are only four types of GET401, POST402, PUT403, and DELETE404. Other methods exist as part of the HTTP standard, but they are limited to four basic persistent functions that almost all computer software has: get, create, update, and delete. The meaning of each of the four methods in this communication API is as follows.

GET 401 is used to acquire content (image file), to acquire camera information and status, and to acquire ability values and setting values of setting items.

The POST 402 is used from an external device to the digital camera 100 to store data such as a content file, to perform shooting, to perform a zoom operation, and to perform other functions of the camera.

A PUT 403 is used to change setting values such as menu settings and shooting parameter settings of the digital camera 100 .

DELETE 404 is used to delete content or initialize setting values.

By narrowing down to the above four methods, complicated HTTP method control is not required. Therefore, a programmer who creates a control program for the smart device 200 for controlling the digital camera 100 can create the program using only the minimum and frequently used HTTP methods.

Next, the top URL of the communication API in this embodiment will be explained. The top URL is a URL defined as the first URL accessed when the client controls the digital camera 100 . The controller must access this top URL before using other APIs for remote control of the camera.

A URL 405 in FIG. 4 is the top URL of the communication API. The host name and domain name of the top URL are composed of the IP address and port number assigned to the digital camera 100 . This is followed by a directory indicating the communication API and a directory indicating the version of the communication API. For example, when the IP address assigned to the digital camera 100 is 192.168.1.1 and the port number is 8080, the top URL is
http://192.168.1.1:8080/api/ver1
becomes.

When the smart device 200 as an HTTP client requests the top URL of the communication API published by the digital camera 100 as an HTTP server using GET 401 , the digital camera 100 returns a response body (JSON) indicated by API 406 . Here, a list of communication APIs supported by the digital camera 100 is described. A characteristic point is that it is a JSON syntax that indicates which HTTP method corresponds to each URL. By accessing the top URL, the smart device 200 can know the types of communication APIs that the digital camera 100 supports.

Next, an API table 407 is a table showing communication API categories. The communication API in this embodiment classifies URLs into a plurality of categories according to the types of functions. Note that the URL notation of the API category in the table is a notation that omits the top URL. In practice, the API category 408 is
http://192.168.1.1:8080/api/ver1/device information
becomes.

Next, categorization of communication API functions will be described. First, an API category 408 is a category for acquiring fixed information of the digital camera 100 . Next, an API category 409 is a category for acquiring status information of the digital camera 100 . Next, the API category 410 is a category for acquiring and changing menu settings of the digital camera 100 and executing menu functions. Next, an API category 411 is a category for executing the photographing function of the digital camera 100 . Next, an API category 412 is a category for obtaining and changing the setting of shooting parameters of the digital camera 100 . Next, an API category 413 is a category for acquiring through-the-lens images output by the digital camera 100 . Next, an API category 414 is a category for acquiring event information issued by the digital camera 100 . Next, an API category 415 is a category for acquiring content saved in media attached to the digital camera 100 .

By categorizing the communication APIs by URL as described above, the programmer who creates the control program for the smart device 200 for controlling the digital camera 100 can easily identify the URL of the communication API to be executed. is characteristic.

For each communication API, the URL is specified in the directory below the above API category.

The above is the description of the basic configuration of the API.

Next, an API for acquiring a through image of the digital camera 100, which is a feature of this embodiment, will be described.

<API for Acquiring Through Image of Digital Camera 100>
An API table 500 in FIG. 5 is a table showing an API group for acquiring a through image (remote live view image) of the digital camera 100, and shows APIs belonging to the API category 413 in FIG.

The API 501 is an API that instructs the digital camera 100 to start and end generation of a through image. When POST 402 executes this API by describing the size of the through image and an instruction as to whether or not to display the through image on the display unit 106 of the digital camera 100 in the request body, the digital camera 100 displays the through image according to the contents of the instruction. Start and stop generation.

An API 502 is an API for acquiring one frame of a through image of the digital camera 100 . By executing this API with GET401, one frame of through image set with API501 can be obtained.

The API 503 is an API for acquiring a through image of the digital camera 100 by chunk transmission. Chunked Transfer is one of the data transfer mechanisms defined in HTTP1.1 (RFC2616). Chunk transmission is a transmission method in which even if the size of the entire response data is unknown in advance, the size of each chunk (block) of data is recorded and the response is returned. The API 503 is more effective than the API 502 when the total amount of data is unknown or when data is continuously acquired. Since the detailed mechanism is a known technique, the explanation here is omitted. When this API is executed by the GET 401, as shown in the API table 500, the live view continues to be transmitted in the order of size information of the live view and actual data of the live view. In the present embodiment, it is assumed that through images are transmitted to the smart device 200 frame by frame. Also, when this API is executed by DELETE 404, as shown in the last line of the API table 500, the digital camera 100 transmits through image size information as 0, and stops transmission of through image chunks.

