JP2003204500A - Method and device for image transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a device for image transmission capable of varying the handling of thumbnail images depending on main images to be transmitted, rejecting redundant information and thereby avoiding wasteful use of communication traffics. <P>SOLUTION: When an image is transmitted, a main image and its thumbnail image is compared with respect to the data volume, and if the data volume of the thumbnail image is relatively large, in other words, the size of the main image is small and the difference in sizes between the two images is small, the main image is transmitted without the attached thumbnail image, as the usability of the thumbnail image is low. When the main image as well as its thumbnail image is transmitted, at least either the number of pixels or the compression ratio of the thumbnail image is adjusted so that the data volume of the thumbnail image is under a predetermined rate with respect to that of the main image transmitted to the receiving device. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image transmitting method and apparatus, and more particularly to handling thumbnail (reduced image) data attached to an image file to be transmitted.

[0002]

2. Description of the Related Art In an image data transmission system disclosed in Japanese Patent Laid-Open No. 8-237490, a receiving side device is equipped with JPE.
It is determined whether or not the G decompression function is installed, and depending on the presence or absence of the decompression function, the device on the transmitting side determines the JP of the thumbnail data.
It is determined whether or not to perform the EG compression process. When the thumbnail data is compressed during transmission, the data size becomes smaller, so it is possible to reduce communication traffic.

[0003] Further, Japanese Patent Application No. 200 related to the application of the present inventor.
0-40590 (Japanese Patent Laid-Open No. 2001-230999)
Then, a system with a function to convert the image to an arbitrary size on the transmitting side, and a system that can acquire the image after scaling from the transmitting side by requesting the desired size from the receiving side to the transmitting side is provided. Disclosure.

[0004]

In such a system, the size after scaling can range from the original image size (for example, the number of pixels of 1600 × 1200) to the thumbnail size (for example, 160 × 120). If the size after scaling is close to the thumbnail size, even if the thumbnail is compressed and attached using the technique disclosed in Japanese Patent Laid-Open No. 8-237490, the required size of the thumbnail with respect to the entire size of the image file to be transmitted Is relatively large. When the size of the main image and the size of the attached thumbnail are close to each other, the thumbnail itself is considered redundant as information, and in such a case, the ratio of waste of communication traffic increases.

The present invention has been made in view of the above circumstances, and provides an image transmitting method and apparatus capable of varying the handling of thumbnail images according to the image to be transmitted and preventing waste of communication traffic. The purpose is to

[0006]

In order to achieve the above object, the invention according to claim 1 is an image transmitting method for transmitting image data from a transmitting side device to a receiving side device. Depending on the amount, it is determined whether to add thumbnail image data, which is a reduced image of the main image, to the image file for transmission, and the image file to which the thumbnail image is added or the thumbnail image is omitted according to the determination result. It is characterized in that an image file is generated and the generated image file is transmitted.

The thumbnail image is useful when the data amount of the thumbnail image is relatively large with respect to the main image to be transmitted, that is, when the main image is relatively small and the size difference between the main image and the thumbnail image is small. Sex is relatively low. It is recognized that adding a thumbnail image to the file of the main image in such a situation increases redundancy as data. Therefore, in the present invention, the attachment of the thumbnail image is omitted in such a situation, and the image file without the thumbnail image is transmitted. This can prevent waste of communication traffic. In addition,
The “data amount” is a value that reflects the number of pixels (image size), the compression rate, and the like.

As a specific method of determining whether or not to attach a thumbnail image, as shown in claim 2, when the pixel size of the main image to be sent to the receiving side device is smaller than a predetermined determination criterion, There is a mode in which an image file including the main image is transmitted without attaching the thumbnail image. As the “predetermined criterion”, for example, a fixed value that is predetermined for the number of pixels in at least one of the vertical direction and the horizontal direction can be used.

Further, as described in claim 3, when both the main image and the thumbnail image are compressed, the compression size of the main image is smaller than a predetermined multiple of the compression size of the thumbnail image. In this case, there is a mode in which the image file including the main image is transmitted without attaching the thumbnail image. The term “compressed size” means the size after compression after the actual compression process or the size after compression expected before the compression process (expected compression size).

According to a fourth aspect of the invention, in the image transmitting method of transmitting image data from the transmitting side device to the receiving side device, a reduced image of the main image is transmitted with respect to the data amount of the main image to be transmitted. The data amount of the thumbnail image is adjusted so that the data amount of a certain thumbnail image is equal to or less than a predetermined ratio, an image file including the thumbnail image with the adjusted data amount and the main image is generated, and the generated image It is characterized by sending files.

According to the present invention, the data amount of the thumbnail image, which is a reduced image of the main image, is adjusted according to the data amount of the main image to be transmitted, and a predetermined ratio with respect to the data amount of the main image. Since the thumbnail image data amount is changed and the image file with the thumbnail image is transmitted as described below, waste of communication traffic can be prevented.

