human detector via Image Processing in both Day and Night

Hi guys,
I am an final year Electronics Engineering Student, and want to make an project having some image processing......


first of all i want an
" automatic human detector via Image Processing in both Day and Night"

so i wanted to know, which kind of camera i should use......
i came across:
-> Normal Camera i.e most probably a web cam (but it cant detect in night)
-> IR Camera with IR LED's (i think this kind of camera can detect anything which can reflect the IR rays send by the camera...)
-> Thermal Camera

so from all the information i have of above cameras i can say......
that thermal camera is best as it will only detect warn objects, and will further simplify the work of image processing......




so i want you guys to Suggest me which camera i should use for this and why ?
as i don't know much about how these cameras...work with image processing......

thanking you, :-D
Nikhil.