Here, a case where some error occurs in the digital camera 100 and a through image cannot be generated will be described. When the counterpart machine executes the API 502 for the digital camera 100, the digital camera 100 transmits one frame of through image as a response to the request. Therefore, for example, if an error occurs in the digital camera 100 during live view, the digital camera 100 stores information indicating the error in the HTTP response header, thereby preventing the error from occurring in the counterpart device. can notify you that Furthermore, the HTTP standard defines a code for indicating an error in the HTTP response header. Also, the HTTP response header is always referred to in HTTP communication. As a result, the smart device 200 can determine whether an error has occurred in the digital camera 100 by referring to the HTTP response header without requiring a special algorithm.

On the other hand, when the counterpart device executes the API 503 for the digital camera 100, the digital camera 100 continues to continuously transmit through images as an HTTP response body after transmitting an HTTP response header as a response to the request. In the chunk transmission method, the digital camera 100 cannot transmit an HTTP response header while transmitting a through image. Therefore, even if an error occurs in the digital camera 100 during live view, the digital camera 100 cannot notify the details of the error using the HTTP response header. Also, as one solution, there is a method of creating a data area for including the contents of the error in the data structure of the HTTP response body or live view, and having the counterpart machine analyze the data area. However, with this method, the counterpart machine needs to analyze the HTTP response body or through image. Therefore, the method of analyzing the HTTP response body (through image) on the counterpart device increases the implementation load when developing the counterpart application.

In this embodiment, even with the chunk transmission method, the smart device 200, which is the counterpart device, notifies the user of the counterpart device that the digital camera 100 cannot generate the through image without analyzing the HTTP response body or the through image. For this reason, when the digital camera 100 cannot generate a through image in chunk transmission according to this embodiment, it transmits a dummy image.

<Description of method for acquiring through-the-lens image frame by frame in this embodiment>
First, a method of acquiring a through image frame by frame for chunk transmission will be described. FIG. 6A is an example of a sequence diagram showing the flow of processing when the communication API 502 shown in FIG. 5 is executed. FIGS. 7A (a) and (b) are diagrams showing examples of UI screens of the smart device 200 during live view.

Steps S601A and S602A in FIG. 6A are the sequence when the API 501 is executed. Steps S603A, S604A, S605A, S606A, and S607A in FIG. 6A are the sequence when the API 502 is executed.

In step S601A, the control unit 201 of the smart device 200 acquires a value for starting generation of a live view recorded in the work memory 204 by program processing. Then, the control unit 201 forms a data set based on the JSON syntax for requesting a value for starting through image generation, describes it in the HTTP request body, and sends the API 501 to the digital camera 100 via the communication unit 211 via POST 402 . request at. In this step, the control unit 201 instructs the size information of the through image and whether or not to display the through image on the display unit 106 of the digital camera 100 according to the specifications of the API 501 . When the control unit 101 of the digital camera 100 detects the reception of this request via the communication unit 111, it analyzes the JSON syntax described in the request body. Then, the control unit 101 starts processing for generating a through image according to the size of the through image requested by the smart device 200 and the instruction as to whether or not to display the through image on the display unit 106 of the digital camera 100 . The control unit 101 sequentially and temporarily records the generated live view images in the working memory 104 .

In step S<b>602</b>A, the control unit 101 of the digital camera 100 forms the response value into a data set based on the JSON syntax, describes it in the HTTP response body, and transmits the response to the smart device 200 via the communication unit 111 . .

In step S<b>603</b>A, the control unit 201 of the smart device 200 requests the digital camera 100 via the communication unit 211 for the API 502 using GET 401 .

In step S604A, upon detecting that the control unit 101 of the digital camera 100 has received this request via the communication unit 111, it acquires through images that are temporarily recorded successively from the working memory 104, and uses them as responses. Shape into a dataset. Then, the control unit 101 describes the formed data set in an HTTP response body and transmits it to the smart device 200 via the communication unit 111 .

Note that the API 502 is repeatedly executed by the smart device 200 to realize live view display on the smart device 200 . For example, the live view display is displayed on the display unit 206 of the smart device 200, as shown in the screen 701A of FIG. 7A(a).

Here, a case where the control unit 101 of the digital camera 100 cannot generate a through image (through image generation disabled section 690) will be described. For example, when a menu for changing shooting parameter settings is displayed on the display unit 106 and when the work memory 104 does not have enough capacity to hold a through image, the control unit 101 of the digital camera 100 displays the through image. do not generate. In addition, for example, when an image stored in the recording medium 110 is undergoing development processing, or when other processing that inhibits generation of a through image is being executed, the control unit 101 of the digital camera 100 cannot generate a through image.

