JP3937137B2 - Image transmission method and apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image transmission method and apparatus, and more particularly to handling of thumbnail (reduced image) data attached to an image file to be transmitted.
[0002]
[Prior art]
In the image data transmission system disclosed in Japanese Patent Laid-Open No. 8-237490, it is determined whether or not a JPEG decompression function is installed in a receiving apparatus, and thumbnail data is transmitted from the transmitting apparatus according to the presence or absence of the decompression function. Whether or not to perform JPEG compression processing is determined. When thumbnail data is compressed at the time of transmission, the data size is reduced, so that communication traffic can be reduced.
[0003]
In Japanese Patent Application No. 2000-40590 (Japanese Patent Application Laid-Open No. 2001-230999) relating to the application of the present inventor, a device on the transmission side has a function of converting an image into an arbitrary size, and the transmission side to the transmission side. A system is disclosed that can acquire a scaled image from the transmission side by requesting a desired size.
[0004]
[Problems to be solved by the invention]
In such a system, the size after scaling can be from the original image size (for example, the number of pixels of 1600 × 1200) to the thumbnail size (for example, 160 × 120), but the size after scaling is the thumbnail size. In this case, even if the thumbnail is compressed and attached using the technique disclosed in Japanese Patent Application Laid-Open No. 8-237490, the required size of the thumbnail with respect to the entire size of the transmitted image file becomes relatively large. When the size of the main image and the size of the attached thumbnail are close, it is considered that the thumbnail itself is redundant as information. Therefore, in such a case, the proportion of waste of communication traffic increases.
[0005]
The present invention has been made in view of such circumstances, and an object of the present invention is to provide an image transmission method and apparatus capable of changing the handling of thumbnail images according to the image to be transmitted and preventing waste of communication traffic. And
[0006]
[Means for Solving the Problems]
In order to achieve the above object, an invention according to claim 1 is an image transmission method for transmitting image data from a transmission side device to a reception side device, in accordance with a data amount of the main image to be transmitted. Determine whether to add thumbnail image data, which is a reduced image, to the image file for transmission, and generate an image file with the thumbnail image added or an image file with the thumbnail image omitted according to the determination result. It is characterized by transmitting an image file.
[0007]
When the amount of thumbnail image data is relatively large compared 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, the usefulness of the thumbnail image is relative. Lower. In such a situation, it is recognized that adding a thumbnail image to a main image file increases the redundancy of data. Therefore, in the present invention, attachment of thumbnail images is omitted in such a situation, and an image file without thumbnail images is transmitted. Thereby, waste of communication traffic can be prevented. The “data amount” is a value reflecting the number of pixels (image size), compression rate, and the like.
[0008]
As a specific determination method for determining whether or not to attach a thumbnail image, when the pixel size of the main image to be sent to the receiving-side apparatus is smaller than a predetermined determination criterion as described in claim 2, the thumbnail image There is a mode in which an image file including the main image is transmitted without attaching the image. As the “predetermined determination criterion”, for example, a fixed value determined in advance for the number of pixels in at least one of the vertical direction and the horizontal direction can be used.
[0009]
Further, as described in claim 3, when both the main image and the thumbnail image are compressed, and the compression size of the main image is smaller than a predetermined multiple of the compression size of the thumbnail image, There is a mode in which an image file including a main image is transmitted without attaching a thumbnail image. The “compressed size” means a post-compression size after actual compression processing or a post-compression size expected before the compression processing (expected compression size).
[0010]
According to a fourth aspect of the present invention, in the image transmission method for transmitting image data from the transmission side device to the reception side device, a thumbnail image which is a reduced image of the main image 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 the image becomes equal to or less than a predetermined ratio, an image file including the thumbnail image with the data amount adjusted and the main image is generated, and the generated image file is transmitted. It is characterized by doing.
[0011]
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 becomes a predetermined ratio or less with respect to the data amount of the main image. As described above, since the amount of thumbnail image data is changed and the image file with the thumbnail image is transmitted, waste of communication traffic can be prevented.
[0012]
As a method for adjusting the data amount, as described in claim 5, at least of the compression ratio of the thumbnail image and the number of pixels so as to be less than a predetermined ratio with respect to the data amount of the main image sent to the receiving side device There is a mode in which one of them is adjusted to generate an image file with a thumbnail image.
