Patent ID: 6141440
Filing Date: 2000-10-31
Classification: G01C,G06K,G06T,H04N

Abstract:
An apparatus for determining disparity in at least two data sets, the apparatus comprising:a data memory for storing a reference data set, and for storing a target data set;a central processing unit (CPU) coupled to the data memory, which CPU has access to the reference data set and the target data set;a program memory coupled to the CPU, for storing an array of instructions, which instructions, when executed by the CPU, cause the CPU to:select a first interrogation region in the reference data set, the first interrogation region being a first size;select more than one initial candidate region in the target data set;for each initial candidate region, determine an associated similarity value, each similarity value quantifying the similarity between the associated initial candidate region and the first interrogation region;use a first threshold and the similarity values associated with the initial candidate regions to determine whether any initial candidate region meets a similarity criterion specified by the first threshold;responsive to at least one of the initial candidate regions meeting the similarity criterion specified by the first threshold:determine as a matching region an initial candidate region which meets the similarity criterion specified by the first threshold; anddetermine as a disparity value the difference between the position of the first interrogation region in the reference data set and the position of the matching region in the target data set; andresponsive to none of the initial candidate regions meeting the similarity criterion specified by the first threshold:select a second interrogation region in the reference data set, the second interrogation region being a second size, the second size being larger than the first size;select more than one subsequent candidate region in the target data set;for each subsequent candidate region, determine an associated similarity value, each similarity value quantifying the similarity between the associated subsequent candidate region and the second interrogation region;use a second threshold and the similarity values associated with the subsequent candidate regions to determine whether any subsequent candidate region meets a similarity criterion specified by the second threshold; andresponsive to at least one of the subsequent candidate regions meeting the similarity criterion specified by the second threshold:determine as the matching region a subsequent candidate region which meets the similarity criterion specified by the second threshold; anddetermine as the disparity value the difference between the position of the second interrogation region in the reference data set and the position of the matching region in the target data set.