In step S<b>605</b>A, the control unit 201 of the smart device 200 requests the digital camera 100 via the communication unit 211 for the API 502 using GET 401 .

In step S606A, when the control unit 101 of the digital camera 100 detects that this request has been received via the communication unit 111, it forms a response data set including an error message describing that a through image cannot be generated. Then, the control unit 101 describes the formed data set in a response body and transmits it to the smart device 200 via the communication unit 111 . Upon receiving the error message, the control unit 201 of the smart device 200 determines that an error has occurred in the digital camera 100 by referring to the HTTP response header. Then, the control unit 201 refers to the HTTP response body as necessary, and acquires the content of the error and the like. At this time, the control unit 201 of the smart device 200 displays a message 704A on the display unit 206 as shown in FIG. 7A(b). In this embodiment, the control unit 201 displays the through image acquired before the through image generation disabled section 690, as shown in the screen 703A of FIG. 7A(b). This through image is held in the working memory 204 of the smart device 200 . In the present embodiment, the smart device 200 displays the error message and the through image as described above, but the present invention is not limited to this. For example, the smart device 200 may display the message 704A superimposed on the screen 703A to notify the user of the occurrence of the error.

In the above, a method for acquiring a through image frame by frame has been described.

<Description of chunk transmission in this embodiment>
FIG. 6B is an example of a sequence diagram showing the flow of processing when the communication API 503 shown in FIG. 5 is executed. FIGS. 7B(a) to (c) are diagrams showing examples of UI screens of the smart device 200 during live view.

Steps S601B and S602B in FIG. 6B are sequences when the API 501 is executed. Steps S603B, S604B, S605B, S606B, and S607B in FIG. 6B are the sequence when the API 503 is executed.

In step S601B, the control unit 201 of the smart device 200 acquires a value for starting generation of a live view recorded in the work memory 204 by program processing. Then, the control unit 201 forms a data set based on the JSON syntax for requesting a value for starting through image generation, describes it in the HTTP request body, and sends the API 501 to the digital camera 100 via the communication unit 211 via POST 402 . request at. In this step, the control unit 201 instructs the size information of the through image and whether or not to display the through image on the display unit 106 of the digital camera 100 according to the specifications of the API 501 . When the control unit 101 of the digital camera 100 detects the reception of this request via the communication unit 111, it analyzes the JSON syntax described in the request body. Then, the control unit 101 starts processing for generating a through image according to the size of the through image requested by the smart device 200 and the instruction as to whether or not to display the through image on the display unit 106 of the digital camera 100 . The control unit 101 sequentially and temporarily records the generated live view images in the working memory 104 .

In step S602B, the control unit 101 of the digital camera 100 forms the response value into a data set based on the JSON syntax, describes it in the HTTP response body, and transmits it as a response to the smart device 200 via the communication unit 111. .

In step S<b>603</b>B, the control unit 201 of the smart device 200 requests the digital camera 100 via the communication unit 211 for the API 503 using GET 401 .

In step S<b>604</b>B, when the control unit 101 of the digital camera 100 detects that this request has been received via the communication unit 111 , it reads the through image from the working memory 104 . The control unit 101 forms the obtained live view image into a response data set. Then, the control unit 101 describes the formed data set in an HTTP response body and transmits it to the smart device 200 via the communication unit 111 . The control unit 201 of the smart device 200 displays the received live view image on the display unit 206 as shown in the screen 701B of FIG. 7B(a). The control unit 101 of the digital camera 100 sequentially transmits through images temporarily recorded in the work memory 104 to the smart device 200 .

Here, a case where the control unit 101 of the digital camera 100 cannot generate a through image (through image generation disabled section 690) will be described. For example, when a menu for changing shooting parameter settings is displayed on the display unit 106 and when the work memory 104 does not have enough capacity to hold a through image, the control unit 101 of the digital camera 100 displays a through image. cannot be generated. In addition, for example, when an image stored in the recording medium 110 is being developed, or when other processing that hinders the generation of a through image is being performed, the control unit of the digital camera 100 101 cannot generate a through image. Note that when the digital camera 100 displays a menu for changing the settings of the shooting parameters on the display unit 106 , the menu is displayed on the display unit 106 . When the work memory 104 does not have enough capacity to hold a through image, or when the image stored in the recording medium 110 is being developed, the digital camera 100 displays the through image on the display unit 106. Display a warning that it is not possible.

Also, as described above, when the API 503 is executed, the digital camera 100 cannot use the HTTP response header to send the details of the error to the smart device 200 . Therefore, in this embodiment, the digital camera 100 transmits to the smart device 200 a dummy image for notifying the content of the error.