As a method for adjusting the amount of data, as described in claim 5, the compression ratio and the number of pixels of the thumbnail image are set so as to be less than a predetermined ratio with respect to the amount of data of the main image sent to the receiving side device. There is a mode in which at least one of them is adjusted to generate an image file with a thumbnail image.

For example, the number of pixels of the thumbnail image may be adjusted so as to be less than or equal to a predetermined ratio with respect to the pixel size of the main image to be transmitted, or less than or equal to a predetermined ratio with respect to the data size of the main image. At least one of the compression rate and the number of pixels of the thumbnail image may be adjusted so that

According to a sixth aspect of the present invention, there is provided an image transmitting apparatus capable of transmitting image data to a receiving side apparatus to provide an apparatus for implementing the method invention according to the first aspect. The apparatus includes a communication unit that exchanges data with the receiving side apparatus, a data reading unit that reads an image file including image contents selected as a transmission target from an image storage unit that stores image data, Determining means for determining whether or not to add thumbnail image data, which is a reduced image of the main image, to the image file for transmission according to the data amount of the main image to be transmitted, and the determination result of the determining means According to the transmission image file generating means for generating an image file to which a thumbnail image is added or an image file omitting the thumbnail image, and the transmission image file generating means. It is characterized in that the generated image file for transmission and a control unit for performing control of transmitting to the receiving device Te.

The image storing means may be built in the image transmitting apparatus or may be detachable from the image transmitting apparatus main body such as a removable medium.

The invention according to claim 7 provides an apparatus embodying the method invention according to claim 4, which is an image transmitting apparatus capable of transmitting image data to a receiving side apparatus. The apparatus includes a communication unit that transfers data to and from the receiving side apparatus, and a data reading unit that reads an image file including image contents selected as a transmission target from an image storage unit that stores image data. A data amount changing means for changing the data amount of the thumbnail image which is a reduced image of the main image according to the data amount of the main image to be transmitted; and the data of the thumbnail image with respect to the data amount of the main image. A transmission image file generating means for generating an image file to which a thumbnail image having a data amount adjusted so that the amount thereof is equal to or less than a predetermined ratio is generated; It is characterized in that the image file for transmission which is generated and a control means for controlling to transmit to the receiving device by means.

The embodiment shown in claim 8 is claim 6 or 7.
In the image transmitting device according to the item 1, further comprising means for providing information of an image file that can be transmitted to the receiving side device, and in response to a request from the receiving side device, a pixel size of the requested pixel size The feature is that an image file including an image is transmitted.

An image transmitting apparatus according to any one of claims 6 to 8 is
The program can be realized by a computer, and a program for causing the computer to function as the image transmitting device is recorded on a recording medium such as a CD-ROM, a magnetic disk or the like, and the program is provided to a third party through the recording medium. Alternatively, it is possible to provide a download service for the program through a communication line such as the Internet.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of an image transmitting method and apparatus according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic diagram showing the configuration of an image transfer system to which the present invention is applied. The system shown in the figure is
It is composed of a digital camera (hereinafter referred to as a camera) 10 and a personal computer (PC) 50, and both can exchange data with each other via a wireless communication interface 60. In this embodiment, the receiving personal computer 5
The system will be described as a pull model system in which a request is sent from 0 to the camera 10 on the transmitting side, and the personal computer 50 acquires a desired image from the image group stored on the camera 10 side.

The camera 10 functions as an image transmitting apparatus according to the embodiment of the present invention. An image pickup device (not shown) (for example, CCD image sensor or C
A MOS image sensor or the like) is provided, and an image of a subject is formed on the light receiving surface of the image pickup element via the taking lens 12 and converted into an electric signal (image signal) by photoelectric conversion.

The personal computer 50 functions as a receiving side device. The personal computer 50 shown in FIG. 1 has an input keyboard 5
1 is a portable small personal computer having a structure in which a display unit 53 is rotatably connected to a main body unit 52 provided with 1. However, the receiving side device is not limited to this example when implementing the present invention, and a desktop Type personal computer, PDA (Person
Various devices such as an al Digital Assistant), a mobile phone, and a printer can be used.

FIG. 2 is an external perspective view showing the rear side of the camera 10. As shown in FIG. 1, the camera 10 includes a power switch 14 for instructing start and stop of the camera function, a release button 15 for instructing the user to perform shooting (recording of images), and a camera 10 provided with the camera 10. There is provided a mode switching dial 16 for setting various modes.

Further, the camera 10 is provided with a liquid crystal monitor 20 as display means, and is also provided with an increment button 22, a decrement button 23, an erase button 24 and a setting button 25 as instruction input means. On the liquid crystal monitor 20, a video being picked up, a reproduced image of a recorded image,
Information on the currently set mode, image compression rate information, date and time information, frame number display 28, and the like are displayed.

The liquid crystal monitor 20 is also used as a user interface display screen when the user performs various setting operations and the like, and menu information such as setting items is also displayed if necessary.

