Least squares image matching: A comparison of the performance of robust estimators
Least squares image matching (LSM) has been extensively applied and researched for high matching accuracy. However, it still suffers from some problems. Firstly, it needs the appropriate estimate of initial value. However, in practical applications, initial values may contain some biases from the in...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2014-11-01
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| Series: | ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences |
| Online Access: | http://www.isprs-ann-photogramm-remote-sens-spatial-inf-sci.net/II-1/37/2014/isprsannals-II-1-37-2014.pdf |
| Summary: | Least squares image matching (LSM) has been extensively applied and researched for high matching accuracy. However, it still
suffers from some problems. Firstly, it needs the appropriate estimate of initial value. However, in practical applications, initial
values may contain some biases from the inaccurate positions of keypoints. Such biases, if high enough, may lead to a divergent
solution. If all the matching biases have exactly the same magnitude and direction, then they can be regarded as systematic errors.
Secondly, malfunction of an imaging sensor may happen, which generates dead or stuck pixels on the image. This can be referred as
outliers statistically. Because least squares estimation is well known for its inability to resist outliers, all these mentioned deviations
from the model determined by LSM cause a matching failure. To solve these problems, with simulation data and real data, a series of
experiments considering systematic errors and outliers are designed, and a variety of robust estimation methods including RANSACbased
method, M estimator, S estimator and MM estimator is applied and compared in LSM. In addition, an evaluation criterion
directly related to the ground truth is proposed for performance comparison of these robust estimators. It is found that robust
estimators show the robustness for these deviations compared with LSM. Among these the robust estimators, M and MM estimator
have the best performances. |
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| ISSN: | 2194-9042 2194-9050 |