Improved mirror ball projection for more accurate merging of multiple camera outputs and process monitoring
This is an incremental improvement for manufacturing process monitoring in hazardous environments like high heat or vacuum.
The paper tackles the problem of parallax shift when merging multiple camera outputs for process monitoring in hazardous environments by introducing an improved mirror ball projection that corrects distortion at the pole, resulting in more accurate image merging.
Using spherical mirrors in place of wide-angle cameras allows for cost-effective monitoring of manufacturing processes in hazardous environment, where a camera would normally not operate. This includes environments of high heat, vacuum and strong electromagnetic fields. Moreover, it allows the layering of multiple camera types (e.g., color image, near-infrared, long-wavelength infrared, ultraviolet) into a single wide-angle output, whilst accounting for the different camera placements and lenses used. Normally, the different camera positions introduce a parallax shift between the images, but with a spherical projection as produced by a spherical mirror, this parallax shift is reduced, depending on mirror size and distance to the monitoring target. This paper introduces a variation of the 'mirror ball projection', that accounts for distortion produced by a perspective camera at the pole of the projection. Finally, the efficacy of process monitoring via a mirror ball is evaluated.