The increment button 22 is an operation unit operated when the frame number or the like displayed on the liquid crystal monitor 20 is incremented (frame advance operation) or the cursor on the menu screen is moved upward. .
The decrement button 23 is an operation unit operated when decrementing a frame number or the like displayed on the liquid crystal monitor 20 (frame returning operation) or moving the cursor downward.

The delete button 24 is an operation unit used for deleting a desired object such as an image file or item displayed on the liquid crystal monitor 20, or canceling an input operation. The setting button 26 is an operation unit used when registering (executing) desired items such as items displayed on the liquid crystal monitor 20.

FIG. 3 is a plan view of the mode switching dial 16. As shown in the figure, the mode switching dial 16 includes a wireless mode (Wireless) 32, a shooting mode (C
am) 34, playback mode (Play) 36, and setup mode (Setup) 38 are displayed, and any one of these modes can be selected.

The wireless mode 32 is a mode for carrying out wireless communication with another communication device (the personal computer 50 in this example). The shooting mode 34 is a mode for shooting (recording an image), and in this example, XGA size (1024 x 768 pixels)
It is possible to record a still image of. The reproduction mode 36 is a mode for reproducing the recorded image. The setup mode 38 is a mode for setting the date, the number of recorded pixels, the compression rate, the auto power off time, the volume of the warning sound, and the like.

FIG. 4 is a block diagram showing the internal structure of the camera 10. As shown in the figure, the camera 10 includes an image pickup unit 120 that photoelectrically converts an optical image of a subject and outputs the image signal as an image signal, and a correlated double sampling for an image signal (analog signal) output from the image pickup unit 120. Analog signal processing unit 12 that performs processing such as processing, color separation, and gain adjustment
4, an A / D converter 126 that converts an analog image signal that has been subjected to predetermined processing in the analog signal processing unit 124 into a digital signal, and a luminance / color difference signal (YC) conversion process for the digital image signal. , A digital signal processing unit 128 that performs image processing such as white balance correction and gamma correction.

Further, the digital camera 10 has a strobe (flash device) 130 which emits light to supplement the light quantity of a subject at the time of photographing, and a strobe control section 132 which controls the light emission timing and the light emission quantity of the strobe 130. And a scaling unit 1 for converting the image size of the acquired image data
34, a compression / expansion unit 136 for performing compression control of image data by a method typified by JPEG and MPEG, and processing for expanding / decompressing compressed data, and a card slot 14.
There is provided a card interface section 144 that performs data conversion necessary for writing data to or reading data from the memory card 142 attached to the memory card 142.

The scaling processing unit 134 is an image processing unit that performs pixel number conversion processing such as pixel thinning-out processing, and the captured image (XGA size) is SVGA (800 × 600 pixels), VGA (640 × 480). Pixel), QVGA (320 x 2)
40 pixels) and QQVGA (160 x 120 pixels) can be resized at high speed.

In this example, the memory card 142 which can be attached to and detached from the camera 10 is used as a means for storing the image data, but the form of the recording medium is not limited to this, and a semiconductor memory, a magnetic disk, an optical disk, an optical disk. Various types of media such as magnetic disks can be applied. Of course, the medium is not limited to the removable medium, and a recording medium (internal memory) built in the camera body can be used.

The camera 10 is a means for displaying images and various information on the screen of the liquid crystal monitor 20, and a frame memory 150 for temporarily storing image data for display,
An OSD circuit 152 for on-screen display of various characters and symbols such as date and time and mode information, and a message,
D / that converts data in digital format into an analog signal for display (for example, NTSC composite signal)
An A converter 154 is provided. Frame memory 1
The image data stored in 50 is sent to the D / A converter 154, and is output to the liquid crystal monitor 20 together with information such as characters generated from the OSD circuit 152.

The input / output means 160 of the camera 10 includes the power switch 14, the release button 15, the mode switching dial 16, the increment button 22, the decrement button 23, the erase button 24, and the setting button 25 described with reference to FIG.
Etc., and various display means such as a finder LED and a self-timer LED (not shown). Figure 4
As shown in FIG. 1, the I / O control unit 1 that controls the input / output of the input signals input from the various operation units of the input / output unit 160 and the output signals output to the LEDs and the like in the camera 10.
62 is provided.

The communication means of the camera 10 is composed of an antenna 170 for transmitting and receiving information on radio waves, and a wireless interface section 172 for performing signal conversion necessary for transmitting and receiving signals via the antenna 170. For example, using a communication standard such as wireless LAN or Bluetooth, the camera 1
0 is capable of exchanging data with the personal computer 50 and other external devices.

In this embodiment, radio communication by radio waves is used. However, the communication mode is not limited to this when implementing the present invention, and communication by light may be used, or wireless communication means may be used instead. USB interface and I
It is also possible to use a wired communication means such as an EEE1394 interface. The communication means corresponding to the communication method used is mounted on the camera 10.

