Panoramic Image Color Matching via Histogram Analysis

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Solution Overview

Problem

Panoramic image stitching often results in color inconsistencies due to differences in exposure and white balancing between images, making the final panoramic image appear less realistic.

Innovation Solution

A method that involves removing unreliable overlapping pixels, generating and matching histograms to determine corresponding pixel values, and applying an optoelectronic conversion function with optimized parameters to align the colors of the images, using a golden section search to minimize color matching error.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If multiple images are stitched together to form a panoramic image, then the field of view is expanded, but color inconsistencies appear between images

Engineering Contradiction:

Improvefield of viewVSAvoidcolor consistency

Core Design Contradiction:

Area of stationary objectVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by adjusting the optoelectronic conversion function parameters (gamma values and scaling factors) to transform pixel values between overlapping regions. This mathematical transformation aligns the color histograms of adjacent images, resolving color inconsistencies while preserving the expanded field of view benefit

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses histogram matching as an intermediary process between image stitching and final color correction. By comparing and aligning histograms of overlapping regions, it creates a reference framework that guides the optoelectronic conversion function to achieve consistent colors across all stitched images

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If histogram matching is performed on all overlapping pixels, then color matching accuracy is improved, but processing time increases due to unreliable pixels

Engineering Contradiction:

Improvecolor matching accuracyVSAvoidprocessing time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent extracts and removes unreliable overlapping pixels from the processing pipeline by identifying pixels with extreme brightness differences or low confidence scores. This extraction eliminates noisy data that would otherwise degrade color matching accuracy and waste computational resources, thereby improving both precision and efficiency

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies partial action by performing histogram matching only on reliable overlapping pixels rather than all pixels. This selective approach focuses computational effort on the most informative regions, achieving effective color matching without the excessive processing time that would result from analyzing every pixel including unreliable ones

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS7840067B2Color matching and color correction for images forming a panoramic image

Publication Date: 2010.11.23 ARCSOFT INC

AI summary

A method for color matching a first image and a second image, wherein a first region of the first image and a second region of the second image overlap, includes removing overlapping pixels in the first and the second regions that have pixel values are too different, generating a first histogram of the first region, generating a second histogram of the second region, determining corresponding pixel values in the first and the second histograms, determining parameters of an optoelectronic conversion function that matches the corresponding pixel values, and color matching the second image to the first image by applying the optoelectronic conversion function with the determined parameters to the second image.