Subject Tracking Zone Segmentation for Camera Focus and Exposure

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Solution Overview

Problem

Existing camera systems face low tracking reliability when the tracking zone is small, but larger zones increase processing load for focus detection and exposure calculation.

Innovation Solution

A subject tracking device that sets a tracking zone around the main subject within the captured image, using a tracking unit to follow the subject based on image outputs from the central area, with optional image data reduction and display of tracking zones for improved focus detection and exposure calculation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a large tracking zone is used to improve tracking reliability, then tracking reliability is improved, but processing load increases

Engineering Contradiction:

Improvetracking reliabilityVSAvoidprocessing load

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the tracking zone into multiple sub-regions and processes only specific areas within the tracking zone for focus detection and exposure calculation, rather than processing the entire large tracking zone. This segmentation allows maintaining a large tracking zone for reliability while reducing the actual processing load to manageable levels.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different processing strategies to different areas within the tracking zone. Specifically, it identifies a central area within the tracking zone for focus detection and exposure calculation, while using the broader tracking zone for subject tracking. This local differentiation allows the system to maintain high tracking reliability through the large tracking zone while minimizing processing load by concentrating intensive calculations only in the central area.

Inventive Principle:

Principle #3Local quality

2Device complexity

If a small tracking zone is used to reduce processing load, then processing load is reduced, but tracking reliability deteriorates

Engineering Contradiction:

Improveprocessing loadVSAvoidtracking reliability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent segments the tracking zone into a central processing area and surrounding tracking areas. The central area is used for intensive focus detection and exposure calculation, while the surrounding areas contribute to tracking reliability without requiring full processing. This allows using a larger overall tracking zone for reliability while keeping the processed area small enough to manage processing load.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different quality levels of processing to different parts of the tracking zone. The central area receives full processing for accurate focus and exposure, while the periphery provides tracking information with reduced processing. This local quality differentiation resolves the contradiction by ensuring reliability through the extended tracking zone while maintaining acceptable processing load through selective processing intensity.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS8433097B2Subject tracking device, subject tracking method, subject tracking program product and optical device

Publication Date: 2013.04.30 NIKON CORP

AI summary

A subject tracking device includes: a tracking zone setting unit that sets an area where a main subject is present within a captured image as a tracking zone; a tracking unit that tracks the main subject based upon an image output corresponding to the tracking zone; and an arithmetic operation unit that determines through arithmetic operation image-capturing conditions based upon an image output corresponding to a central area within the tracking zone.