Further, the camera 10 has a central processing unit (C
PU) 180, system memory 182, rewritable non-volatile memory 184, and calendar clock 186 for managing date and time such as shooting date and time. C
The PU 180 functions not only as a control unit that controls the entire camera but also as a calculation unit that performs various calculation processes, and controls exposure and readout of the image pickup unit 120, image processing control, image data recording control, and the memory card 142. Read / write control, file management in the memory card 142,
Communication control, display control of the liquid crystal monitor 20, and the like are performed.

The system memory 182 is composed of a ROM in which operation programs and various constants are stored, and a high-speed readable / writable RAM serving as a work area during program execution and a temporary storage area for image data. There is.
The non-volatile memory 184 stores various constants and setting information related to camera operation, and these information are retained even when the power is cut off.

As shown in FIG. 1, the CPU 180 and the peripheral circuits are connected by a bus 188, which enables high-speed transmission of information to each other and C
The PU 180 can control each circuit according to a program.

Next, the operation of the camera 10 configured as described above will be described. [Photographing Mode] When the mode switching dial 16 is set to the “photographing mode”, the photographing mode is set and the image pickup unit 120 operates. The image signal output from the imaging unit 120 is subjected to predetermined processing such as color separation and gain adjustment in the analog signal processing unit 124, and then converted into a digital signal by the A / D converter 126, and the digital signal processing unit. Sent to 128. The image signal input to the digital signal processing unit 128 is converted into a luminance signal (Y signal) and a color difference signal (Cr, Cb signal) and subjected to predetermined processing such as gamma correction, and then the system memory 182. It is stored in the internal RAM.

When the image being picked up is displayed and output to the liquid crystal monitor 20, the image signal stored in the RAM is transferred to the frame memory 150, and a signal of a predetermined system for display (for example, an NTSC system color composite video signal). After being converted into, the data is output to the liquid crystal monitor 20. The image data in the frame memory 150 is periodically rewritten by the image signal output from the image pickup unit 120, and the video signal generated from the image data is supplied to the liquid crystal monitor 20, so that the image being picked up is displayed in real time. LCD monitor 20
Is displayed in. The photographer can confirm the photographing angle of view by the image (through image) displayed on the liquid crystal monitor 20.

When the photographer presses the release button 15, a photographing start instruction (release ON) signal is issued. The CPU 180 responds to the reception of this photographing instruction signal and starts capturing (exposure and data reading) of image data for recording. The data of the photographed image is subjected to required processing in the digital signal processing unit 128, and then compressed in the compression / expansion unit 136 in accordance with a predetermined format such as JPEG.

The CPU 180 creates a single image file by associating the compressed image data with the auxiliary information such as the shooting conditions regarding the image. The image file thus generated is stored in the card interface unit 144.
And is recorded in the memory card 142 via the memory card slot 140.

FIG. 5 is a structural diagram of a photographed image file (original image file) recorded in the memory card 142 by the camera 10 of this example. As shown in the figure, the image file of the still image includes tag information (attached information), a thumbnail image, and a main image. That is, in the case of the camera 10 of this example, the main image is always recorded in XGA size (1024 × 768 pixels), and 160 × 12 indicating the image content of the main image is displayed.
A thumbnail image of 0 pixels (QQVGA size) and attached information about the main image are always attached to the image file.

By using the thumbnail image as a heading image and displaying a list together with thumbnail images of other image files, the user can easily search for the image. As attached information, information of shooting date and time,
Various information about the main image such as information about shooting conditions and a title for classification is recorded. When the value of each of these information is unknown, "UNKNOW" as shown in FIG.
It is also possible to describe "N".

In this example, the XGA size (10
Although a still image of 24 × 768 pixels) is compressed and recorded in accordance with a predetermined format such as JPEG, the number of recording pixels and the compression rate can be set appropriately. Camera 10
It is preferable to provide a means for designating the number of recording pixels and the compression rate, and to allow the user to change the number of recording pixels and the compression rate before or after shooting as necessary. Similarly, for the thumbnail image, a thumbnail image of 160 × 120 pixels is also recorded in this example, but the pixel size and compression rate of the thumbnail image can be set as appropriate. The thumbnail image data may be uncompressed data or compressed data.

FIG. 6 shows an actual image recording structure (actual directory structure) for the memory card 142. As shown in the figure, each image file is stored by dividing the directory for each related image file group. According to FIG. 6, a root directory “Root” is provided in the information recording area of the memory card 142, and an area “IMAGE” for storing image files is provided under the root directory.

In the "IMAGE" directory, a directory "001VACATION" created by the user and "002B"
There is a directory called "IRTHDAY". The directory name is the character string arbitrarily specified by the user with the directory number added to the beginning. The directory number is automatically given by the CPU 180 in the camera 10.

In the "001 VACATION" directory, "DS
Image file groups such as "CF0001.JPG", "DSCF0002JPG", "DSCF0003.JPG" are recorded. The file name is "DS
The file number and extension are added after the character string "CF". The CPU 180 automatically assigns a file number in the order of recording and automatically generates a file name.

