Image Sensor Pixel Array Dual-Exposure HDR Generation
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Solution Overview
Problem
Existing image sensing devices struggle to generate high-quality high dynamic range (HDR) images without sacrificing image resolution, particularly when dealing with scenes containing both high and low brightness areas.
Innovation Solution
The image sensing device includes a pixel array with sensing pixels connected to multiple data readout lines, allowing each sensing pixel to output signals corresponding to different exposure periods. The processing circuit generates HDR images by fusing these signals, enabling simultaneous capture of data under varying exposure conditions without blurring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple images are captured with different exposure settings and synthesized into HDR image, then dynamic range coverage is improved, but image quality deteriorates due to hand shaking or object movement causing alignment failure and blurred areas
Solution Approach 1:
The patent divides the single image capture process into multiple exposure periods (first exposure period and second exposure period) within the same row exposure period. Each exposure period captures image data under different exposure settings using the same sensing pixel, enabling HDR synthesis without requiring multiple separate captures that would cause alignment issues.
Solution Approach 2:
The patent introduces a temporal dimension by capturing multiple exposure periods sequentially within the same row exposure period. This allows different exposure settings to be applied to the same spatial pixel at different times, achieving HDR effect while maintaining spatial alignment since all captures occur at the same moment in time.
2Adaptability or versatility
If different sensing pixel units are designed to capture images based on different exposure settings, then dynamic range coverage is improved, but image resolution deteriorates
Solution Approach 1:
The patent makes each sensing pixel multi-functional by enabling it to capture multiple exposure periods sequentially. Instead of having different pixel types for different exposures, all sensing pixels can perform both short and long exposure captures within the same row exposure period, maintaining full image resolution while achieving HDR dynamic range coverage.
Solution Approach 2:
The patent introduces dynamic exposure control where the exposure period length can be adjusted for each sensing pixel based on the scene brightness. The processing circuit determines appropriate exposure periods dynamically, allowing the system to adapt to varying lighting conditions while maintaining consistent image resolution across all pixels.
3Quantity of substance
If single image capture is used, then image resolution is maintained, but dynamic range coverage is insufficient causing overly dark or excessively exposed areas
Solution Approach 1:
The patent performs preliminary exposure setup by determining appropriate exposure periods before actual image capture. The processing circuit calculates and sets the first and second exposure periods based on scene analysis, enabling optimal exposure for both dark and bright areas before the capture process begins.
Solution Approach 2:
The patent changes the exposure period parameter to achieve different dynamic ranges. By adjusting the length of the first and second exposure periods, the system can capture both dark and bright areas of the scene. The processing circuit modifies this parameter dynamically based on the specific imaging requirements and scene conditions.
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 allows for the generation of high-quality HDR images with preserved image resolution, effectively addressing the challenges of capturing dynamic range extremes in a single image.
Implementation Method 1
each of the sensing pixels outputs a first sensing signal corresponding to a first exposure period within a row exposure period through the first data readout line, and each of the sensing pixels outputs a second sensing signal corresponding to a second exposure period within the row exposure period through the second data readout line
Data Source
AI summary
An image sensing device and an HDR image generation method thereof are provided. The image sensing device includes a pixel array, a readout circuit, and a processing circuit. The pixel array includes multiple sensing pixels electrically connected to multiple data readout lines. The readout circuit is electrically connected to the data readout lines and the processing circuit, and the data readout lines of each sensing pixel include a first data readout line and a second data readout line. Each sensing pixel outputs a first sensing signal corresponding to a first exposure period within a row exposure period through the first data readout line, and each sensing pixel outputs a second sensing signal corresponding to a second exposure period within the row exposure period through the second data readout line. The processing circuit generates an HDR image based on the first sensing signal and the second sensing signal.