Method and system for optical distance measurement

Patent metadata

Field	Value
Publication number	US-10088568-B2
Application number	US-201514864809-A
Country	US
Kind code	B2
Filing date	Sep 24, 2015
Priority date	Dec 29, 2014
Publication date	Oct 2, 2018
Grant date	Oct 2, 2018

Abstract

An optical distance measurement method includes: acquiring a plurality of sensed values based on detecting light; performing a filtering operation to select a plurality of selected sensed values from the plurality of sensed values; determining a location of a center of gravity according to the plurality of selected sensed values; and calculating a plurality of depth values with respect to a plurality of detection points according to the location of the center of gravity and a plurality of depth information transformation functions respectively corresponding to the detection points.

First claim

What is claimed is:

1. An optical distance measurement method, comprising:
acquiring a plurality of sensed values based on detecting light, wherein the plurality of sensed values include a plurality of rows of sensed values;
performing a filtering operation to select a plurality of selected sensed values from the plurality of sensed values, comprising:
configuring a threshold value for each row of sensed values, comprising:
calculating a maximum of sensed values of a row;
calculating a mean of the sensed values of the row; and
configuring the threshold value for the row according to an average of the mean and the maximum;

comparing sensed values of each row with a corresponding threshold value to select the plurality of selected sensed values;

determining a location of a centroid according to the plurality of selected sensed values; and
calculating a plurality of depth values with respect to a plurality of detecting points according to the location of the centroid and a plurality of depth information transformation functions respectively corresponding to the detecting points.

2. The optical distance measurement method of claim 1 , wherein the step of performing the filtering operation comprises:
selecting the plurality of selected values from a plurality of specific sensed values that are within in a specific region of a sensed frame according to relative positions of the plurality of sensed values with respect to the sensed frame.

3. The optical distance measurement method of claim 1 , further comprising:
configuring a depth information transformation function corresponding to a detecting point, comprising:
configuring the depth information transformation function according to a plurality of first degree polynomials.

4. An optical distance measurement system, comprising:
an optical sensing device, arranged for acquiring a plurality of sensed values based on detecting light, wherein the plurality of sensed values include a plurality of rows of sensed values;
a filtering module, coupled to the optical sensing device and arranged for performing a filtering operation to select a plurality of selected sensed values from the plurality of sensed values, wherein the filtering module configures a threshold value for each row of sensed values, and compares sensed values of each row with a corresponding threshold value to select the plurality of selected sensed values; and the filtering module calculates a maximum of sensed values of a row; calculates a mean of the sensed values of the row; and configures the threshold value for the row according to an average of the mean and the maximum;
a centroid determination module, coupled to the filtering module and arranged for determining a location of a centroid according to the plurality of selected sensed values; and
a depth information calculation module, coupled to the centroid determination module and arranged for calculating a plurality of depth values with respect to a plurality of detecting points according to the location of the centroid and a plurality of depth information transformation functions respectively corresponding to the detecting points.

5. The optical distance measurement system of claim 4 , wherein the filtering module selects the plurality of selected value from a plurality of specific sensed values that are within in a specific region of a sensed frame according to relative positions of the plurality of sensed values with respect to the sensed frame.

6. The optical distance measurement system of claim 4 , wherein the depth information calculation module configures a depth information transformation function of a detecting point according to a plurality of first degree polynomials.

7. An optical distance measurement method, comprising:
acquiring a plurality of optical sensed values at different times;
performing a filtering operation to select a plurality of selected optical sensed values from the plurality of optical sensed values, comprising:
calculating a confidence level for each row of optical sensed values, and compares the confidence level of each row with a lowest confidence level to select the plurality of selected optical sensed values;

determining a plurality of locations of centroid according to the plurality of optical sensed values; and
calculating a plurality of depth information corresponding to the plurality of locations of centroid according to the plurality of locations of centroid and a plurality of transformation functions.

8. The optical distance measurement method of claim 7 , wherein the plurality of depth information transformation functions are linear functions.

9. An optical distance measurement method, comprising:
acquiring a plurality of sensed values based on detecting light, wherein the plurality of sensed values include a plurality of rows of sensed values;
performing a filtering operation to select a plurality of selected sensed values from the plurality of sensed values, comprising:
calculating a confidence level for each row of sensed values, and compares the confidence level of each row with a lowest confidence level to select the plurality of selected sensed values;

determining a location of a centroid according to the plurality of selected sensed values; and
calculating a plurality of depth values with respect to a plurality of detecting points according to the location of the centroid and a plurality of depth information transformation functions respectively corresponding to the detecting points.

10. The optical distance measurement method of claim 9 , wherein the step of configuring the confidence level comprises:
calculating a summation of sensed values of a row that is higher than a threshold value;
calculating a mean of the sensed values of the row that are lower than the threshold value; and
determining the confidence level for the row according to a ratio of the summation to the mean.

11. An optical distance measurement method, comprising:
acquiring a plurality of sensed values based on detecting light;
performing a filtering operation to select a plurality of selected sensed values from the plurality of sensed values;
determining a location of a centroid according to the plurality of selected sensed values;
calculating a plurality of depth values with respect to a plurality of detecting points according to the location of the centroid and a plurality of depth information transformation functions respectively corresponding to the detecting points; and
configuring a depth information transformation function for each detecting point, comprising:
determining the depth information transformation function for each detecting point according to at least one weighting coefficient and at least one of a plurality of specific depth information transformation functions corresponding to a plurality of specific detecting points.

12. An optical distance measurement system, comprising:
an optical sensing device, arranged for acquiring a plurality of sensed values based on detecting light, wherein the plurality of sensed values include a plurality of rows of sensed values;
a filtering module, coupled to the optical sensing device and arranged for performing a filtering operation to select a plurality of selected sensed values from the plurality of sensed values, wherein the filtering module calculates a confidence level for each row of sensed values, and compares the confidence level of each row with a lowest confidence level to select the plurality of selected sensed values;
a centroid determination module, coupled to the filtering module and arranged for determining a location of a centroid according to the plurality of selected sensed valu

Assignees

• Pixart Imaging Inc

Inventors

• Wang guo-zhen

Classifications

• G01S17/48 Primary

  Active triangulation systems, i.e. using the transmission and reflection of electromagnetic waves other than radio waves · CPC title

• G01S7/4912

  Receivers · CPC title

• G01S7/4913

  Circuits for detection, sampling, integration or read-out · CPC title