US 2020/0053377 A1Published application

Image statistics for motion detection

AssigneeApple Inc.

InventorsMuge Wang, Sheng Lin, Weichun Ku, Hsiao-Chen Chang, Yixiang Tao

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Abstract

Embodiments of the present disclosure relate to generating motion vectors. An image signal processor includes a statistics circuit and a vector correlation analysis circuit. The statistics circuit determines image statistics such as vectors representing sums of pixel values of rows or columns of blocks of an image. Additionally, the statistics circuit may mix or aggregate sums of multiple color components. The vector correlation analysis performs cross-correlation between vectors of a current image and reference vectors of a prior image to determine cross-correlation scores. The vector correlation analysis generates a motion vector by identifying shifts in horizontal and vertical directions corresponding to peak values of cross-correlation scores.

Claims20

Dependent claims

An image signal processor comprising:

a statistics circuit configured to:
determine row sums of pixel values of each block of pixels in a current image, and
determine column sums of the pixel values of each block of pixels in the current image;
and
a vector correlation analysis (VCA) circuit coupled to the statistics circuit, the VCA circuit configured to:
determine first cross-correlation scores between the row sums of the pixel values of each block of pixels in the current image with row sums of pixel values of a corresponding block of pixels in a prior image preceding the current image,
determine second cross-correlation scores between the column sums of the pixel values of each block of pixels in the current image with column sums of the pixel values of a corresponding block of pixels in the prior image, and
generate a motion vector for each block of pixels in the current image by identifying a vertical shift corresponding to a greatest one of the first cross-correlation scores and a horizontal shift corresponding to a greatest one of the second cross-correlation scores.

5 more elements

A method comprising:

determining row sums of pixel values of each block of pixels in a current image, and
determining column sums of the pixel values of each block of pixels in the current image;
determining first cross-correlation scores between the row sums of the pixel values of each block of pixels in the current image with row sums of pixel values of a corresponding block of pixels in a prior image preceding the current image;
determining second cross-correlation scores between the column sums of the pixel values of each block of pixels in the current image with column sums of the pixel values of a corresponding block of pixels in the prior image;
and
generating a motion vector for each block of pixels in the current image by identifying a vertical shift corresponding to a greatest one of the first cross-correlation scores and a horizontal shift corresponding to a greatest one of the second cross-correlation scores.

3 more elements

An electronic device comprising:

an image sensor configured to capture a current image;
and
an image signal processor coupled to the image sensor, the image signal processor
comprising:
a statistics circuit configured to:
determine row sums of pixel values of each block of pixels in the current image
determine column sums of the pixel values of each block of pixels in the current image;
and
a vector correlation analysis (VCA) circuit coupled to the statistics circuit, the VCA circuit configured to:
determine first cross-correlation scores between the row sums of the pixel values of each block of pixels in the current image with row sums of pixel values of a corresponding block of pixels in a prior image preceding the current image,
determine second cross-correlation scores between the column sums of the pixel values of each block of pixels in the current image with column sums of the pixel values of a corresponding block of pixels in the prior image, and
generate a motion vector for each block of pixels in the current image by identifying a vertical shift corresponding to a greatest one of the first cross-correlation scores and a horizontal shift corresponding to a greatest one of the second cross-correlation scores.

9 more elements

Dependencies are inferred from the claim text.