Modified Goldstein Algorithm using Boundary Information in Phase Unwrapping

Title
Modified Goldstein Algorithm using Boundary Information in Phase Unwrapping
Authors
Keywords
Goldstein Algorithm; Digital Holography; Phase Unwrapping
Issue Date
2009-04
Publisher
OSA DH 2009
Citation
VOL 2009, NO 04, 1-3
Abstract
The object phase information obtained by an interferometer such as digital holography is used to analyze the 3-dimensional phase data of the object. In this process, the information is including the phase difference between the reference wave and the object wave. This difference is called wrapped phase. The object phase value is always larger than 2π, however the phase difference value is between -p &pound;f < p . Phase unwrapping process is a method to restore the wrapped phase data of the object using a numerical calculation as a tool. Itoh’s theory is normally applied to phase unwrapping algorithm at one dimensioned specially.[1] However, the unwrapping algorithm applied this theory is possible to use to the place when the wrapped phase value can be differential as well as differentiated value between the wrapped phase and the object phase to be same. However, all the data in the wrapping process are not possible to differentiate, thus residue will be create in the process. As the same way, if residue does not exist in the 2-dimension array then all of the differentiated values to be equal to the original object phase information, if else residue exists then there are integrated value revealed different result. To overcome this problem, many different algorithms are reported. Goldstein algorithm is selected and used widely because it has some advantage such as short execution time needed and small usage of the memory. [2] This algorithm is performed such following that connecting the residues placed close to each other which called branch-cut, and then integrating wrapped phase data all of direction in the data map. However, the result by used Goldstein algorithm is pulled out incorrect unwrapped data when some residues are located nearer than the pair of original residue. To overcome this problem, we suggested a method which using the boundary information. This information will be used to identify the residue with branch-cut process.
URI
http://pubs.kist.re.kr/handle/201004/35355
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KIST Publication > Conference Paper
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