Imaging Control Device Low-Sensitivity Pixel Dynamic Range

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Solution Overview

Problem

Existing imaging technologies face challenges in obtaining appropriate exposure conditions during second photographing for generating images with expanded dynamic range, as the first photographing often results in saturated image signals, leading to unnecessary exposure in the second photographing.

Innovation Solution

Incorporating a low-sensitivity pixel with lower photoelectric conversion sensitivity and an infrared cut-filter to generate a low-sensitivity histogram, which allows for calculating a short-time exposure condition for the second photographing, enabling the combination of image signals to achieve an appropriate exposure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a histogram is generated from an image signal obtained by first photographing to determine exposure condition for second photographing, then the dynamic range can be expanded, but the acquired image is unnecessarily exposed because the histogram does not completely match the distribution of luminance of the subject when high luminance areas are saturated

Engineering Contradiction:

Improveexposure condition accuracyVSAvoidluminance distribution information

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The imaging element is segmented into normal pixels and low-sensitivity pixels. Normal pixels capture the full dynamic range including saturated high luminance areas, while low-sensitivity pixels specifically capture the luminance distribution of bright areas without saturation. This segmentation allows separate histogram analysis for determining optimal exposure conditions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Low-sensitivity pixels act as an intermediary to obtain accurate luminance distribution information of bright areas. These pixels have reduced photoelectric conversion sensitivity, preventing saturation in high luminance regions and providing a histogram that accurately reflects the subject's luminance distribution, which then guides the exposure condition calculation for the second photographing.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If the imaging element uses normal pixels with high photoelectric conversion sensitivity, then the image signal has high sensitivity, but the image signal becomes saturated in high luminance areas during first photographing

Engineering Contradiction:

Improveimage signal sensitivityVSAvoidsignal saturation

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The imaging element is divided into two types of pixels: normal pixels with high sensitivity for capturing dark and mid-tone areas, and low-sensitivity pixels for capturing bright areas without saturation. This segmentation allows each pixel type to operate within its optimal range, preventing information loss.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The photoelectric conversion sensitivity parameter is changed by creating two types of pixels with different sensitivity characteristics. Normal pixels maintain high sensitivity for general imaging, while low-sensitivity pixels have reduced sensitivity specifically to prevent saturation in high luminance areas, allowing both functions to coexist.

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach ensures accurate exposure conditions during second photographing, preventing unnecessary exposure and effectively expanding the dynamic range of the combined images.

Implementation Method 1

a low-sensitivity pixel for generating a low-sensitivity image signal and having lower photoelectric conversion sensitivity to visible light than the normal pixel

Methodology Applied

Scientific EffectPhotoelectric conversion: Photoelectric Effect

Implementation Method 2

Incorporating a low-sensitivity pixel with lower photoelectric conversion sensitivity and an infrared cut-filter

Methodology Applied

Scientific EffectInfrared cutoff: Absorption (EM radiation)

Data Source

PatentUS9894284B2Imaging control device, imaging apparatus, and imaging control method

Publication Date: 2018.02.13 SONY SEMICON SOLUTIONS CORP

AI summary

To obtain an appropriate exposure condition even in second photographing when generating an image with an expanded dynamic range. An exposure control unit controls an imaging element including a normal pixel for generating an image signal and a low-sensitivity pixel for generating a low-sensitivity image signal and having lower photoelectric conversion sensitivity to visible light than the normal pixel under a predetermined exposure condition and causes the imaging element to output the image signal and the low-sensitivity image signal. A low-sensitivity histogram generating unit generates a low-sensitivity histogram indicating an appearance frequency distribution of the low-sensitivity image signal based on the low-sensitivity image signal. A short-time exposure condition calculating unit calculates a short-time exposure condition with an exposure time shorter than the exposure condition based on the generated low-sensitivity histogram. A short-time exposure control unit controls the imaging element under the calculated short-time exposure condition and causes the imaging element to output a short-time exposure image signal as an image signal generated by the normal pixel. A combining unit combines the image signal and the short-time exposure image signal.