Optics and Precision Engineering, Volume. 33, Issue 4, 641(2025)

Improved phase correlation and clustering ideas for Micro-LED chip microscopic image stitching

Jianpu LIN1,2, Tingyu WANG1,2, Bipeng CAI2,3, Jianhao ZHANG1,2, Ting MEI2,3, Shanling LIN1,2, Zhixian LIN1,2,3, Jianbi LE2、*, and Chaoxing WU2,3
Author Affiliations
  • 1School of Advanced Manufacturing,Fuzhou University,Quanzhou362252,China
  • 2China Fujian Photoelectric Information Science and Technology Innovation Laboratory, Fuzhou350116,China
  • 3School of Physics and Information Engineering,Fuzhou University,Fuzhou50116,China
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    Aiming at the problem of slow algorithmic stitching and low accuracy due to the existence of a large number of similar and neatly arranged LEDs in the existing microscopic images of Micro-LED chips, this paper proposed a clustering-based Micro-LED chip micro-image stitching method. Firstly, the OTSU method was used to preprocess the images, and then the adaptive area expansion phase correlation method was used to peak the overlapping regions of two adjacent images to obtain the offset of the preliminary alignment. Subsequently, the optimized alignment strategy using image chunking and the DHash algorithm was employed to obtain the optimized offset. Finally, density-based spatial clustering of applications with noise was introduced to automatically screen out and deal with the possible erroneous offsets. The experimental results show that the average time consumption of this paper's algorithm is 64 ms, which meets the demand of real-time stitching, the stitching correct rate reaches 99.4%, the alignment accuracy is controlled within 1 pixel, and the fusion processing can achieve a perfect stitching effect subjectively, which also provides a new solution to the overall misalignment problem caused by the wrong offsets. The algorithm in this paper effectively solves the key link of microscopic image stitching in wafer-level Micro-LED chip inspection and can be promoted and applied to other machine vision automation fields with repetitive features and high precision requirements, with high practical engineering application value.

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    Jianpu LIN, Tingyu WANG, Bipeng CAI, Jianhao ZHANG, Ting MEI, Shanling LIN, Zhixian LIN, Jianbi LE, Chaoxing WU. Improved phase correlation and clustering ideas for Micro-LED chip microscopic image stitching[J]. Optics and Precision Engineering, 2025, 33(4): 641

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    Paper Information

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    Received: Aug. 7, 2024

    Accepted: --

    Published Online: May. 20, 2025

    The Author Email: Jianbi LE (lejianbi@fjoel.cn)

    DOI:10.37188/OPE.20253304.0641

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