[danger]

There are many different actual tasks that technically are PASCAL challenges, but when people say "PASCAL VOC challenge" (Visual Object Classes), they typically mean either the _classification_ or _detection_ challenge:

Classification: For each of the twenty classes, predicting presence/absence of an example of that class in the test image.

Detection: Predicting the bounding box and label of each object from the twenty target classes in the test image.

Neither uses the full ImageNet data set. Instead, it's images from 20 classes of object, like shown here: http://pascallin.ecs.soton.ac.uk/challenges/VOC/voc2010/exam...

[nl]

Here are the results: http://pascallin.ecs.soton.ac.uk/challenges/VOC/voc2010/resu...

I find the results quite impressive - especially for classification - 90%+ precision for detecting people in photos seems like a good result.