[0013]
For example, the number of pixels of the thumbnail image may be adjusted so as to be equal to or less than a predetermined ratio with respect to the pixel size of the main image to be transmitted, or may be equal to or less than a predetermined ratio with respect to the data size of the main image. In addition, at least one of the compression ratio and the number of pixels of the thumbnail image may be adjusted.
[0014]
An invention according to claim 6 is an image transmitting apparatus capable of transmitting image data to a receiving-side apparatus in order to provide an apparatus that embodies the method invention according to claim 1, wherein the apparatus includes: Communication means for exchanging data with the receiving apparatus, data reading means for reading out an image file including the image content selected as a transmission target from the image storage means in which image data is stored, and data to be transmitted According to the data amount of the main image, a determination unit that determines whether or not to add thumbnail image data that is a reduced image of the main image to the image file for transmission, and the thumbnail image according to the determination result of the determination unit Generated by the transmission image file generating means for generating the image file with the image added or the thumbnail image omitted, and the transmission image file generating means. And control means for performing control of transmitting the image file for transmission to the reception side apparatus is characterized by comprising a.
[0015]
The image storage means may be built in the image transmission device, or may be configured to be detachable from the image transmission device main body like a removable medium.
[0016]
The invention described in claim 7 provides an apparatus that embodies the method invention described in claim 4, and is an image transmitting apparatus capable of transmitting image data to a receiving-side apparatus, the apparatus A communication means for exchanging data with the receiving side device, a data reading means for reading an image file including an image content selected as a transmission target from an image storage means in which image data is stored, and a transmission A data amount changing unit that changes a data amount of a thumbnail image that is a reduced image of the main image according to a data amount of the main image, and a data amount of the thumbnail image is predetermined with respect to the data amount of the main image; The transmission image file generation means for generating an image file to which a thumbnail image whose data amount has been adjusted so as to be less than or equal to the ratio is transmitted by the transmission image file generation means. The generated image file for transmission is characterized by and a control means for controlling to transmit to the receiving device.
[0017]
The aspect shown in claim 8 is the image transmission apparatus according to claim 6 or 7, further comprising means for providing information on an image file that can be transmitted to the reception side apparatus, and the reception side apparatus In response to a request from, an image file including a main image having a pixel size according to the request is transmitted.
[0018]
The image transmission device according to any one of claims 6 to 8 can be realized by a computer, and a program for causing the computer to function as the image transmission device is recorded on a CD-ROM, a magnetic disk, or other recording media. It is also possible to provide the program to a third party through a recording medium, or to provide a program download service through a communication line such as the Internet.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of an image transmission method and apparatus according to the present invention will be described below with reference to the accompanying drawings.
[0020]
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 FIG. 1 includes a digital camera (hereinafter referred to as a camera) 10 and a personal computer (PC) 50, which can exchange data with each other via a wireless communication interface 60. In the present embodiment, a pull model system in which a request is sent from the reception-side personal computer 50 to the transmission-side camera 10 and the personal computer 50 acquires a desired image from a group of images stored on the camera 10 side. Will be described.
[0021]
The camera 10 functions as an image transmission apparatus according to the embodiment of the present invention. An image pickup device (not shown) (for example, a CCD image sensor or a CMOS image sensor) is disposed in the camera 10, and an image of a subject is formed on the light receiving surface of the image pickup device via the photographing lens 12. It is converted into an electric signal (image signal) by photoelectric conversion.
[0022]
The personal computer 50 functions as a receiving side device. A personal computer 50 shown in FIG. 1 is a portable personal computer having a structure in which a display unit 53 is rotatably connected to a main body unit 52 having an input keyboard 51. In implementing the present invention, the personal computer 50 shown in FIG. The receiving apparatus is not limited to this example, and various devices such as a desktop personal computer, a PDA (Personal Digital Assistant), a mobile phone, and a printer can be used.
[0023]
FIG. 2 is an external perspective view showing the back side of the camera 10. As shown in the figure, the camera 10 includes a power switch 14 for instructing start and stop of a camera function, a release button 15 for a user to instruct execution of shooting (image recording), and the camera 10. A mode switching dial 16 for setting various modes is provided.
[0024]
The camera 10 includes a liquid crystal monitor 20 as display means, and an increment button 22, a decrement button 23, an erase button 24, and a setting button 25 as instruction input means. The liquid crystal monitor 20 displays the image being captured, the reproduced image of the recorded image, information on the currently set mode, information on the compression rate of the image, date and time information, frame number display 28, and the like.
