Auto-exposure Technique in Camera Shutter Assembly

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Solution Overview

Problem

Conventional cameras lack an effective auto-exposure mechanism to optimize image brightness for specific regions of interest within a scene, often resulting in suboptimal image quality due to varying light levels.

Innovation Solution

A camera system that uses an image processor to configure the shutter assembly with optimal exposure parameters by identifying a region of interest, such as a face, and adjusting exposure time, aperture size, and gain to achieve desired brightness levels within that region, regardless of other areas in the scene.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If conventional exposure techniques are used to control light incident on the capturing medium, then the overall brightness of the captured image can be adjusted, but the brightness of specific regions of interest (such as human skin) cannot be optimized independently

Engineering Contradiction:

Improvebrightness of region of interestVSAvoidability to handle varying light levels in different regions

Core Design Contradiction:

Illumination intensityVSAdaptability or versatility

Solution Approach 1:

The patent applies local quality by making the exposure control region-specific rather than global. The system identifies a region of interest (such as human skin) within the scene and calculates exposure parameters specifically for that region, allowing different parts of the image to have different exposure characteristics. This enables optimal brightness for the region of interest while other regions may have different brightness levels.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent segments the scene into a region of interest and other regions. By detecting and isolating the region of interest (such as using face detection or skin tone analysis), the system can independently calculate and apply exposure parameters to that specific segment, rather than treating the entire scene uniformly.

Inventive Principle:

Principle #1Segmentation

2Extent of automation

If manual exposure techniques are used to configure exposure parameters, then users can obtain desired brightness levels, but the system lacks automation and requires user expertise

Engineering Contradiction:

Improveautomatic configuration of exposure parametersVSAvoiduser configuration requirement

Core Design Contradiction:

Extent of automationVSEase of operation

Solution Approach 1:

The patent implements self-service by enabling the camera system to automatically perform exposure parameter configuration without requiring user input. The system autonomously identifies the region of interest, analyzes its luminance characteristics, calculates appropriate exposure parameters, and configures the shutter assembly accordingly. This eliminates the need for manual user configuration while achieving optimized exposure for the detected region.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system uses feedback by continuously monitoring the luminance of the detected region of interest and adjusting exposure parameters based on this feedback. The image processor analyzes the brightness levels in real-time and modifies exposure settings to achieve the desired brightness target, creating a closed-loop control system that automatically adapts to varying lighting conditions.

Inventive Principle:

Principle #23Feedback

3Manufacturing precision

If exposure parameters are optimized for the entire scene, then overall image brightness can be balanced, but specific regions of interest may not achieve desired brightness levels

Engineering Contradiction:

Improvebrightness precision for region of interestVSAvoidoverall scene brightness

Core Design Contradiction:

Manufacturing precisionVSIllumination intensity

Solution Approach 1:

The patent prioritizes local quality by optimizing exposure parameters specifically for the region of interest rather than achieving uniform brightness across the entire scene. The system calculates exposure parameters based on the luminance characteristics of the detected region (such as human skin), ensuring that this specific area achieves the desired brightness level, while accepting that other regions may have different brightness characteristics.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS8290357B2Auto-exposure technique in a camera

Publication Date: 2012.10.16 NVIDIA CORP

AI summary

An image processor, which determines appropriate exposure parameters for a shutter assembly in a camera. The image processor may computationally determine a region of interest in a scene sought to be captured, and set the parameters to ensure that the exposure parameters are set to capture an image of the scene with the region of interest having a desired brightness level. In an embodiment, pixel values of multiple frames (each frame with a corresponding set of configuration parameters of the shutter assembly) may be examined to determine the frame having pixel values with the region having the desired brightness level. The shutter assembly may be configured with the parameters corresponding to such a frame to provide an auto-exposure feature.