From the OpenCV Foundation:

OpenCV Foundation with support from DARPA and Intel Corporation are launching a community-wide challenge to update and extend the OpenCV library with state-of-art algorithms. An award pool of $50,000 is provided to reward submitters of the best performing algorithms in the following 11 CV application areas: (1) image segmentation, (2) image registration, (3) human pose estimation, (4) SLAM, (5) multi-view stereo matching, (6) object recognition, (7) face recognition, (8) gesture recognition, (9) action recognition, (10) text recognition, (11) tracking.

Conditions:

The OpenCV Vision Challenge Committee will judge up to five best entries.

You may submit a new algorithm developed by yourself or your implementation of an existing algorithm even if you are not the author of the algorithm. 
You may enter any number of categories. 
If your entry wins the contest you will be awarded $1K.
To win an additional $7.5 to $9K, you must contribute the source code as an OpenCV pull request under a BSD license. 
You acknowledge that your contributed code may be included, with your copyright, in OpenCV.

You may explicitly enter code for any work you have submitted to CVPR 2015 or its workshops. We will not unveil it until after CVPR.

Timeline:

Submission Period: Now – May 8th 2015 
Winners Announcement: June 8th 2015 at CVPR 2015

(full details)