[0025]
The liquid crystal monitor 20 is also used as a display screen for a user interface when the user performs various setting operations and the like, and menu information such as setting items is displayed as necessary.
[0026]
The increment button 22 is an operation unit that is operated when incrementing the frame number displayed on the liquid crystal monitor 20 (frame advance operation) or moving the cursor on the menu screen upward. The decrement button 23 is an operation unit that is operated when decrementing a frame number or the like displayed on the liquid crystal monitor 20 (frame returning operation) or moving the cursor downward.
[0027]
The delete button 24 is an operation unit used for deleting a desired target 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) a desired item such as an item displayed on the liquid crystal monitor 20.
[0028]
FIG. 3 is a plan view of the mode switching dial 16. As shown in the figure, the mode switching dial 16 has a display indicating each mode of a wireless mode (Wireless) 32, a shooting mode (Cam) 34, a playback mode (Play) 36, and a setup mode (Setup) 38. It is provided so that any one of these modes can be selected.
[0029]
The wireless mode 32 is a mode for performing wireless communication with another communication device (in this example, the personal computer 50). The shooting mode 34 is a mode for performing shooting (recording of an image). In this example, a still image of XGA size (1024 × 768 pixels) can be recorded. The playback mode 36 is a mode for playing back recorded images. 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.
[0030]
FIG. 4 is a block diagram showing the internal configuration of the camera 10. As shown in the figure, the camera 10 includes an imaging unit 120 that photoelectrically converts an optical image of a subject and outputs it as an image signal, and correlated double sampling with respect to an image signal (analog signal) output from the imaging unit 120. An analog signal processing unit 124 that performs processing such as processing, color separation, and gain adjustment; and 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; A digital signal processing unit 128 that performs image processing such as luminance / color difference signal (YC) conversion processing, white balance correction, and gamma correction on the digital image signal is provided.
[0031]
Further, the digital camera 10 includes a strobe (flash device) 130 that emits light to supplement the amount of light of the subject at the time of shooting, and a strobe control unit 132 that controls the timing and amount of light emission of the strobe 130. A scaling unit 134 for converting the image size of the image data, a compression / decompression unit 136 for controlling the compression of the image data by a technique typified by JPEG or MPEG, and a process for expanding / decompressing the compressed data, A card interface unit 144 that performs data conversion necessary to write data to or read data from the memory card 142 mounted in the card slot 140 is provided.
[0032]
The scaling processing unit 134 is an image processing unit that performs conversion processing of the number of pixels by pixel thinning processing or the like. The captured image (XGA size) is converted to SVGA (800 × 600 pixels), VGA (640 × 480 pixels), Resizing at high speed is possible for each size of QVGA (320 × 240 pixels) and QQVGA (160 × 120 pixels).
[0033]
In this example, the memory card 142 that can be attached to and detached from the camera 10 is used as means for storing image data. However, the form of the recording medium is not limited to this, and a semiconductor memory, magnetic disk, optical disk, magneto-optical disk, and the like Various media can be applied. Of course, the recording medium (internal memory) built in the camera body can be used without being limited to the removable medium.
[0034]
The camera 10 has a frame memory 150 for temporarily storing image data for display as means for displaying images and various information on the screen of the liquid crystal monitor 20, and various characters / symbols and messages such as date / time and mode information. Is provided with an OSD circuit 152 for on-screen display, and a D / A converter 154 for converting digital data into an analog signal for display (for example, NTSC composite signal). The image data stored in the frame memory 150 is sent to the D / A converter 154 and output to the liquid crystal monitor 20 together with information such as characters generated from the OSD circuit 152.
[0035]
The input / output means 160 of the camera 10 includes various operation units such as the power switch 14, the release button 15, the mode switching dial 16, the increment button 22, the decrement button 23, the delete button 24, and the setting button 25 described in FIG. And various display means such as a finder LED and a self-timer LED (not shown). As shown in FIG. 4, an I / O control unit 162 that performs input / output control of input signals input from various operation units of the input / output unit 160 and output signals output to the LEDs or the like is provided in the camera 10. Is provided.
[0036]
The communication means of the camera 10 includes an antenna 170 that transmits and receives information carried on radio waves, and a wireless interface unit 172 that performs signal conversion necessary for transmission and reception of signals via the antenna 170. For example, using a communication standard such as a wireless LAN or Bluetooth, the camera 10 can exchange data with the personal computer 50 and other external devices.
