Fig. 5: Programmable imaging of the MMAT-OCT facilitated by angle control.

a (I) The input magnetic field in the PMSM’s coordinate system {\({{{\mathcal{N}}}}\)} is unobservable due to catheter deformation, making positional information alone in the global coordinate system {\({{{\mathcal{M}}}}\)} insufficient for precise angular control. (II) The state of the EPM’s fixed coordinate system {\({{{\mathscr{Q}}}}\)} is observable. With the known origin of probe’s coordinate system {\({{{\mathcal{P}}}}\)}, effective angular control in {\({{{\mathcal{M}}}}\)} is feasible. b Raw B-frames of scanning angle of 90° (I) and 360° (II), with red boxes signifying similar tissue areas. (III) The effective scanning area scales from -15% to 15%, using the circular scan image as a template for feature matching. The full-circle scanning duty cycle is set to 1 by default. The unit “a.u.” stands for arbitrary units. c Angular errors (n = 5) increase with the predefined scanning angle. Data are presented as mean values +/− SD. d Polar plots of post-processed OCT angular scanning. The red arrows indicate the epidermis; the blue arrows indicate the dermis, and the blue asterisks indicate the air gaps. e 3D programmable imaging of the capital “CUHK” on mouse colon tissue. (I) Targeted 3D scanning region defined as the capital letters “CUHK”. (II) 3D reconstruction via back-projection to reflect the pattern’s morphology. (III) Patterned scanning results (top view) on mouse colon tissue. Scale bars are 250 µm. (IV) Representative B-scan images at 200 µm intervals. Source data are provided as a Source Data file. a Created with BioRender.com released under a Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International license (https://creativecommons.org/licenses/by-nc-nd/4.0/deed.en).