Depth Map Correction Using Object Size Thresholds

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Solution Overview

Problem

Existing depth map estimation techniques, such as the stereo method, depth from defocus (DFD), and depth from focus (DFF), suffer from errors, especially in areas with little texture, leading to inaccurate distance calculations and increased measurement errors, and previous correction methods do not adequately consider distance estimation accuracy or account for object size and texture.

Innovation Solution

An image processing apparatus and method that detects objects in an image, determines their size relative to a threshold, and corrects distance values in areas with low estimation accuracy by using a representative value, such as a mean, median, or mode, to improve depth map accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If clustering processing is performed to correct depth map without considering distance estimation accuracy, then correction processing can be applied uniformly, but correction is performed even for areas with accurate distance estimation, increasing deviation from correct distance

Engineering Contradiction:
Improvedistance estimation accuracyVSAvoidcorrection accuracy
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent applies different correction strategies to different regions of the depth map based on local characteristics. Areas with low texture (poor estimation accuracy) receive clustering-based correction, while areas with high texture (good estimation accuracy) are left uncorrected. This local differentiation resolves the contradiction by ensuring correction is only applied where needed, maintaining both measurement precision and reliability.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If clustering is used to divide local areas for correction, then correction can be applied to regions, but correction to make the distance of each object the same cannot be performed

Engineering Contradiction:
Improvedistance estimation accuracyVSAvoidobject-specific correction capability
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent segments the depth map into multiple candidate regions using clustering, then performs object detection within each region. This allows the system to identify individual objects and apply object-specific corrections, making the correction process adaptable to different objects while maintaining regional processing efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent dynamically adjusts the correction approach based on detected object characteristics. For each detected object, the system determines whether to apply uniform regional correction or object-specific correction based on the object's properties, enabling versatile adaptation to different object types and sizes.

Inventive Principle:
Principle #15Dynamics

3Reliability

If distance correction is applied to all areas, then comprehensive correction is achieved, but unnecessary corrections increase deviation from correct distances in accurately estimated areas

Engineering Contradiction:
Improveoverall correction coverageVSAvoiddistance estimation accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent changes the parameter of correction application from uniform (all areas) to conditional (only low-texture areas). By using texture analysis to identify areas with poor distance estimation accuracy, the system selectively applies correction only where needed, maintaining overall correction coverage while preserving accuracy in well-estimated areas.

Inventive Principle:
Principle #35Parameter changes

4Device complexity

If object size is not considered in correction processing, then processing is simplified, but correction cannot be adapted to different object sizes and textures

Engineering Contradiction:
Improveprocessing complexityVSAvoidobject-specific correction adaptability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent performs preliminary object detection and size classification before applying correction processing. By detecting objects and categorizing them by size and texture characteristics in advance, the system prepares object-specific correction parameters, enabling adaptable correction without significantly increasing processing complexity during the main correction phase.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS9799118B2Image processing apparatus, imaging apparatus and distance correction method
Publication Date: 2017.10.24 CANON KK
  • US9799118B2 patent drawing
  • US9799118B2 patent drawing
  • US9799118B2 patent drawing

AI summary

An image processing apparatus for correcting, on the basis of an image and a depth map corresponding to the image, the depth map, includes: a detection unit that detects an object included in the image; a determination unit that determines whether a size of the object detected by the detection unit is a threshold or less; and a correction unit that corrects a distance in a target area which corresponds to an area of the object in the depth map, when the size of the detected object is the threshold or less.