WO2005025205A1

WO2005025205A1 - Method and apparatus for storing digital images

Info

Publication number: WO2005025205A1
Application number: PCT/IB2004/051590
Authority: WO
Inventors: Brian P. Griffiths; David W. Myers
Original assignee: Koninklijke Philips Electronics N.V.
Priority date: 2003-09-04
Filing date: 2004-08-27
Publication date: 2005-03-17
Also published as: GB0320701D0

Abstract

The invention provides methods and apparatus for storing still digital images in video recording apparatus. In accordance with the invention tiles representing fractions of the image are converted to video frames and stored as a video stream. By including with the frames reference data defining the sequence in which the tiles must be assembled to reproduce the image, a reproduction of the original image can be created from the video frames.

Description

DESCRIPTION

METHOD AND APPARATUS FOR STORING DIGITAL IMAGES This invention relates to the storing of still digital images. In particular the invention relates to a method for storing still digital images on equipment conventionally used to store video data.

It is well known to store high resolution still digital images, for example those captured by digital cameras, in a compressed image file (e.g. in the JPEG format) on a hard disk of a PC/MAC platform. Such files can then be later retrieved for subsequently viewing, editing, distribution and printing. With more computing functionality now being provided on PC/MAC platforms (such as digital TV receivers and portable devices such as mobile phones, PDAs and the like), the consumer has become less reliant on a home PC/MAC platform to receive, access and view information and images. Thus, the need to retain a PC/MAC platform for storage of information and images is increasingly inconvenient for the consumer. The present invention aims to provide a method and apparatus for storing high resolution digital still images which does not require the use of a PC/MAC platform.

In accordance with a first aspect, the present invention provides a method for converting a still digital image to a sequence of video frames for recording on a video recording apparatus comprising the steps of ; i) dividing the image into a plurality of image tiles; and ii) representing each tile as a video frame. The method may further include the step of: iii) associating with one or more of the tiles identification data which defines the order in which the tiles must be assembled to recreate the image. The method may further include the step of; iv) transmitting the video frames of step iii) to a video recording apparatus and configuring the video recording apparatus to record the video frames. In accordance with a second aspect, the invention provides a method for representing a sequence of video frames as a single still image for display or printing comprising the steps of; v) identifying a sequence of video frames to be represented as parts of single image; vi) tiling the images represented in the sequence of frames in a predetermined order to provide a single image; and vii) configuring the single image of step vi) in a form which may be displayed or printed. It will be appreciated that the series of video frames may be recorded by the video recording apparatus using conventional technology. The identification data defines the sequence in which the individual video frames are to be retrieved and the position of each tile of the complete image relative to the others. Thus, the tiled image can be stored as a series of video frames and the original image reproduced by tiling images from the individual video frames in sequence. Retrieval of the video frames in the defined sequence results in a gradual recreation of the original image which can be displayed through conventional means, for example on a TV screen. If desired, the recreated images could be printed from screen or directly from the recording apparatus using stand alone printers. For example, a still digital image may be captured by a digital camera and stored in JPEG format. The JPEG file, by application of the method of the invention, can be stored as a series of MPEG frames of an MPEG file on disc or tape using conventional video recording techniques. When it is desired to reproduce the original image, whether on a display screen or by printing, the images represented in the MPEG file can be reassembled (using the identification data to define the correct order in which the images are to be assembled) creating a new JPEG file for display or printing by conventional techniques. Whilst an advantage of the invention is that it eliminates the need for a PC/MAC to store and reproduce a still digital image, it is to be understood that the method could still be employed to store digital still images in such media. In another aspect, the invention provides an apparatus for converting a still digital image to a sequence of video frames for storage comprising; means for receiving digital data defining the still digital image; means for dividing the image into a plurality of image tiles; and means for associating with one or more of the tiles identification data which data defines the order in which the tiles must be assembled to recreate the image; means for representing each tile as a video frame; and means for transmitting the video frames to a video recording apparatus. Optionally, the apparatus includes or is embodied in a video recording apparatus. In an alternative option, the apparatus is embodied in a digital camera. In a further alternative option, the device is embodied in a TV receiving apparatus. Optionally, the apparatus further includes a printer, preferably a stand alone printer. The video recording apparatus may be any device capable of storing video images on magnetic or optical media, for example (but not strictly limited to) a digital video tape recorder or a DVD recorder. The identification data is conveniently in the form of meta data, a meta tag being associated with one or more of the tiles. The data may take the form of binary encoded imagery similar to that used with teletext. In contrast to teletext data, the imagery may be encoded into the video frame. The identification data may be adopted from standards or may be bespoke for a given image. Optionally identification data is associated with a single tile only, the single tile providing a reference frame for the sequence of frames. For example, for all images, the top left hand corner tile may be tagged to provide a reference frame. In such an embodiment, standard protocols may be used to define the sequence in which frames must be recorded and the tiles reassembled to reproduce the original image. The means for dividing, means for associating and means for representing conveniently are provided in the form of a suitably programmed microprocessor, optionally embodied on a chip. The chip may be introduced into existing equipment (e.g. cameras, VTR, DVD-R or printers) as an add-on. The means for receiving and means for transmitting may comprise conventional means, for example one or more bus ports and optical or electrical cable. Wireless technologies may also be employed in such means. Desirably, there is also associated with one or more tiles a colour test pattern containing colour balance information. When an image is reassembled this colour balance information may be used to identify colour discrepancies between individual video frames which may have been introduced during the recording process. Using suitable algorithms, corrections can be made to the video frames to remove these discrepancies so as to produce a high quality reproduction of the original image. Tiles are conveniently rectangular in shape to conform with the shape of a standard video frame, although it is conceivable that other shapes could be used. The size and number of tiles can be selected according to the desired quality of the recorded image. It will be appreciated that larger numbers of smaller tiles may be needed to record high resolution images and produce high quality image reproductions.

