Stereo image encoding apparatus, its method, and image pickup apparatus having stereo image encoding apparatus

• US 8,983,217 B2
• Filed: 04/26/2012
• Issued: 03/17/2015
• Est. Priority Date: 05/17/2011
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Sakamoto, Daisuke, Otsuki, Jun
• Primary Examiner(s): BEKELE, MEKONEN T
• Application Number:
  US13/456,798
• Publication Number:
  US 20120294546A1
• Time in Patent Office: 1,055 Days
• Field of Search: 382/233, 382/246, 382/236, 382/238, 375/240.12, 375/240, 375/240.15, 375/506, 375/240.16, 375/240.18, 375/240.08
• US Class Current: 382/238
• CPC Class Codes: H04N 13/161 Encoding, multiplexing or demultiplexing different image signal components for multi-view video sequence encoding H04N19/597
• CPC Class Codes: H04N 19/56 Motion estimation with initialisation of the vector search, e.g. estimating a good candidate to initiate a search
• CPC Class Codes: H04N 19/57 Motion estimation characterised by a search window with variable size or shape
• CPC Class Codes: H04N 19/597 specially adapted for multi-view video sequence encoding
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 2013/0081 Depth or disparity estimation from stereoscopic image signals

Abstract

When a plurality of image signals of an object picked up by a plurality of image pickup units are encoded on a predetermined pixel block basis by using an inter-prediction between images, difference information showing an offset between the images is generated from the plurality of image signals, and a search range which is set in order to detect a vector on the predetermined pixel block basis is adaptively set in accordance with the generated difference information.

Claims

1. An image encoding apparatus comprising:

an input unit configured to input a first image data corresponding to one of a left eye image and a right eye image and a second image data corresponding to another of the left eye image and the right eye image;

a detection unit configured to detect a parallax vector of an encoding-subject block of the second image,

wherein the detection unit detects the parallax vector of the encoding-subject block of the second image data by using image data of a search range in a reference picture of the first image data;

an encoding unit configured to obtain prediction image data from the reference picture of the first image data in accordance with the parallax vector detected by the detection unit and encode the encoding-subject block of the second image data by using the prediction image data;

a controlling unit configured to detect a difference value between the image data of the encoding-subject block of the second image data and the image data at a position corresponding to that of the encoding-subject block in the reference picture of the first image data and set the search range in the reference picture of the first image data for detecting the parallax vector by the detection unit in accordance with the detected difference value;

wherein the controlling unit changes a size of the search range in accordance with the difference value, and

wherein the detection unit detects the parallax vector of the encoding-subject block of the second image data by using the image data of the search range, which is set by the controlling unit, in the reference picture of the first image data.

2. An apparatus according to claim 1, wherein when the difference value is larger than a threshold value, the controlling unit sets the size of the search range to a first size, and when the pixel difference value is equal to or less than the threshold value, the controlling unit sets the size of the search range to a second size smaller than the first size.

3. An apparatus according to claim 2, wherein the controlling unit controls the detection unit so that the number of times of search for detecting the parallax vector of the encoding-subject block is a predetermined value irrespective of the size of the search range.

4. An apparatus according to claim 1, wherein when the difference value is larger than a threshold value, the controlling unit controls the detection unit so as to roughly search the set search range, and when the difference value is equal to or less than the threshold value, the controlling unit controls the detection unit so as to finely search the set search range.

5. An image encoding apparatus comprising:

an input unit configured to input a first image data corresponding to one of a left eye image and a right eye image and a second image data corresponding to another of the left eye image and the right eye image;

a detection unit configured to detect a parallax vector of an encoding-subject block of the second image,

wherein the detection unit detects the parallax vector of the encoding-subject block of the second image data by using image data of a search range in a reference picture of the first image data;

an encoding unit configured to obtain prediction image data from the reference picture of the first image data in accordance with the parallax vector detected by the detection unit and encode the encoding-subject block of the second image data by using the prediction image data;

a controlling unit configured to detect a difference value between the image data of the encoding-subject block of the second image data and the image data at a position corresponding to that of the encoding-subject block in the reference picture of the first image data and set the search range in the reference picture of the first image data for detecting the parallax vector by the detection unit in accordance with the detected difference value;

wherein the controlling unit sets the search range at a first position in the reference picture of the first image data if the difference value is equal to or less than a threshold value, and sets the search range at a second position different in a horizontal direction from the first position if the difference value is larger than the threshold value, and

wherein the detection unit detects the parallax vector of the encoding-subject block of the second image data by using the image data of the search range, which is set by the controlling unit, in the reference picture of the first image data.