Image Sensor Dark Current Noise Control via Temperature-Adaptive Black Image Capture
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Solution Overview
Problem
In continuous shooting, the uneven noise levels in composite images arise due to inconsistent dark current removal across images, as existing methods either require frequent light-shielding for black image capture or fail to accurately remove noise in intermediate shots.
Innovation Solution
An image capturing apparatus and method that determines the need for light-shielding and dark current removal based on temperature and the number of images to be shot, controlling the image sensor to capture black images only when necessary, ensuring consistent noise reduction across all images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dark current removal is performed on each continuously shot image by capturing black images, then noise removal accuracy is improved, but the shooting interval increases due to frequent light-shielding operations
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the dark current removal strategy based on temperature conditions. When the image sensor temperature is below a predetermined threshold, dark current removal is performed on all continuously shot images. When the temperature exceeds the threshold, dark current removal is performed only on the first image or every Nth image, thereby adapting the noise removal frequency to temperature conditions and reducing unnecessary light-shielding operations.
2Loss of time
If dark current removal is performed only on the first and last images in continuous shooting, then the shooting interval is reduced, but the noise removal accuracy decreases for intermediate images
Solution Approach 1:
The patent introduces a temperature-based parameter change mechanism that determines the frequency of black image capture. Instead of uniformly applying dark current removal to all images or only boundary images, the system adjusts the removal frequency based on temperature conditions, ensuring adequate noise removal accuracy while minimizing the impact on shooting interval.
3Productivity
If dark current removal is performed selectively based on temperature and shot number, then the shooting efficiency is improved, but the complexity of determining when to perform dark current removal increases
Solution Approach 1:
The patent manages control logic complexity by establishing clear temperature thresholds and predetermined shot intervals (N) that guide dark current removal decisions. The controller uses these predefined parameters to automatically determine when black image capture is necessary, avoiding the need for complex real-time analysis while maintaining shooting efficiency.
4Measurement precision
If black images are captured frequently during continuous shooting, then dark current noise is effectively removed, but the uniformity of noise levels in composite images deteriorates when mixing images with and without dark current removal
Solution Approach 1:
The patent ensures noise level uniformity by applying dark current removal consistently to all continuously shot images when the temperature is below the threshold. This uniform application prevents mixing of images with different noise characteristics in composite images, maintaining composition stability while still allowing reduced frequency when temperature conditions warrant it.
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 prevents mixing of images with and without dark current removal, maintaining uniform noise levels in composite images and reducing the shooting interval by optimizing dark current removal during continuous shooting.
Implementation Method 1
a light shielding member; determines, before starting the continuous shooting, whether or not to shoot a black image with the image sensor being shielded from light by the light shielding member
Implementation Method 2
a thermometer that measures temperature of the image sensor
Implementation Method 3
an image sensor; Image signals obtained from image sensors
Data Source
AI summary
An image capturing apparatus comprises: an image sensor; a light shielding member; a thermometer that measures temperature of the image sensor; and a controller that controls the image sensor so as to perform continuous shooting to obtain a plurality of images. The controller determines a number of images to be shot in the continuous shooting, determines, before starting the continuous shooting, whether or not to shoot a black image with the image sensor being shielded from light by the light shielding member based on the temperature measured by the thermometer and the determined number of images to be shot, and in a case where it is determined to shoot a black image, controls to shoot a black image every time an image is shot in the continuous shooting.