We held the iQIYI Celebrity Video Identification Challenge in ACMMULTIMEDIA 2019. The purpose was to encourage the research on video-based person identification. We released the iQIYI-VID-2019 dataset, which contains 200K videos of 10K celebrities. In this paper, we introduce the organization of the challenge, the dataset, the evaluation process, and the results.

In Hartley-Kang's paper [7], they directly treated a planar calibration pattern as an image to construct an image pair together with a radial distorted image of the planar calibration pattern, and then proposed a very efficient method to determine the center of radial distortion by estimating the epipole in the radial distorted image. After determined the center of radial distortion, a least square method was utilized to recover the radial distortion function using the monotonicity constraints. In this paper, we present a convex optimization method to recover the radial distortion function using the same constraints as those required by Hartley-Kang's method, whereas our method can obtain better results of radial distortion correction. The experiments validate our approach.

The Perspective-3-Point problem (P3P) is a classical and fundamental problem in computer vision. All possible solution sets for the P3P problem are from 1 to 4 solutions. In this paper, we propose a very simple way to reduce the ambiguity of numbers of possible solutions in P3P using a planar mirror. For three reference points, if they and their reflections in a planar mirror are both observed, we may obtain two P3P problems: One is from the three original reference points, and the other is from their reflections. A trivial procedure may be suggested: Solve for each of the two P3P problems, and then find the intersections of the two solution sets. Different from the trivial case, we propose an efficient method which employs the ratio relations of the unknowns in the two P3P problems. The ratio relations are arise from mirror reflection, and can be easily determined before solving the two P3P problems. With the ratio relations, a system of 6 equations with 3 unknowns can be determined. To solve the over-constraint problem, we utilize an efficient algorithm by finding all local minima of least-squares residual. Experiments validate our approach.