System and method of feature descriptor processing

A method of generating a feature descriptor, the method comprising:

• determining, at a processor, a first output histogram of an input by processing a first group of pixels of the input to determine first contributions to bins of the first output histogram, the input including orientation values and gradient magnitude values of a portion of an image that is in a region of a detected feature;
• writing the first output histogram to a cache after updating the bins of the first output histogram during a first iteration of an iterative feature descriptor operation;
• after processing the first group of pixels, determining, at the processor, a second output histogram of the input by processing a second group of pixels of the input to determine second contributions to bins of the second output histogram;
• and
• writing the second output histogram to the cache after updating the bins of the second output histogram during a second iteration of the iterative feature descriptor operation.

A non-transitory computer readable medium comprising at least one instruction, the at least one instruction, when executed by a processor, causing the processor to perform operations comprising:

• determining a first output histogram of an input by processing a first group of pixels of the input to determine first contributions to bins of the first output histogram, the input including orientation and gradient magnitude values of a portion of an image that is in a region of a detected feature;
• writing the first output histogram to a cache after updating the bins of the first output histogram during a first iteration of an iterative feature descriptor operation;
• after processing the first group of pixels, determining a second output histogram of the input by processing a second group of pixels of the input to determine second contributions to bins of the second output histogram;
• and
• writing the second output histogram to the cache after updating the bins of the second output histogram during a second iteration of the iterative feature descriptor operation.

An apparatus comprising:

• means for loading registers with data of a group of pixels of an input, the group of pixels selected in accordance with a particular iteration of an iterative feature descriptor operation;
• means for performing vector processing of the data to determine first contributions to bins of an output histogram that is selected in accordance with the particular iterations;
• first means for storing first values corresponding to even bins of the output histogram;
• and
• second means for storing second values corresponding to odd bins of the output histogram,
• wherein the means for performing vector processing is further configured to perform even/odd detection to selectively route a first output value of a first pixel of the group of pixels to one of the first means for storing or the second means for storing and to selectively route a second output value of the first pixel to the other of the first means for storing or the second means for storing.