Gain Map Resizing for Accurate HDR-to-SDR Image Conversion

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Solution Overview

Problem

Existing image processing technologies do not effectively handle the resizing of gain maps when a main image, which has been added with a gain map, is enlarged or reduced, leading to potential issues in displaying high dynamic range (HDR) images on standard dynamic range (SDR) compatible display devices.

Innovation Solution

An image processing apparatus and method that generates and resizes gain maps in conjunction with resizing the main image, using techniques such as bilinear interpolation, bicubic interpolation, and super-resolution processing, to ensure accurate conversion between HDR and SDR images during resizing operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a gain map is added to a main image and stored in an image file, then HDR image conversion to SDR is enabled, but the handling of gain map during resizing is not addressed

Engineering Contradiction:
ImproveHDR to SDR conversion capabilityVSAvoidgain map resizing handling
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system performs preliminary action by resizing the gain map before storing it in the image file, rather than handling it during subsequent processing. This pre-resizing approach simplifies the overall system complexity by preparing the gain map in advance for the intended use case.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts the gain map resolution based on the main image resolution. When the main image is resized, the gain map is correspondingly resized to maintain proper alignment and conversion accuracy, creating a dynamic adaptation between the two components.

Inventive Principle:
Principle #15Dynamics

2Quantity of substance

If the main image is resized, then image size is reduced for storage or display, but the gain map conversion accuracy may be compromised

Engineering Contradiction:
Improveimage data sizeVSAvoidgain map conversion accuracy
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The system changes the parameter of gain map resolution to match the resized main image dimensions. By adjusting the gain map's spatial parameters (width and height) to correspond with the main image after resizing, the system maintains conversion accuracy while reducing overall data size.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The gain map resolution is dynamically adjusted in response to main image resizing operations. The system monitors the main image dimensions and automatically adjusts the gain map accordingly, ensuring that conversion accuracy is maintained throughout the resizing process.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If gain map resizing is performed, then compatibility with SDR displays is maintained, but processing time increases

Engineering Contradiction:
ImproveSDR display compatibilityVSAvoidprocessing time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The gain map is resized in advance during image capture or initial processing, rather than during subsequent display or conversion operations. This preliminary resizing eliminates the need for time-consuming resize operations later in the workflow, reducing overall processing time while maintaining SDR compatibility.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system performs gain map resizing dynamically based on the actual needs of the main image processing workflow. By integrating the resizing operation into the existing processing pipeline at the most efficient point, the system minimizes additional processing time while ensuring ongoing compatibility with SDR displays.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4654123A1Image processing apparatus, control method, storage medium and program
Publication Date: 2025.11.26 CANON KK
  • EP4654123A1 patent drawingFigure 1
  • EP4654123A1 patent drawingFigure 2
  • EP4654123A1 patent drawingFigure 3A~3D

AI summary

An image processing apparatus includes a first generation unit configured to generate first conversion information used when images having different dynamic ranges are generated from a first image, an image resizing processing unit configured to execute resizing processing on the first image, and a control unit configured to control whether or not to execute resizing processing on the first conversion information added to the first image when resizing processing is executed on the first image.