Imaging Device Focus Control Using Bokeh State Index
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Solution Overview
Problem
Existing imaging devices face challenges in accurately performing focus detection, particularly in night scenes with point light sources, leading to false focus issues due to the difficulty in handling scenes with significant Bokeh effects.
Innovation Solution
An imaging device equipped with an image sensor and a processor that generates indices representing image types and Bokeh states, allowing for precise focus control adjustments based on these indices to prevent false focus in challenging scenes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If correction processing is executed to prevent false focus in night scenes, then false focus is prevented, but focusing may become impossible in other scenes
Solution Approach 1:
The patent implements dynamic switching between different focus detection methods based on scene classification. The control section selects either the contrast AF method or the correction processing method according to the detected scene type, allowing the system to adapt its behavior to match the specific imaging conditions rather than using a fixed approach
Solution Approach 2:
The patent applies different focus detection strategies to different scene types. By classifying scenes into categories such as night scenes with point light sources versus general scenes, the system applies locally optimized processing - using correction processing only where needed (night scenes) while maintaining standard contrast AF for other scenes, thus preserving versatility while preventing false focus where necessary
2Productivity
If contrast AF method is used for focus detection, then focus detection is simple and fast, but false focus occurs in night scenes with point light sources
Solution Approach 1:
The patent introduces a feedback mechanism where the scene classification result informs the focus detection process. The control section receives scene type information from the classification and uses this feedback to select the appropriate focus detection method, creating a closed-loop system that adapts based on environmental conditions
Solution Approach 2:
The system dynamically adjusts the focus detection approach based on real-time scene analysis. When night scenes with point light sources are detected, the system switches from standard contrast AF to correction processing, optimizing both speed and accuracy for the specific conditions without sacrificing the rapid performance of contrast AF in suitable scenarios
3Reliability
If correction processing is applied to all scenes, then false focus is prevented, but wasteful AF operation occurs in easy-to-handle scenes
Solution Approach 1:
The patent applies correction processing only partially - specifically to night scenes with point light sources where false focus is problematic - rather than to all scenes. This selective application avoids the wasteful AF operations that would occur in easy-to-handle scenes while still providing the reliability benefits where needed
Solution Approach 2:
The system applies different levels of processing intensity to different scene types. Easy-to-handle scenes receive standard contrast AF processing with no additional correction, while night scenes with point light sources receive the enhanced correction processing, optimizing the balance between reliability and operational efficiency for each specific condition
Data Source
AI summary
An imaging device, comprising an image sensor that receives subject light and generates image data, and a processor comprising a focus control section, an index generating section, and a control section, wherein the focus control section performs focus detection based on the image data, and controls focus drive based on focus detection results, the index generating section is input with the image data, and generates a first index representing which image of a given plurality of types of image the image data is close to, and a second index representing Bokeh state of an image corresponding to the image data, and the control section changes control of focus drive by the focus control section based on output of the index generating section.