In the "002BIRTHDAY" directory,
"DSCF0001.JPG", "DSCF0003JPG", "DSCF0004.JP
A group of image files such as "G" is recorded. The file number of the image file deleted by the user operation becomes a missing number. The frame number for specifying the image file is represented by a combination of the directory number and the file number (for example, 001-0003). [Playback Mode] When the “playback mode” is selected by the mode switching dial 16, the latest image file recorded in the memory card 142 (the last recorded image file) is read out. The data of the image file is
The liquid crystal monitor 2 is expanded by the compression / expansion unit 136 and passed through the frame memory 150 and the D / A converter 154.
It is output to 0. By operating the increment button 22 or the decrement button 23 at the time of this one-frame reproduction, it is possible to perform frame advance (file advance) in the forward direction or the reverse direction, and to change the image to be reproduced. [Wireless Mode] When the “wireless mode” is selected by the mode switching dial 16, the communication function of the camera 10 is activated and another communication device (in this example, the personal computer 5).
Data communication with 0) is possible.

When the CPU 180 receives a command for inquiring about the directory structure of image data or file information related to the transfer of image data from the personal computer 50 by communication, the CPU 180 determines based on the image file recorded in the memory card 142. A virtual directory (including a virtual folder) and a virtual image file are newly generated, and the virtual directory information is provided to the personal computer 50.

FIG. 7 shows an example of a virtual directory structure which the camera 10 shows to the personal computer 50.
This virtual directory is classified by image size. That is, the CPU 180 of the camera 10
In addition to the actually recorded original image (XGA), creates a virtual directory of an image size that can be resized by the camera 10 and virtually forms a directory for each image file group under the directory.

According to FIG. 7, the root directory "Roo
A virtual directory "QQVGA" that stores a series of virtual image files of QQVGA (160 x 120 pixels) size and a series of virtual image files of QVGA (320 x 240 pixels) are newly stored in the layer under "t". A virtual directory "QVGA" and a virtual directory "VGA" that stores a series of image files of VGA (640 x 480 pixels) size,
Virtual directory “SVGA” that stores a series of virtual image files of SVGA (800 × 600 pixels) size, and XGA
A virtual directory "XGA" that stores a series of virtual image files of size (1024 × 768 pixels), and a directory "Property" that stores a text data file group (attached information file group) related to the contents of tag information attached to the image file. Is generated.

Further, directories "001VACATION" and "002BIRTHDAY", which are divided by the user, are newly created in the hierarchy below each directory classified by the number of pixels as described above. And each directory "001VACATIO
The virtual image files “DSCF0001.JPG”, “DSCF0002.JPG”, “DSCF000” based on the actually recorded real image files are further provided in the layer below “N” and “002BIRTHDAY”.
3. JPG ”... and are generated and registered. Although these virtual directories and virtual files are directories and file names that do not actually exist, the CPU 1 on the camera 10 side
When the computer 80 receives a transfer request for these virtual image files from the personal computer 50 side, it can perform the necessary resizing processing from the original image data and provide the computer 50 with the corresponding image size file.

8 to 10 are examples of screens when the desired image is selected by the personal computer 50 in the virtual directory shown in FIG. 8 to 10 show screen examples of "windows explorer" which is a file management application manufactured by Microsoft Corporation.

As shown in FIG. 8, by selecting the upper directory, the classification of "number of pixels" is selected.
As shown in, the directory corresponding to the image file group is selected. Furthermore, as shown in FIG. 10, by selecting a desired image file, it is possible to specify (request) an image having a desired number of pixels having the same contents as the corresponding original image file to the camera 10. Becomes

11 and 12 show the structure of an image file transmitted from the camera 10 in response to a request from the personal computer 50. FIG. 11 is a structural diagram of an image file transmitted when the number of pixels of the requested main image is equal to or larger than the VGA size. In this case, the image file with the thumbnail image attached is the same as the original image file on the PC 5
It is sent to the 0 side. Therefore, the personal computer 50 side receiving this can easily browse the image contents by using the thumbnail image data without opening the main image having a large pixel size.

FIG. 12 is a structural diagram of an image file transmitted when the number of pixels of the main image requested from the personal computer 50 side is QVGA or less. In this case, the thumbnail image is omitted, and the image file in which the tag information is added to the main image is sent to the personal computer 50 side. PC 50 that received this
Needs to generate and display a thumbnail image for the received image file, but since the pixel size before resizing is small, the burden on the resizing process is small. Further, in the case of this main image size (QVGA or less), the pixel size (QQVGA) of the thumbnail image cannot be said to be sufficiently smaller than that of the main image, so that it is possible to realize a reduction in transfer time by omitting the thumbnail image.

If the main image size is sufficiently larger than the thumbnail size (for example, if the main image size is VG
In the case of A or more), the data amount of the main image becomes dominant,
Since the thumbnail size can be ignored, omitting the thumbnail hardly contributes to the improvement of the transmission speed. Therefore, FIG.
As described in 1, when the main image size is VGA or more, the image file with the thumbnail attached is sent.

Next, the procedure of the operation of transmitting an image from the camera 10 to the personal computer 50 will be described.