In step S605B, the control unit 101 of the digital camera 100 generates a dummy image and forms it into a response data set. Then, the control unit 101 describes the formed data set in an HTTP response body, and transmits it to the smart device 200 via the communication unit 111 . For example, the digital camera 100 generates, as a dummy image, an image describing an error message as shown in the screen 702B of FIG. 7B(b). As a result, the digital camera 100 can notify the user of the content of the error by displaying the transmitted image on the display unit 206 of the smart device 200 in the same way as before the live view generation disabled section 690 . Here, the smart device 200 does not analyze the received through image. In this embodiment, the dummy image is an image with an error message, but it is not necessary to be limited to this. For example, the dummy image may be an image simply painted black. Further, in this embodiment, the control unit 101 of the digital camera 100 generates the dummy image with the same resolution and the same aspect ratio as the through image. As a result, even if the control unit 201 of the smart device 200 receives the dummy image, it is possible to smoothly switch the display without adding processing such as adjusting the angle of view. As a result, the control unit 201 of the smart device 200 does not need to perform special processing such as analyzing the data set received from the digital camera 100 or adjusting the angle of view of the image even in the live view generation disabled section 690 .

In step S606B, the control unit 201 of the smart device 200 requests the digital camera 100 via the communication unit 211 to use the API 503 and DELETE 404 to end the live view.

In step S607B, when the control unit 101 of the digital camera 100 detects that this request has been received via the communication unit 111, it sets the through-the-lens image size information to 0 and forms a response data set. Then, the control unit 101 describes the formed data set in a response body and transmits it to the smart device 200 via the communication unit 111 . The smart device 200 that has received this data set terminates the live view display. This completes the chunk transmission processing between the digital camera 100 and smart device 200 .

The chunk transmission in this embodiment has been described above.

Next, an example of the operation of the digital camera 100 and an example of the operation of the smart device 200 according to this embodiment will be described.

FIG. 6C is a flow chart showing an example of the operation of the digital camera 100 according to this embodiment. The control unit 101 of the digital camera 100 starts this processing triggered by detection of a GET 401 request from the smart device 200 via the communication unit 111 .

In step S601C, the control unit 101 determines the API type of the received request. If it is determined that the request is made by the API 502, the control unit 101 transitions to step S606C in order to transmit one frame of through image. This case corresponds to step S603A in FIG. 6A. If it is determined that the request is made by the API 503, the control unit 101 transitions to step S602C in order to transmit the through image by chunk transmission. This case corresponds to step S603B in FIG. 6B.

In step S<b>602</b>C, the control unit 101 reads the through image from the working memory 104 , creates response data from the through image, and records it in the working memory 104 .

In step S<b>603</b>C, the control unit 101 transmits the created response data to the smart device 200 via the communication unit 111 . This step corresponds to step S604B in FIG. 6B.

In step S<b>604</b>C, the control unit 101 determines whether an instruction to end chunk transmission has been received from the smart device 200 via the communication unit 111 . Upon receiving an instruction to end chunk transmission from the smart device 200, the control unit 101 transitions to step S605C. If an instruction to end chunk transmission has not been received from the smart device 200, the control unit 101 returns to step S602C and continues chunk transmission.

In step S<b>605</b>C, the control unit 101 transmits response data for ending chunk transmission to the smart device 200 via the communication unit 111 .

In step S<b>606</b>C, the control unit 101 reads the through image from the working memory 104 , creates response data from the through image, and records it in the working memory 104 .

In step S<b>607</b>C, the control unit 101 transmits the created response data to the smart device 200 via the communication unit 111 . This step corresponds to step S604A in FIG. 6A if no error has occurred.

An example of the operation of the digital camera 100 according to the present embodiment has been described above.

Next, an example of the operation of smart device 200 will be described. FIG. 6D is a flow chart showing an example of the operation of the smart device 200 according to this embodiment. When the control unit 201 of the smart device 200 issues a GET 401 request to the digital camera 100 via the communication unit 211, this processing is started.

In step S601D, the control unit 201 determines the API type of the transmitted request. When requested by the API 502, the control unit 201 transitions to step S607D in order to acquire one frame of through image. This case corresponds to step S603A in FIG. 6A. When requested by the API 503, the control unit 201 transitions to step S602D in order to acquire a through image by chunk transmission. This case corresponds to step S603B in FIG. 6B.

In step S602D, the control unit 201 determines whether or not response data has been received. When the response data is received, the control unit 201 transitions to step S603D. If response data has not been received, the control unit 201 repeats this process. This step corresponds to step S604D in FIG. 6B.

In step S603D, control unit 201 displays the received through image on display unit 206. FIG.

