Method for detecting objects with light
A method for detecting an object using light comprises providing a light source having a function of illuminating an environment. The light source is driven to emit light in a predetermined mode, with light in the predetermined mode being emitted such that the light source maintains said function of illuminating an environment. A reflection/backscatter of the emitted light is received from an object. The reflection/backscatter is filtered over a selected wavelength range as a function of a desired range of detection from the light source to obtain a light input. The presence or position of the object is identified with the desired range of detection as a function of the light input and of the predetermined mode.
1. A method for detecting an object using light, comprising:
obtaining a light source having a function of illuminating an environment, the light source comprising at least one light-emitting diode;
driving the light source to emit light in a pulse-width modulation of variable duty cycle intended for standard illumination, such that the light source maintains said function of illuminating an environment;
receiving a reflection or backscatter of the emitted light from an object;
identifying rapid transients in the reflection or backscatter received; and
calculating a distance of the object from the rapid transients received and rapid transients from the pulse-width modulation.
2. The method according to claim 1 , wherein:
driving the light source to emit light in a pulse-width modulation comprises emitting pulses;
identifying rapid transients comprises identifying the pulses in the reflection or backscatter received; and
calculating a distance comprises calculating from the pulses from the pulse-width modulation.
3. The method according to claim 2 , wherein emitting pulses comprises superimposing a pulse of short duration to a leading edge of each cycle of the pulse-width modulation.
4. The method according to claim 2 , wherein emitting pulses comprises inserting at least one pulse of short duration in an off-state period of each cycle of the pulse-width modulation.
5. The method according to claim 1 , wherein:
identifying rapid transients in the reflection or backscatter received comprises identifying leading edges of the reflection or backscatter received; and
calculating a distance comprises calculating from leading edges of the pulse-width modulation.
6. The method according to claim 1 , wherein:
identifying rapid transients in the reflection or backscatter received comprises identifying leading edges and falling edges of the reflection or backscatter received; and
calculating a distance comprises calculating from leading edges and falling edges of the pulse-width modulation.
7. The method according to claim 2 , wherein emitting pulses comprises inserting at least one pulse of short duration in an on-state period of each cycle of the pulse-width modulation.
8. The method according to claim 1 , wherein driving the light source comprises providing a switching shunt path for the continuous output current to bypass the light source.
9. The method according to claim 1 , wherein driving the light source comprises temporarily storing energy and subsequently discharging the energy to the light source to generate a pulse of short duration.
10. The method according to claim 1 , wherein obtaining the light source comprises obtaining at least one phosphor-converted light-emitting diode.