HDR Image Processing Band Limiting Centroid Deviation

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Solution Overview

Problem

Existing image processing techniques for HDR monitors suffer from centroid deviation and high frequency component propagation issues during signal transmission, leading to incorrect signal reproduction and false signals, especially on the high signal value side.

Innovation Solution

An image processing apparatus and method that generates color signal components for luminance and color difference in a first color space, performs nonlinear processing, integrates and separates signals, and applies band limitation processing based on frequency characteristics to suppress centroid deviation and high frequency component propagation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If odd-numbered phase signals are thinned out and copied from adjacent pixel values of even-numbered phase signals, then signal transmission efficiency is improved, but centroid deviation occurs between luminance-based signals and color difference-based signals

Engineering Contradiction:

Improvesignal transmission efficiencyVSAvoidcentroid alignment accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

A phase adjustment unit is introduced as an intermediary component between the thinning process and signal integration. This unit adjusts the phase of the thinned-out odd-numbered phase signals to match the phase of even-numbered phase signals, ensuring centroid alignment while maintaining the thinning-based transmission efficiency improvement

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The phase parameter of the thinned-out signals is changed through adjustment processing. By modifying the phase parameter to align with the reference signal's phase, the system maintains both transmission efficiency (through thinning) and centroid alignment accuracy (through phase parameter adjustment)

Inventive Principle:

Principle #35Parameter changes

2Reliability

If luminance-based signals and color difference-based signals are integrated, then complete image signal reconstruction is achieved, but high frequency components from luminance signals are propagated to color difference signals causing false signals

Engineering Contradiction:

Improveimage signal reconstruction completenessVSAvoidfalse signal generation

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The harmful high frequency components are extracted and removed from the color difference signals through band limitation processing. This extraction separates the useful signal components from the harmful propagated high frequency components, allowing complete reconstruction while preventing false signal generation

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The band limitation processing converts the harmful effect of high frequency propagation into a benefit by using the frequency characteristics information to design appropriate filters. The harmful high frequency components are identified and selectively removed, while the useful frequency components are preserved for accurate image reconstruction

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Productivity

If time division multiplexing is used for signal transmission, then transmission bandwidth efficiency is improved, but signal reproduction accuracy on HDR monitors deteriorates due to centroid deviation and high frequency propagation

Engineering Contradiction:

Improvetransmission bandwidth efficiencyVSAvoidsignal reproduction accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

Phase adjustment and band limitation processing are performed as preliminary actions before time division multiplexing transmission. This preliminary processing ensures that centroid alignment and high frequency component control are established beforehand, preventing reproduction accuracy deterioration while maintaining bandwidth efficiency

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The phase adjustment unit and band limitation unit act as intermediary processing stages between signal generation and time division multiplexing transmission. These intermediaries prepare the signals with correct phase alignment and filtered frequency content before transmission, ensuring accurate reproduction on HDR monitors while maintaining transmission efficiency

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS10825136B2Image processing apparatus and method, and image capturing apparatus

Publication Date: 2020.11.03 CANON KK

AI summary

An image processing apparatus comprises: first and generation units that generate color signal components for luminance and color signal components for color difference, respectively, in a first color space from an input image signal; an integration unit that integrates the color signal components for luminance and color difference to generate color signal components common for luminance and color difference; a processing unit that performs nonlinear processing on the color signal components common for luminance and color difference; a separation unit that generates luminance and color difference signals in a second color space from the signal that has undergone the nonlinear processing; and a band limiting unit that performs band limitation processing on the color difference signals. A characteristic of the band limitation processing is set on the basis of frequency characteristics of the luminance color difference signals.