Camera Sensor Sensitivity Correction for Consistent Image Noise
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Solution Overview
Problem
High-quality image data recording in cameras, particularly motion picture cameras, faces challenges in compensating for changes in exposure conditions without using neutral density filters, which can introduce unwanted noise and design complexities.
Innovation Solution
A method that adjusts the sensitivity of the image sensor and applies noise corrections to ensure consistent brightness and noise levels across image data recorded under varying exposure conditions, using exposure correction values and noise filtering techniques to match the image data with the target sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If ND filters are used to compensate for exposure changes, then brightness consistency is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces the mechanical/optical ND filter system with an electronic/image processing system. Instead of physically filtering light with ND filters, the invention uses software-based noise correction algorithms that analyze and adjust image data to compensate for exposure changes, thereby eliminating the need for additional optical components and reducing device complexity
Solution Approach 2:
The patent creates a virtual model of noise characteristics at different exposure levels and uses this model to generate corrected image data. By copying and adjusting noise patterns computationally rather than physically modifying light paths, the system achieves brightness consistency without requiring physical filters
2Illumination intensity
If ND filters are attached in front of the lens, then exposure compensation is achieved, but reflections and interference occur
Solution Approach 1:
The patent eliminates the physical ND filter component that causes reflections and interference by substituting it with a computational approach. The system processes image data digitally to achieve exposure compensation, completely avoiding the optical interference problems associated with physical filters
Solution Approach 2:
The patent introduces an intermediate processing step between light capture and final image output. Instead of directly modifying light paths with physical filters, the system uses image processing algorithms as an intermediary to achieve exposure compensation without introducing optical artifacts
3Illumination intensity
If sensitivity of the image sensor is adjusted to compensate for exposure changes, then brightness is improved, but noise levels change perceptibly
Solution Approach 1:
The patent employs feedback mechanisms by analyzing the actual noise characteristics in captured images and using this information to guide the correction process. The system continuously monitors exposure conditions and adjusts noise correction parameters accordingly, creating a closed-loop system that maintains noise consistency while adjusting for brightness changes
Solution Approach 2:
The patent changes the parameters used for noise correction based on exposure conditions. Instead of applying fixed noise correction, the system dynamically adjusts correction parameters according to the actual exposure level and noise characteristics, allowing it to maintain noise consistency across varying brightness conditions
4Illumination intensity
If additional equipment like ND filters is used, then exposure control is improved, but ease of operation deteriorates
Solution Approach 1:
The patent enables the camera system to automatically compensate for exposure changes without requiring user intervention to attach or adjust physical filters. The system self-adjusts by processing image data to maintain consistent brightness and noise levels, making the operation simpler and more automated
Solution Approach 2:
The patent replaces manual filter attachment operations with automated image processing. Instead of requiring users to physically handle and install ND filters, the system uses software-based correction that operates automatically, significantly improving ease of operation
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 method allows for seamless compensation of exposure changes without the need for neutral density filters, maintaining consistent image quality and avoiding perceptible noise differences, thus ensuring high-quality image data recording.
Implementation Method 1
light that emanates from (is radiated or reflected by) objects of the scene is deflected by an optics of the camera onto an image sensor of the camera so that the scene is imaged onto the image sensor. The image sensor in this respect generally comprises a plurality of light-sensitive detector elements that are arranged in rows and columns and that are each configured to generate a respective electric charge in dependence on the intensity of the light incident on the respective detector element
Data Source
AI summary
A method for recording image data by means of a camera, in particular by means of a motion picture camera, is provided. In this respect, the camera comprises an image sensor with an adjustable sensitivity that comprises a plurality of light-sensitive detector elements arranged in rows and columns and that is configured to generate a respective electric charge in dependence on the intensity of light that is incident on a respective detector element during a respective single exposure, to amplify said respective electric charge in dependence on the set sensitivity and to convert it into a respective image signal value. The method comprises: a recording sensitivity and a target sensitivity being predefined, wherein the recording sensitivity deviates from the target sensitivity by an exposure correction value; image data being recorded by means of the camera while the sensitivity of the image sensor is set to the recording sensitivity; a noise correction being determined in dependence on the target sensitivity and/or the exposure correction value; and corrected image data being generated by modifying the recorded image data based on the noise correction.