How to implement automotive smart rear-view cameras

Customizable code
The smart back-up camera module is approximately 1” cube in size, and uses a single VGA (640x480 pixel) wide dynamic range (WDR) sensor with a 180 degree fish-eye lens. At power-up, the system is required to boot and detect an object in the scene in under 500 msec. All processing is performed on-chip in the camera module and video with overlay is rendered to the driver’s display through analog video.




SmartEBC Algorithm& Application for Vision Based Obstacle Detection and Distance Estimation
The rear-view camera system is automatically activated each time the vehicle is placed into reverse, since it’s powered directly from the vehicle’s reversing lights. Incoming raw video frames are first dewarped and transforms are performed on the image scene. Image features across multiple frames are detected and tracked using optimized versions of both Good Features To Track (GFFT) and Block Matching algorithms. The SmartEBC algorithm does not require CAN bus vehicle input speed for assessing whether or not the vehicle is reversing. Instead, the algorithm was designed to calculate ground speed algorithmically by tracking features on the ground, in addition to tracking features associated with obstacles in the scene. An image feature in the context of the algorithm is either a corner or a speckle found within  a small patch of the image, and is detected by analyzing these patches for strong gradients occurring in a least two different directions. The algorithm uses 3D triangulation of points in space and point motion vectors for determining the distance between the camera and the object.
 
During the course of algorithm development, it became clear that two separate obstacle detectors were required – one for stationary objects, and one for moving objects. A moving obstacle detector with no distance calculation was necessary because distance information between a moving vehicle and a moving object is not practical to present to the driver, given the object could change speed and/or direction at any time. In this scenario, a moving object triggers an alarm to warn of an imminent collision. In the case of a stationary obstacle, such as a post or fence that the vehicle is reversing toward, distances are continually calculated as the vehicle approaches the obstacle and updated on-screen for the driver to accommodate appropriate braking.