Image block classification
AssigneeTelefonaktiebolaget L M Ericsson (publ)
InventorsJonatan Samuelsson, Kenneth Andersson, Clinton Priddle
Life of this patent
Estimating the term…
Abstract
An image processing method involves determining a global motion between a reference frame and a current frame in a frame sequence. A reference block is identified in the reference frame for a current block based on the global motion. A classification parameter is calculated based on the pixel values of the current block and the reference block. The parameter can be used for classifying the block as belonging to the background or foreground of the current frame. The parameter is preferably also utilized in frame rate-up conversion when extrapolating or interpolating new frames.
Claims23
An image processing method applicable to a frame sequence comprising multiple frames, each frame comprising multiple groups of image elements, said method comprising the steps of:
- determining a representation of a global motion of image element property values from at least a reference portion of a reference frame (20) to at least a portion of a frame;
- identifying, for a first group of at least one image element in said frame, a first reference group of at least one image element in said reference frame based on said global motion representation;
- and
- calculating a first classification parameter as being representative of a difference in image element property values of said first group and said first reference group;
- identifying a second reference group of at least one image element in said reference frame based on a displacement vector associated with said first group;
- identifying a second group of at least one image element in said frame based on said global motion representation and said second reference group;
- and
- calculating a second classification parameter representative of a difference in image element property values of said second reference group and said second group, said first classification parameter and said second classification parameters are indicative of whether said first group belongs to a foreground or a background of said frame
A method of estimating property values of a group of at least one image element in a frame associated with a time instance in a video sequence, said method comprising the steps of:
- providing a first set of multiple first candidate groups in a first frame associated with a first different time instance in said video sequence, each first candidate group comprises at least one image element and is associated with a respective first displacement vector;
- for each first candidate group in said first set:
- determining a respective first classification parameter and a respective second classification parameter;
- identifying a respective second group of at least one image element in a second frame associated with a second different time instance in said video sequence;
- and
- calculating a respective measure representative of a difference in property values of the respective first candidate group and said respective second group identified for said respective first candidate group;
- selecting a first candidate group of said first set based on said respective measures, said respective first classification parameters and said respective second classification parameters;
- and
- determining said property value of said group based on the property values of said selected first candidate group and the respective second group associated with said selected first candidate group.
An image processor applicable to a frame sequence comprising multiple frames, each frame comprising multiple groups of image elements, said processor comprising:
- a global motion determiner for determining a representation of a global motion of image element property values from at least a reference portion of a reference frame to at least a portion of a frame;
- a group identifier for i) identifying, for a first group of at least one image element in said frame, a first reference group of at least one image element in said reference frame based on said global motion representation, ii) identifying a second reference group of at least one image element in said reference frame based on a displacement vector associated with said first group, and iii) identifying a second group of at least one image elements in said frame based on said global motion representation and said second reference group;
- and
- a calculator for i) calculating a first classification parameter as being representative of a difference in image element property values of said first group and said first reference group and ii) calculating a second classification parameter representative of a difference in image element property values of said second reference group and said second group, said first classification parameter and said second classification parameter are indicative of whether said first group belongs to a foreground or a background of said frame.
A device for estimating property value of a group of at least one image element in a frame associated with a time instance in a video sequence, said device comprising:
- a set provider for providing a first set of multiple first candidate groups in a first frame associated with a first different time instance in said video sequence, each first candidate group comprises at least one image element and is associated with a respective first displacement vector;
- an image processor for calculating a respective first classification parameter and a respective second classification parameter for each first candidate group in said first set;
- a group identifier for identifying, for each first candidate group in said first set, a respective second group of at least one image element in a second frame associated with a second different time instance in said video sequence;
- a measure calculator for calculating, for each first candidate group in said first set, a respective measure representative of a difference in property values of the respective first candidate group and said respective second group identified by said group identifier for said respective first candidate group;
- a group selector for selecting a first candidate group based on said respective measures, said respective first classification parameters and said respective second classification parameters;
- and
- a value determiner for determining said property value of said group based on the property values of said selected first candidate group and the respective second group associated with said selected first candidate group.
Dependencies are inferred from the claim text.