Light-source characterizer and associated methods
A method characterizes a scanning light source configured to emit illumination propagating in any one of a plurality of directions spanning an angular range. The method includes (i) detecting, with a camera, illumination propagating at each of the plurality of directions; (ii) storing image data corresponding to a response of the camera to the detected illumination. The method also includes (iii) processing the image data to characterize at least one of the angular range, pointing accuracy, pointing jitter, a divergence of the illumination, a uniformity of the illumination, and a fidelity of a scanning pattern, formed by the scanning light source, to a predetermined pattern.
1. A light-source tester for characterizing a scanning light source that emits illumination propagating in any one of a plurality of directions spanning an angular range, the tester comprising:
a camera unit including a plurality of cameras, each of the cameras (i) including a lens, a working distance thereof being between fifty millimeters and seventy millimeters, (ii) having a system field of view determined at least in part by the working distance and equal to or exceeding the angular range, and (iii) having at least one of (a) a respective one of a plurality of mutually coplanar optical axes intersecting a vertex of the angular range and spanning an angular range greater than or equal to the angular range and (b) a respective one of a plurality of entrance pupils, the vertex of the angular range being in a respective plane of each of the plurality of entrance pupils;
a processor coupled to the camera unit; and
a memory storing machine-readable instructions that, when executed by the processor, control the processor to:
detect, with the camera unit, illumination propagating at each of the plurality of directions;
store image data corresponding to a response of the camera unit to the illumination imaged thereon; and
process the image data to characterize at least one of the angular range, pointing accuracy, pointing jitter, a divergence of the illumination, a uniformity of the illumination, and a fidelity of a scanning pattern, formed by the scanning light source, to a predetermined pattern.
2. The light-source tester of claim 1 , further comprising an actuator configured to translate a camera of the plurality of cameras along a circular arc around a vertex of the angular range and in a plane perpendicular to an optical axis of the camera.
3. The light-source tester of claim 1 , each of the plurality of cameras including an imaging lens having field curvature less than 0.1 percent across a full field-of-view of the camera.
4. The light-source tester of claim 1 , the memory also storing machine-readable instructions that, when executed by the processor, control the processor to, when detecting illumination:
capture a single illumination image that includes, for each direction of the plurality of directions, a respective one of a plurality of pixel-value groups generated by the illumination incident on an entrance pupil of each of the plurality of cameras at an incident angle corresponding to the direction, the image data including the plurality of pixel-value groups.
5. The light-source tester of claim 1 , the memory also storing machine-readable instructions that, when executed by the processor, control the processor to, when detecting illumination:
capture, for each direction of the plurality of directions, a respective one of a plurality of illumination images that includes a respective one of a plurality pixel-value groups generated by the illumination incident on an entrance pupil of each of the plurality of cameras at an incident angle corresponding to the direction, the image data including the plurality of pixel-value groups.
6. The light-source tester of claim 1 , the memory also storing machine-readable instructions that, when executed by the processor, control the processor to, when detecting illumination and for each of the plurality of directions:
detect the illumination at a respective position on a pixel array of each of the plurality of cameras.