Image processing apparatus, image processing method, and non-transitory computer-readable storage medium

Patent metadata

Field	Value
Publication number	US-2016284092-A1
Application number	US-201615075736-A
Country	US
Kind code	A1
Filing date	Mar 21, 2016
Priority date	Mar 23, 2015
Publication date	Sep 29, 2016
Grant date	—

Abstract

A feature point is extracted from an input image including an image region for which depth values of pixels change consecutively. A transformation that normalizes depth values of pixels of a vicinity of the feature point with respect to a region of at least a portion of the input image is set as a normalization transformation, and an image for a feature amount calculation is generated by performing the normalization transformation on a pixel position of the feature point. A feature amount is calculated from the image for the feature amount calculation.

First claim

What is claimed is:

1 . An image processing apparatus, comprising:
an extraction unit configured to extract a feature point from an input image including an image region in which depth values of pixels change consecutively; a generation unit configured to, a normalization transformation being a transformation that normalizes depth values of pixels of a vicinity of the feature point with respect to a region of at least a portion of the input image, generate an image for a feature amount calculation by performing the normalization transformation on a pixel position of the feature point; and a calculation unit configured to calculate a feature amount from the image for the feature amount calculation generated by the generation unit.

2 . The image processing apparatus according to claim 1 , wherein the generation unit identifies a pixel position on the input image that is transformed by the normalization transformation to be a peripheral pixel position of a pixel position obtained by performing the normalization transformation on the feature point, and generates the image for the feature amount calculation based on a pixel value of a pixel at the identified pixel position or of a pixel in a periphery thereof.

3 . The image processing apparatus according to claim 1 , wherein the generation unit determines, as the normalization transformation, a transformation that causes a normal vector of a plane including three-dimensional coordinates of the pixels in the vicinity of the feature point which are represented by coordinates of the pixels of the vicinity of the feature point and depth values of the pixels to be parallel with a depth direction of the input image.

4 . The image processing apparatus according to claim 1 , wherein the generation unit generates the image for the feature amount calculation if a difference between a maximum depth value and a minimum depth value among the depth values of the pixels of the vicinity of the feature point is greater than or equal to a predetermined value.

5 . The image processing apparatus according to claim 4 , wherein
if the difference is smaller than the predetermined value, the calculation unit calculates the feature amount from a region of the vicinity of the feature point without the generation unit generating the image for the feature amount calculation.

6 . The image processing apparatus according to claim 1 , wherein the generation unit generates the image for the feature amount calculation for the entirety of the input image.

7 . The image processing apparatus according to claim 1 ,
further comprising a partition unit configured to partition an image region including the feature point into a plurality of partitioned regions, wherein the generation unit generates the image for the feature amount calculation for at least one of the partitioned regions, and the calculation unit calculates a feature amount from the image for the feature amount calculation generated by the generation unit.

8 . The image processing apparatus according to claim 1 , further comprising
a registering unit configured to associate and register, in a memory, the feature amount calculated by the calculation unit and information unique to an image that is an acquisition source of the feature amount.

9 . The image processing apparatus according to claim 8 , further comprising:
a search unit configured to search for information registered in the memory in association with feature amounts that are respectively the same as or similar to feature amounts that the calculation unit calculates for a comparison source image; and a display unit configured to, based on the information that the search unit searched, display information unique to an image whose feature amount is similar to a feature amount of the comparison source image.

10 . The image processing apparatus according to claim 1 , wherein the extraction unit sets each of a plurality of reduced images generated by recursively reducing a source image, and the source image as the input image, and extracts a feature amount from the input image.

11 . An image processing method that an image processing apparatus performs, the method comprising:
extracting a feature point from an input image including an image region in which depth values of pixels change consecutively; a normalization transformation being a transformation that normalizes depth values of pixels of a vicinity of the feature point with respect to a region of at least a portion of the input image, generating an image for a feature amount calculation by performing the normalization transformation on a pixel position of the feature point; and calculating a feature amount from the generated image for the feature amount calculation.

12 . A non-transitory computer-readable storage medium storing a computer program for causing a computer to function as
an extraction unit configured to extract a feature point from an input image including an image region in which depth values of pixels change consecutively; a generation unit configured to, a normalization transformation being a transformation that normalizes depth values of pixels of a vicinity of the feature point with respect to a region of at least a portion of the input image, generate an image for a feature amount calculation by performing the normalization transformation on a pixel position of the feature point; and a calculation unit configured to calculate a feature amount from the image for the feature amount calculation generated by the generation unit.

Assignees

• Canon Kk

Inventors

• Matsushita Masahiro
• Shiiyama Hirotaka
• Sorakado Hideki

Classifications

• G06V30/1607

  Correcting image deformation, e.g. trapezoidal deformation caused by perspective · CPC title

• G06F18/22

  Matching criteria, e.g. proximity measures · CPC title

• G06V20/64 Primary

  Three-dimensional [3D] objects · CPC title

• G06V30/10

  Character recognition · CPC title

• G06K9/52

  Physics · mapped topic