METHOD AND APPARATUS FOR RECORDING IMAGE DATA

• US 20080018746A1
• Filed: 07/17/2007
• Published: 01/24/2008
• Est. Priority Date: 07/19/2006
• Status: Active Grant

• Current Assignee: PENTAX RICOH IMAGING COMPANY, LTD.
• Original Assignee: Pentax Corporation (Hoya Corporation)
• Inventors: KAWANAMI, Naoto
• Granted Patent: US 8,009,924 B2
• Time in Patent Office: Days
• US Class Current: 348/207.99
• CPC Class Codes: H04N 1/2112 using still video cameras
• CPC Class Codes: H04N 19/12 Selection from among a plurality of transforms or standards, e.g. selection between discrete cosine transform [DCT] and sub-band transform or selection between H.263 and H.264
• CPC Class Codes: H04N 19/15 by monitoring actual compressed data size at the memory before deciding storage at the transmission buffer
• CPC Class Codes: H04N 19/172 the region being a picture, frame or field
• CPC Class Codes: H04N 2101/00 Still video cameras
• CPC Class Codes: H04N 5/772 the recording apparatus and the television camera being placed in the same enclosure
• CPC Class Codes: H04N 9/7921 for more than one processing mode

Abstract

An apparatus for recording image data has an encoding processor that compresses original image data (for example, RAW data), having a plurality of pixels, in accordance with a lossless compression coding; and a recording processor that records the compressed image data or the original image data into a memory. If the size of the compressed image data is larger than that of the original image data, the recording processor records the original image data into the memory without carrying out a compression process.

Claims

1. An apparatus for recording image data comprising:

an encoding processor that compresses original image data having a plurality of pixels in accordance with a lossless compression coding; and

a recording processor that records the compressed image data or the original image data into a memory, said recording processor recording the original image data into said memory without carrying out a compression process if the size of the compressed image data is larger than that of the original image data.

2. The apparatus of claim 1, further comprising a first determiner that determines whether the size of the compressed image data that is obtained by actually compressing the original image data is larger than the size of the original image data,

wherein said recording processor records the actually compressed image data into said memory if the size of the compressed image data is not larger than that of the original image data, whereas said recording processor records the original image data if the size of the compressed image data is larger than that of the original image data.

3. The apparatus of claim 1, further comprising:

an extracting processor that extracts a part of the original image data to form a partial image data;

a preliminary encoder that encodes the partial image data in accordance with the lossless coding to generate partially-compressed image data;

a calculator that calculates an estimated size of the compressed image data, corresponding to the actual amount of compressed image data, from the size of the partially-compressed image data on the basis of the correspondence relationship between the partial image data and the original image data; and

a second determiner that determines whether the estimated size of the compressed image data is larger than the size of the original image data,

wherein said recording processor records the compressed image data into said memory if the estimated size of the compressed image data is not larger than that of the original image data, whereas said recording processor records the original image data if the estimated size of the compressed image data is larger than that of the original image data.

4. The apparatus of claim 3, wherein said calculator calculates the estimated size of compressed image data on the basis of the image-size ratio of the partially-compressed image data and the original image data.

5. The apparatus of claim 3, wherein said extracting processor divides the original image data into a plurality of blocks, and extracts a part of the blocks such that the extracted part of the blocks has a correlation relationship relative to the original image data.

6. The apparatus of claim 3, wherein said extracting processor carries out a down sampling.

7. The apparatus of claim 1, wherein said encoding processor carries out an entropy coding.

8. The apparatus of claim 1, wherein said encoding processor encodes a difference value between neighboring pixels.

9. The apparatus of claim 1, wherein a color filter, having a plurality of color element, is provided on an image sensor, said recording processor encodes a difference value between neighboring pixels, which are opposite elements of the same color.

10. A computer readable medium that stores a program for recording image data, comprising:

an encoding code segment for compressing original image data having a plurality of pixels in accordance with a lossless compression coding; and

a recording code segment for recording the compressed image data or the original image data into a memory, said recording code segment recording the original image data into said memory without a compression process if the size of the compressed image data is larger than that of the original image data.

11. A method for recording image data comprising:

compressing the original image data, having a plurality of pixels, in accordance with a lossless compression coding;

determining whether the size of the compressed image data is larger than that of the original image data; and

recording the original image data into said memory without carrying out a compression process if the size of the compressed image data is larger than that of the original image data.

12. A digital camera comprising:

an image sensor;

an exposure controller that carries out a photographing action to form an object image on said image sensor;

a signal processor that processes image-pixel signals from said image sensor to generate original image data having a plurality of pixels;

an encoding processor that compresses the original image data in accordance with a lossless compression coding; and

a recording processor that records the compressed image data or the original image data into a memory, said recording processor recording the original image data into said memory without carrying out a compression process if the size of the compressed image data is larger than that of the original image data.

13. The digital camera of claim 12, wherein said camera is capable of shooting continuously to obtain a series of captured images, said recording processor recording the original image data or the compressed image data based on a first-captured image, said recording processor recording the remaining images so as to be similar to the firstly captured image.