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 determining a dominant gradient orientation for a target region within an image, the method comprising:
- determining a plurality of gradient samples for the target region, wherein each of the gradient samples represents a variation in pixel values within the target region;
- converting the gradient samples into double-angle gradient vectors;
- combining the double-angle gradient vectors, wherein combining the double-angle gradient vectors comprises determining a compound gradient vector for the target region;
- and
- determining a dominant gradient orientation for the target region in dependence on the combined double-angle gradient vectors, wherein determining the dominant gradient orientation for the target region comprises converting the compound gradient vector to a dominant gradient vector, the dominant gradient vector representing the dominant gradient orientation for the target region.
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:
- determining a plurality of gradient samples for the target region, wherein each of the gradient samples represents a variation in pixel values within the target region;
- converting the gradient samples into double-angle gradient vectors;
- combining the double-angle gradient vectors;
- and
- determining a dominant gradient orientation for the target region in dependence on the combined double-angle gradient vectors;
- and
- steering the anisotropic filter in dependence on the determined dominant gradient orientation.
An image processing system for determining a dominant gradient orientation for a target region within an image, the image processing system comprising:
- a gradient sampling unit configured to determine a plurality of gradient samples for the target region, wherein each of the gradient samples represents a variation in pixel values within the target region;
- a conversion unit configured to convert the gradient samples into double-angle gradient vectors;
- a combining unit configured to combine the double-angle gradient vectors bar determining a compound gradient vector for the target region;
- and
- a determining unit configured to determine a dominant gradient orientation for the target region in dependence on the combined double-angle gradient vectors by converting the compound gradient vector to a dominant gradient vector, the dominant gradient vector representing the dominant gradient orientation for the target region.
Dependencies are inferred from the claim text.