Imaging Device Pixel Interpolation for Phase Difference Detection
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Solution Overview
Problem
Existing imaging devices face challenges in maintaining image quality due to the need for phase difference detecting pixels, which reduce the number of imaging pixels and introduce irregular patterns when densely arranged, and existing correction methods either deteriorate image quality or increase circuit complexity.
Innovation Solution
An imaging device with two-dimensionally arranged pixels, including normal imaging pixels and functional phase difference detecting pixels at nonuniform intervals, uses a memory section to record pixel arrangements, calculates weights based on these arrangements, and performs pixel interpolation using these weights to correct pixel values, thereby maintaining image quality without increasing circuit complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If phase difference detecting pixels are densely arranged to detect all frequencies, then measurement precision is improved, but the number of imaging pixels decreases and image quality deteriorates
Solution Approach 1:
The imaging element is segmented into two distinct pixel types: phase difference detecting pixels arranged in stepped portions and normal imaging pixels in non-stepped portions. This segmentation allows each pixel type to perform its specialized function without compromising the other, resolving the contradiction between detection precision and imaging quality.
Solution Approach 2:
Phase difference detecting pixels are arranged in stepped portions that extend in a direction different from the phase difference detecting direction. This dimensional arrangement allows dense packing of detection pixels without reducing the number of normal imaging pixels in the imaging direction, thereby maintaining both detection precision and imaging quality.
2Measurement precision
If phase difference detecting pixels are arranged in stepped portions to increase density, then measurement precision is improved, but irregular patterns are generated and image quality deteriorates
Solution Approach 1:
The harmful effect of irregular pattern generation is extracted and isolated to specific regions where stepped portions are located. Normal pixels in non-stepped portions continue to function without generating irregular patterns, while phase difference detection is performed using the stepped arrangement. This separates the detection function from the harmful pattern generation.
Solution Approach 2:
Different regions of the imaging element have different functions: stepped portions contain phase difference detecting pixels for high-precision detection, while non-stepped portions contain normal imaging pixels for high-quality imaging. This local differentiation allows each region to optimize its specific function without negatively affecting the other.
3Device complexity
If simple average correction is applied to phase difference detecting pixel outputs, then device complexity is reduced, but image quality deteriorates
Solution Approach 1:
Pixel values for phase difference detecting pixels are preliminarily calculated using interpolation processing based on surrounding normal pixel values before actual detection. This preliminary action provides corrected pixel values that maintain image quality without requiring complex real-time correction algorithms during operation.
Solution Approach 2:
Pixel values from normal imaging pixels are copied and interpolated to generate pixel values for phase difference detecting pixels. This copying approach maintains consistency between detection pixels and imaging pixels, preventing image quality deterioration while keeping the correction mechanism simple.
4Manufacturing precision
If adaptive filter coefficient adjustment is used to correct pixel values, then image quality is maintained, but circuit scale and power consumption increase
Solution Approach 1:
Instead of using adaptive filter coefficients that require complex circuitry, the patent changes the parameter approach by using fixed interpolation weights based on the known stepped portion arrangement. This parameter change maintains image quality through consistent interpolation while significantly reducing circuit complexity and power consumption.
Data Source
AI summary
An imaging device includes an imaging element, a weight calculating section, and an interpolation processing section. The imaging element includes normal pixels and functional pixels, the functional pixels being arranged at nonuniform intervals in a first direction. The weight calculating section calculates a first weight and a second weight, the second weight being smaller than the first weight. The interpolation processing section performs pixel interpolation to interpolate the pixel value of each of the functional pixels based on the pixel values obtained by the peripheral normal pixels where the first weight and the second weight are applied to a pixel value obtained by each of the normal pixels arranged in the first direction and a direction different from the first direction, respectively.