Abstract:
To shorten the time required to transfer image data from a first information processing apparatus (e.g., an electronic camera) to a second information processing apparatus (e.g., a personal computer) the first information processing apparatus reduces the image data when it is determined that a slow interface is being used. Additionally, the reduced image data being transferred can be altered in size (enlarged or further reduced) prior to compression so that its size is best suited for the particular compression process.

Description:
RELATED PROVISIONAL APPLICATIONS 
     This nonprovisional application claims the benefit of Provisional Applications Nos. 60/060,787 and 60/060,798, both filed Oct. 3, 1997. 
    
    
     INCORPORATION BY REFERENCE 
     The disclosures of the following priority applications are herein incorporated by reference: Japanese Patent Application No. 9-23487, filed Feb. 6, 1997 and Japanese Patent Application No. 9-82560, filed Apr. 1, 1997. 
     BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The present invention relates to an information processing system, apparatus, method and recording medium for controlling same and in particular to such apparatus and methods in which data, such as image data, is transferred in an efficient manner. 
     2. Description of Related Art 
     With the progress of semiconductor technologies, recording apparatus such as electronic cameras that record images or sound as digital data, and electronic notebooks that record images in the form of memos have become wide-spread among the public. Many of the apparatus include an interface so that the apparatus can be connected to external apparatus, such as a personal computer (PC), to output data such as recorded images and sound to the PC. Some of these recording apparatus include a plurality of interfaces. 
     The external apparatus (e.g., PC) can perform display of the images and/or reproduce the sound stored in the above mentioned recording apparatus. The recording apparatus that have a plurality of interfaces send data in the same way regardless of the interface that is actually being used. When an interface having a slow transfer speed is used, there is a problem that if the capacity of the transferred data is large, the transferring of the data takes an extremely long time. 
     For example, when an electronic camera transfers 30 KB of image data (640×480 pixels) via an SCSI interface, and when the computer changes the size of that image data to 106×80 pixels for display, since the transfer time of the data is approximately 160 milliseconds, and the time required to change the size of the image data and to display is approximately 173 milliseconds, it only takes a total of 333 milliseconds to display the image stored in the recording apparatus. On the other hand, when a serial interface having a transfer speed of 19,200 bps (bits per second) is used, the transfer time of the data is approximately 16 seconds, and the time for the size change of the image data and displaying of the image is approximately 173 milliseconds, and thus an extra 16 seconds is required to transfer and display the image stored in the recording apparatus. 
     When some of these recording apparatus transfer image data to a computer, it is common that the image data that is transferred has been compressed by, for example, the JPEG (Joint Photographic Experts Group) method. 
     In order to further decrease the data amount to be transferred, it is possible to reduce the picture image data by decreasing the number of pixels of picture image data to be sent. However, because the transfer speed is slow when using a serial interface and the like, it is preferred that the data amount be further reduced when sending even a reduced-size picture image. For this reason, the reduced-size picture image also can be compressed. 
     However, with the JPEG compression method, since the compression process is performed on blocks of, e.g., 8×8 pixels, it is preferable that the number of pixels on each side of the compression process (i.e., before compression and after decompression) are in multiples of 8. Thus, when compressing by the JPEG method after reducing the picture image data, depending on the number of pixels of the post-reduction picture image, it may be necessary to adjust the number of pixels on each side of the compression process thereby creating the problem where the process of reducing the data amount becomes complicated. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to shorten the time required for transferring image data by reducing the amount of image data to be transferred according to the type of the interface that will be used. 
     According to one aspect of the investigation, an information processing system includes a first information processing apparatus coupled to a second information processing apparatus via either a first interface having a first transfer speed or via a second interface having a second, slower transfer speed. When coupled via the first interface, image data is transferred to the second information processing apparatus. When coupled via the second interface, image data is transferred to the second information processing apparatus after the image data is reduced. 
     The first information processing apparatus of this system includes evaluating means for evaluating whether the interface to be used is the first interface having the first transfer speed or the second interface having the second transfer speed. A reducing means reduces the data amount of the image data when the second interface having the second transfer speed is used. Transfer means transfers the image data via the first interface having the first transfer speed, or transfers the image data reduced by the reducing means via the second interface having the second transfer speed. 