FIG. 13 is a flow chart showing the procedure of the image transmission control between the camera and the PC. As shown in FIG. 13, the camera 10 is set to the wireless mode (step S310) so that the connection request from the personal computer 50 can be received. On the other hand, the browsing software is launched on the personal computer 50 side (step S510) to prepare for access to the camera 10.

Camera 10 whose pairing has been completed in advance
When the personal computer 50 issues a wireless communication I / F connection request to the computer (step S512), the camera 10 confirms the connection and establishes a communication path. When the communication path is established, the camera 10 notifies the personal computer 50 of the completion of connection (step S114). PC 5 that received the connection completion notification
0 requests the camera 10 for a directory list (step S516). When the camera 10 requests the directory list, the camera 10 creates the directory list of the virtual directory described in FIG. 7 (step S120),
This list is sent to the personal computer 50 side (step S12)
2).

The personal computer 50 acquires the directory information from the camera 10 and displays the directory information on the display (step S520, see FIGS. 8 to 10).
The user selects a desired directory or file here (step S522).

When the directory is selected, the camera 10 is instructed to change the current directory (step S524). The camera 10 performs a process of changing the current directory to the designated directory (step S130). When the directory change processing is completed, the camera 10 notifies the personal computer 50 of the directory change completion (step S132). Upon receiving this notification, the personal computer 50 requests the camera 10 for a directory list (step S534).

When the camera 10 requests a directory list, it creates a virtual directory list (step S
140), and sends this to the personal computer 50 side (step S1)
42). The personal computer 50 acquires the directory information from the camera 10 and displays the directory information on the display (step S540). In this state, the user can input an instruction to change the current directory or select an image (step S542).

When the image file is selected, the camera 10 is requested to send the image file (step S544). The camera 10 determines the number of pixels of the image file to be transmitted from the upper directory to which the requested image file belongs, generates an image file for transmission (step S150), and transmits this to the personal computer 50 (step S152). .

The personal computer 50 adds a necessary thumbnail image to the received image file to generate a save image file to be recorded in the hard disk (HDD) or the like (step S550). After that, the image file is saved (step S552), and the thumbnail of the received image is displayed (step S554).
After that, the process returns to step S516 and the above process is repeated.

FIG. 14 shows the procedure of the process of creating the transmission image file in step S150.

When the camera 10 is requested by the personal computer 50 to send an image file, the transmission image file creation process shown in FIG. 14 starts. First, the camera 10
Returns the original file of the specified image to the memory card 142
Is performed (step S610), and it is determined whether the number of pixels of the designated image is the same as the number of pixels of the original image file (step S612). If an image file with the same number of pixels as the original image file is requested,
Since the original image file can be used as it is as the image file for transmission, this processing routine is terminated and the process returns to the flowchart of FIG.

In step S612 of FIG. 14, if the number of pixels of the designated image is different from the number of pixels of the original image file, the process proceeds to step S614, and thumbnail data is extracted from the original image file (step S612).
614), and processing for extracting the data of the tag information from the original image file is performed (step S616). The extracted thumbnail data and tag data are stored in the memory.

After that, a process of converting the main image of the original image file into the designated number of pixels is executed (step S61).
8). This resizing processing is performed by the scaling processing unit 1 described with reference to FIG.
At 34, a method such as pixel thinning is performed.

Then, the process proceeds to step S620 in FIG. 14, and it is determined whether the designated image file is VGA or more (step S620). If the designated main image size is VGA or larger, the process proceeds to step S622. In step S622, the thumbnail data and tag data extracted in steps S614 and S616 are reattached to the image obtained by the resizing process in step S618 to create a transmission image file (step S62).
2).

On the other hand, the main image size specified in step S620 is smaller than VGA (that is, QVGA
And the following), the process proceeds to step S630. In step S630, only the tag data extracted in step S616 is attached to the image obtained by the resizing process in step S618 (thumbnail data is omitted).
Create an image file for transmission. Note that step S62
2. In S630, if there is a tag related to the image size, it is changed to a value that reflects the number of pixels after resizing.

In this way, when the generation of the transmission image file is completed in step S622 or step S630, this processing routine is ended and the process returns to the flowchart of FIG.

FIG. 15 shows the processing contents of step S550 in FIG. 13, that is, the processing flow after the personal computer 50 receives the image file. When the process of creating the save image file shown in FIG. 15 starts, the personal computer 50 first determines whether or not the image requested (designated) to the camera 10 has the same QQVGA size as the thumbnail size (step S710). ). When the designated image (that is, the image received from the camera 10) has the QQVGA size, the thumbnail image is not useful even if added, and thus the received image file is directly used as the save image file (step S720). ).

If NO is obtained in step S710, the process proceeds to step S712, and it is determined whether thumbnail data is attached to the received image file (step S712). When thumbnail data is attached to the received image file, the received image is directly used as the save image file (step S72).
0).

On the other hand, if thumbnail data is not attached to the received image file in step S712, the main image is extracted from the received image file (step S714), and the main image is resized to generate a thumbnail. Processing is performed (step S716), and the generated thumbnail is added to the received image file to generate a save image file (step S718).