[0037]
In the present embodiment, wireless communication using radio waves is used. However, the communication mode is not limited to this when implementing the present invention, and communication using light may be used. Instead of wireless communication means, USB communication may be used. It is also possible to use wired communication means such as an interface or an IEEE 1394 interface. A communication unit corresponding to the communication method to be used is mounted on the camera 10.
[0038]
The camera 10 is also provided with a central processing unit (CPU) 180, a system memory 182, a rewritable nonvolatile memory 184, and a calendar clock 186 for managing date and time such as shooting date and time. The CPU 180 functions as a control unit that controls the entire camera, and also functions as a calculation unit that performs various calculation processes. The CPU 180 performs exposure and readout control of the imaging unit 120, image processing control, image data recording control, and a 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.
[0039]
The system memory 182 includes a ROM that stores operation programs and various constants, and a high-speed readable / writable RAM that serves as a work area during program execution and a temporary storage area for image data. The nonvolatile memory 184 stores various constants and setting information relating to camera operation, and these information are retained even when the power is turned off.
[0040]
As shown in FIG. 1, the CPU 180 and its peripheral circuits are connected by a bus 188, and can transmit information to each other at high speed, and the CPU 180 can control each circuit according to a program.
[0041]
Next, the operation of the camera 10 configured as described above will be described.
[Shooting mode]
When the mode switching dial 16 is set to the “shooting mode”, the shooting mode is set and the imaging unit 120 is activated. 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. 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 after undergoing predetermined processing such as gamma correction, the system memory 182 Stored in the internal RAM.
[0042]
When the image being captured is displayed on the LCD monitor 20, the image signal stored in the RAM is transferred to the frame memory 150 and converted into a predetermined signal for display (for example, an NTSC color composite video signal). And then 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 imaging unit 120, and the video signal generated from the image data is supplied to the liquid crystal monitor 20, so that the image being captured is real-time. Are displayed on the liquid crystal monitor 20. The photographer can check the shooting angle of view from the image (through image) displayed on the liquid crystal monitor 20.
[0043]
When the release button 15 is pressed by the photographer, a shooting start instruction (release ON) signal is issued. The CPU 180 starts taking in image data for recording (exposure and data reading) in response to the reception of the photographing instruction signal. The captured image data undergoes a required process in the digital signal processing unit 128 and then compressed in a compression / expansion unit 136 according to JPEG or another predetermined format.
[0044]
The CPU 180 generates a single image file by associating the compressed image data with attached information such as shooting conditions regarding the image. Thus, the generated image file is sent to the card interface unit 144 and recorded in the memory card 142 via the memory card slot 140.
[0045]
FIG. 5 is a structural diagram of a captured image file (original image file) recorded on the memory card 142 by the camera 10 of this example. As shown in the figure, the still image file 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 the XGA size (1024 × 768 pixels), the thumbnail image of 160 × 120 pixels (QQVGA size) indicating the image content of the main image, and the main image. Attached information is always attached to the image file.
[0046]
By using a thumbnail image as a header image and displaying a list together with thumbnail images of other image files, the user can easily search for the image. As the attached information, various types of information related to the main image, such as information on the shooting date and time, information on shooting conditions, and titles for classification, are recorded. If the value of each piece of information is unknown, “UNKNOWN” as shown in FIG. 5 can be described.
[0047]
In this example, a still image of XGA size (1024 × 768 pixels) is recorded as a main image after being compressed according to a predetermined format such as JPEG, but the number of recording pixels and the compression rate can be set as appropriate. . It is preferable that the camera 10 is provided with means for designating the number of recording pixels and the compression rate so that the user can change the number of recording pixels and the compression rate before or after photographing as necessary. Similarly, in this example, a thumbnail image of 160 × 120 pixels is recorded for the thumbnail image, 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.
[0048]
FIG. 6 shows an actual image recording structure (real directory structure) for the memory card 142. As shown in the figure, each image file is stored with a directory divided 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 an image file is provided under the root directory.
[0049]
In the “IMAGE” directory, a directory “001VACATION” generated by the user and a directory “002BIRTHDAY” are provided. The directory name has a directory number added to the beginning of a character string arbitrarily designated by the user. The directory number is automatically given by the CPU 180 in the camera 10.