     In the information processing system, when the first information processing apparatus (for example, an electronic camera) is connected to the second information processing apparatus (for example, a PC) via the interface having the first transfer speed (for example, the SCSI interface), it transfers the image data to the second information processing apparatus via the first interface. When the first information processing apparatus is connected to the second information processing apparatus via the second interface having the second transfer speed (for example, an RS-232C interface), the data amount of the image data is reduced, and the reduced image data is transferred to the second information processing apparatus via the second interface. 
     An information processing system according to another aspect of the invention includes a first information processing apparatus having reduction means for reducing prescribed image data to reduced image data having a number of pixels suited to the compression process of a prescribed compression method. A compression means compresses the reduced image data by the prescribed compression method, and a transfer means transfers the compressed reduced image data to a second information processing apparatus through an interface. The second information processing apparatus includes decompressing means for decompressing the compressed reduced image data that was transferred through the transfer means. 
     As an alternative to reducing the image data to obtain image data having a number of pixels suited to the particular compression process, the first information processing apparatus can include dummy data attachment means that makes the number of pixels of the image data suitable for the compression process by adding dummy data when the prescribed image data has a number of pixels that are not suited to the compression process. The compression means then performs the compression process of the prescribed image data together with the dummy data that was attached by way of the dummy data attachment means. 
     A recording medium includes a control program having computer-readable instructions so that the first information processing apparatus selectively reduces image data based on the type of interface being used and/or reduces or attaches dummy data to the image data prior to compression. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be described in conjunction with the following drawings in which like reference numerals designate like elements and wherein: 
     FIG. 1 is a block diagram of an information processing system according to one embodiment of the present invention; and 
     FIG. 2 is a flow chart explaining the operation when displaying a reduced image of an image stored in the electronic camera on a display. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIG. 1 shows an information processing system according to one embodiment of the present invention. In this information processing system, a computer  1  and an electronic camera  2  are coupled via at least either high speed SCSI interfaces  18  and  42  or low speed serial interfaces  19  and  43 . 
     In the computer  1 , the CPU  11  operates in accordance with a program stored in the memory  12 , which includes, for example ROM and/or RAM. The program also can be stored in the hard disk  14 . CPU  11  performs various processing according to such programs. 
     The memory  12  temporarily stores programs or data being processed, and also stores programs or data that perform specified operations. The VRAM  13  has memory areas that correspond to each pixel of a display  3 , and outputs the value of those memory areas to the display  3 . 
     The hard disk  14  can store various programs or data, for example, the program that carries out the operations that will be described hereafter. 
     The D/A converter  15  converts sound data provided from the CPU  11  to an analog signal and outputs to the speaker  16 . 
     The interface  17  is connected to input devices such as, for example, the keyboard  4  or the mouse  5  or the like, and supplies signals from these devices to the CPU  11 . 
     The SCSI interface  18  performs the sending and receiving of the data in accordance with the standards of the SCSI (Small Computer System Interface). 
     The serial interface  19  performs sending and receiving of the data, for example in accordance with the standards of the RS-232C. 
     In the electronic camera  2 , the CPU  31  (which functions as evaluating means, reducing means, compression means and transfer means) operates in accordance with one or more programs stored in the memory  32 , which includes a ROM, RAM, flash memory or the like, and performs various processing. 
     The memory  32  temporarily stores in the RAM data that is in the middle of processing, and also stores programs or data that perform specified operations. Memory  32  stores recorded image data or sound data in the flash memory part. 
     The microphone  33  converts sound to an analog sound signal, and outputs that signal to the A/D converter  34 . The A/D converter  34  converts the supplied analog sound signal to a digital sound signal, and outputs that signal to the ADPCM encoder and decoder  35 . The ADPCM encoder and decoder  35  compresses the digital sound signal in accordance with the ADPCM method, and also converts (decompresses) the compressed data to a digital sound signal by the ADPCM method. 
     The D/A converter  36  converts the digital sound signal supplied from the ADPCM encoder and decoder  35 , and outputs it to the speaker  37  as analog sound data. 
