Apparatus and method for extracting a portion of an image

• US 5,999,161 A
• Filed: 07/24/1996
• Issued: 12/07/1999
• Est. Priority Date: 07/28/1995
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Kajimoto, Masato, Murase, Hirofumi
• Primary Examiner(s): Hjerpe, Richard A.
• Assistant Examiner(s): NGUYEN, FRANCIS N
• Application Number:
  US08/685,518
• Time in Patent Office: 1,231 Days
• Field of Search: 345/127, 345/129-131, 345/132, 345/203, 345/515, 345/516, 345/118, 345/507-508, 382/198, 382/232-233, 382/300, 382/199, 358/451, 358/470, 358/530, 395/200.77, 395/114, 348/403
• US Class Current: 345/24
• CPC Class Codes: G06T 9/007 Transform coding, e.g. discrete cosine transform

Abstract

An apparatus and method for extracting a desired portion of an image represented by compressed data. The compressed data is expanded in an expanding circuit and outputted therefrom in accordance with clock pulses. Such clock pulses, or data transfers or addresses associated therewith, are counted so as to determine the position of the data. The determined position of the data is compared to the desired portion so as to determine whether the data is within the desired portion. If the data is determined to be within the desired portion, such data is stored in an image memory. As a result, such extraction may be performed without utilizing an additional memory for temporarily storing the expanded data.

Claims

1. A video apparatus comprising:

image expanding means for expanding compressed image data;

an image memory for storing expanded image data;

counter means for counting a number of expanded image data transfers from the image expanding means;

position computing means responsive to an output of said counter means for determining positions of the image data from the image expanding means;

means for designating a part of the image data for display;

means for comparing a respective position of the image data from the image expanding means with positions of image data within the part of the image data designated for display; and

memory control means responsive to an output of the comparing means for controlling said image memory such that the expanded image data from said image expanding means is stored in said image memory when the image data is determined to be within the part designated for display and the expanded image data from said image expanding means is not stored in said image memory when the image data is not determined to be within the part desionated for display.

2. The video apparatus according to claim 1, wherein said memory control means controls said image memory such that the expanded image data from said image expanding means is enlarged or reduced scale only when the expanded image data is determined to be within the part designated for display.

3. A video memory controller for controlling a video memory so as to extract a part of an original picture, said controller comprising:

means for dividing a compressed picture into a plurality of blocks of data;

means for expanding each block of data to an original picture;

counting means for counting each block address of the plurality of blocks;

selecting means for selecting the part of the picture to be extracted;

comparison means for comparing the address from the counting means and the address corresponding to the part selected by the selecting means; and

controlling means for controlling a write operation of the video memory in accordance with the result of said comparison means such that expanded data from the expanding means is stored in said video memory when the data is within the part selected to be extracted and the expanded data from the expanding means is not stored in said video memory when the data is not within the part selected to be extracted.

4. A video memory controller according to claim 3, wherein the controlling means includes means for enlarging or decreasing the size of the extracted picture.

5. A video memory controller according to claim 3, wherein the compressed picture is compressed in accordance with a Joint Photographic Coding Expert Group (JPEG) technique.

6. A video memory controller for controlling a video memory so as to extract a part of an original picture, said controller comprising:

a divider for dividing a compressed picture into a plurality of blocks of data;

an expander for expanding each block of data to an original picture;

a counter for counting each block address of the plurality of blocks;

a selector for selecting the part of the picture to be extracted;

a comparator for comparing the address from the counter and the address corresponding to the part selected by the selector; and

a controller for controlling a write operation to the video memory in accordance with the result of the comparator such that expanded data from the expander is stored in said video memory when the expanded data is within the part selected to be extracted and the expanded data from the expander is not stored in said video memory when the expanded data is not within the part selected to be extracted.

7. Method for extracting a portion of an original picture, said method comprising the steps of:

designating the portion of the original picture to be extracted;

expanding data of a compressed picture to data of the original picture;

counting addresses of the original picture;

comparing the addresses of the original picture and an address corresponding to the portion of the original picture designated to be extracted; and

storing the extracted portion in a memory in accordance with the comparison result such that expanded data is stored in said memory when the expanded data is within the portion designated to be extracted and the expanded data is not stored in said memory when the expanded data is not within the portion designated to be extracted.

8. A method for extracting picture according to claim 7, further comprising the step of enlarging or decreasing the size of the extracted picture.

9. A method for extracting picture according to claim 7, wherein the compressed picture is compressed in accordance with a Joint Photographic Coding Experts Group (JPEG) technique.

10. An apparatus for extracting a portion of an image represented by image data recorded on a recording medium in a compressed form, said apparatus comprising:

image expanding means for expanding the compressed image data;

means for determining positions of the expanded image data;

means for designating the portion of the image to be extracted;

means for comparing a position of a respective expanded image data with image positions of the portion of the image designated to be extracted so as to determine if the respective expanded image data is within the designated portion; and

image memory means for storing the respective expanded image data if the comparing means indicates that the position of the respective expanded image data is within the designated portion and for not storing the respective expanded image data if the comparing means fails to indicate that the position of the respective expanded image data is within the designated portion.

11. An apparatus for extracting a portion of an image represented by compressed image data, said apparatus comprising:

image expanding means for expanding the compressed image data so as to form a plurality of data samples and for outputting each of said data samples in response to a clock pulse;

means for counting the clock pulses so as to determine positions of said data samples;

means for designating the portion of the image to be extracted;

means for comparing a position of a respective data sample with the portion of the image designated to be extracted so as to determine if the respective data sample is within the designated portion; and

image memory means, responsive to an output of the comparing means, for storing the respective data sample if the comparing means indicates that the position of the respective data sample is within the designated portion and for not storing the respective data sample if the comparing means fails to indicate that the position of the respective data sample is within the designated portion.

12. An electronic still camera apparatus for extracting a portion of an image represented by compressed image data, said apparatus comprising:

image expanding means for expanding the compressed image data so as to form a plurality of data samples and for outputting each of said data samples in response to a clock pulse;

means for designating the portion of the image to be extracted;

a memory controller having a write enable signal generating circuit including a counter for counting information associated with the clock pulses, a circuit for determining positions of said data samples based upon the counted clock pulses, and a circuit for comparing a position of a respective data sample with the portion of the image designated to be extracted so as to determine if the respective data sample is within the designated portion and if the position of the respective data sample is within the designated portion for generating a write enable signal, said memory controller further having an address generating circuit receiving an output from said write enable signal generating circuit and said clock pulses for determining address information; and

an image memory for storing the data samples pertaining to the designated portion in response to the write enable signal and at addresses corresponding to the address information.