Phase-Difference Pixel Discrimination for Image Quality
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The integration of phase-difference detection pixels in image-capturing devices for distance measurement degrades image quality due to reduced pixel numbers, and existing correction methods are inefficient in utilizing partially shielded phase-difference detection pixel outputs.
Innovation Solution
An image-capturing device with a phase-difference pixel discriminating unit that classifies pixels into first and second categories based on spectral sensitivity, applying lower precision correction to first pixels with less noticeable quality degradation and higher precision correction to second pixels, while using a number-of-pixels-reducing unit to adjust pixel density and mixing processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If phase-difference detection pixels are arranged with high density to enable distance measurement at every frequency, then distance measurement capability is improved, but image quality degrades due to reduction of pixels that form the image
Solution Approach 1:
The patent segments pixels into two functional categories: phase-difference detection pixels (for distance measurement) and imaging pixels (for image formation). This segmentation allows each type to be optimized for its specific function while coexisting in the same image-capturing element, resolving the contradiction between distance measurement capability and image quality
Solution Approach 2:
The patent applies local quality by assigning different spectral sensitivities to different regions of the image-capturing element. Specifically, pixels with spectral sensitivity in the blue wavelength band are used as phase-difference detection pixels, while other pixels maintain full imaging capability. This localized functional differentiation allows distance measurement without compromising overall image quality
2Loss of information
If phase-difference detection pixels are arranged across pixels with different spectral sensitivities to prevent information loss, then spectral information is preserved, but circuit scale and power consumption increase
Solution Approach 1:
The patent extracts only the necessary spectral sensitivity information (blue wavelength band) for phase-difference detection, rather than preserving all spectral information across all pixels. This extraction approach maintains sufficient spectral information for distance measurement while significantly reducing circuit complexity and power consumption
Solution Approach 2:
The patent changes the spectral sensitivity parameter of specific pixels to be specialized in the blue wavelength band for phase-difference detection. This parameter specialization allows the system to achieve distance measurement functionality with reduced circuit complexity compared to maintaining full spectral information across all pixels
3Measurement precision
If phase-difference detection pixels are partially shielded from light to enable phase-difference detection, then distance measurement function is achieved, but image quality degrades due to altered pixel outputs
Solution Approach 1:
The patent converts the harmful effect of light shielding (which alters pixel outputs and degrades image quality) into a beneficial feature by using the altered outputs specifically for phase-difference detection purposes. The shielded pixels' unique characteristics are leveraged for distance measurement rather than being treated as defects to be corrected
Solution Approach 2:
Instead of treating shielded pixels as imaging pixels that need correction (the conventional approach), the patent inverts the approach by designating shielded pixels exclusively for phase-difference detection and using unshielded pixels for imaging. This inversion eliminates the need for complex correction processing and improves overall system efficiency
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach improves image quality by effectively utilizing phase-difference detection pixels with reduced circuit scale and power consumption, balancing image quality and computational efficiency.
Implementation Method 1
an image-capturing element that converts an optically formed optical image into an electrical signal
Data Source
AI summary
An image-capturing device includes: an image-capturing element in which a plurality of pixels, which have different spectral sensitivities, are arrayed in a two-dimensional matrix manner, and phase-difference detection pixels are arranged as some of the pixels; a phase-difference pixel discriminating unit that classifies the phase-difference detection pixels arranged in the image-capturing element as first pixels, which have a spectral sensitivity at which degradation of image quality is more difficult to discern for human eyes than the other spectral sensitivities, and second pixels which are the phase-difference detection pixels other than the first pixels; and a phase-difference pixel value correcting unit that subjects the first pixels classified by the phase-difference pixel discriminating unit to correction processing of a lower precision than that for the second pixels.