How do I create dense or random sampling of interest point for local feature extraction of image?

Hello,

I'am working on local feature extraction using SURF, HOG etc from images. Now I'am using detector e.g hessian, harris, mser etc to extract the features.

Now, instead of using detector, i want to use sampling method to generate interest points such as random or dense sampling so that I can extract the features using e. surf, sift, hog etc.

Anyone can help me?