DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claims 1-4, 11-12, and 16-19 are rejected under 35 U.S.C. 103 as being unpatentable over Lee EP 3370078 B1 in view of Oh US 20210184684 A1.
Regarding claim 1, Lee teaches a method of determining a distance of a closest target using a time-of-flight (ToF) ranging system, the method comprising:
receiving, by a processor, a histogram generated by a ToF imager of the ToF ranging system (Fig. 1A, 102-103, [0030]), wherein the ToF imager is configured to transmit a light pulse for ranging purpose ([0031-33]);
finding a first rising edge in the histogram that corresponds to a rising edge of a reflected light pulse from the closest target (Fig. 9, [0137-139, 166-182]); and
Lee does not explicitly teach calculating a first estimate of the distance of the closest target by adding a pre-determined offset to a distance of the first rising edge.
Oh teaches correcting distance information based on a previously created lookup table ([0127])
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified Lee to include calculating a first estimate of the distance of the closest target by adding a pre-determined offset to a distance of the first rising edge similar to Oh with a reasonable expectation of success. This would help improve the accuracy of distance measurements.
Regarding claim 2, Lee as modified above teaches the method of claim 1, wherein finding the first rising edge comprises:
generating a differential histogram by computing differences between adjacent histogram bins of the histogram and assigning the computed differences as values of respective histogram bins of the differential histogram (Fig. 9, [0171, 178-181, 205]); and
finding a first histogram bin of the differential histogram, wherein a first value of the first histogram bin of the differential histogram is larger than a pre-determined threshold, or is a maximum value of the values of the histogram bins of the differential histogram ([0173, 181]).
Regarding claim 3, Lee as modified above teaches the method of claim 2, wherein the first histogram bin is a leftmost histogram bin of the differential histogram that has the first value (Fig. 9 finds the leftmost bin; Lee also discusses separating into separate windows when multiple targets are present, e.g. Figs. 8B-8F).
Regarding claim 4, Lee as modified above teaches the method of claim 3, wherein the pre-determined threshold is determined by an ambient noise level in the histogram and a user-specified confidence level (ambient threshold based on ambient noise and selected sigma threshold, [0168-170]).
Regarding claim 11, Lee teaches a method of operating a time-of-flight (ToF) ranging system, the method comprising:
transmitting, by a light source of the ToF ranging system, light pulses toward one or more targets ([0030-33]);
receiving, by a ToF sensor of the ToF ranging system, the light pulses reflected by the one or more targets ([0030, 34-37];
generating a histogram based on the received light pulses (Fig. 1A, 102-103, [0030, 40]);
generating a differential histogram by computing differences between adjacent histogram bins of the histogram and assigning the computed differences as values of respective histogram bins of the differential histogram (Fig. 9, [0171, 178-181, 205]);
finding a first histogram bin of the differential histogram, wherein a first value of the first histogram bin of the differential histogram is larger than a pre-determined threshold or is a maximum value of the values of the histogram bins of the differential histogram ([0173, 181]); and
Lee does not explicitly teach computing an estimate of a distance of a closest target by adding a pre-determined offset to a first distance of the first histogram bin.
Oh teaches correcting distance information based on a previously created lookup table ([0127])
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified Lee to include calculating a first estimate of the distance of the closest target by adding a pre-determined offset to a distance of the first rising edge similar to Oh with a reasonable expectation of success. This would help improve the accuracy of distance measurements.
Regarding claim 12, Lee as modified above teaches the method of claim 11, wherein the first histogram bin is a leftmost histogram bin of the differential histogram that has the first value (Fig. 9 finds the leftmost bin; Lee also discusses separating into separate windows when multiple targets are present, e.g. Figs. 8B-8F).
Regarding claim 16, Lee as modified above teaches the method of claim 12, wherein the pre-determined threshold is determined by an ambient noise level in the histogram and a user-specified scale factor (ambient threshold based on ambient noise and selected sigma threshold, [0168-170]).
Regarding claim 17, Lee teaches a time-of-flight (ToF) ranging system comprising:
a light source configured to transmit light pulses for illuminating one or more targets ([0030-33]);
a ToF sensor configured to receive reflected light pulses from the one or more targets and to generate a histogram based on the reflected light pulses ([0030, 34-37]);
a processor (processing device 103, [0030]) configured to determine a distance of a closest target of the one or more targets by:
finding a first rising edge in the histogram that corresponds to a rising edge of a reflected light pulse reflected by the closest target (Fig. 9, [0137-139, 166-182]); and
Lee does not explicitly teach calculating an estimate of the distance of the closest target by adding a pre-determined offset to a distance of the first rising edge.
Oh teaches correcting distance information based on a previously created lookup table ([0127])
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified Lee to include calculating a first estimate of the distance of the closest target by adding a pre-determined offset to a distance of the first rising edge similar to Oh with a reasonable expectation of success. This would help improve the accuracy of distance measurements.
Regarding claim 18, Lee as modified above teaches the ToF ranging system of claim 17, wherein finding the first rising edge comprises:
computing differences between adjacent histogram bins of the histogram and assigning the computed differences as gradients of respective histogram bins of the histogram (Fig. 9, [0171, 178-181, 205]); and
finding a first histogram bin of the histogram having a first value, wherein the first value is a maximum value of the computed differences, or is larger than a pre-determined threshold value ([0173, 181]).
Regarding claim 19, Lee as modified above teaches the ToF ranging system of claim 18, wherein the first histogram bin is a leftmost histogram bin of the histogram having the first value (Fig. 9 finds the leftmost bin; Lee also discusses separating into separate windows when multiple targets are present, e.g. Figs. 8B-8F).
Allowable Subject Matter
Claims 5-10, 13-15, and 20 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
The following is a statement of reasons for the indication of allowable subject matter: The prior art of record does not explicitly teach or render obvious:
The method of claim 5, specifically including: the pre-determined offset is determined by a shape of the light pulse transmitted by the ToF imager, and corresponds to half of the transmitted light pulse width
The method of claim 9, specifically including: the first histogram bin has a first bin index, wherein the method further comprises fine-tuning the first estimate of the distance of the closest target by adding an adjustment term to the first estimate, wherein the adjustment term is calculated based on the first value of the first histogram bin of the differential histogram, a second value of a second histogram bin of the histogram having the first bin index, and a third value of a third histogram bin of the histogram adjacent to the second histogram bin
The method of claim 13, specifically including: the pre-determined offset is proportional to half of a width of a light pulse transmitted by the light source
The method of claim 15, specifically including: the first histogram bin has a first bin index, wherein the method further comprises fine-tuning the estimate of the distance of the closest target by adding an adjustment term to the estimate, wherein the adjustment term is calculated based on the first value and values of the histogram bins of the histogram around the first bin index
The method of claim 20, specifically including: the pre-determined offset is proportional to half of a width of a transmitted light pulse
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure:
Lee US 20240077586 A1 teaches adjusting signals to have the same reference distance to help correct distance measurements ([0619])
Ma US 20220236386 A1 teaches calculating differences between adjacent time bins ([0046])
Shoji US 20220236412 A1 teaches correcting distance measurement by half width of the reflected pulse ([0057]).
Adachi US 20210349184 A1 teaches distance correction by half-width of the peak detected signal ([0081]).
Any inquiry concerning this communication or earlier communications from the examiner should be directed to JOSEPH C FRITCHMAN whose telephone number is (571)272-5533. The examiner can normally be reached M-F 8:00 am - 5:00 pm.
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/J.C.F./Examiner, Art Unit 3645
/ISAM A ALSOMIRI/ Supervisory Patent Examiner, Art Unit 3645