Optoelectronic modules operable to recognize spurious reflections and to compensate for errors caused by spurious reflections
Optoelectronic modules ( 100 ) are operable to distinguish between signals indicative of reflections from an object of interest and signals indicative of a spurious reflection. Various modules are operable to recognize spurious reflections by means of dedicated spurious-reflection detection pixels ( 126 ) and, in some cases, also to compensate for errors caused by spurious reflections.
1. An optoelectronic module comprising:
a light emitter to generate light to be emitted from the module;
a plurality of spatially distributed light sensitive elements arranged to detect light from the emitter that is reflected by an object outside the module;
one or more dedicated spurious-reflection detection pixels; and
circuitry operable to use a signal from the one or more dedicated spurious-reflection detection pixels to correct for a spurious reflection.
2. The optoelectronic module of claim 1 wherein the light emitter is disposed in a first chamber of the module and the spatially distributed light sensitive elements and one or more dedicated spurious-reflection detection pixels are disposed on a second chamber of the module.
3. The optoelectronic module of claim 1 including circuitry operable to use a signal from the one or more dedicated spurious-reflection detection pixels to factor out a component of light reflected by a smudge present on a transmissive cover from a component of light detected by the spatially distributed light sensitive elements.
4. The optoelectronic module of claim 1 including circuitry operable to use output signals from the one or more dedicated spurious-reflection detection pixels to determine whether a smudge is present on a glass cover of a host device in which the module is disposed.
5. The optoelectronic module of claim 1 wherein the spatially distributed light sensitive elements are demodulation pixels, the module further including processing circuitry operable to determine a distance to an object outside the module based at least in part on signals from the demodulation pixels.
6. The optoelectronic module of claim 1 further including a reflector to direct a spurious light reflected by a smudge or a transmissive cover to the one or more dedicated spurious-reflection detection pixels.
7. The optoelectronic module of claim 6 wherein the module is disposed within a host device that includes a transmissive cover, and wherein the reflector is disposed so to direct light reflected by a smudge on the transmissive cover to the one or more dedicated spurious-reflection detection pixels.
8. The optoelectronic module of claim 1 further including a light guide to direct light from a transmissive cover of a host device within which the module is disposed to the one or more dedicated spurious-reflection detection pixels.
9. The optoelectronic module of claim 8 wherein the light guide is disposed to receive light reflected by a smudge on a surface of the transmissive cover and reflected internally within the transmissive cover, and to guide the received light to the one or more dedicated spurious-reflection detection pixels.