[0050]
In the “001VACATION” directory, image file groups such as “DSCF0001.JPG”, “DSCF0002JPG”, and “DSCF0003.JPG” are recorded. The file name is a character string “DSCF” followed by a file number and extension. The CPU 180 automatically assigns file numbers in the order of recording and automatically generates file names.
[0051]
In the directory “002BIRTHDAY”, image file groups such as “DSCF0001.JPG”, “DSCF0003JPG”, “DSCF0004.JPG” and the like are recorded. Note that the file number of an image file deleted by a user operation is a missing number. A frame number for specifying an image file is represented by a combination of a directory number and a file number (for example, 001-0003).
[Playback mode]
When “reproduction mode” is selected by the mode switching dial 16, the latest image file (last recorded image file) recorded on the memory card 142 is read. The data of the image file is decompressed by the compression / decompression unit 136 and output to the liquid crystal monitor 20 via the frame memory 150 and the D / A converter 154. By operating the increment button 22 or the decrement button 23 at the time of this one-frame reproduction, it is possible to frame forward (file advance) in the forward direction or the reverse direction, and to change the reproduction target image.
[Wireless mode]
When “wireless mode” is selected by the mode switching dial 16, the communication function of the camera 10 is activated, and data communication is possible with another communication device (in this example, the personal computer 50).
[0052]
When the CPU 180 receives a command to inquire about the directory structure and file information of the image data related to the transfer of the image data from the personal computer 50 by communication, the CPU 180 newly creates a virtual image based on the image file recorded in the memory card 142. A directory (including a virtual folder) and a virtual image file are generated, and the virtual directory information is provided to the personal computer 50.
[0053]
FIG. 7 shows an example of a virtual directory structure that the camera 10 can show to the personal computer 50. This virtual directory is classified for each image size. That is, the CPU 180 of the camera 10 creates a virtual directory having an image size that can be resized by the camera 10 in addition to the actually recorded original image (XGA), and creates a virtual directory for each image file group under the directory. Form.
[0054]
According to FIG. 7, a virtual directory “QQVGA” for newly storing a series of virtual image files of QQVGA (160 × 120 pixels) size in the hierarchy below the root directory “Root”, and a QVGA (320 × 240 pixels) size A virtual directory “QVGA” for storing a series of virtual image files, a virtual directory “VGA” for storing a series of image files of VGA (640 × 480 pixels) size, and a series of SVGA (800 × 600 pixels) size Virtual directory "SVGA" for storing virtual image files, virtual directory "XGA" for storing a series of virtual image files of XGA (1024 x 768 pixels) size, and text data regarding the contents of tag information attached to image files A directory “Property” for storing a file group (attached information file group) is generated.
[0055]
Further, directories “001VACATION” and “002BIRTHDAY” classified by the user are newly generated in the lower hierarchy of each directory classified by the number of pixels as described above. Further, under the directories “001VACATION” and “002BIRTHDAY”, virtual image files “DSCF0001.JPG”, “DSCF0002.JPG”, “DSCF0003” based on the actual image files actually recorded are further displayed. .JPG "... and register it. These virtual directories and virtual files are directories and file names that do not actually exist. However, when the CPU 180 on the camera 10 receives a transfer request for these virtual image files from the personal computer 50 side, it is necessary from the data of the original image. By executing the resizing process, a file having a corresponding image size can be provided to the personal computer 50 side.
[0056]
8 to 10 are examples of screens when a desired image is selected by the personal computer 50 for the virtual directory shown in FIG. 8 to 10 show screen examples of “windows explorer”, which is a file management application made by Microsoft Corporation.
[0057]
As shown in FIG. 8, by selecting the upper directory, the “number of pixels” classification is selected, and as shown in FIG. 9, 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 designate (request) an image with a desired number of pixels having the same contents as the corresponding original image file to the camera 10. It becomes.
[0058]
FIGS. 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 main image according to the request is equal to or larger than the VGA size. In this case, like the original image file, an image file with a thumbnail image attached is sent to the personal computer 50 side. Accordingly, on the personal computer 50 side receiving this, it is possible to easily browse the image contents using the thumbnail image data without opening a main image having a large pixel size.
[0059]
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 an image file in which tag information is added to the main image is sent to the personal computer 50 side. The personal computer 50 that has received this needs to generate and display a thumbnail image for the received image file. However, since the pixel size before resizing is small, the burden on resizing processing 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 small with respect to the main image, so that the transfer time can be shortened by omitting the thumbnail image.