     The lens  38  collects light from the photographic object onto the CCD  39 . The CCD  39  photoelectrically converts the light from the object, and outputs an analog signal which corresponds to the image of the object to the A/D converter  40 . The A/D converter  40  converts the analog image signal to a digital image signal, and outputs that signal to the JPEG encoder and the decoder  41 . The JPEG encoder and decoder  41  compresses the supplied digital image signal in accordance with the JPEG (Joint Photographic Experts Group) method, and outputs the compressed data (JPEG data) to the CPU  31 . The JPEG encoder and decoder  41  also decompresses specified JPEG data to a digital image signal. 
     The SCSI interface  42  performs sending and receiving of the data in accordance with the SCSI (Small Computer System interface) standards. The serial interface  43  performs sending and receiving of the data, for example, in accordance with the RS-232C standards. 
     Next, referring to the flow chart of FIG. 2, for example, when displaying a list of the images stored in the electronic camera  2 , the operation of displaying the reduced images (thumbnail images) of the images stored in the electronic camera  2  on the display  3  is explained. In this example, it is assumed that the images are stored in the electronic camera in a compressed state. 
     In step S 1 , the CPU  31  of the electronic camera  2  evaluates (i.e., determines) whether it is connected to the computer  1  via the SCSI interfaces  42  and  18 . When it is not connected to the computer  1  via the SCSI interface  42 , flow proceeds to step S 2 . In step S 2 , the CPU  31  decompresses the specified JPEG images into images of 640×480 pixels using the JPEG encoder and decoder  41 . 
     Then, in step S 3 , the CPU  31  thin-outs (i.e., reduces) specified pixels of the decompressed image data of 640×480 pixels, and creates image data of a reduced image having a pixel number of 1/64 (80×60 pixels compared to the original image). 
     Because it is easier to compress blocks of 8×8 pixels using the JPEG method, the size of the reduced image is altered so that its horizontal and vertical dimensions are multiples of 8. The number of pixels in the horizontal direction is 80, which is a multiple of 8. Since 60 is not a multiple of 8, in step S 31 , the CPU  31  attaches 4 lines of dummy data to the picture image data of 80×60 pixels, thereby creating picture image data of 80×64 pixels. In this way, the dummy data is added so as to make the number of pixels in the vertical direction a multiple of 8. As the attached dummy data, any of the data described below, which have a small adverse effect, are added as the first 4 lines when compressing and reproducing are used: 
     Intermediate grey data such as R=128, G=128, B=128 
     horizontal data for the front 4 lines 
     copy data for the front 4 lines 
     Alternatively, data can be eliminated from the reduced image (e.g., making it a size of 80×56 pixels) so that it is more suitable for JPEG compression. 
     Next, in step S 4 , the CPU  31  causes the JPEG encoder and decoder  41  to compress the image data having a pixel number of 80×64 pixels. The CPU  31  then outputs the compressed JPEG data to the computer  1  via the serial interface  43  in step S 5 . 
     Then, the CPU  11  of the computer  1  receives the JPEG data via the serial interface  19 , and in step S 6 , decodes (decompresses) the JPEG data and replays the decompressed image data, which has a pixel number of 80×64. Alternatively, in step S 6 , the CPU  11  of the computer  1  can decompress the transferred JPEG data and replay the reduced size image of only 80×60 pixels. In other words, the 4 lines of dummy data need not be replayed. 
     Next, in step S 7 , the CPU  11  of the computer  1  performs interpolation processing with respect to the decompressed image which has a pixel number of 80×64 (or 80×60), and creates an image (thumbnail image) having 106×80 pixels. Then in step S 8 , CPU  11  outputs the image data of that thumbnail image to the VRAM  13 , and displays it on the display  3 . 
     For example, when the electronic camera  2  transfers the 30 KB of image data (JPEG data) via the serial interface  43 , which has a transfer speed of 19.2 kbps, the time required for decompressing the JPEG data in the electronic camera  2 , thinning-out the image data, and re-compressing to the JPEG data is approximately 2 seconds, the transfer time of the data is approximately 1.6 seconds, and the time required for changing the size of the image data and displaying the image is approximately 157 milliseconds. Thus the total time is 3.7 seconds. The thumbnail image of the image stored in the electronic camera  2  is then displayed on the display  3  which is connected to the computer  1 . 
