Stereo image processing device and stereo image processing method

• US 10,009,594 B2
• Filed: 07/04/2013
• Issued: 06/26/2018
• Est. Priority Date: 09/27/2012
• Status: Expired due to Fees

• Current Assignee: Panasonic Intellectual Property Management Co., Ltd. (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Intellectual Property Management Co., Ltd. (Panasonic Holdings Corporation)
• Inventors: Nanri, Takuya, Kurokawa, Hisashi, Ishihara, Takeshi, Nishimura, Hirofumi
• Primary Examiner(s): Dang, Hung
• Application Number:
  US14/431,089
• Publication Number:
  US 20150249814A1
• Time in Patent Office: 1,818 Days
• Field of Search: 386223-224, 386239-248, 386341
• CPC Class Codes: G01B 11/026 by measuring distance between sensor and object G01B11/0608 takes precedence
• CPC Class Codes: G06T 2207/10012 Stereo images
• CPC Class Codes: G06T 2207/20056 Discrete and fast Fourier transform, [DFT, FFT]
• CPC Class Codes: G06T 2207/30261 Obstacle
• CPC Class Codes: G06T 7/593 from stereo images
• CPC Class Codes: H04N 13/106 Processing image signals for multi-view video sequence encoding H04N19/597
• CPC Class Codes: H04N 13/204 using stereoscopic image cameras stereoscopic photography G03B35/00

Abstract

Device (100) comprises: a stereo image acquisition unit (101) for acquiring a standard image and a reference image for a stereo image; an image segmenting unit (102) for acquiring standard pixel data and reference pixel data from the stereo image; a phase correction unit (103) for carrying out for each of the pixel data a phase correction process making the values of the standard pixel data more symmetrical; a windowing unit (104) for applying a windowing function to each of the pixel data that have undergone phase correction; a phase correlation unit 105 for calculating a phase correlation value between the two pixel data that have undergone windowing; and a peak position detection unit (106) for calculating, on the basis of the phase correlation value, the parallax of a corresponding point of the reference image with respect to a standard point on the standard image.

Claims

1. A stereo image processing apparatus comprising:

a stereo image acquiring section that acquires a target image and a reference image of a stereo image;

an image clipping section that clips partial images parallel to a baseline length direction of the stereo image from the target image and the reference image respectively and acquires one-dimensional pixel data sequences each indicating a distribution of pixel values of a corresponding one of the partial images in the baseline length direction;

a target pixel data phase shift section that applies a phase shift filter which shifts phases of some or all frequency components by 90 degrees with respect to the target pixel data and that calculates phase-shifted target pixel data;

a symmetry determination value calculating section that calculates symmetry determination values indicating symmetry of values for the phase-shifted target pixel data and the reference pixel data respectively;

a symmetry determination value comparison section that compares the symmetry determination value calculated from the phase-shifted target pixel data with the symmetry determination value calculated from the target pixel data and that determines whether or not the symmetry of the phase-shifted target pixel data is higher than the symmetry of the target pixel data;

a reference pixel data phase shift section that applies the phase shift filter to the reference pixel data and that calculates phase-shifted reference pixel data,

a windowing section that performs windowing on phase-corrected target pixel data obtained by performing the phase correction process on the target pixel data and phase-corrected reference pixel data obtained by performing the phase correction process on the reference pixel data respectively;

a phase correlation section that calculates a phase correlation value indicating a degree of correlation between windowed target pixel data obtained by performing the windowing on the phase-corrected target pixel data and windowed reference pixel data obtained by performing the windowing on the phase-corrected reference pixel data; and

a peak position detecting section that calculates a disparity of a corresponding point in the reference image corresponding to a target point in the target image based on the phase correlation value, wherein

the windowing section handles, when the symmetry of the phase-shifted target pixel data is higher than the symmetry of the target pixel data, the phase-shifted target pixel data and the phase-shifted reference pixel data as the phase-corrected target pixel data and the phase-corrected reference pixel data respectively, and handles, when the symmetry of the phase-shifted target pixel data is not higher than the symmetry of the target pixel data, the target pixel data and the reference pixel data as the phase-corrected target pixel data and the phase-corrected reference pixel data respectively.

2. The stereo image processing apparatus according to claim 1, wherein the phase shift filter is a differential filter.

3. A stereo image processing method comprising:

acquiring a target image and a reference image of a stereo image;

clipping partial images parallel to a baseline length direction of the stereo image from the target image and the reference image respectively and acquiring one-dimensional pixel data sequences each indicating a distribution of pixel values of a corresponding one of the partial images in the baseline length direction;

applying a phase shift filter which shifts phases of some or all frequency components by 90 degrees with respect to the target pixel data and which calculates phase-shifted target pixel data;

calculating symmetry determination values indicating symmetry of values for the phase-shifted target pixel data and the reference pixel data respectively;

comparing the symmetry determination value calculated from the phase-shifted target pixel data with the symmetry determination value calculated from the target pixel data and determining whether or not the symmetry of the phase-shifted target pixel data is higher than the symmetry of the target pixel data;

applying the phase shift filter to the reference pixel data and calculating phase-shifted reference pixel data,

performing windowing on phase-corrected target pixel data obtained by performing the phase correction process on the target pixel data and phase-corrected reference pixel data obtained by performing the phase correction process on the reference pixel data respectively;

calculating a phase correlation value indicating a degree of correlation between windowed target pixel data obtained by performing the windowing on the phase-corrected target pixel data and windowed reference pixel data obtained by performing the windowing on the phase-corrected reference pixel data; and

calculating a disparity of a corresponding point in the reference image corresponding to a target point in the target image based on the phase correlation value, wherein

the performing windowing handles, when the symmetry of the phase-shifted target pixel data is higher than the symmetry of the target pixel data, the phase-shifted target pixel data and the phase-shifted reference pixel data as the phase-corrected target pixel data and the phase- corrected reference pixel data respectively, and handles, when the symmetry of the phase-shifted target pixel data is not higher than the symmetry of the target pixel data, the target pixel data and the reference pixel data as the phase-corrected target pixel data and the phase-corrected reference pixel data respectively.