[0060]
Note that when the main image size is sufficiently larger than the thumbnail size (for example, when the main image size is VGA or larger), the data amount of the main image is dominant, and the thumbnail size can be ignored. Hardly contributes to the improvement of the transmission speed. Therefore, as described with reference to FIG. 11, when the main image size is VGA or larger, an image file with a thumbnail attached is sent.
[0061]
Next, an operation procedure for transmitting an image from the camera 10 to the personal computer 50 will be described.
[0062]
FIG. 13 is a flowchart showing the procedure of 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 a connection request from the personal computer 50 can be received. On the other hand, the personal computer 50 side starts up browsing software (step S510) and prepares access to the camera 10.
[0063]
When a connection request for wireless communication I / F is made from the personal computer 50 to the camera 10 that has been paired in advance (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). Receiving the connection completion notification, the personal computer 50 requests the directory list from the camera 10 (step S516). When there is a request for a directory list, the camera 10 creates a directory list of the virtual directory described in FIG. 7 (step S120), and sends this list to the personal computer 50 side (step S122).
[0064]
The personal computer 50 acquires directory information from the camera 10 and displays the directory information on the display (step S520, see FIGS. 8 to 10). Here, the user selects a desired directory or file (step S522).
[0065]
If a 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 instructed directory (step S130). When the directory change process is completed, the camera 10 notifies the personal computer 50 of the completion of the directory change (step S132). Upon receiving this notification, the personal computer 50 requests the directory list from the camera 10 (step S534).
[0066]
When requested by the directory list, the camera 10 creates a virtual directory list (step S140) and sends it to the personal computer 50 side (step S142). The personal computer 50 acquires 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).
[0067]
When the image file is selected, the camera 10 is requested to transmit 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 it to the personal computer 50 (step S152). .
[0068]
The personal computer 50 adds a necessary thumbnail image to the received image file and generates a save image file to be recorded on a hard disk (HDD) or the like (step S550). Thereafter, the image file is saved (step S552), and a thumbnail of the received image is displayed (step S554). Thereafter, the process returns to step S516 and the above steps are repeated.
[0069]
FIG. 14 shows the procedure for creating a transmission image file in step S150.
[0070]
When the camera 10 is requested to transmit an image file from the personal computer 50 side, the transmission image file creation process shown in FIG. 14 starts. First, the camera 10 performs a process of reading the original file of the designated image from the memory card 142 (step S610), and determines whether or not 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 having the same number of pixels as that of the original image file is requested, the original image file can be used as it is as an image file for transmission, so that this processing routine is terminated and the process returns to the flowchart of FIG.
[0071]
When the number of pixels of the designated image is different from the number of pixels of the original image file in step S612 in FIG. 14, the process proceeds to step S614 to perform processing for extracting thumbnail data from the original image file (step S614). Processing for extracting tag information data from the image file is performed (step S616). The extracted thumbnail data and tag data are stored in the memory.
[0072]
Thereafter, a process of converting the main image of the original image file into the designated number of pixels is executed (step S618). This resizing process is performed by a scaling process unit 134 described with reference to FIG.
[0073]
Next, the process proceeds to step S620 in FIG. 14 to determine whether or not 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 attached to the image obtained by the resizing process in step S618 to create a transmission image file (step S622).
[0074]
On the other hand, when the main image size specified in step S620 is less than VGA (that is, QVGA or less), the process proceeds to step S630. In step S630, a transmission image file is created by attaching only the tag data extracted in step S616 (omitting thumbnail data) to the image obtained by the resizing process in step S618. In steps S622 and S630, if there is a tag relating to the image size, the value is changed to a value reflecting the number of pixels after resizing.
[0075]
In this way, when the generation of the transmission image file is completed in step S622 or step S630, this processing routine is terminated, and the process returns to the flowchart of FIG.
[0076]
FIG. 15 shows the processing content of step S550 of FIG. 13, that is, the processing flow after the personal computer 50 receives the image file. When the save image file creation process shown in FIG. 15 is started, first, the personal computer 50 determines whether or not the image requested (designated) from the camera 10 has the same QQVGA size as the thumbnail size (step S710). ). If the designated image (that is, the image received from the camera 10) has a QQVGA size, since it is not useful even if a thumbnail image is added, the received image file is directly used as a saving image file (step S720). ).
