Ghost Noise Correction in Image Capturing Apparatus

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Solution Overview

Problem

Image capturing apparatuses with focus-detection pixels experience image noise due to ghost light, which affects image quality, as ghost light interacts differently with focus-detection pixels and adjacent image pixels, leading to crosstalk and noise.

Innovation Solution

An image capturing apparatus with a ghost detection circuit, correction-target image setting circuit, and pixel correction circuit that identifies and corrects pixels affected by ghost light crosstalk, using interpolation from surrounding pixels to minimize noise and maintain image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If focus-detection pixels with different color filter permeation characteristics are installed in the image capturing element, then focus detection capability is improved, but image noise increases due to ghost light crosstalk affecting adjacent image pixels differently

Engineering Contradiction:

Improvefocus detection capabilityVSAvoidimage noise from ghost light

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the image capturing element into distinct functional zones: focus-detection pixels with specific color filter characteristics and adjacent image pixels with different color filter characteristics. This segmentation allows the system to handle ghost light crosstalk differently for each zone, applying targeted correction to affected image pixels while preserving focus detection accuracy.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by recognizing that different pixels in the image capturing element have different susceptibility to ghost light crosstalk based on their position relative to focus-detection pixels. The correction processing is applied locally to specific image pixels that are adjacent to focus-detection pixels, rather than uniformly to all pixels, thereby maintaining image quality where needed while preserving focus detection functionality.

Inventive Principle:

Principle #3Local quality

2Object-affected harmful factors

If ghost correction processing is applied to all image pixels, then image noise is reduced, but processing complexity and computational load increase

Engineering Contradiction:

Improveimage noise from ghost lightVSAvoidcorrection processing complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent applies partial action by selectively correcting only those image pixels that are adjacent to focus-detection pixels and therefore most susceptible to ghost light crosstalk. Rather than applying correction processing to all image pixels uniformly, the system identifies and corrects only the specific pixels that require correction, reducing computational load while maintaining effective noise suppression.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The patent replaces complex mechanical or hardware-based ghost light blocking structures with a computational approach that uses software-based correction processing. By detecting ghost light crosstalk and applying digital correction to affected pixels, the system achieves ghost suppression without adding physical complexity to the optical path or requiring additional hardware components.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Object-affected harmful factors

If uniform correction processing is applied to all pixels near focus-detection pixels, then ghost light effects are suppressed, but image quality decreases due to over-correction of pixels not affected by crosstalk

Engineering Contradiction:

Improveghost light crosstalkVSAvoidimage quality accuracy

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent applies local quality by determining the specific positional relationship between each image pixel and adjacent focus-detection pixels. Correction processing is applied only to image pixels that are actually affected by ghost light crosstalk from neighboring focus-detection pixels, while leaving unaffected pixels unchanged. This selective approach prevents over-correction and maintains image quality accuracy.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent performs preliminary identification of which image pixels are affected by ghost light crosstalk before applying correction processing. By pre-determining the correction targets based on the spatial relationship between focus-detection pixels and image pixels, the system avoids unnecessary correction of unaffected pixels and ensures that correction is applied only where needed, preserving image quality.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS10469779B2Image capturing apparatus

Publication Date: 2019.11.05 OLYMPUS CORPORATION(JP)

AI summary

An image capturing apparatus includes: a ghost detection unit that detects a ghost generated in a signal obtained from an image capturing element; a correction-target-pixel setting unit that sets, as a correction-target pixel, an image pixel affected by crosstalk of the ghost from among image pixels adjacent to a focus-detection pixel; and a pixel correction unit that corrects the correction-target pixel according to a correction value calculated from an image pixel located in the vicinity of the correction-target pixel.