Abstract:
A portable image transfer system includes a digital still camera which captures images in digital form and stores the images in a camera memory, a cellular telephone transmitter, and a central processing unit (CPU). The CPU controls the camera memory to cause it to output data representing an image and the CPU controls the cellular telephone transmitter to cause a cellular telephone to transmit the data received from the camera memory. A receiving station is coupled to the cellular telephone transmitter by a cellular network to receive image data and store the images.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to the field of digital still video cameras (DSVC&#39;s). More specifically, one embodiment of the present invention provides for improved storage of images generated by a DSVC. A portable DSVC is convenient for taking pictures at various locations because of the cameras&#39;s size and weight. Unfortunately, as users have come to expect small weights and compact sizes for consumer electronics, DSVC&#39;s have tended to be limited in the number of images which could be stored. One solution to the problem is to add additional memory modules, but this is an expensive solution given that the memory modules must be miniaturized so as not to adversely affect the portability of the DSVC. 
     What is needed is a DSVC with a large image storage capacity where the image storage is not unduly expensive and does not unreasonably impact the size of the portable cameras. 
     SUMMARY OF THE INVENTION 
     An improved portable image capture system is provided by virtue of the present invention. In one embodiment, a central processing unit (CPU), a modem and a cellular telephone transmitter are coupled to an image memory of a DSVC. The CPU is also coupled to a display and a command input device, which might be a voice activated device or a touch screen device integrated with the display. The CPU executes programs as needed to download images through the cellular telephone transmitter to a server station according to a protocol optimized for the connection available. Where the connection is a direct cellular telephone line, data is sent through the cellular telephone transmitter to cellular telephone system and it is received by a modem at the server station. A CPU at the server station directs the file to be stored in a data storage device, which is typically a large-capacity, inexpensive device such as a hard drive. 
     In variations of the present invention, the server station might perform complex analysis of the received images in order to instruct the DSVC to obtain additional images which the server station determines are needed for the analyses. The analyses include image resolution enhancement, stereoscopic matching, photocopying, and the like, as well as subjective evaluation of camera angle and image compression. In a specific implementation, the server station transmits images back to the remote station for viewing or forwarding to a local facsimile device or digital camera. 
     A further understanding of the nature and advantages of the inventions herein may be realized by reference to the remaining portion of the specification and the attached drawing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram of a remote station according to the present invention coupled to a server station via a cellular telephone system. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIG. 1 , a image transfer system  10  is shown with a remote station  12  coupled to a server station  14  via a cellular telephone system  16 . Remote station  12  includes a digital camera made up of a capture device  20  and an image memory  24 . Image memory  24  is a memory configured to hold a small number of images captured by capture device  20 . In some embodiments, capture device  20  and image memory  24  are provided by a conventional digital still video camera, such as the Ricoh RDC-1 still video camera supplied by Ricoh Company, Ltd. of Tokyo Japan. Whether an existing DSVC is used or the camera is integrated, a CPU  22  is coupled to image memory  24 , a modem  26  and a cellular telephone transmitter  28 . The coupling between the various elements is such that CPU  22  can control image memory  24  to transfer data representing an image from image memory  24  to modem  26 , which converts the image data into a signal suitable for transmission over a telephone line. Modem  26  is coupled to provide that signal to cellular telephone transmitter  28 , which transmits the signal through cellular system  16  to modem  56  of server station  14 . 
     Remote station  12  also includes a display  30  and a command input device  32  for interacting with the user of remote station  12  and accepting commands. The programs executed by CPU  22  are stored in a code EPROM  34  which respond to the commands sent by a user using input command device  32 . Command input device  32  might be a voice activated device or a touch screen integrated with display  30 . Code EPROM  34  includes code necessary to perform certain processing functions on an image before it is transmitted, such as a protocol packetizing program  36 , an encryption module  38  and an e-mail handler  40 . 
     Server station  14  is shown comprising modem  56  which is controlled by a CPU  52  which executes code stored in its own code EPROM  54 . The programs stored in code EPROM  54  are instructions for CPU  52  to transfer data received by modem  56  into data storage device  58  while processing the received image to handle the requirements of the protocols used to send the image. 
     In one example of the operation of image transfer system  10 , CPU  22  executes a program with instructions to periodically read an image from image memory  24  and mark the image as being read, allowing image memory  24  to be overwritten by subsequent images. As each image is read, the image data is encrypted and formatted as an electronic mail message. Where cellular system  16  is not a direct modem link, but a SLIP/PPP connection using TCP/IP, additional protocol packaging is performed on the image for transmission. When the images are received at server station  14 , they are decrypted and unpackaged, then stored in data storage  58 . If desired, some or all of the images in data storage  58  can be made available over the Internet. If a TCP/IP connection is used, CPU  20  might also execute a routine stored in code EPROM  34  to “ping” a destination before sending an image. The ping process sends a dummy message through a channel to determine whether or not the destination, such as server station  14 , is available, ready and willing to receive data. If an affirmative response to the ping is received by remote station  12 , only then does CPU  22  transmit the image package. If location information is to be included with each image, a Global Positioning System (GPS) receiver  60  can be coupled to CPU  22 , such as a PCMCIA-compatible GPS receiver manufactured by Trimble Navigation of Sunnyvale, Calif. 
     Many uses of the present invention are contemplated, some of which are mentioned here, others of which are apparent after reading the disclosure. One use is the collection of vacation photos. Since the remote station is extremely portable, it is convenient for a vacationer to pack the remote station and carry it on their travels. When the capture of an image is desired, the vacationer activates remote station  12  using command input device  32 , captures the image and, if image memory  24  is full, transmits images back to server station  14 . This allows the vacationer to take as many pictures as desired without worrying about running out of film or image memory capacity, or needing to carry around sufficient memory to hold all the images from an entire trip. 
