Moving image region detection device

Patent metadata

Field	Value
Publication number	US-9367927-B2
Application number	US-201214131417-A
Country	US
Kind code	B2
Filing date	May 10, 2012
Priority date	Jul 13, 2011
Publication date	Jun 14, 2016
Grant date	Jun 14, 2016

Abstract

The moving image region detection device includes an updated block detection means, a natural image updated block determination means, and a moving image block extraction means. The updated block detection means compares pixel values between a frame of an input video and the previous frame, and detects a block including a pixel in which a value having been changed, as an updated block. The natural image updated block determination means calculates an index value representing a degree of continuity of changes in pixel values in the updated block, compares the calculated index value with a threshold, and determines whether it is an updated block of a natural image. The moving image block extraction means extracts a block determined to be an updated block of a natural image a given number of times or more in most recent frames including the frame, as a moving image block of a natural image.

First claim

The invention claimed is:

1. A moving image region detection device, comprising:
a memory containing program instructions; and
a processor coupled to the memory, wherein the processor is configured to execute the program instructions to:
compare, with respect to a frame of an input video, pixel values between the frame and a previous frame of the frame;
detect, from among a plurality of blocks formed by dividing the frame into blocks, a block including a pixel in which a value has been changed as an updated block;
calculate, with respect to the updated block of the frame, an index value representing a degree of continuity of changes in pixel values in the updated block;
compare the calculated index value with a threshold;
determine whether or not the updated block is an updated block of a natural image;

extract, with respect to the frame, a block determined to be an updated block of a natural image a given number of times or more in a plurality of most recent frames including the frame, as a moving image block of a natural image;
link, with respect to the frame, the moving image blocks of a natural image, which are spatially adjacent to each other;
acquire a circumscribed rectangle of the linked moving image blocks of the natural image as a moving image region seed of the natural image;
search for and determine, with respect to four edges on top, bottom, left, and right of the moving image region seed of the natural image, a boundary of the moving image region of the natural image in pixel units;
attempt to expand, in block units, each of the four edges on top, bottom, left, and right of the moving image region of the natural image given in block units;
calculate, with respect to a block which may be newly added to the moving image region of the natural image by expansion, the average number of times that the block has been determined to be an updated block of a natural image within a given number of most recent frames; and
add the block to the moving image region of the natural image if a calculated value exceeds a given value.

2. A moving image region detection device comprising:
a memory containing program instructions; and
a processor coupled to the memory, wherein the processor is configured to execute the program instructions to:
compare, with respect to a frame of an input video, pixel values between the frame and a previous frame of the frame;
detect, from among a plurality of blocks formed by dividing the frame into blocks, a block including a pixel in which a value has been changed as an updated block;
calculate, with respect to the updated block of the frame, an index value representing a degree of continuity of changes in pixel values in the updated block;
compare the calculated index value with a threshold;
determine whether or not the updated block is an updated block of a natural image;
extract, with respect to the frame, a block determined to be an updated block of a natural image a given number of times or more in a plurality of most recent frames including the frame, as a moving image block of a natural image;
link, with respect to the frame, the moving image blocks of a natural image, which are spatially adjacent to each other;
acquire a circumscribed rectangle of the linked moving image blocks of the natural image as a moving image region seed of the natural image; and
search for and determine, with respect to four edges on top, bottom, left, and right of the moving image region seed of the natural image, a boundary of the moving image region of the natural image in pixel units,
wherein searching for and determining a boundary comprises
determining a boundary in pixel units with respect to each of the four edges on top, bottom, left, and right of the moving image region of the natural image given in block units, and
selecting as a moving image region boundary, from among a plurality of lines for one inside block and one outside block of the region boundary given, a line in which non-continuity of changes in pixel values in temporal and spatial directions becomes highest between the outside and the inside of the line.

3. The moving image region detection device, according to claim 2 , wherein
with respect to each of the plurality of the lines, the pixel unit region boundary determination unit calculates a difference D P between a pixel value of the line in the frame and a pixel value of the line in the previous frame, calculates a difference D N between the pixel value of the line in the frame and a pixel value of a line outside the line by one line, calculates a difference D NL between pixel values of the line outside the line by one line in the frame, in a direction parallel to the line, calculates a difference D PN between a pixel value in the frame and a pixel value in the previous frame of the frame, of the line outside the line by one line of the frame, and selects a line in which a value calculated by D N −D NL +D P −D PN becomes maximum as the moving image region boundary.

4. The moving image region detection device, according to claim 1 , wherein the processor is further configured to:
calculate transitions in a spatial direction of pixel values within the frame, and
determine a block in which an average value of the calculated transitions is small to be an updated block of the natural image.

5. The moving image region detection device, according to claim 1 , wherein the processor is further configured to:
calculate transitions in a spatial direction of pixel values within the frame and transitions of pixel values of the same pixels between the frame and the previous frame of the frame, and
determine a block in which an average value of the calculated transitions is small to be an updated block of the natural image.

6. A moving image region detection method, comprising:
comparing, with respect to a frame of an input video, pixel values between the frame and a previous frame of the frame;
detecting, from among a plurality of blocks formed by dividing the frame into blocks, a block including a pixel in which a value has been changed as an updated block;
calculating, with respect to the updated block of the frame, an index value representing a degree of continuity of changes in pixel values in the updated block;
comparing the calculated index value with a threshold;
determining whether or not the updated block is an updated block of a natural image;
extracting, with respect to the frame, a block determined to be an updated block of a natural image a given number of times or more in a plurality of most recent frames including the frame, as a moving image block of a natural image;
linking, with respect to the frame, the moving image blocks of a natural image, which are spatially adjacent to each other;
acquiring a circumscribed rectangle of the linked moving image blocks of the natural image as a moving image region seed of the natural image;
searching for and determining, with respect to four edges on top, bottom, left, and right of the moving image region seed of the natural image, a boundary of the moving image region of the natural image in pixel units;
attempting to expand, in block units, each of the four edges on top, bottom, left, and right of the moving image region of the natural image given in block units;
calculating, with respect to a block which may be newly added to the moving image region of the natural image by expansion, the average number of times that the block has been determined to be an updated block of a natural image within a given number of most recent frames; and
adding the block to the moving image region of the natural image if a calculated value exceeds a given value.

7. A non-transitory computer readable medium having stored thereon a program for causing a c

Assignees

• Takada Jun
• Nec Corp

Inventors

• Takada Jun

Classifications

• G09G2320/103

  Detection of image changes, e.g. determination of an index representative of the image change · CPC title

• H04N19/174

  the region being a slice, e.g. a line of blocks or a group of blocks · CPC title

• H04N19/136

  Incoming video signal characteristics or properties · CPC title

• H04N19/543

  using regions · CPC title

• G06T7/40

  Analysis of texture (depth or shape recovery from texture G06T7/529) · CPC title