Optical Sensor Histogram Skewness for Mixed-Object Distance Sensing

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Solution Overview

Problem

Existing distance calculation methods using time of flight sensors are inaccurate when reflected light components from multiple target objects are mixed due to the presence of non-target objects, leading to distorted histograms that hinder precise distance measurement.

Innovation Solution

An optical sensor system that generates a histogram of light intensity and time of flight, calculates skewness to correct for histogram distortion, and adjusts distance calculations using a distortion coefficient to improve accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If reflected light from multiple objects is measured using a histogram, then distance measurement can be performed, but measurement precision deteriorates when non-target objects are present causing histogram distortion

Engineering Contradiction:
Improvedistance measurement accuracyVSAvoidmeasurement reliability in presence of non-target objects
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent segments the histogram data by calculating skewness to identify and separate the target object's reflected light component from non-target objects. By dividing the mixed histogram into distinct segments based on skewness characteristics, the system can accurately measure distance to the target object even when multiple objects are present in the measurement region.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the parameter of histogram analysis by introducing skewness calculation as an additional parameter. Instead of relying solely on the standard histogram peak, the system uses skewness to detect and correct for distortion caused by non-target objects, thereby improving measurement accuracy in complex environments.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If simple histogram peak detection is used, then calculation process is simple, but measurement precision deteriorates due to histogram distortion from mixed reflected light

Engineering Contradiction:
Improvedistance calculation accuracyVSAvoidcalculation process complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent enhances the simple histogram peak detection by adding skewness as a correction parameter. This parameter change allows the system to maintain relative computational simplicity while significantly improving accuracy by compensating for distortion effects through a single additional calculation step.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces complex multi-step signal processing mechanisms with a more efficient mathematical approach using skewness calculation. Instead of using elaborate filtering or segmentation algorithms, the system substitutes a relatively simple statistical parameter calculation that achieves similar or better distortion correction with less computational overhead.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables accurate distance measurement to target objects even when non-target objects are present by correcting for histogram skewness, resulting in improved precision and reduced influence from non-target objects.

Implementation Method 1

a light-emitting element configured to emit light in a region where an object is present, a light-receiving element configured to receive reflected light from the object

Methodology Applied
Scientific EffectLight emission and reflection: Reflection

Implementation Method 2

reflected light is counted by a time to digital converter (TDC) circuit for each time period from emission of light to reception of the reflected light from a target object (time of flight of light)

Methodology Applied
Scientific EffectTime of flight measurement: Time of Flight

Data Source

PatentUS12571890B2Optical sensor, electronic device, distance calculation method, and storage medium of program
Publication Date: 2026.03.10 SHARP SEMICON INNOVATION CORP TENRI CITY
  • US12571890B2 patent drawing
  • US12571890B2 patent drawing
  • US12571890B2 patent drawing

AI summary

An optical sensor comprises a light-emitting element configured to emit light in a region where an object is present; a light-receiving element configured to receive reflected light from the object; a generation unit configured to generate a histogram indicating a relationship between a time from emission of the light by the light-emitting element to reception of the reflected light by the light-receiving element and an intensity of the reflected light received by the light-receiving element; a first calculation unit configured to calculate skewness of the histogram; and a second calculation unit configured to calculate a distance between the optical sensor and the object with reference to the histogram and the skewness.