     Another application in television reporting. A field reporter could use the remote station to capture images at the scene of a news event and have those images transmitted to a server station controlled by the television studio, thus allowing up-to-the-minute news photos without requiring expensive and bulky equipment such as is now required in a news van. 
     In a typical operation, display  30  indicates the amount of free space remaining in image memory  24 . When the user decides to free up additional memory by transmitting images already stored in image memory  24 , the user initiates a command sequence using command input device  32 . This begins the process of CPU  22  dialing a cellular number for server station  14  or otherwise setting up the link between remote station  12  and server station  14 . CPU  22  then packages an image as required by the protocols, encryption or mailing procedures and directs the package as needed and flags the images in image memory  24  as being sent. One method for labeling images as being sent is to include a binary flag for each block of image memory  24  available for images. As an image is captured by capture device  20 , the flag is set to indicate that the block is in use. As an image is transmitted by CPU  22 , the flag is reset to indicate that the block is again available for image storage. 
     One application in which the present invention finds a use is in-field stereo image capture. With in-field stereo image capture, a camera is on location capturing an image and the server is processing the images. One problem with developing high quality stereo reconstructions is accuracy in image areas where the scene geometry changes quickly, i.e., sharp edges. The need for increased accuracy can be accommodated by capturing more images where needed to increase accuracy. Unfortunately, in the prior art, a photographer would either have to return from a site to process the images to determine if any more images are needed, often necessitating a second trip to the site, or have take the image processing computers to the site. With the present invention, images can be captured and sent to the server for processing with the server interactively responding with requests for the additional images. Thus, the server would process the captured images to determine if a good stereo image can be created. If portions of the stereo image are unacceptable, the server can signal, via the digital still video camera, the photographer to capture additional images. 
     Face recognition is a similar example. The capture device and the server could cooperate to interactively perform stereo matching, with the server requesting additional captures to improve face recognition. This would overcome the need for subjects to have stereo photographs stored in a laboratory. 
     Another use of the present invention is to obtain photocopies in locations, such as libraries, where it is not convenient to bring the item to be copied to a photocopy machine. At photocopier resolutions, a single uncompressed page image might require about 15 megabits of memory (1 bit/pixel ×400 dpix×8.5″×11″=1496 mbit). In order to reduce the memory requirements, the image can be compressed at the DSVC, but this requires considerable computation power at the DSVC. With the present invention, a low resolution image (e.g., 100 dpi) can be captured and sent to the server station. The server station then analyzes the low resolution image and identifies all white or black areas of the image as well as boundaries of the areas. To convert to a higher resolution image, the server represents each low resolution pixel with sixteen high resolution pixels. Where the image is all black or all white the high resolution pixels are correctly colored, while the blocks of sixteen high resolution pixels near an edge might not all be one color. To refine these areas, the server station sends image capture instructions to the DSVC instructing it to capture additional information from the edge areas. 
     Once the image is created at the server station with the desired high resolution, it can be sent to an printer or facsimile machine, typically one located near the user of the DSVC. A user of the DSVC desiring a photocopy could then indicate, using command input  32 , the telephone number of a nearby facsimile machine. The DSVC would then obtain a low resolution image of the page of which a hard copy is desired, and send a low resolution image to server station  14 . Server station  14  then determines the areas of the image for which additional information is needed. Server station  14  communicates the locations of those areas on the image and the DSVC recaptures those areas of the image. The increased resolution required for the high resolution image can be obtained by using a higher resolution lens on the DSVC, or simply capturing multiple images at low resolution and averaging. The resulting image can be compressed by server station  14  if the printing device is a facsimile machine, so that server station  14  need only transmit a compressed facsimile file. Alternatively, server station  14  can retransmit the compressed file to remote station  12 , which would then dial the facsimile machine directly through cellular telephone network  16 . 
     In  FIG. 1 , CPU  52  is shown connected to external printing devices  70 , which could be facsimile machines, printers, or digital copiers. Other variations include the external printing devices  70  coupled to cellular telephone network  16 , especially in the case of the external printing device being a facsimile machine. External printing device  70  might also be coupled directly to remote station  12 . If the size and weight of remote station  12  is not too constrained, a printer might be included thereon. If desired, remote station  12  can be configured to display the captured image on display  30  or in a viewfinder of camera  20 . 
     Yet another application is stereoscopic matching. Suppose remote station  12  is carried by a geologist who is backpacking to a remote region and desires to capture three-dimensional (3D) images of a landscape. Stereoscopic images are formed from two images of one scene taken at slight offset of each other. In many stereoscopic systems, the precise relative position of the camera between the two images is needed. However, it is now possible to perform stereographic “matching” (alignment of the two images to create the 3D effect) without alignment information. One such system is the C3D technology sold by The Turing Institute of Glasgow, Scotland. Combining that system with the present invention, the geologist could upload the dual images and have a C3D system at the server station immediately evaluate the images to determine if a lock on a 3D image can be made. If not, the server station sends a message to the geologist to reposition the camera and recapture an image, thus avoiding a second trip to the site for image capture. 
     The above description is illustrative and not restrictive. Many variations of the invention will become apparent to those skilled in the art upon review of this disclosure. For example, the server station  14  can be either a stationary system or a semi-portable system, so long as it need not be as portable as remote station  12 . Also, the remote station  12  might be controlled from server station  14  by allowing remote station  12  to receive command messages from server station  14  over cellular system  16 . The scope of the invention should, therefore, be determined not with reference to the above description, but instead should be determined with reference to the appended claims along with their full scope of equivalents.