Remapping methods to reduce distortions in images
Inventors
Assignees
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Publication Number
US-8929688-B2
Publication Date
2015-01-06
Expiration Date
Abstract
The present invention provides software, methods, and systems for characterizing an actual scan pattern of a scanning beam device. The characterization of the actual scan pattern may be used in an image remapping method and/or a drive signal remapping method to reduce distortions in an image.
Core Innovation
The invention remaps an image obtained or generated by a scanning beam device by compensating for a scan pattern that is not exactly known during imaging. It characterizes an actual illumination-spot scan pattern by scanning an illumination spot in a scan pattern and capturing a position of the scanning illumination spot at selected time points, with the time and position information stored and used to construct an image.
After characterizing the scan pattern, the scanning beam device is positioned adjacent a target area and the illumination spot is scanned over the target area in the same scan pattern. Backscattered light from the target area is captured at a plurality of time points in the scan pattern, and the remapped image is constructed by placing the captured backscattered-light samples into pixel positions that correspond to the position of the illumination spot for the same time point.
The described approach also includes drive-signal remapping based on comparing captured illumination positions to ideal positions. A remapped drive signal is constructed as a lookup table or algorithm, and the approach can be combined with drive and image remapping. Per-color remapping is also described to reduce chromatic aberrations via correction of distortions, including radial distortions and phase distortions.
Claims Coverage
The document provides two independent methods for image remapping, each focused on characterizing an illumination-spot scan pattern with time-position data and reconstructing a remapped image by placing time-aligned backscattered-light samples into pixel positions corresponding to measured illumination-spot positions. The core coverage includes time point correlation, pixel placement based on illumination-spot position, and memory storage of time/position data via a calibration apparatus.
Time-indexed scan-pattern characterization and pixel placement
Characterizing a scan pattern prior to scanning by scanning an illumination spot in a scan pattern and capturing a position of the scanning illumination spot at selected time points; positioning the scanning beam device adjacent a target area and scanning the illumination spot over the target area; capturing backscattered light from the target area at a plurality of time points in the scan pattern; and constructing an image by placing the captured backscattered light in a pixel position that corresponds to the position of the illumination spot for the same time point.
Calibration apparatus sensor characterization with stored time/position data
Characterizing a scan pattern by positioning the scanning beam device adjacent to one or more sensors of a calibration apparatus; enabling an illumination source to deliver light through the scanning beam device; scanning an illumination spot in a scan pattern over the one or more sensors; capturing a position of the scanning illumination spot at selected time points in the scan pattern; and storing the time points and the positions of the illumination spot in a memory module; then positioning the scanning beam device adjacent a target area, scanning the illumination spot over the target area, capturing backscattered light at a plurality of time points, and constructing an image by placing the captured backscattered light in a pixel position that corresponds to the position of the illumination spot for the same time point.
Across the independent claims, the inventive core is the same: measure the illumination-spot position as a function of time during scan-pattern characterization, then reconstruct the image by time-aligned placement of backscattered-light samples into pixel locations corresponding to the measured illumination-spot positions. One independent claim additionally specifies a calibration apparatus with one or more sensors and storing time/position pairs in a memory module.
Stated Advantages
Reduced data and memory for drive remapping.
Correction of chromatic aberrations via per-color remapping.
Enables use of less expensive lenses.
Documented Applications
Imaging with a scanning fiber endoscope, including use cases characterized in the document such as an endoscope, catheter, fiberscope, boroscope, and microscope.
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