Image stitching for probe-based confocal laser endomicroscopy via a motion consistency constraint

Probe-based confocal laser endomicroscopy (pCLE) enables in vivo optical biopsy with cellular resolution, but its limited field of view makes large-area tissue inspection difficult and necessitates image stitching. Under clinically relevant probe motion, variable-speed acquisition introduces nonlinear scanning distortion and severe inter-frame deformation, making stable registration and globally consistent stitching difficult. Here, we propose an incremental pCLE image stitching framework whose core is a non-rigid registration method, termed probe motion space-based mismatch rejection (PMS-MR). The main innovation is a motion consistency constraint for robust mismatch rejection and deformation estimation. To achieve this, the point scanning mechanism for confocal imaging is exploited to map feature correspondences into the probe motion space (PMS). Experimental results show that, compared with state-of-the-art registration methods, the proposed method achieves competitive pairwise registration and more reliable stitching, keeps the cumulative error on a standard target within 4 pixels, and supports large-area mosaic reconstruction over 400 frames for clear visualization of lesion boundaries. These results indicate that the proposed method supports stable, globally consistent extension of the field of view and facilitates more flexible probe manipulation in clinical practice.