Panoramic Camera Rolling Shutter Timing Parallax
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Solution Overview
Problem
Imaging systems with multiple cameras in a rosette formation face challenges with spatial parallax and image distortion due to different entrance pupils, particularly with rolling-shutter CMOS sensors causing warping and blooming issues.
Innovation Solution
The solution involves positioning rolling-shutter CMOS sensors in a portrait orientation and timing the exposure of cameras to align their entrance pupils during motion, using motion parallax to reduce spatial parallax and minimize distortion by staggering the start of image capture between sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple cameras are positioned in a rosette formation to capture panoramic images, then the field of view is improved, but spatial parallax causes ghosting and distortion in stitched images
Solution Approach 1:
The system pre-calculates timing offsets for each camera based on their spatial positions and the vehicle's motion characteristics. Before capturing panoramic images, the controller establishes synchronized exposure timing that compensates for the spatial separation of entrance pupils, thereby eliminating parallax-induced ghosting in the final stitched image
Solution Approach 2:
The system dynamically adjusts the exposure timing of each camera based on real-time vehicle motion data. The controller modifies the capture sequence adaptively, staggering exposures according to the vehicle's speed and direction, which allows the moving entrance pupils to effectively occupy the same spatial position during exposure, reducing spatial parallax
2Manufacturing precision
If rolling-shutter CMOS sensors are used to avoid blooming and streaking, then image quality is improved, but image distortion occurs when the camera is moving
Solution Approach 1:
The system pre-calculates the expected distortion pattern based on vehicle motion parameters and sensor readout characteristics. Before image capture, it establishes a distortion compensation model that maps the rolling shutter's sequential line exposure to the actual scene geometry, enabling post-processing correction that restores proper image shape
Solution Approach 2:
The system uses vehicle motion sensors (accelerometers, GPS) to provide real-time feedback on position and velocity changes during the rolling shutter exposure sequence. This feedback is fed into the controller, which dynamically adjusts the distortion compensation parameters to accurately correct geometric distortion caused by vehicle motion during the rolling readout
3Shape
If interline-shutter CCD sensors are used to avoid rolling shutter distortion, then image geometry is improved, but blooming and streaking occur when portions of the sensor are over-exposed
Solution Approach 1:
The system uses rolling-shutter CMOS sensors, which are more cost-effective and compact than interline-shutter CCD sensors. By combining these affordable sensors with computational distortion correction methods, the system achieves acceptable geometric accuracy without incurring the costs and physical constraints of expensive CCD technology
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 effectively reduces distortion and spatial parallax in panoramic images, improving the stitching of images from multiple cameras while avoiding the blooming and streaking issues associated with interline-shutter CCDs.
Implementation Method 1
Each camera includes an image sensor that converts an optical signal into an electrical signal to form an image
Implementation Method 2
Parallax refers to a perceived shift of an imaged object against a background caused by the different viewpoints of the entrance pupils of the cameras
Data Source
AI summary
The present invention relates to the field of panoramic still and motion photography. In a first embodiment, a camera apparatus for panoramic photography includes a first image sensor positioned to capture a first image. The first image sensor has a rolling-shutter readout arranged in portrait orientation. The camera apparatus also includes second image sensor positioned to capture a second image. The second image sensor has a rolling-shutter readout arranged in portrait orientation. Finally, the camera apparatus includes a controller configured to signal the second image sensor to start capturing the second image before the first image sensor finishes capturing the first image. At least a portion of the first image is in front of the second image relative to a forward direction of the camera apparatus.