Descriptors adjustment when using steerable pyramid to extract features for content based search

A method of filtering images, comprising:

• constructing a plurality of orientation maps and a plurality of energy maps from input images, the input images adjusted by a factor prior to applying filters, the adjustment factor being such that the plurality of orientation maps and the plurality of energy maps are non-negative;
• removing resulting adjustment factors from the plurality of energy maps;
• extracting, for each input image, a plurality of descriptors from corresponding non-negative orientation and energy maps;
• and
• combining the plurality of descriptors into an image descriptor to be used for image processing.

A method comprising:

• filtering an input image at a first time to produce a corresponding orientation map and a corresponding energy map, each of the orientation map and the energy map being represented by a corresponding histogram and a corresponding set of co-occurrence matrices;
• adjusting the input image by an adjustment factor if the orientation map and/or the energy map is negative, the adjustment factor being such that when the adjusted input image is filtered, the orientation map and/or the energy map is non-negative;
• filtering the adjusted input image at a second time to produce non-negative orientation and energy maps;
• extracting a plurality of descriptors from the non-negative orientation and energy maps;
• and
• combining the plurality of descriptors into an image descriptor to be used for image processing.

A computer readable medium containing executable instructions which, when executed in a processing system, causes the system to perform a method comprising:

• getting a Laplacian image from corresponding Gaussian images in a steerable pyramid;
• verifying the Laplacian image for negative value;
• adjusting the Laplacian image to eliminate the negative value;
• applying a steerable filter to the adjusted Laplacian image to generate orientation data and energy data;
• removing resulting adjustments;
• extracting a plurality of descriptors from the orientation data and the energy data;
• and
• combining the plurality of descriptors into an image descriptor to be used for image processing.

An apparatus, comprising:

• means for filtering input images to produce corresponding orientation maps and energy maps, each of the orientation maps and the energy maps being represented by a corresponding histogram and a corresponding set of co-occurrence matrices;
• means for adjusting the input images such that the corresponding orientation maps and/or energy maps are non-negative;
• means for extracting, for each input image, a plurality of descriptors from corresponding non-negative orientation and energy maps;
• and
• combining the plurality of descriptors into an image descriptor to be used for image processing.

A method comprising:

• filtering input images to produce corresponding orientation maps and energy maps, each of the orientation maps and the energy maps being represented by a corresponding histogram and a corresponding set of co-occurrence matrices;
• adjusting the input images such that the corresponding orientation maps and/or energy maps are non-negative;
• extracting a plurality of descriptors from corresponding non-negative orientation and energy maps;
• and
• combining the plurality of descriptors into an image descriptor to be used for image processing.

A computer system comprising:

• a processor;
• and
• an image processing logic coupled to the processor, comprising
• generation logic to form Gaussian images from an original image and to form a Laplacian image from the corresponding two Gaussian images,
• adjustment logic to add a value to the Laplacian image such that the Laplacian image is non-negative,
• logic to apply a steerable filter to the adjusted Laplacian image to produce an energy map and an orientation map, each of the orientation map and the energy map being represented by a corresponding histogram and a corresponding set of co-occurrence matrices;
• and
• image descriptor logic to extract a plurality of descriptors from the orientation map and the energy map, and to combine the plurality of descriptors into an image descriptor to be used for image processing.