Digital camera device providing improved methodology for rapidly taking successive pictures

• US 8,564,683 B2
• Filed: 12/06/2010
• Issued: 10/22/2013
• Est. Priority Date: 01/21/2000
• Status: Active Grant

• Current Assignee: RPX Corporation
• Original Assignee: VeriSign, Inc.
• Inventors: Bodnar, Eric O., Easwar, Venkat V.
• Primary Examiner(s): NGUYEN, LUONG TRUNG
• Application Number:
  US12/961,397
• Publication Number:
  US 20110128403A1
• Time in Patent Office: 1,051 Days
• Field of Search: None
• US Class Current: 348/222.1
• CPC Class Codes: G06T 9/007 Transform coding, e.g. discrete cosine transform
• CPC Class Codes: H04N 1/2112 using still video cameras
• CPC Class Codes: H04N 1/46 Colour picture communication systems
• CPC Class Codes: H04N 1/64 Systems for the transmission or the storage of the colour picture signal; Details therefor, e.g. coding or decoding means therefor H04N19/00 takes precedence
• CPC Class Codes: H04N 2201/3247 Data linking a set of images to one another, e.g. sequence, burst or continuous capture mode

Abstract

An in-camera two-stage compression implementation is described that reduces the latency between snapshots to a fraction of that otherwise required by other systems that either process complete compression following each snapshot or that incorporate heavy, bulky, and expensive RAM hardware capable of maintaining several raw luminosity records (unprocessed file containing a digital image). In the 1st stage compression the raw luminosity record is quickly, yet partially, compressed to available RAM buffer space to allow a user to expeditiously capture a succeeding image. When the higher-priority processes, the user shooting pictures, and stage one compression subside, a 2nd stage compression, which is slower but more effective, decompresses the earlier partially-compressed images, and re-compresses them for saving in flash memory until they are distributed to a remote platform to be finally converted to the JPEG2000 format.

Claims

1. A method comprising:

receiving a digital image;

applying a first fast compression technique to the digital image to temporarily compress the digital image, the first fast compression technique occurring in a high-priority thread in a multi-threaded execution environment;

storing the digital image in an image buffer;

deferring a second thorough compression of the digital image to a period of time after tasks in the high-priority thread have been processed in the multi-threaded execution environment; and

decompressing the digital image that was temporarily compressed, and applying the second thorough compression technique to the digital image, on a low-priority thread subordinate to a high-priority thread at the period of time.

2. The method of claim 1, wherein the first fast compression technique requires fewer processing resources for completion than the second thorough compression technique.

3. The method of claim 1, further comprising:

receiving a sequence of digital images;

applying the first fast compression technique to at least a subset of the sequence of the digital images.

4. The method of claim 3, wherein the sequence of digital images comprises a series of images captured in rapid succession.

5. The method of claim 1, further comprising:

deleting the received digital image, after the digital image is temporarily compressed and the temporarily compressed digital image is stored in the image buffer.

6. The method of claim 1, further comprising after the digital image is temporarily compressed:

storing a compressed file of a given digital image in a RAM buffer, and

transferring the compressed file from the RAM buffer to flash memory.

7. The method of claim 6, wherein the compressed file is transferred when the RAM buffer is nearly exhausted.

8. The method of claim 1, further comprising:

receiving the digital image as a luminosity record; and

applying pre-compression to each luminosity record, in preparation for compression.

9. The method of claim 8, wherein the pre-compression comprises selected ones of noise smoothing and de-mosaicing.

10. The method of claim 1, further comprising:

determining whether additional images are being received; and

deferring the second thorough compression to a period of time when no additional images are being received.

11. A device comprising:

an image capturing system for capturing a digital image to an image buffer;

a first rapid compression module for temporarily compressing the digital image upon capture, thereby freeing up available storage in the image buffer, wherein the first rapid compression module occurs in a high-priority thread;

a decompression module to decompress the temporarily compressed digital image at a period of time after tasks that occur in the high-priority thread have been processed; and

a second thorough compression module for compressing, at the period of time, the digital image more thoroughly than that provided by the first rapid compression module, wherein a thorough compression occurs in a low-priority thread subordinate to the high-priority thread.

12. The device of claim 11, wherein the low-priority thread of compressing more thoroughly occurs after tasks in the high-priority thread have been processed in a multi-threaded execution environment.

13. The device of claim 11, wherein the first rapid compression module employs a relatively-fast compression technique that requires fewer processing resources for completion than the second thorough compression module.

14. The device of claim 11, wherein the device supports multithreaded execution and wherein the second thorough compression module employs a compression technique that operates as a background execution thread.

15. The device of claim 11, wherein the digital image is one of a series of digital images, and at least some of the series of digital images comprises successive pictures rapidly captured.

16. The device of claim 11, further comprising:

a RAM buffer for storing a given digital image that has been temporarily compressed.

17. The device of claim 11, wherein the digital image is deleted from the image buffer after the digital image is temporarily compressed and the temporarily compressed digital image is stored in the image buffer.

18. The device of claim 11, wherein the first rapid compression module further includes a module to apply pre-compression to an image captured as a luminosity record, in preparation for compression.

19. The device of claim 18, wherein the pre-compression comprises selected ones of noise smoothing and de-mosaicing.

20. A digital camera system comprising:

an image capturing system for capturing a plurality of digital images;

an image buffer to temporarily store the plurality of digital images;

a first rapid compression module for temporarily compressing at least one of the plurality of digital images and store the temporarily compressed images in the image buffer, wherein the compression of the at least one of the plurality of digital images occurs in a high-priority thread in a multi-threaded execution environment;

a decompression module to decompress the temporarily compressed digital images at a period of time after tasks that occur in the high-priority thread have been processed; and

a second thorough compression module for compressing the plurality of digital images more thoroughly, at a later time when no images are being captured, wherein the second compression occurs in a low-priority thread in the multi-threaded execution environment.