In this way, when the save image file is generated in step S718 or step S720, this processing routine is terminated and the process returns to the flowchart of FIG.

<Other Control Example> In the flowchart described in FIG. 14, it is determined whether or not to attach a thumbnail image, but the scope of application of the present invention is not limited to this. A mode in which the amount of thumbnail data can be changed by changing the number or the compression rate of thumbnails is also possible.

FIG. 16 shows another flowchart of the transmission image file creation process. Steps in FIG. 16 that are common to those in FIG. 14 are given the same reference numerals and description thereof will be omitted. FIG.
After the main image of the original image file is resized to the specified number of pixels in step S618,
Proceed to 619. In step S619, it is determined whether the number of pixels of the requested image is the XGA size or more.

If an image of XGA size or more is requested, the process advances to step S622 to attach the extracted thumbnail and tag data to the resized image file to create a transmission image file (step S).
622).

If a NO determination is obtained in step S619, the flow advances to step S621 to determine whether the designated image file is VGA or higher. If the specified number of pixels is VGA or more and less than XGA, the process proceeds to step S624. In step S624, the extracted thumbnail data is further compressed to reduce the amount of thumbnail image data. Then, in step S626, the recompressed thumbnail data and tag data are attached to the resized image file to generate a transmission image file. If there is a tag relating to the image size in steps S622, S626, and S630, the tag is changed to a value that reflects the number of pixels after resizing.

If the image file specified in step S621 is less than VGA, step S6
Proceed to 30. Thus, step S622 and step S
When the transmission image file has been generated in step 626 or step S630, this processing routine ends, and the processing in FIG.
Return to the flowchart.

In FIG. 16, an example in which the thumbnail size is adjusted by changing the compression rate has been described, but the scope of application of the present invention is not limited to this, and instead of changing the compression rate or in combination therewith, The thumbnail size may be adjusted by changing the number of pixels of the thumbnail image (resizing).

Further, in the above-described embodiment, the camera 1
The user interface that provides virtual directory information from the 0 side to the personal computer 50 and selects a desired image file on the screen of the personal computer 50 has been described as an example, but the present invention is not limited to this example. For example,
The camera side has a resizeable pixel count menu on the PC 5
It is also possible to present it on the 0 side and select the desired image content and the number of pixels from the personal computer 50 side.

In the above-described embodiment, a digital camera is illustrated as one form of the image transmitting apparatus, but the scope of application of the present invention is not limited to the digital camera, and a personal computer or PD
It can be applied to various devices such as A and mobile phones.

Although the pull model image transfer system has been described in the above-mentioned embodiment, when the present invention is implemented,
The present invention is not limited to this example, and the present invention can be applied to a so-called push model image transfer system of a method of selecting an image to be transmitted from the transmission side device and transmitting image data related to the selection to the reception side device.

The following is a summary of specific examples of how thumbnails are handled during image transfer. [When the pixel size of the thumbnail is fixed] (1) When the pixel size of the main image sent to the receiving side is smaller than a fixed value, the thumbnail image is not attached and the main image (tag information is added if necessary). The added image file) is transmitted. To determine whether to attach a thumbnail image, compare whether the number of pixels in at least one of the vertical and horizontal directions of the image is smaller than a predetermined number of pixels (fixed value that is the determination standard). And judge.

(2) When both the main image and the thumbnail are compressed, the size after compression of the main image (or the expected compression size) is a predetermined multiple (for example, the size after compression) of the thumbnail (or the expected compression size). If it is smaller than 5 times), the thumbnail is not attached and transmitted. [When the thumbnail size is variable] (3) Add the thumbnail by adjusting the number of pixels of the thumbnail so that the size is less than or equal to a predetermined ratio (for example, 1/5) with respect to the main image pixel size sent to the receiving side. And then transmit.
The “predetermined ratio” is appropriately set in consideration of the utility value of the thumbnail image.

(4) Thumbnail image data size (thumbnail size) so that the ratio is less than or equal to a predetermined ratio (for example, 1/5) of the size of the main image file sent to the receiving side.
Adjust and send with thumbnails. A method of adjusting the thumbnail size is realized by changing at least one parameter of the compression rate and the number of pixels of the thumbnail image.

The thumbnail size may be adjusted at the time of image transmission, or the thumbnail size may be adjusted at the time of photographing (at the time of recording an image).

Furthermore, a mode in which the presence / absence of thumbnail attachment and the adjustment of the thumbnail size are combined is possible. For example, the size of the thumbnail to be attached may be adjusted according to the size of the main image file, or the thumbnail attachment may be omitted.

[0094]

As described above, according to the present invention, the presence or absence of thumbnail attachment is determined according to the amount of data of the main image to be transmitted, and attachment of thumbnail images of low usefulness is omitted. Waste of communication traffic can be prevented, and communication time can be shortened.

