Multi-stage image pattern recognizer

An apparatus comprising:

• a processor;
• and
• a memory storing code which, when executed by the processor, instantiates
• a plurality of converters, each to input an input image and to compute a potential as a measure of contrast in the input image for each of a plurality of units of the input image, each converter further to generate as output a ranked set of coordinates containing a coordinate of each unit in the input image whose potential exceeds a first threshold, the set of coordinates being ranked based on potential;
• a first plurality of observers to process the outputs of the converters to recognize features in the input image that correspond to coordinates in the outputs of the converters;
• and
• a first plurality of pattern filters, each operatively coupled between a different pair of a converter of the plurality of converters and an observer of the first plurality of observers, the first plurality of pattern filters being individually configured so that each observer of the first plurality of observers can recognize features at a different angular orientation in the input image.

A method comprising:

• using a plurality of contrast converters to identify a plurality of units of an input image as potentially representing a feature in the input image;
• using the plurality of contrast converters to generate a first output set that contains a ranking of coordinates of the identified units of the input image;
• using a plurality of observers to attempt to recognize, in the input image, a feature from each of a first plurality of feature categories, based on the first output set, by independently using each of a first plurality of weight patterns to integrate a potential for each of the identified units, based on the ranking of coordinates in the first output set;
• and
• using the plurality of observers to generate a plurality of second output sets as results of attempting to recognize a feature from each of the first plurality of feature categories, each said second output set corresponding to a different one of the first plurality of feature categories.

An apparatus comprising:

• means for inputting an input image;
• means for computing a potential as a measure of contrast in the input image for each of a plurality of units of the input image;
• means for producing a first output set including a coordinate of each unit of the input image whose potential exceeds a first threshold, such that coordinates are located in the first output set according to a ranking based on potential;
• means for integrating, for each coordinate in the first output set, a corresponding potential, based on the ranking;
• means for identifying one or more coordinates in the first output set whose potential exceeds a second threshold after said integrating;
• and
• means for including, for each said unit whose potential exceeds the second threshold, the coordinate of the unit in a second output set.

An apparatus comprising:

• a processor;
• and
• a memory storing code which, when executed by the processor, causes instantiation of
• a plurality of converters, each to input an input image and to compute a potential as a measure of contrast in the input image for each of a plurality of units of the input image, each converter further to generate as output a set of coordinates of each unit in the input image whose potential exceeds a first threshold, said output ranked based on potential;
• and
• a plurality of observers coupled downstream from the plurality of converters, each observer to process output of an upstream converter or observer, by,
• for each coordinate in the output of the upstream converter or observer, integrating a corresponding potential over a range of time slices, and
• for each said unit whose potential exceeds a second threshold after said integrating, including the coordinate of the unit in an output set.

An apparatus comprising:

• a plurality of converters, each to input an input image and to generate an output list indicative of a measure of contrast in the input image, by
• computing a potential for each of a plurality of units of the input image based on the measure of contrast, each unit having a coordinate in the input image,
• applying each of the potentials to a first threshold, and
• for each said unit whose potential exceeds the threshold, linearly rescaling the potential to a range corresponding to a number of time slices, and adding the coordinate of the unit in the input image to the output list in a position which is based on the potential of the unit, such that coordinates in the output list are ranked according to potential;
• a plurality of first stage observers coupled downstream from the plurality of converters, each first stage observer to process an output list of an upstream converter of the plurality of converters, by,
• for each coordinate in the output list in the upstream converter, integrating the corresponding potential over said range of time slices, including applying a modulation factor to a corresponding weight value, wherein the weight value is from a first matrix of weight values, and
• for each said unit whose potential exceeds a second threshold after said integrating, adding the coordinate of the unit to an output list;
• a plurality of second stage observers coupled downstream from the plurality of first stage observers, each second stage observer to process an output list of an upstream observer of the plurality of first stage observers, by,
• for each coordinate in the output list in the upstream observer, integrating the corresponding potential over a range of values, including applying a modulation factor to a corresponding weight value, wherein the weight value is from a second matrix of weight values, and
• for each said unit whose potential exceeds the threshold after said integrating, adding the coordinate of the unit to an output list;
• and
• an engine to form a detection list for each of the plurality of first stage and second stage observers by keeping only a coordinate representing a local maximum from the output list of each said observer.