     On the other hand, when the CPU  31  of the electronic camera  2  is connected to the computer  1  via the SCSI interface  42 , flow proceeds from step S 1  to step S 9 . In step S 9 , the CPU  31  outputs (transfers) the JPEG data of the specified image that has a pixel number of 640×480 pixels via the SCSI interface  42 . 
     Then the CPU  11  of the computer  1  receives the data via the SCSI interface  18 , and in step S 10 , the CPU  11  decompresses that data and replays ¼ of the image data for which the pixel number is 160×120 pixels. The ¼ image data results from replaying only ¼ of the decompressed JPEG data of 640×480 pixels as image data of 160×120 pixels. 
     Next, in step S 11 , the CPU  11  of the computer performs thin-out processing on the image for which the pixel number is 160×120 pixels, and creates an image (thumbnail image) of 106×80 pixels. Then, in step S 8 , the CPU  11  outputs the image data of that thumbnail image to the VRAM  13 , and displays it on the display  3 . 
     As described above, the CPU  31  of the electronic camera changes the pixel number of the transferred image data in accordance with the kind of interface which is used for the transfer. 
     Furthermore, in the above mentioned embodiment, the pixel number of the thumbnail image has been described as being 106×80. However it is not limited to this pixel number. 
     Although in FIG. 2, a description was provided of a single flow chart for a convenient explanation of the programs shown in the flow chart, the program that is executed by the CPU  31  of the electronic camera  2  is stored in the memory  32 , and the program that is executed by the CPU  11  of the computer  1  is stored in the hard disk  14 . Moreover, the programs shown in the flow chart of FIG. 2 may be supplied to the user already stored in the memory  32  and the hard disk  14 , or they may be supplied to the user in the form of a CD-ROM (compact disk ROM) where they may be able to be copied to the memory  32  and the hard disk  14 . The program(s) also can be provided via a communications network such as the Internet (World Wide Web). 
     Furthermore, in the embodiment described above, the number of pixels in the picture image data subsequent to reduction is 80×60, however, other sizes are possible. 
     In addition, in the embodiment described above, the program executed by the CPU  31  of the electronic camera  2  is stored in the memory  32 , and the program that is executed by the CPU  11  of the computer  1  is stored in the hard disk  14 . However, if CPU  11  of the computer  1  has the ability to execute the control which is executed by the CPU  31  of the electronic camera  2 , then the program in the flow chart shown in FIG. 2 may be stored entirely in the hard disk  14  of the computer  1  and it may be executed by the CPU  11 . Conversely, the program may be stored in the memory  32  of the electronic camera  2  and executed by the CPU  31 . 
     The invention is not limited to only SCSI and RS-232C interfaces. Additionally, the interfaces can be hardwired, as shown, or wireless (for example, radiowave or infrared). 
     The image information can be a picture image (a photographed or scanned image) or a line drawing, for example. 
     The invention also is not limited to processes in which the optimal size for compression is blocks having a size that is a multiple of 8. 
     Additionally, as should be clear from the above description, according to one aspect of the invention, the data transmitted via the faster interface may or may not be compressed data. In either case, however, the data transmitted via the slower interface is reduced relative to the data transmitted via the faster interface. 
     The invention is not limited to JPEG compression. Thus, other compression methods can be used. 
     The invention is not limited to implementation by a programmed general purpose computer as shown in the preferred embodiment. For example, the invention can be implemented using one or more special purpose integrated circuit(s) (e.g., ASIC). It will be appreciated by those skilled in the art that the invention can also be implemented using one or more dedicated or programmable integrated or other electronic circuits or devices (e.g., hardwired electronic or logic circuits such as discrete element circuits, or programmable logic devices such as PLDs, PLAs, PALs or the like). In general, any device or assembly of devices on which a finite state machine capable of implementing the flow chart shown in FIG. 2 can be used. 
     While this invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, the preferred embodiments of the invention set forth herein are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the invention as defined in the following claims.