Further, according to the present invention, since the data amount of the thumbnail image is adjusted according to the data amount of the main image to be transmitted, waste of communication traffic can be prevented,
The communication time can be shortened.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration of an image transfer system to which the present invention is applied.

FIG. 2 is an external perspective view showing the back side of the camera shown in FIG.

FIG. 3 is a plan view of a mode switching dial of the camera shown in FIG.

4 is a block diagram showing an internal configuration of the camera shown in FIG.

FIG. 5 is a diagram showing a structure of an image file recorded on a memory card.

FIG. 6 is a diagram showing an example of a recording structure of an image file recorded in a memory card.

FIG. 7 is a diagram showing an example of a virtual directory structure shown to a personal computer as a receiving side device.

8 is a diagram showing an example of a screen when a desired image is selected on the personal computer side that has acquired the information of the virtual directory shown in FIG.

FIG. 9 is a diagram showing an example of a screen when a desired image is selected on the personal computer side that has acquired the information of the virtual directory shown in FIG.

10 is a diagram showing an example of a screen when a desired image is selected on the personal computer side that has acquired the information of the virtual directory shown in FIG.

FIG. 11 is a diagram showing an example of the structure of an image file with a thumbnail transmitted from the camera.

FIG. 12 is a diagram showing an example of the structure of an image file without thumbnails transmitted from the camera.

FIG. 13 is a flowchart used to explain the operation of the camera and personal computer in this embodiment.

FIG. 14 is a flowchart showing the procedure of a transmission image file creation process.

FIG. 15 is a flowchart showing a procedure of a process of creating a save image file.

FIG. 16 is a flowchart showing another example of a transmission image file creation process.

[Explanation of symbols]

10 ... Camera, 50 ... Personal computer, 60 ... Wireless communication interface, 120 ... Imaging unit, 128 ... Digital signal processing unit, 134 ... Magnification processing unit, 142 ... Memory card, 1
70 ... Antenna, 172 ... Wireless interface part, 1
80 ... CPU, 182 ... System memory

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Claims (8)

[Claims] 1. An image transmission method for transmitting image data from a transmission side device to a reception side device, in which thumbnail image data, which is a reduced image of the main image, is transmitted according to the data amount of the main image to be transmitted. It is characterized in that it is determined whether or not to add to the image file for use with, a thumbnail image added image file or an image file omitting the thumbnail image is generated according to the determination result, and the generated image file is transmitted. Image transmission method. 2. If the pixel size of the main image sent to the receiving device is smaller than a predetermined criterion, an image file without thumbnail images is generated as the image file for transmission. The image transmission method according to claim 1. 3. The image file for transmission, wherein the data of the main image and the data of the thumbnail image are both compressed, and when the compressed size of the main image is smaller than a predetermined multiple of the compressed size of the thumbnail image. The image transmitting method according to claim 1, wherein the image file is generated by omitting the thumbnail image. 4. An image transmission method for transmitting image data from a transmission side device to a reception side device, wherein a data amount of a thumbnail image which is a reduced image of the main image is smaller than a data amount of a main image to be transmitted. The data amount of the thumbnail image is adjusted so as to be a predetermined ratio or less, an image file including the thumbnail image with the adjusted data amount and the main image is generated, and the generated image file is transmitted. And image transmission method. 5. The image file is generated by adjusting at least one of the compression ratio and the number of pixels of the thumbnail image so that the ratio is less than or equal to a predetermined ratio with respect to the data amount of the main image sent to the receiving side device. The image transmitting method according to claim 4, wherein. 6. An image transmitting apparatus capable of transmitting image data to a receiving side apparatus, wherein the apparatus stores communication means for exchanging data with the receiving side apparatus and image data is stored. Data reading means for reading an image file containing the image content selected as the transmission target from the image storing means, and thumbnail image data, which is a reduced image of the main image, depending on the data amount of the main image to be transmitted. Judgment means for judging whether or not to add to the transmission image file, and transmission image file generation means for generating an image file with the thumbnail image added or an image file with the thumbnail image omitted according to the judgment result of the judgment means. And a controller for controlling the transmission of the transmission image file generated by the transmission image file generation means to the reception side device. Image transmission apparatus comprising the and. 7. An image transmitting device capable of transmitting image data to a receiving device, wherein the device stores communication means for exchanging data with the receiving device and image data is stored. Data reading means for reading an image file containing the image content selected as the transmission target from the image storing means, and the data amount of the thumbnail image which is a reduced image of the main image according to the data amount of the main image to be transmitted. And a transmission for generating an image file to which a thumbnail image whose data amount is adjusted so that the data amount of the thumbnail image is a predetermined ratio or less with respect to the data amount of the main image is added. Image file generating means, and a control for controlling transmission of the image file for transmission generated by the transmitting image file generating means to the receiving side device. Image transmitting apparatus comprising: the means. 8. An image file including means for providing information of an image file that can be transmitted to the receiving side device, and including a main image of a requested pixel size in response to a request from the receiving side device. The image transmitting device according to claim 6 or 7, wherein the image transmitting device transmits.