Camera Module Region-Specific Auto Focus Calibration
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Solution Overview
Problem
Conventional camera modules require lengthy auto focus scanning from infinity to macro, leading to increased auto focus time and potential defocusing issues, as they rely on center region calibration, which may not accurately represent the user-desired region for focusing.
Innovation Solution
A camera module with an image sensor, image signal processor, display, touch detector, memory, and auto focus driver that allows users to touch a specific region of an image to read and apply corresponding auto focus calibration codes, reducing auto focus time and ensuring accurate focus adjustment by dividing the image into regions with unique calibration codes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If auto focus calibration is performed at the center region only, then the calibration process is simple and fast, but the focus accuracy for user-desired regions (non-center regions) deteriorates
Solution Approach 1:
The image sensor area is divided into multiple regions (e.g., center region, left region, right region, upper region, lower region), and separate auto focus calibration codes are stored for each region. This segmentation allows the system to select the appropriate calibration code based on the user-selected region, thereby improving focus accuracy for non-center regions while maintaining a relatively simple calibration process.
Solution Approach 2:
Different auto focus calibration codes are assigned to different regions of the image sensor. Each region has its own optimized calibration code that reflects the specific focusing characteristics of that region. This local quality approach ensures that when a user selects a particular region for focusing, the camera uses the most appropriate calibration data for that specific area, improving overall focus accuracy.
2Reliability
If auto focus scanning is performed from infinity to macro, then all possible focus positions are covered, but the auto focus time increases
Solution Approach 1:
Auto focus calibration codes for multiple regions are pre-calculated and stored in the memory during manufacturing. When the camera needs to perform auto focus, it directly retrieves the pre-stored calibration code corresponding to the selected region, eliminating the need for real-time scanning from infinity to macro. This preliminary action significantly reduces auto focus time while maintaining reliable focus coverage.
Solution Approach 2:
Instead of performing complete auto focus scanning during operation, the system uses pre-captured calibration data (copies of focus information) stored in memory. These calibration codes represent the focus characteristics of different regions and are copied from the calibration process into the operational memory, allowing rapid retrieval without repeated scanning.
3Measurement precision
If multiple region calibration codes are stored in memory, then focus accuracy for any region is improved, but the memory requirement and device complexity increase
Solution Approach 1:
The calibration data is segmented into discrete region-specific codes that can be stored in a structured manner in memory. Each region (center, left, right, upper, lower) has its own calibration code, organized in a way that facilitates efficient retrieval based on the touched region coordinates.
Solution Approach 2:
The auto focus driver acts as an intermediary that receives the touched region coordinates, determines the appropriate region, and retrieves the corresponding calibration code from memory. This intermediary layer simplifies the management of multiple calibration codes by providing a systematic mapping between region coordinates and calibration data.
Data Source
AI summary
An exemplary embodiment of the present disclosure includes a touch detection unit detecting if a particular region of the image of the object displayed by the display unit is touched, a memory unit stored with an auto focus calibration code of the particular region detected by the touch detection unit, and an auto focus driving unit receiving a coordinate of the particular region detected by the touch detection unit, reading out from the memory unit an auto focus calibration code corresponding to the particular region of the image of the object displayed on the display unit, and driving an auto focus actuator.