Determining dominant gradient orientation in image processing using double-angle gradients
AssigneeImagination Technologies Limited
InventorRuan Lakemond
Life of this patent
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Abstract
Methods and image processing systems are provided for determining a dominant gradient orientation for a target region within an image. A plurality of gradient samples are determined for the target region, wherein each of the gradient samples represents a variation in pixel values within the target region. The gradient samples are converted into double-angle gradient vectors, and the double-angle gradient vectors are combined so as to determine a dominant gradient orientation for the target region.
Claims20
A method of steering an anisotropic filter configured to filter pixel values in an image, the method comprising:
- determining a dominant gradient orientation for a target region within the image by:
- converting gradient samples for the target region into double-angle gradient vectors,
- combining the double-angle gradient vectors to determine a compound gradient vector for the target region, and
- converting the compound gradient vector to a dominant gradient vector, the dominant gradient vector representing the dominant gradient orientation for the target region;
- and
- steering the anisotropic filter in dependence on the determined dominant gradient orientation.
An image processing system configured to perform anisotropic filtering of pixel values in an image, the image processing system comprising:
- a conversion unit configured to convert gradient samples for the target region into double-angle gradient vectors;
- a combining unit configured to combine the double-angle gradient vectors to determine a compound gradient vector for the target region;
- a determining unit configured to convert the compound gradient vector to a dominant gradient vector, the dominant gradient vector representing the dominant gradient orientation for the target region;
- and
- an image processing unit configured to steer an anisotropic filter in dependence on the determined dominant gradient orientation.
A non-transitory computer readable storage medium having stored thereon computer readable instructions that, when executed at a computer system, cause the computer system to perform a method of steering an anisotropic filter configured to filter pixel values in an image, comprising:
- determining a dominant gradient orientation for a target region within the image by:
- converting gradient samples for the target region into double-angle gradient vectors,
- combining the double-angle gradient vectors to determine a compound gradient vector for the target region, and
- converting the compound gradient vector to a dominant gradient vector, the dominant gradient vector representing the dominant gradient orientation for the target region;
- and
- steering the anisotropic filter in dependence on the determined dominant gradient orientation.
Dependencies are inferred from the claim text.