Phase Unwrapping Using Heap and Queue Data Structures
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional phase unwrapping methods in interference measurement apparatuses face challenges with phase non-continuity and high processing time, especially when dealing with phase maps that have steep changes or noise, leading to unwrapping failures and inconsistent phase relations across regions.
Innovation Solution
A phase unwrapping method that uses a combination of a heap data structure for phase differences above a threshold and a queue or stack for those below, allowing for efficient path determination by prioritizing pixels with large phase differences and simplifying the processing of those with smaller differences, thereby avoiding phase non-continuous regions and reducing overall processing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional Minimum Spanning Tree method is used for phase unwrapping, then unwrapping accuracy is maintained, but processing time is excessively long
Solution Approach 1:
The patent segments the phase unwrapping process by dividing pixels into two categories based on phase difference magnitude: pixels with large phase differences (≥ threshold) are processed using heap data structure to maintain accuracy, while pixels with small phase differences (< threshold) are processed using queue data structure to reduce processing time. This segmentation allows selective application of computational complexity based on local phase characteristics.
Solution Approach 2:
The patent introduces a threshold parameter to dynamically change the processing strategy. By comparing phase difference magnitudes against this threshold, the system adapts its computational approach - using heap operations for significant phase changes and queue operations for minor variations, thereby optimizing the balance between accuracy and speed.
2Loss of time
If simple queue-based path search is used, then processing time is reduced, but phase non-continuous regions cause unwrapping failures
Solution Approach 1:
The patent uses phase difference magnitude as a dynamic parameter to select the appropriate data structure. When phase differences exceed the threshold, heap operations are triggered to ensure reliable path finding through non-continuous regions. When phase differences are below the threshold, queue operations provide fast processing without compromising reliability.
Solution Approach 2:
The threshold parameter acts as an intermediary that mediates between the two conflicting requirements of speed and reliability. It determines which data structure (heap or queue) should be used for each pixel, thereby indirectly controlling the balance between processing time and unwrapping success rate without requiring complex decision logic.
3Measurement precision
If heap data structure is used for all pixels, then unwrapping accuracy is maintained, but processing time increases significantly
Solution Approach 1:
The patent segments the pixel population based on phase difference characteristics, applying heap operations only to the subset of pixels where accuracy is critical (large phase differences), while using faster queue operations for the majority of pixels with small phase differences. This selective segmentation maintains overall accuracy while dramatically improving processing speed.
Solution Approach 2:
Different data structures (heap vs. queue) are applied to different local regions of the phase map based on local phase difference characteristics. Regions with large phase differences receive the more accurate but slower heap processing, while regions with small phase differences receive the faster queue processing, optimizing the local quality of processing to match local requirements.
Data Source
AI summary
A candidate pixel generating unit searches a path-undetermined adjacent pixel j which is adjacent around a parent pixel i, and, with respect to the searched adjacent pixel j, generates a candidate pixel having data {j(i,|Wij|)} in which the parent pixel i and magnitude |Wij| of a phase difference Wij in which phase skip between the pixels is corrected are combined. The registration control unit registers the pixel to a heap having a function of ordering the registration order, and order the pixel, if the weight |Wij| is equal to or more than a predetermined threshold value TH; and registers the pixel to a queue not having the function of ordering the registration order if it is less than the threshold value TH. A path determination unit prioritizes the queue to retrieve and eliminate one candidate pixel, and determines a path between the eliminated candidate pixel and the parent pixel.