Pacific Graphics 2014 (PG 2014)
Making in-Front-of Cars Transparent:
Sharing First-Person-Views via Dashcam
Shao-Chi Chen1 Hsin-Yi Chen1 Yi-Ling Chen1,2 Hsin-Mu Tsai1,2 Bing-Yu Chen1,2
1National Taiwan University
2Intel-NTU Connected Context Computing Center
A synthesis result of the proposed view sharing system. (a) The original view of the preceding vehicle. (b) The original view of the subject vehicle with a large portion of the image blocked by the preceding vehicle. (c) The perspective of the preceding vehicle is transferred to the corresponding view of the subject vehicle to “disocclude” the blocked area as if the preceding vehicle becomes transparent.

Visual obstruction caused by a preceding vehicle is one of the key factors threatening driving safety. One possible solution is to share the first-person-view of the preceding vehicle to unveil the blocked field-of-view of the following vehicle. However, the geometric inconsistency caused by the camera-eye discrepancy renders view sharing between different cars a very challenging task. In this paper, we present a first-person-perspective image rendering algorithm to solve this problem. Firstly, we contour unobstructed view as the transferred region, then by iteratively estimating local homography transformations and performing perspective-adaptive warping using the estimated transformations, we are able to locally adjust the shape of the unobstructed view so that its perspective and boundary could be matched to that of the occluded region. Thus, the composited view is seamless in both the perceived perspective and photometric appearance, creating an impression as if the preceding vehicle is transparent. Our system improves the driver’s visibility and thus relieves the burden on the driver, which in turn increases comfort. We demonstrate the usability and stability of our system by performing its evaluation with several challenging data sets collected from real-world driving scenarios.

An overview of the proposed method. Given the target and reference sequences, the occluded region (a) in the target image is estimated and our system automatically finds the corresponding contour (b) in the reference image. To transform the area inside the contour in the reference image to match the occluded region in the target image, the perspective of the region to be transformed are adapted to fit that of the location in the target image by performing (c) perspective adaptation through reference video volume and (d) a stitching process between the two image frames. In the stage of perspective adaptation, a novel view I′ is synthesized by performing local homography estimation and perspective-aware warping. Finally, we stitch the synthesized view and target image where the warped region is seamlessly blended into the target image to make an impression that the vehicle is transparent (e). Note that the “see-through” effect does not cover the entire occluded region such that the viewers remain consciously aware of the existence of the preceding vehicle, thus improving driving safety.
Technical Paper

    author = {Shao-Chi Chen and Hsin-Yi Chen and Yi-Ling Chen and Hsin-Mu Tsai and Bing-Yu Chen},
    title = {Making in-Front-of Cars Transparent: Sharing First-Person-Views via Dashcam},
    journal = {Computer Graphics Forum (Proceedings of Pacific Graphics 2014)},
    year = {2014},
    volume = {33},
    number = {7},
    pages = {289--297},