Scaling Circuit Image Distortion Correction Using Motion Sensor Shift
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Solution Overview
Problem
Cameras with rolling shutters, commonly used in mobile devices, suffer from image distortion due to camera movement during capture, which existing image signal processors address slowly and with high power consumption.
Innovation Solution
A scaling circuit is used to calculate and apply shift values based on camera movement, allowing the image processing to start at fractional pixel positions and dynamically adjust scaling factors to correct distortion, potentially using motion sensor data and multi-tap polyphase filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If image signal processors are used to correct rolling shutter distortion based on image data, then image distortion correction is achieved, but processing speed is slow and power consumption is high
Solution Approach 1:
The patent replaces complex image signal processing operations with a simplified geometric transformation approach. Instead of analyzing image data to detect and correct distortion, the system uses a pre-determined transformation matrix based on camera motion parameters to directly warp the image coordinates, significantly reducing computational complexity and processing time
Solution Approach 2:
The patent performs distortion correction in advance by capturing additional peripheral pixels during the rolling shutter scan and pre-calculating their positions using motion sensor data. This preliminary action allows the main image processing to proceed faster since the correction parameters are already determined before full image processing begins
2Manufacturing precision
If image signal processors are used to correct rolling shutter distortion based on image data, then image distortion correction is achieved, but power consumption is high
Solution Approach 1:
The patent replaces power-intensive image signal processing with a lightweight geometric transformation method that uses simple coordinate mapping and interpolation, dramatically reducing the computational power required while maintaining correction accuracy
Solution Approach 2:
The patent introduces motion sensor data as an intermediary that provides direct measurement of camera motion, eliminating the need for complex image-based distortion analysis and reducing the computational burden on the image signal processor
3Manufacturing precision
If pixels are discarded preceding the line position to correct distortion, then alignment accuracy is improved, but image size is reduced
Solution Approach 1:
The patent dynamically adjusts the image scaling factor based on the calculated distortion parameters and the number of discarded pixels. This allows the system to maintain the desired output image size by compensating for the discarded pixels through proportional scaling of the remaining image content
Solution Approach 2:
The patent changes the scaling parameter of the image processing pipeline to compensate for the loss of pixels during distortion correction. By adjusting the scaling factor, the system restores the original image dimensions while preserving the alignment accuracy achieved through pixel discarding
Data Source
AI summary
Techniques relating to correction of image distortion caused by movement of a camera unit during image capture. In one embodiment, an apparatus may include a camera unit and a scaling circuit. The apparatus may be configured to calculate a shift value for a line of an image captured by the camera unit, where the shift value is indicative of an amount of movement of the camera unit during at least a portion of capture of the image. The scaling circuit may be configured to operate on the line starting at a line position that is based on the calculated shift value. The calculated shift value may be based on movement information generated by a motion sensor. The scaling circuit may include a digital differential analyzer and one or more multi-tap polyphase filters. The line position may be specified as a fractional pixel value.