In step S604D, the control unit 201 determines whether or not to end chunk transmission. For example, the control unit 201 determines to end chunk transmission when receiving an instruction to end the live view from the user via the operation unit 205 (eg, touch panel). When terminating chunk transmission, the control unit 201 transitions to step S605D. If the chunk transmission is not finished, the control unit 201 returns to step S603D to continue chunk transmission.

In step S<b>605</b>D, the control unit 201 transmits an instruction to the digital camera 100 via the communication unit 211 to end chunk transmission.

In step S<b>606</b>D, the control unit 201 determines whether response data for ending chunk transmission has been received via the communication unit 211 . When receiving response data for ending chunk transmission, the control unit 201 ends the process. If response data for ending chunk transmission has not been received, the control unit 201 repeats the process of this step.

In step S607D, the control unit 201 determines whether response data has been received in order to acquire a through image. When the response data is received, the control unit 201 transitions to step S603D. If response data has not been received, the control unit 201 repeats this process. This step corresponds to step S604D in FIG. 6B.

In step S608D, the control unit 201 displays the received through image on the display unit 206, and ends the process.

An example of the operation of the smart device 200 has been described above. In the case of live view display using the API 502 in this embodiment, after acquiring one frame of the through image, the smart device 200 automatically requests the API 502 again with the GET 401 and repeats the process of acquiring one frame of the through image.

The effect of reducing the implementation load of the application on the counterpart device with respect to chunk transmission according to the present embodiment will be described below.

<Effect of Reduction of Implementation Load of Application on Counterpart Machine by Embodiment>
Here, by comparing the conventional method and the chunk transmission in this embodiment, the effect of reducing the implementation load of the application on the counterpart device will be described. First, problems of a conventional method of acquiring through-the-lens images frame by frame and chunk transmission that does not use the conventional embodiment will be described, and then the effects of chunk transmission in this embodiment will be described.

First, an example of the operation of the digital camera 100 and an example of the operation of the smart device 200 in the method of acquiring through-the-lens images frame by frame according to the present embodiment will be described. FIG. 8A is a flow chart showing an example of the operation of the digital camera 100 when acquiring a through image frame by frame according to the present embodiment. The control unit 101 of the digital camera 100 starts this processing triggered by detection of a GET 401 request for the API 502 from the smart device 200 via the communication unit 111 . This trigger corresponds to steps S603A and S605A of FIG. 6A.

In step S801, the control unit 101 determines whether or not a through image can be generated. If the through image cannot be generated, the control unit 101 transitions to step S802. If the through image can be generated, the control unit 101 transitions to step S803.

In step S802, the control unit 101 detects the content of the error that causes the through image to not be generated.

In step S<b>803 , the control unit 101 writes data for notifying that an error has occurred in the HTTP response header, creates response data, and records it in the working memory 104 . Here, the control unit 101 may further describe the specific content of the error in the HTTP response body to create response data.

In step S<b>804 , the control unit 101 reads the through image from the working memory 104 , creates response data from the through image, and records it in the working memory 104 .

In step S<b>805 , the control unit 101 transmits the created response data to the smart device 200 via the communication unit 111 . This step corresponds to step S603A in FIG. 6A if no error has occurred. This step corresponds to step S606A in FIG. 6A if an error has occurred.

An example of the operation of the digital camera 100 when acquiring a through image frame by frame according to the present embodiment has been described above.

FIG. 8B is an example of a flowchart of the smart device 200 when acquiring a through image frame by frame according to the present embodiment. When the control unit 201 of the smart device 200 requests the digital camera 100 for the API 502 via the communication unit 211 using GET 401 and receives a through image from the digital camera 100 as a response, this processing is started. This trigger corresponds to steps S604A and S606A of FIG. 6A.

In step S851, the control unit 201 analyzes the received response data and determines whether or not data for notifying that an error has occurred is included. For example, the control unit 201 determines whether the HTTP response header of the response data includes data for notifying that an error has occurred. If it is determined that the response data includes data for notifying that an error has occurred, the control unit 201 transitions to step S852. If it is determined that the data for notifying that an error has occurred is not included in the response data, the control unit 201 transitions to step S853.

In step S852, the control unit 201 displays the content of the error analyzed in step S851 on the display unit 206. FIG. For example, as shown in FIG. 7B(c), the control unit 201 displays the through image received before the through image generation disabled section 690 on the screen 703B. This through image is held in the working memory 204 of the smart device 200 . The control unit 201 displays an error message 704B below the screen 703B. Alternatively, for example, the control unit 201 may display an error message 704B superimposed on the screen 702B to notify the user of the occurrence of the error. This through image is held in the working memory 204 of the smart device 200 . If the HTTP response body of the received response data contains detailed content of the error, the control unit 201 may display the content on the display unit 206 .