[0077]
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). If thumbnail data is attached to the received image file, the received image is directly used as a save image file (step S720).
[0078]
On the other hand, if no thumbnail data is 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. (Step S716) The generated thumbnail is added to the received image file to generate a save image file (Step S718).
[0079]
Thus, 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.
[0080]
<Other control examples>
In the flowchart described with reference to FIG. 14, it is determined whether or not to attach a thumbnail image. However, the scope of application of the present invention is not limited to this, and the number of pixels of the thumbnail image to be attached can be changed or thumbnail compression can be performed. A mode in which the amount of thumbnail data is variable by changing the rate is also possible.
[0081]
FIG. 16 shows another flowchart of the transmission image file creation process. In FIG. 16, steps that are the same as those in FIG. 14 are given the same reference numerals, and descriptions thereof are omitted. After resizing the main image of the original image file to the designated number of pixels in step S618 in FIG. 16, the process proceeds to step S619. In step S619, it is determined whether or not the requested number of pixels of the image is equal to or larger than the XGA size.
[0082]
If an image of XGA size or larger is requested, the process advances to step S622 to create a transmission image file by attaching the extracted thumbnail and tag data to the resized image file (step S622).
[0083]
If NO is obtained in step S619, the process advances to step S621 to determine whether the designated image file is VGA or more. If the designated number of pixels is greater than or equal to VGA and less than XGA, the process proceeds to step S624. In step S624, processing for further compressing the extracted thumbnail data is performed to reduce the data amount of the thumbnail image. Thereafter, the process proceeds to step S626, in which the re-compressed thumbnail data and tag data are attached to the resized image file to generate a transmission image file. If there is a tag related to the image size in steps S622, S626, and S630, the value is changed to a value reflecting the number of pixels after resizing.
[0084]
If the image file specified in step S621 is less than VGA, the process proceeds to step S630. In this way, when the transmission image file has been generated in step S622, step S626, or step S630, this processing routine is terminated, and the process returns to the flowchart of FIG.
[0085]
In FIG. 16, the example in which the thumbnail size is adjusted by changing the compression rate has been described. However, the scope of application of the present invention is not limited to this, and instead of or in combination with the change of the compression rate, The thumbnail size may be adjusted by changing the number of pixels (resizing).
[0086]
In the above-described embodiment, the user interface that provides virtual directory information from the camera 10 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. The implementation is not limited to this example. For example, a mode in which the camera side presents a resizable pixel number menu to the personal computer 50 side and selects desired image contents and the number of pixels from the personal computer 50 side is also possible.
[0087]
In the above-described embodiment, a digital camera is exemplified as one form of the image transmission device, but the scope of application of the present invention is not limited to the digital camera, and can be applied to various devices such as a personal computer, a PDA, and a mobile phone.
[0088]
In the above-described embodiment, the pull model image transfer system has been described. However, the present invention is not limited to this example, and the image to be transmitted is selected from the transmission side device, and the image data related to the selection is received on the reception side. The present invention can also be applied to a so-called push model image transfer system that sends images to an apparatus.
[0089]
A specific example of handling thumbnails during image transfer is summarized as follows.
[When the pixel size of the thumbnail is fixed]
(1) When the main image pixel size to be sent to the receiving side is smaller than the fixed value, the main image (an image file with tag information added if necessary) is transmitted without attaching a thumbnail image. As a criterion for determining whether or not to attach a thumbnail image, it is compared whether or not 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 (a fixed value as a criterion). Judgment.
[0090]
(2) When both the main image and the thumbnail are compressed, the compressed size (or expected compressed size) of the main image is a predetermined multiple (for example, 5 times) of the compressed size (or planned compressed size) of the thumbnail. If it is smaller than that, it is transmitted without attaching a thumbnail.
[When thumbnail size is variable]
(3) The number of pixels of the thumbnail is adjusted so as to be a predetermined ratio (for example, 1/5) or less with respect to the main image pixel size sent to the receiving side, and the thumbnail is added and transmitted. The “predetermined ratio” is appropriately set in consideration of the utility value of the thumbnail image.
[0091]
(4) The thumbnail image data size (thumbnail size) is adjusted so as to be a predetermined ratio (for example, 1/5) or less with respect to the main image file size sent to the receiving side, and the thumbnail image is transmitted. The method of adjusting the thumbnail size is realized by changing at least one of the thumbnail image compression ratio and the number of pixels.
