tborax

I realize this has been somewhat addressed by other threads, but i didn't quite see the solution.

i'm actualy animating a slideshow using jitter, not using a mov. what i'd like to do is remove the background behind some figures. all of the slideshow is from the same tripod position, thus the photo of just the background is basically identical to the many pics in the slideshow, lighting, everything, save for the fact that the figures are not in it.

i feel that it should be *somewhat* straightforward to compare these two matrices, and simply convert all values to zero that are the same in both images.

however, my assumption that a single operator in jit.op comparing the plain background to an image with the foreground figures could accomplish this was a fail. i tried each operator, and while the results were interesting, none yeilded a "good" clean background removal. subtraction comes close, but is not quite right...the resulting composite leaves the foreground figures too dark and cancels out too much of their shadows etc.

i would be happy if the background was black, because i could then key or other technique.

can i use jit.matrix or something to change those pixels to 0 0 0 0?

the "alpha blending" tutorial didn't quite make sense to me,and also the example, using subtitles, seems in appropriate for what i want.

however, i'm open to the possibility that i'm too dense to see how i could use the exact same process to do what i want.

Hi-
I realize this has been somewhat addressed by other threads, but i didn't quite see the solution.

i'm actualy animating a slideshow using jitter, not using a mov.  what i'd like to do is remove the background behind some figures.  all of the slideshow is from the same tripod position, thus the photo of just the background is basically identical to the many pics in the slideshow, lighting, everything, save for the fact that the figures are not in it.

however, my assumption that a single operator in jit.op comparing the plain background to an image with the foreground figures could accomplish this was a fail.  i tried each operator, and while the results were interesting, none yeilded a "good" clean background removal.  subtraction comes close, but is not quite right...the resulting composite leaves the foreground figures too dark and cancels out too much of their shadows etc.

the "alpha blending" tutorial didn't quite make sense to me,and also the example, using subtitles, seems in appropriate for what i want.  

remove-background-using-two-similar-images

There an example of background subtraction using jit.op(s) here: 

https://cycling74.com/tutorials/making-connections-camera-data/

 - that may be different to how you are trying to do it. Failing that it might be, as Andrew B suggests in that article, worth trying the the cv.jit ( 'optical flow') objects.

There an example of background subtraction using jit.op(s) here: https://cycling74.com/tutorials/making-connections-camera-data/  - that may be different to how you are trying to do it. Failing that it might be, as Andrew B suggests in that article, worth trying the the cv.jit ( 'optical flow') objects.


remove background using two similar images?