In step S853, as a result of the analysis, the received response data does not include data for notifying that an error has occurred, so the control unit 201 displays the through image included in the received response data. .

An example of the operation of the smart device 200 when acquiring a through image frame by frame according to the present embodiment has been described above. In such a case, the smart device 200 needs an algorithm to analyze the data transmitted by the digital camera 100 each time in implementing the application.

Next, an example of the operation of the digital camera 100 and an example of the operation of the smart device 200 in conventional chunk transmission without using this embodiment will be described. FIG. 9A is a flow chart showing an example of the operation of the digital camera 100 in conventional chunk transmission without using this embodiment. The control unit 101 of the digital camera 100 starts this processing triggered by detection of a GET 401 request for the API 503 from the smart device 200 via the communication unit 111 . This trigger corresponds to step S603B in FIG. 6B.

In step S901, the control unit 101 determines whether or not a through image can be generated. If the through image cannot be generated, the control unit 101 transitions to step S902. If the through image can be generated, the control unit 101 transitions to step S903.

In step S<b>902 , the control unit 101 detects the content of the error that causes the through image to not be generated.

In step S<b>903 , the control unit 101 creates response data by describing data for notifying that an error has occurred in the HTTP response body, and records it in the working memory 104 .

In step S<b>904 , the control unit 101 reads the through image from the working memory 104 , creates response data from the through image, and records it in the working memory 104 .

In step S<b>905 , the control unit 101 transmits the created response data to the smart device 200 via the communication unit 111 .

In step S<b>906 , the control unit 101 determines whether an instruction to end chunk transmission has been received from the smart device 200 via the communication unit 111 . Upon receiving an instruction to end chunk transmission from the smart device 200, the control unit 101 transitions to step S907. If an instruction to end chunk transmission has not been received from the smart device 200, the control unit 101 returns to step S901 and repeats this process.

In step S<b>907 , the control unit 101 transmits response data for ending chunk transmission to the smart device 200 via the communication unit 111 .

An example of the operation of the digital camera 100 without using the present embodiment has been described above.

FIG. 9B is an example of a flow chart of the smart device 200 in conventional chunk transmission without using this embodiment. When the control unit 201 of the smart device 200 requests the digital camera 100 via the communication unit 211 for the API 503 using GET 401, this processing is started. This trigger corresponds to step S603B in FIG. 6B.

In step S950, the control unit 201 determines whether or not response data has been received. When the response data is received, the control unit 201 transitions to step S951. If response data has not been received, the control unit 201 repeats step S950. However, if response data has not been received for a predetermined time or longer, the control unit 201 assumes that an error has occurred in the digital camera 100, displays an error on the display unit 206, and terminates the process.

In step S951, the control unit 201 analyzes the received response data and determines whether or not data for notifying that an error has occurred is included. If it is determined that the response data includes data for notifying that an error has occurred, the control unit 201 transitions to step S952. If it is determined that the data for notifying that an error has occurred is not included in the response data, the control unit 201 transitions to step S953.

In step S952, the control unit 201 displays the content of the error analyzed in step S951 on the display unit 206. FIG. For example, as shown in FIG. 7B(c), the control unit 201 displays the through image received before the through image generation disabled section 690 on the screen 703B. This through image is held in the working memory 204 of the smart device 200 . The control unit 201 displays an error message 704B below the screen 703B. Alternatively, for example, the control unit 201 may display an error message 704B superimposed on the screen 702B to notify the user of the occurrence of the error. This through image is held in the working memory 204 of the smart device 200 .

In step S953, as a result of the analysis, the received response data does not include data for notifying that an error has occurred, so the control unit 201 displays the through image included in the received response data. .

In step S954, the control unit 201 determines whether or not to end chunk transmission. For example, the control unit 201 determines to end chunk transmission when receiving an instruction to end the live view from the user via the operation unit 205 (eg, touch panel). When terminating chunk transmission, the control unit 201 transitions to step S955. When chunk transmission is not finished, the control unit 201 returns to step S901 and continues chunk transmission.

In step S<b>955 , the control unit 201 transmits an instruction to the digital camera 100 via the communication unit 211 to end chunk transmission.

In step S<b>956 , the control unit 201 determines whether response data for ending chunk transmission has been received via the communication unit 211 . When receiving response data for ending chunk transmission, the control unit 201 ends the process. If response data for ending chunk transmission has not been received, the control unit 201 repeats the process of this step.

An example of the operation of the smart device 200 in chunk transmission without using the present embodiment has been described above. In such conventional chunk transmission, the smart device 200 requires an algorithm for analyzing the response data transmitted by the digital camera 100 in implementing the application.

