Method and apparatus for processing a histogram output from a detector sensor

Patent metadata

Field	Value
Publication number	US-11120104-B2
Application number	US-201815886353-A
Country	US
Kind code	B2
Filing date	Feb 1, 2018
Priority date	Mar 1, 2017
Publication date	Sep 14, 2021
Grant date	Sep 14, 2021

Abstract

A method includes receiving a histogram output from a detector sensor, and calculating a median point of a pulse waveform within the histogram. The pulse waveform has an even probability distribution over at least one quantization step of the histogram around the median point. A corresponding apparatus can include a detector sensor and a co-processor coupled to the detector sensor.

First claim

What is claimed is:

1. A method comprising:
receiving a histogram output from a detector sensor, the detector sensor being a single photon avalanche diode array sensor, the histogram output comprising time-of-flight sensing data of one or more objects within a field-of-view of the detector sensor, wherein receiving the histogram comprises receiving the histogram as filtered histogram data comprising a plurality of histogram bin values, the filtered histogram data comprising a pulse waveform with a defined width and histogram bin position;
calculating a median point of the pulse waveform within the histogram, the pulse waveform having an even probability distribution over at least one quantization step of the histogram around the median point; and
determining ranges of the one or more objects within the field-of-view of the detector sensor based on the median point of the pulse waveform, wherein determining the ranges comprises determining from the filtered histogram data and based on the median point a parameter associated with the pulse waveform, wherein the parameter comprises an object range, a range noise estimate, or a maximum distance detection value.

2. The method as claimed in claim 1 , wherein determining the parameter comprises determining an object range by determining from the filtered histogram data an object range associated with the pulse waveform comprises applying a linear interpolation to a phase weighted filtered histogram to determine a phase value associated with the median point associated with a zero crossing event.

3. The method as claimed in claim 1 , wherein determining the parameter comprises determining an object range by determining from the filtered histogram data an object range associated with the pulse waveform comprises applying an interpolation to a phase weighted filtered histogram, the phase weighted filter comprising a first part and a second part and generating a first difference value based on a sum of the second part and a negative first part, such that for at least one histogram position where the first difference value crosses zero then the interpolation comprises the determined histogram position value+(|difference value for the bin position|/|difference value for the bin position|+|difference value for the bin position following the zero crossing bin position|).

4. The method as claimed in claim 1 , wherein determining the parameter comprises determining an object range by determining from the filtered histogram data an object range associated with the pulse waveform comprises applying a interpolation to phase weighted filtered histogram to determine a phase value associated with the median point, the phase weighted filter comprising a first part, a second part and a third part and generating a first difference value based on the sum of the first part, the second part and a negative third part, and generating a second difference value based on the sum of the second part, the third part and a negative first part, such that for at least one histogram position where the first difference value and the second difference value are greater than zero then the interpolation comprises the determined histogram position value+0.5+((the third part value−the first part value)/(2*(the second part value−a determined ambient value))).

5. The method as claimed in claim 1 , wherein determining the parameter comprises determining a range noise estimate associated with the pulse waveform by:
determining shot noise contributions from each filter part;
applying a range interpolation based transfer function to each shot noise contribution; and
combining the range interpolation based transfer function components to generate the range noise estimate.

6. The method as claimed in claim 1 , wherein determining the parameter comprises determining a range noise estimate associated with the pulse waveform by:
generating a noise value based on a phase weighted filtered histogram, the phase weighted filter comprising a first part A, a second part B located at a detected median event bin and a third part C, and wherein the noise values is

Noise
combined

=

(

C
+
A

4
×

(

B
-
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)

2

)

+

(

(

C
-
A

)

2

×

(

B
+
amb

)

4
×

(

B
-
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=

Noise
Numerator
2

+

Noise
Denominator
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where

Assignees

• St Microelectronics Res & Dev Ltd
• St Microelectronics Grenoble 2

Inventors

• Moore John Kevin
• Lee Sam
• Mellot Pascal
• Baxter Donald
• Mcleod Stuart
• Dargan Kenneth

Classifications

• G01S7/4876

  by removing unwanted signals (G01S7/495 takes precedence) · CPC title

• G01S7/4813

  Housing arrangements · CPC title

• G01S7/4865

  Time delay measurement, e.g. time-of-flight measurement, time of arrival measurement or determining the exact position of a peak (peak detection in noise, signal conditioning G01S7/487) · CPC title

• G01S7/497

  Means for monitoring or calibrating · CPC title

• G01S7/4863

  Detector arrays, e.g. charge-transfer gates · CPC title