Light Field Camera Defect Pixel Detection via Ray Directional Reconstruction

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Solution Overview

Problem

Conventional real-time defect detection and correction methods for light field cameras face challenges in distinguishing defect pixels from object edges due to the inclusion of ray directional information and the large number of photoelectric conversion elements, leading to increased processing time and memory resource usage.

Innovation Solution

An image processing apparatus that reconstructs the picked-up image based on ray directional information to generate a reconstruction image, allowing for real-time defect pixel detection and correction, with detection parameters adjusted according to refocus information to improve precision and reduce memory usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If real-time defect detection is performed on picked-up images with ray directional information, then defect pixels can be detected, but processing time increases and memory resource usage increases

Engineering Contradiction:
Improvedefect detection accuracyVSAvoidprocessing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent performs defect detection on the picked-up image before the refocus reconstruction process. By detecting defects in advance on the raw picked-up image data, the system avoids the need to process large amounts of reconstruction data, thereby reducing processing time while maintaining defect detection capability

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent extracts and detects defect pixels from the picked-up image separately from the main refocus reconstruction process. This allows defect detection to be performed on a subset of data rather than the entire reconstruction dataset, reducing memory resource usage and processing time

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If defect detection is performed on picked-up images with ray directional information, then defect pixels can be detected, but memory resource usage increases

Engineering Contradiction:
Improvedefect detection accuracyVSAvoidmemory resource usage
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent performs defect detection on the picked-up image before the refocus reconstruction process. By detecting defects in advance on the raw picked-up image data, the system avoids the need to process large amounts of reconstruction data, thereby reducing processing time while maintaining defect detection capability

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent extracts and detects defect pixels from the picked-up image separately from the main refocus reconstruction process. This allows defect detection to be performed on a subset of data rather than the entire reconstruction dataset, reducing memory resource usage and processing time

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If conventional defect detection methods are used on light field camera images, then defect pixels can be detected, but precision decreases due to difficulty in distinguishing defect pixels from object edges

Engineering Contradiction:
Improvedefect detection capabilityVSAvoiddefect pixel discrimination precision
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent adjusts the detection threshold dynamically based on local image characteristics and refocus information. By making the threshold adaptive rather than fixed, the system can distinguish defect pixels from object edges more accurately in different regions of the image

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent uses refocus information as feedback to improve defect detection precision. The refocus reconstruction results are used to verify and refine defect pixel identification, allowing the system to distinguish true defects from edge artifacts more effectively

Inventive Principle:
Principle #23Feedback

Data Source

PatentUS9456155B2Image processing apparatus, method, and program, and image pickup apparatus having image processing apparatus
Publication Date: 2016.09.27 CANON KK
  • US9456155B2 patent drawing
  • US9456155B2 patent drawing
  • US9456155B2 patent drawing

AI summary

An image processing apparatus obtains a picked-up image which is output from an image pickup element which includes a microlens array for obtaining the picked-up image including ray directional information of an object image formed by a photographing optical system, generates a reconstruction image by reconstructing the obtained picked-up image on the basis of the ray directional information, and detects a defect pixel of the generated reconstruction image.