Finally, an example of operations of the digital camera 100 and the smart device 200 in chunk transmission using this embodiment in contrast to the conventional chunk transmission example will be described. FIG. 10A is a flow chart showing an example of the operation of the digital camera 100 according to this embodiment. The control unit 101 of the digital camera 100 starts this processing triggered by detection of a GET 401 request for the API 503 from the smart device 200 via the communication unit 111 . This trigger corresponds to step S603B in FIG. 6B.

In step S1001, the control unit 101 determines whether or not a through image can be generated. If the through image cannot be generated, the control unit 101 transitions to step S1002. If the through image can be generated, the control unit 101 transitions to step S1003. This step is the same as step S901 in FIG. 9A.

In step S<b>1002 , the control unit 101 detects the content of the error that causes the through image to not be generated. This step is the same as step S902 in FIG. 9A.

In step S<b>1003 , the control unit 101 generates a dummy image as data to be transmitted and stores it in the work memory 104 . Here, the control unit 101 includes a message indicating the details of the error detected in step S1002 in the dummy image. This message is included in the dummy image so that it becomes a user-visible message. It should be noted that the processing for generating this dummy image is not a processing with a greater load than the processing for reading through images. Further, the process for generating the dummy image may be the process of reading an image prepared in advance for notifying an error. In this case, the image for notifying the error is recorded in the nonvolatile memory 103 .

In step S<b>1004 , since a live view can be generated, the control unit 101 reads the live view, generates response data, and stores it in the work memory 104 .

In step S1005, the control unit 101 transmits the response data held in the work memory 104 to the smart device 200 via the communication unit 111, and the process ends.

In step S<b>1006 , the control unit 101 determines whether an instruction to end chunk transmission has been received from the smart device 200 via the communication unit 111 . Upon receiving an instruction to end chunk transmission from the smart device 200, the control unit 101 transitions to step S1007. If an instruction to end chunk transmission has not been received from the smart device 200, the control unit 101 returns to step S1001 and repeats this process.

In step S<b>1007 , the control unit 101 transmits response data for ending chunk transmission to the smart device 200 via the communication unit 111 .

An example of the operation of the digital camera 100 when using the present embodiment has been described above.

A processing flow of the smart device 200 according to this embodiment will be described with reference to FIG. 10B. This flowchart starts when the control unit 201 of the smart device 200 requests the digital camera 100 via the communication unit 211 for the API 503 using GET 401 and receives a through image as a response. This trigger corresponds to step S604B in FIG. 6B.

In step S1050, control unit 201 determines whether or not response data has been received. When the response data is received, the control unit 201 transitions to step S1051. If response data has not been received, the control unit 201 repeats step S1050. However, if response data has not been received for a predetermined time or longer, the control unit 201 assumes that an error has occurred in the digital camera 100, displays an error on the display unit 206, and terminates the process.

In step S<b>1051 , control unit 201 displays the received through image on display unit 206 . This step corresponds to step S604B in FIG. 6B.

In step S1052, the control unit 201 determines whether or not to end chunk transmission. For example, the control unit 201 determines to end chunk transmission when receiving an instruction to end the live view from the user. When terminating chunk transmission, the control unit 201 transitions to step S1053. When chunk transmission is not finished, the control unit 201 returns to step S1051 to continue chunk transmission.

In step S<b>1053 , the control unit 201 transmits an instruction to the digital camera 100 via the communication unit 211 to end chunk transmission.

In step S<b>1054 , the control unit 201 determines whether response data for ending chunk transmission has been received via the communication unit 211 . When receiving response data for ending chunk transmission, the control unit 201 ends the process. If response data for ending chunk transmission has not been received, the control unit 201 repeats the process of this step.

An example of the operation of the smart device 200 when using the present embodiment has been described above.

As described above, in the conventional method of acquiring through-the-lens images one frame at a time and in the conventional chunk transmission that does not use this embodiment, the smart device 200, which is the counterpart device, determines whether or not the received response data contains an error. required processing to analyze the On the other hand, in the API for acquiring a through image by chunk transmission according to the present embodiment, when the digital camera 100 cannot generate a through image, it transmits a dummy image instead. The smart device 200 displays the received dummy image without analyzing whether it contains an error. Therefore, in chunk transmission according to the present embodiment, the smart device 200 does not need an algorithm for analyzing data transmitted by the digital camera 100 in implementing an application. This makes it possible to reduce the implementation load of the application using the communication API. In particular, this method can reduce the application implementation load on the smart device 200 side. Furthermore, the digital camera 100 can reduce the processing of the smart device 200 by using the dummy image as an image that visually displays the content of the error.

