Imaging Apparatus FPN Correction via Live View Averaging
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Solution Overview
Problem
Conventional cameras suffer from reduced precision in correcting fixed pattern noises (FPN) due to the method of reading out signals during pixel reset and subtracting them from acquired image signals.
Innovation Solution
The imaging apparatus includes an image sensor, a calculation unit that calculates correction values for pixel signals, and a correction unit that corrects these signals using averaging techniques in live view mode, allowing for precise FPN correction without the need for new pixel signal acquisition during still image capture or continuous shooting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If FPN correction is performed by reading out signals during pixel reset and subtracting from acquired image signals, then correction can be implemented, but precision deteriorates
Solution Approach 1:
The patent applies preliminary action by calculating correction values during live view mode before still image capture. The correction values are computed in advance by averaging pixel signals from multiple frames, and then these pre-calculated values are used to correct the final still image, avoiding the need to perform correction during the actual image capture moment.
Solution Approach 2:
The patent implements periodic action by continuously updating correction values during live view mode through periodic averaging of pixel signals from multiple frames. This periodic calculation creates a refined correction value that is then applied to the still image, improving correction precision through repeated measurements.
2Productivity
If correction values are calculated during live view mode, then processing load during still image capture is reduced, but additional processing is required beforehand
Solution Approach 1:
The patent performs correction value calculation in advance during live view mode, storing these values for later use. This preliminary computation transfers the processing load from the still image capture moment to the live view period, reducing processing requirements when the shutter is pressed.
Solution Approach 2:
The patent dynamically adjusts the timing of correction value calculation based on the operational mode. During live view, correction values are continuously updated and averaged, while during still image capture, the pre-calculated values are directly applied without recalculation, optimizing processing timing for each mode.
3Measurement precision
If multiple correction values are averaged in live view mode, then correction precision improves, but processing complexity increases
Solution Approach 1:
The patent merges multiple pixel signal measurements by calculating their average to generate a single correction value. This combining of multiple data points improves the accuracy of the correction value while using a straightforward averaging algorithm that maintains processing simplicity.
Solution Approach 2:
The patent changes the parameter of correction values by continuously updating and averaging them across multiple frames during live view mode. This parameter transformation from individual frame corrections to averaged multi-frame corrections improves precision while using simple arithmetic operations.
Data Source
AI summary
An imaging apparatus includes: an image sensor having a plurality of pixels arranged in an array that captures an image of a subject and outputs pixel signals; a calculation unit that calculates a correction value for correcting an error of the pixel signals read out from the image sensor for each column of the array of the pixels; and a correction unit that corrects the image signals using the correction value calculated by the calculation unit. In a live view mode, the calculation unit calculates a new correction value by averaging the calculated correction value and a correction value for a previous frame.