My SIFT implementation and comparisons

Im trying to implement SIFT in matlab and compare it with other implementations
the comparisons are against the following:
original SIFT code by LOWE found at this URL
the other is the popular A. Vedaldi Code found at this URL


This is the result of the vadaldi code that finds 262 key points

This is the original SIFT code by David Lowe showing 249 keypoints



This is from my code showing 315 keypoints.

from all 3 images you can see that there are points that are outside of the image and a surprising 70 extra keypoints on my implementation. obviously my implementation is wrong, so i tried to go through the code and adjusted a few things

Now i get 195 keypoints and as you can see from the image, all the keypoints are located inside of the image. my next problem is the magnitude.

from the previous images, the code from LOWE and VEDALDI have a very good magnitude however my implementation has very small.




All yellow markers are from my implementation