Skin Hue Correction for 1-Second Liveness Detection

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Solution Overview

Problem

Existing biometric authentication systems face challenges in accurately distinguishing between living and non-living bodies within a short time frame due to the mixing of pulsation and noise frequency components, leading to prolonged determination times and user inconvenience.

Innovation Solution

A video processing apparatus that corrects skin color hues in video frames using a correction coefficient and determines living bodies based on average hue values, employing a discriminator to analyze amplitude ratios of corrected hues for accurate classification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If FFT is used to acquire frequency spectrum from time-series color data, then frequency spectrum can be obtained, but determination time becomes excessively long requiring 3-5 seconds of data

Engineering Contradiction:
Improvefrequency spectrum accuracyVSAvoiddetermination time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent extracts only the necessary frequency information (pulsation frequency component) from the color signal using band-pass filtering, rather than performing a complete FFT analysis of the entire frequency spectrum. This extraction approach obtains the critical authentication information without the computational overhead of full spectrum analysis, enabling rapid determination while maintaining accuracy.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies band-pass filtering as a preliminary processing step to isolate the pulsation frequency band before further analysis. This preliminary action pre-separates the relevant frequency components, eliminating the need for lengthy FFT processing and enabling quick authentication decisions within 1 second or less.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If time-series data of 3-5 seconds is used to distinguish pulsation frequency from noise, then frequency components can be distinguished, but user convenience deteriorates due to prolonged waiting time

Engineering Contradiction:
Improvepulsation frequency distinction accuracyVSAvoiduser convenience
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent extracts and isolates only the pulsation frequency band using band-pass filtering, removing the need to analyze the entire frequency spectrum. This extraction enables accurate pulsation detection from short 1-second videos by focusing computational resources on the relevant frequency range, thereby improving user convenience while maintaining measurement precision.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of performing complete spectrum analysis, the patent applies partial action by using band-pass filtering to target only the specific pulsation frequency range. This selective approach achieves sufficient authentication accuracy with significantly reduced processing time, allowing authentication within 1 second and greatly improving user convenience.

Inventive Principle:
Principle #16Partial or excessive action

3Productivity

If short video of about one second is used for authentication, then user wait time is reduced, but frequency components of pulsation and noise become mixed making accurate determination difficult

Engineering Contradiction:
Improveauthentication speedVSAvoidspoofing determination accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent introduces band-pass filtering as an intermediary processing step that separates pulsation frequency components from noise. This intermediary filter acts as a mediator between the short video input and the authentication decision, enabling accurate spoofing determination from 1-second videos by selectively passing only the relevant pulsation frequencies while blocking noise.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the processing parameter from complete FFT spectrum analysis to band-pass filtered frequency extraction. This parameter change transforms the approach from analyzing all frequency components to selectively extracting only the pulsation band, enabling accurate authentication from short 1-second videos and significantly improving productivity.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS12555348B2Video processing apparatus, method for controlling the same, and non-transitory computer-readable storage medium
Publication Date: 2026.02.17 CANON KK
  • US12555348B2 patent drawing
  • US12555348B2 patent drawing
  • US12555348B2 patent drawing

AI summary

The present invention provides a technique for determining whether an object is a living body with a high degree of accuracy even for a relatively short video of about one second. To achieve this, a video processing apparatus configured to determine whether an object is a living body from video data of the object constituted by a plurality of frames, comprises a correction unit configured to correct each of the plurality of frames constituting the video data based on a correction coefficient for correcting to colors of a plurality of target hues different from each other; and a determination unit configured to determine whether the object is a living body based on an average hue value of a skin area of the object in each of the plurality of frames being corrected.