Free-form surface solutions can be divided into the following categories:
Feature recognition method based on boundary matching: This method recognizes features by comparing the boundary of the free-form surface with the boundary of a known shape.
Feature recognition method based on stereo decomposition: This method decomposes the free-form surface into multiple small parts and then performs feature recognition on each part .
Application of free-form surfaces in AR glasses:
In the optical display solution of AR glasses, the free-form surface solution uses a free-form surface reflector with a certain reflection/transmission value. A free-form surface is a complex, unconventional surface shape with a relatively complex mathematical expression and usually does not have rotational symmetry. The light emitted by the display is directed to the concave mirror/synthesizer and reflected back into the eye. Ideally, the display source should be located directly above the eye, but in actual design it is usually moved "out of axis" and set above the forehead. Due to the distortion of the off-axis display on the concave mirror, correction is required on the software/display side