[Other embodiments]
The present invention supplies a program that implements one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and one or more processors in the computer of the system or apparatus reads and executes the program. It can also be realized by processing to It can also be implemented by a circuit (for example, ASIC) that implements one or more functions.

It should be noted that the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying constituent elements without departing from the scope of the present invention at the implementation stage. Further, various inventions can be formed by appropriate combinations of the plurality of constituent elements disclosed in the above embodiments. For example, some components may be omitted from all components shown in the embodiments. Furthermore, components across different embodiments may be combined as appropriate.

Claims (10)

generating means for generating a live view image ;
an operating means;
means of communication;
a process of generating a response from the live view image generated by the generating means when a second request is received from an external device via the communication means when the live view image is generated by the generating means; transmitting the generated response to the external device via the communication means as a response corresponding to the second request;
generating a response including information for notifying the occurrence of an error when the second request is received from the external device via the communication means when the live view image is not generated by the generating means; and transmitting the generated response to the external device via the communication means as a response corresponding to the second request,
When a first request is received from the external device via the communication means, a process of generating a response from the live view image generated by the generating means, and corresponding the generated response to the first request. a process of transmitting a response to the external device via the communication means, and
A process of generating a response from the live view image generated by the generating means and a process of transmitting the generated response to the external device via the communication means as a response corresponding to the first request are repeatedly performed. when the live view image is not generated, a process of generating a response from a predetermined image instead of the live view image that was not generated by the generating means, and sending the generated response to the first a control means for controlling a process of transmitting a response corresponding to the request to the external device via the communication means;
A communication device comprising: 2. The communication apparatus according to claim 1 , wherein the predetermined image includes information for notifying the reason why the live view image was not generated by the generating means . 3. The communication device according to claim 1 , further comprising a memory in which said predetermined image is recorded . 4. The communication device according to claim 1 , wherein said communication device operates as a server and said external device operates as a client . 5. The communication device according to any one of claims 1 to 4 , wherein the resolution or aspect ratio of the predetermined image is the same as the resolution or aspect ratio of the live view image generated by the generation means. . 6. The communication device according to any one of claims 1 to 5, wherein a communication protocol used by said communication means is HTTP (Hyper Text Transfer Protocol) . A process of generating a response from the live view image generated by the generating means and a process of transmitting the generated response to the external device via the communication means as a response corresponding to the first request are repeatedly performed. 7. The control means terminates the transmission of the live-view image when receiving a request requesting to terminate the transmission of the live-view image when the The communication device according to item 1. 8. The communication device according to any one of claims 1 to 7 , wherein said control means starts communication with said external device in response to being operated by said operation means . A control method for a communication device having communication means and operation means, comprising:
a generation step of generating a live view image;
a process of generating a response from the live view image generated in the generating step when a second request is received from an external device via the communication means when the live view image is generated in the generating step; a step of transmitting the generated response to the external device via the communication means as a response corresponding to the second request;
When the live view image is not generated in the generating step and the second request is received from the external device via the communication means, a response including information for notifying the occurrence of an error is generated. and transmitting the generated response to the external device via the communication means as a response corresponding to the second request;
a process of generating a response from the live view image generated in the generating step when a first request is received from the external device via the communication means; and corresponding the generated response to the first request. a step of repeatedly performing a process of transmitting a response to the external device via the communication means;
A process of generating a response from the live view image generated in the generating step and a process of transmitting the generated response to the external device via the communication means as a response corresponding to the first request are repeatedly performed. when the live view image is not generated, a process of generating a response from a predetermined image instead of the live view image that was not generated in the generating step, and sending the generated response to the first a step of transmitting a response corresponding to the request to the external device via the communication means;
A control method characterized by having In a computer of a communication device having communication means and operation means,
a generation step of generating a live view image;
a process of generating a response from the live view image generated in the generating step when a second request is received from an external device via the communication means when the live view image is generated in the generating step; a step of transmitting the generated response to the external device via the communication means as a response corresponding to the second request;
When the live view image is not generated in the generating step and the second request is received from the external device via the communication means, a response including information for notifying the occurrence of an error is generated. and transmitting the generated response to the external device via the communication means as a response corresponding to the second request;
a process of generating a response from the live view image generated in the generating step when a first request is received from the external device via the communication means; and corresponding the generated response to the first request. a step of repeatedly performing a process of transmitting a response to the external device via the communication means;
A process of generating a response from the live view image generated in the generating step and a process of transmitting the generated response to the external device via the communication means as a response corresponding to the first request are repeatedly performed. when the live view image is not generated, a process of generating a response from a predetermined image instead of the live view image that was not generated in the generating step, and sending the generated response to the first a step of transmitting a response corresponding to the request to the external device via the communication means;
program to run the

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