Method for illuminating an object
AssigneeOdos Imaging Ltd.
InventorsChris Yates, Chris Softley
Life of this patent
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Abstract
A method is provided for illuminating an object and for determining a distance value R. The object is illuminated with a light source and the light intensity of the light source is switched at a time T0 from an intensity Iout,h to an intensity Iout,l being lower than Iout,h and switched back to Iout,h at a time T0+Tn. A signal value U is outputted at the end of an integration window time period which has such a predetermined delay relative to T0 that either Ttof or Ttof+Tn is between an integration start point in time Tsd of the integration window time period and an integration end point in time Tsd+Ts, with Ttof being a point in time when light with the intensity Iin,l arrives first at the photo element, and Ts is longer than Tn.
Claims20
A method for illuminating an object by an illumination device and for determining a distance value R between the object and said illumination device, wherein said illumination device includes a light source and at least one photo element, wherein said photo element is configured (a) to capture light emitted by said light source subsequent to the light being reflected back from the object, (b) to be activated during integration window time periods, and (c) to output signal values at end times of the integration window time periods, wherein the signal values are proportional to an energy of the light arriving at said photo element as said photo element is activated, the method comprising:
- illuminating the object with said light source so as to allow a human user to view the object with an unaided eye;
- at a first point in time T0, switching a light intensity of the light source from a first light intensity Iout,h to a second light intensity Iout,l, wherein said second light intensity Iout,l is lower than said first light intensity Iout,h;
- at a second point in time T0+Tn, switching the light intensity of said light source from said second light intensity Iout,l back to said first light intensity Iout,h, wherein the light that arrives at said photo element and that corresponds to the light emitted with said first light intensity Iout,h has a third light intensity Iin,h and, and wherein the light that arrives at said photo element and that corresponds to the light emitted with said second light intensity Iout,l has a fourth light intensity Iin,l;
- outputting a first signal value U at an end of a first integration window time period, wherein said first signal value U is proportional to the energy of the light arriving at said photo element during said first integration window time period, wherein said first integration window time period has a predetermined time delay relative to the first point in time T0 so that either a third point in time Ttof or a fourth point in time Ttof+Tn lies between an integration time start point Tsd of the first integration window time period and an integration time end point Tsd+Ts of the first integration window time period, wherein the third point in time Ttof is a point in time at which the light with the fourth light intensity Iin,l first arrives at the photo element, and wherein a first duration Ts of the first integration window time period is longer than a second duration Tn;
- determining a fifth light intensity Iin=Iin,h−Iin,l by measuring a second signal value U2 by the photo element during a second integration window time period;
- and,
- calculating the distance value R from the first signal value U and the fifth light intensity Iin.
A method for illuminating an object by an illumination device and for determining a distance value R between the object and said illumination device, wherein said illumination device includes a light source and at least one photo element, wherein said photo element is configured (a) to capture light emitted by said light source subsequent to the light being reflected back from the object, (b) to be activated during integration window time periods, and (c) to output signal values at end times of the integration window time periods, wherein the signal values are proportional to an energy of the light arriving at said photo element as said photo element is activated, the method comprising:
- illuminating the object with said light source so as to allow a human user to view the object with an unaided eye;
- at a first point in time T0, switching a light intensity of the light source from a first light intensity Iout,h to a second light intensity Iout,l, wherein said second light intensity Iout,l is lower than said first light intensity Iout,h;
- at a second point in time T0+Tn, switching the light intensity of said light source from said second light intensity Iout,l back to said first light intensity Iout,h, wherein the light that arrives at said photo element and that corresponds to the light emitted with said first light intensity Iout,h has a third light intensity Iin,h and, and wherein the light that arrives at said photo element and that corresponds to the light emitted with said second light intensity Iout,l has a fourth light intensity Iin,l;
- outputting a first signal value U at an end of a first integration window time period, wherein said first signal value U is proportional to the energy of the light arriving at said photo element during said first integration window time period, wherein said first integration window time period has a predetermined time delay relative to the first point in time T0 so that either a third point in time Ttof or a fourth point in time Ttof+Tn lies between a first integration time start point Tsd of the first integration window time period and a first integration time end point Tsd+Ts of the first integration window time period, wherein the third point in time Ttof is a point in time at which the light with the fourth light intensity Iin,l first arrives at the photo element, and wherein a first duration Ts of the first integration window time period is longer than a second duration Tn;
- outputting a second signal value U2 at an end of a second integration window time period having a second integration time start point Tsd2 being later than the first integration time start point Tsd and a second integration time end point Tsd2+Ts, wherein the third point in time Ttof lies between the second integration time start point Tsd2 and the second integration time end point Tsd+Ts, and wherein the fourth point in time Ttof+Tn is later than the second integration time end point Tsd2+Ts;
- or
- outputting the second signal value U2 at the end of the second integration window time period having the second integration time start point Tsd2 being later than the first integration time start point Tsd and the second integration time end point Tsd2+Ts, wherein the fourth point in time Ttof+Tn lies between the second integration time start point Tsd2 and the first integration time end point Tsd+Ts, and wherein the third point in time Ttof is earlier than the first integration time start point Tsd;
- and,
- calculating the distance value R from the first signal value U and the second signal value U2.
A method for illuminating an object by an illumination device and for determining a distance value R between the object and said illumination device, wherein said illumination device includes a light source and at least one photo element, wherein said photo element is configured (a) to capture light emitted by said light source subsequent to the light being reflected back from the object, (b) to be activated during integration window time periods, and (c) to output signal values at end times of the integration window time periods, wherein the signal values are proportional to an energy of the light arriving at said photo element as said photo element is activated, the method comprising:
- illuminating the object with said light source so as to allow a human user to view the object with an unaided eye;
- at a first point in time T0, switching a light intensity of the light source from a first light intensity Iout,h to a second light intensity Iout,l, wherein said second light intensity Iout,l is lower than said first light intensity Iout,h;
- at a second point in time T0+Tn, switching the light intensity of said light source from said second light intensity Iout,l back to said first light intensity Iout,h, wherein the light that arrives at said photo element and that corresponds to the light emitted with said first light intensity Iout,h has a third light intensity Iin,h and, and wherein the light that arrives at said photo element and that corresponds to the light emitted with said second light intensity Iout,l has a fourth light intensity Iin,l;
- outputting a first signal value U at an end of an integration window time period, wherein said first signal value U is proportional to the energy of the light arriving at said photo element during said integration window time period, wherein said integration window time period has a predetermined time delay relative to the first point in time T0 so that either a third point in time Ttof or a fourth point in time Ttof+Tn lies between an integration time start point Tsd of the integration window time period and an integration time end point Tsd+Ts of the integration window time period, wherein the third point in time Ttof is a point in time at which the light with the fourth light intensity Iin,l first arrives at the photo element, and wherein a first duration Ts of the integration window time period is longer than a second duration Tn;
- repeating the illuminating of the object with the light source and the switching of the light intensity of said light source at a plurality of first points in time T0 and a plurality of second points in time T0+Tn;
- forming a correlation function fc based on the intensity of the light arriving at the photo element and the integration window time period by varying a delay D of the integration window time period relative to the first point in time T0;
- and,
- calculating the distance value R from the correlation function fc.
Dependencies are inferred from the claim text.