[0092]
The thumbnail size may be adjusted at the time of image transmission, or the thumbnail size may be adjusted at the time of shooting (image recording).
[0093]
Furthermore, it is possible to combine the presence / absence of thumbnail attachment and the adjustment of thumbnail size. For example, the thumbnail size to be attached may be adjusted according to the main image file size, or switching between omitting thumbnail attachment may be switched.
[0094]
【The invention's effect】
As described above, according to the present invention, the presence / absence of thumbnail attachment is determined according to the data amount of the main image to be transmitted, and the attachment of the thumbnail image with low usefulness is omitted. This can prevent the communication time from being shortened.
[0095]
In addition, 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 and communication time can be shortened.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing the configuration of an image transfer system to which the present invention is applied.
FIG. 2 is an external perspective view showing a rear side of the camera shown in 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 the 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 on a memory card.
FIG. 7 is a diagram showing an example of a virtual directory structure to be shown to a personal computer that is a receiving 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 virtual directory information shown in FIG. 7;
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 virtual directory information shown in FIG. 7;
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 virtual directory information shown in FIG. 7;
FIG. 11 is a diagram illustrating an example of the structure of an image file with thumbnails transmitted from a 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 for explaining operations of the camera and the personal computer in the present embodiment.
FIG. 14 is a flowchart showing a procedure for creating a transmission image file.
FIG. 15 is a flowchart showing a procedure for creating a save image file;
FIG. 16 is a flowchart showing another example related to the generation processing of a transmission image file.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Camera, 50 ... Personal computer, 60 ... Wireless communication interface, 120 ... Imaging part, 128 ... Digital signal processing part, 134 ... Scaling processing part, 142 ... Memory card, 170 ... Antenna, 172 ... Wireless interface part, 180 ... CPU, 182 ... system memory

Claims (8)

In an image transmission method for transmitting image data from a transmission side device to a reception side device,
According to the data amount of the main image to be transmitted, it is determined 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 determination result, an image file with a thumbnail image added or an image file with the thumbnail image omitted is generated.
An image transmission method comprising transmitting the generated image file. The image file in which a thumbnail image is omitted is generated as the image file for transmission when the pixel size of the main image sent to the receiving apparatus is smaller than a predetermined criterion. Image transmission method. When both the main image data and the thumbnail image data are compressed, and the compression size of the main image is smaller than a predetermined multiple of the compression size of the thumbnail image, the thumbnail image is used as the image file for transmission. The image transmission method according to claim 1, wherein an omitted image file is generated. In an image transmission method for transmitting image data from a transmission side device to a reception side device,
Adjusting the data amount of the thumbnail image so that the data amount of the thumbnail image, which is a reduced image of the main image, is equal to or less than a predetermined ratio to the data amount of the main image to be transmitted,
Generating an image file including a thumbnail image with the data amount adjusted and the main image;
An image transmission method comprising transmitting the generated image file. 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 amount of data of the main image to be sent to the receiving side apparatus is less than a predetermined ratio. The image transmission method according to claim 4. An image transmitting device capable of transmitting image data to a receiving side device,
A communication means for exchanging data with the receiving side device;
Data reading means for reading out an image file including image content selected as a transmission target from an image storage means in which image data is stored;
Determining means for determining whether 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;
An image file generation unit for transmission that generates an image file to which a thumbnail image is added or an image file from which the thumbnail image is omitted according to the determination result of the determination unit;
Control means for performing control to transmit the transmission image file generated by the transmission image file generation means to the reception side device;
An image transmitting apparatus comprising: An image transmitting device capable of transmitting image data to a receiving side device,
A communication means for exchanging data with the receiving side device;
Data reading means for reading out an image file including image content selected as a transmission target from an image storage means in which image data is stored;
Data amount changing means for changing the data amount of a thumbnail image, which is a reduced image of the main image, according to the data amount of the main image to be transmitted;
A transmission image file generating means for generating an image file to which a thumbnail image with the data amount adjusted so that the data amount of the thumbnail image is equal to or less than a predetermined ratio with respect to the data amount of the main image;
Control means for performing control to transmit the transmission image file generated by the transmission image file generation means to the reception side device;
An image transmitting apparatus comprising: Means for providing image file information that can be transmitted to the receiving device;
8. The image transmission apparatus according to claim 6, wherein an image file including a main image having a pixel size according to the request is transmitted in response to a request from the reception side apparatus.

Images