How to count number of objects in a video using MATLAB

I have an infrared video which I have r开发者_如何学Goecorded during nights and my camera was facing the sky so I was basically trying to track the bird movements in the video.I took few video frames and plotted the trajectory of moving objects but now I would like to extend this same concept to the entire video.But there are few things that are troubling me.

1. I have selected a static threshold of 0.6 to convert the gray scale frame into BW frame.But since I am interested in applying this algorithm to the entire video I should try to use a dynamic or adaptive threshold.

2. I would also like to count the number of objects present in the video so that after running the entire video I should be able to display the number of moving objects in the video.

So any help regarding adaptive threshold and counting number of objects in video will be sincerely appreciated.

You can use a way similar to histogram equalization and morphological operations stuff as in this post. And for the number of the birds, you can count the number of the connected components with bwlabeln.