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•Driver’ arm and steering wheel blocking camera’s view.

•       For the two camera and Lexus setup, Driver ‘arm and steering wheel is coming in and out of ROI frequently in the normal operation condition of the vehicle. The arm and steering wheel not only block the view of driver’s face which is ROI of the algorithm, it also make the sensor exposure control very difficult. Whenever the ROI be blocked, the algorithm has no image to process and lost the tracking of the features. Once the blockage move out of the way, the camera will still take few frames to stabilize. The algorithm also takes time to re-track and reclassify the features. So the gaze and face detection function will be intermittent, the Gesture control function which a lot of customer want is not very feasible. 

•Resolution across the working envelope

•          The issue with the ICI application of current setup is the working range of camera inside the working envelope is much larger than the DOF. The camera working range inside the working envelope is the 3D projection of working envelope on to the optical axis of camera. For the Audi setup we have today, this working range is 69.8 cm which is considerably more than the 14 cm DOF of the system. We have progressive loss of resolution when out of focus until about 20% of the 1280X960 resolution.

•     That basically mean we have no chance to keep the 1280X960 sensor level resolution across the working envelope which the algorithm team think as minimum. Just boost up the sensor pixel numbers by 5M sensor is not the solution neither. Since that resolution can only be achieved in very small range of 7 cm.

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•Illumination uniformity across the image

•       The illumination can change average 5.5 times across the working range. It is also blocked by the driver’s arm and steering wheel from time to time. The correct exposure level is very hard to achieve. We suspect if we choose auto exposure mode, the image will be oscillation and also the ROI exposure will not be at optimized range. If we choose Manual exposure control, we have a difficulty to have appropriate exposure across the working range. Some area will be saturated and other will under exposure which makes the ROI in that range dark and noisy.