TD = download time
TC = CV time


Time        0               TD               2TD              3TD               4TD                    4TD + TC
            |                |                |                |                 |                        |
Thread 1    |   dl tex 1/4   |   dl tex 2/4   |   dl tex 3/4   |   dl tex 4/4    |        idle            |
Thread 2    |     idle       |   cvFindContour 1/4    |                      idle                         |
Thread 3    |             idle                |   cvFindContour 1/4    |          idle                    |
Thread 4    |                     idle                         |   cvFindContour 1/4    |       idle      |
Thread 5    |                                  idle                              |   cvFindContour 1/4    |