By way of example, an embodiment of the invention will now be further described with reference to the following figures in which: Figure 1 illustrates a still digital image divided into tiles in accordance with the first step of the method of the invention. Figure 2 illustrates a sequence of video frames representing the tiles of Figure 1 . Figure 3 illustrates an embodiment of an apparatus in accordance with the invention Figure 4 illustrates the method of one aspect of the invention in the form of a flow chart. Figure 5 illustrates the method of a second aspect of the invention in the form of a flow chart.

Figure 1 illustrates a still digital image 1 for example a real life image captured using a digital camera. As can be seen the image can be tiled into twelve similar shaped and sized rectangular tiles T1 , T2, T3, T12 having an aspect ratio similar to that of a video frame. Figure 2 illustrates a series of video frames F1 , F2, F3, F4 F12 provided by applying the method of the first aspect of the invention. The frames are ordered in a sequence which follows rows from the top left hand corner, ending at the bottom right corner. In the arrangement shown, the identification data each frame may, for example include a grid reference defining the row and column position of the corresponding tile in a grid representing the original still image. In such an embodiment, the grid reference for frame F1 might be (1 , 1), for frame F2 (1 ,2) for F4 (2,1), for F9 (3, 3) and so on and so forth. Figure 3 illustrates an embodiment of a system incorporating apparatus in accordance with the invention. The figure shows a digital camera 4, a DVD recorder 2 and a stand alone printer 3. The DVD recorder includes a chip 2a programmed to perform the methods of the invention. The chip 2a is able communication with the camera 4 and printer 3 by means of cables 5a, 5b connected to the respective devices via conventional bus ports (not shown). In use the camera 4 captures a digital still image, for example in JPEG format. The file is downloaded to the chip 2a in the DVD-R 2 where the method of the first aspect of the invention is performed. The video frames produced are recorded onto a DVD using conventional recording techniques. When it is desired to reproduce the image, the chip, applying the second aspect of the invention produces a new JPEG file which is transmitted to the printer 3 via cable 5b. The new JPEG file is printed using conventional techniques. Figures 4 and 5 illustrates steps S1 to S10 which may be performed in exemplary methods in accordance with the invention. Steps S1 to S5 relate to the conversion of the still image and recording of the frames. Steps 6 to 10 relate to the retrieval of the frames, reassembly and reproduction of the image. Step S1 in Figure 4 involves the receiving of the original image and dividing it into an appropriate number of tiles. Step S2 involves associating with the tiles identification date which defines the sequence in which the tiles must be assembled to reproduce the image. Step S3 involves the representation of each tile as a video frame, for example by saving the data in MPEG format. In Step S4, the video frames are transmitted to a suitable video recording apparatus. In step S5, the video frames are recorded onto a storage medium using conventional techniques. In Figure 5, Step S6 involves identifying a reference frame. Conveniently, the reference frame may correspond to the first frame to be positioned in a reference grid. For example frame F1 with grid reference (1 ,1). With the reference frame identified, Step S7 involves assembly of the images represented in the frames in the appropriate sequence. Step S8 corresponds to a colour matching exercise where discrepancies in colour between frames which may have occurred during the recording of the frames are identified. In step S9, colour discrepancies are corrected for. It will be appreciated that steps S8 and S9 may be performed prior to Step S7 Finally, in Step S 10, the reassembled image is represented in a format (eg a new JPEG file) suitable for display or printing using conventional techniques. In respect of some video encoding formats including MPEG, it may be necessary to present the tiles to the recording device for a distinct period of time so as to enable the still images to 'saturate' the MPEG encoder and be recorded without such a sequence blurring together.

Claims

1. A method for converting a still digital image to a sequence of video frames for recording on a video recording apparatus comprising the steps of; i) dividing the image into a plurality of image tiles; and ii) representing each tile as a video frame.

2. The method of claim 1 further comprising the step of iv) transmitting the video frames of step ii) to a video recording apparatus and configuring the video recording apparatus to record the video frames.

3. The method of claim 1 further comprising the step of: (iii) associating with one or more of the tiles identification data which defines the order in which the tiles must be assembled to recreate the image.

4. The method of claim 3 wherein the identification data is provided in the form of meta data.

5. The method of claims 3 wherein identification data is associated with only one tile.

6. The method of claim 3 or 4 wherein the meta data comprises binary encoded imagery.

7. A method for representing a sequence of video frames as a single still image for display or printing comprising the steps of; v) identifying a sequence of video frames to be represented as parts of single image; vi) tiling the images represented in the sequence of frames in a predetermined order to provide a single image; and vii) configuring the single image of step vi) in a form which may be displayed or printed.

8. A method as claimed in claim 7 further comprising the steps of identifying colour discrepancies between frames and correcting the discrepancies.

9. An apparatus for converting a still digital image to a sequence of video frames for storage comprising; means for receiving digital data defining the still digital image; means for dividing the image into a plurality of image tiles; and means for associating with one or more of the tiles identification data which data defines the order in which the tiles must be assembled to recreate the image; means for representing each tile as a video frame; and means for transmitting the video frames to a video recording apparatus.

10. An apparatus as claimed in claim 9 wherein the means for dividing, means for associating and means for representing are provided in the form of a suitably programmed microprocessor.

11. An apparatus as claimed in claim 9 or 10 embodied in a digital camera.

12. An apparatus as claimed in claim 9 or 10 embodied in a video recording apparatus.

13. An apparatus as claimed in any of claims 10 to 13 further including a printer.