Question: Simple question, when the test is done executing, does the Start item in the Run menu become enabled again ? I see it disabled for a period while my test is running and then become enabled again. I ask because I've been running Jmeter for 3 days and don't see the tests completing but see start become re-enabled.

Cheers

Answer: 
As with most computer vision algorithms, [Google Scholar](http://scholar.google.com/schhp?hl=en&as_sdt=0,1&as_vis=1) is your friend :) I would suggest reading a few papers on how it works. [Here](http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.115.404&rep=rep1&type=pdf) is one of the most referenced papers on HoG for you to start with. 

Another tip when researching in computer vision is to note the authors of the papers you find interesting, and try to find their websites. They will tend to have an implementation of their algorithms as well as rules of thumb on how to use them. Also, look up the references that are sited in the paper about your algorithm. This can be very helpful in aquiring the background knowledge to truly understand how the algorithm works and why.
Your terminology is a bit mixed up. HOG is a feature descriptor. You can train a classifier using HOG, which can in turn be used for object detection. OpenCV includes a people detector that uses HOG features and an SVM classifier. It also includes CascadeClassifier, which can use HOG, and which is typically used for face detection. 

There is a program in OpenCV called [opencv\_traincascade](http://docs.opencv.org/doc/user_guide/ug_traincascade.html), which lets you train a cascade object detector, an which gives you the option to use HOG. There is a function in the Computer Vision System Toolbox for MATLAB called [trainCascadeObjectDetector](http://www.mathworks.com/help/vision/ug/train-a-cascade-object-detector.html), which does the same thing.