this is a photograph of Le Harve Oswald it shows him carrying a gun holstering a pistol and you can't see what's on the newspaper but he's holding these Marxist or communist newspapers and the photograph was very damning first of all it showed that he had weapons and it also sort of was further evidence of his communist sympathies at the time and um if this photograph is fake it would almost certainly point to a broader conspiracy because it means the police doctored a photographed try to spin a story and the thing that has people really bothered
about this Photograph primarily is the lighting and the Shadows so if you look at his the the cast Shadow by his body you see it going back into his right which would suggest that the that the light is sort of relatively low it's a long Shadow and off to his left that would sort of give rise to that now what I'm showing you here is a magnified view of his face and you see this very long Shadow being cast by his nose and that would suggest that the light is above him and I have to
say when I first looked at this I it seemed weird to me I'm like well how did that happen so I thought wow I wonder if this is really a fake image now at the same time we had been doing a study to try to understand the limitations of the visual system in reasoning about shadows and lighting and 3D geometry and it turns out we are spectacularly bad at it I mean really it's unbelievable how bad we are so I was able to temper my suspicions a little bit with an understanding that my brain just
isn't very good at this so I wanted to really not just do a qualitative study I really wanted to sort of get at this at a very quantitative and mathematical way and fortunately there's just now enough technology that we were able to go back and look at this photograph from 1963 to try to answer this question if we're interested in reasoning about Shadows the first thing we have to realize is that everything here is happening in a three-dimensional World we're looking at a two-dimensional image but everything here happened in the world and if we want
to recreate this we need 3D models of everything so we can figure out well if I put the light here the camera here the person here where does all the light so we have to build 3D models so the first challenge is his head okay so this is on the top a mug shot of Oswald um so profile and frontal view and what I'm showing you here are the corresponding views of my 3D model okay so we now have a 3D model the most important thing of course here is not every little tiny detail but
it's the size of his nose cuz that's eventually what is going to cause the shadow that we care about so you can see that the the shape of the nose is about right okay so now we need a 3D model of the body and maybe a little bit of the scene around him more or less we now know where oswal was standing relative to the camera and more importantly where was the light cuz we now know where the light would have to be to cast that shadow so now the interesting question is what does his
face look like because if this is actually composite then the Shadows on the face will be inconsistent so here's the original and here's the model from the previous scene and there's all kinds of interesting things here so first of all look at the inside the wells of the eyes you see the same type of Darkness um under the the lower lip you see the the darkness from the shadow um of course the nose is almost perfect it's a very long Shadow which is really surprising by the way and my favorite part which is on the
neck you see the shadow cutting in like exactly like you have here so everything in this photograph is exactly consistent so you can build a quantitative three-dimensional model of the scene of the person of the head figure out where the camera the light was reconstruct and everything is perfect so if this was a fake it would have been almost unimaginable how they could have done this in 1963 because the lighting and the Shadows from the person from the the the beam would have been exactly right which even today would have been extremely hard to do
so it's almost certainly the case that the reason why people think this is a fake is simply a failing of the visual system to reason about 3D lighting and 3D geometry because in fact when you do the Reconstruction everything is 100% perfect you know you tend to think about digital forensics is this modern-day tool answering modern-day problems but the reality is because photo manipulation does have a long history we now have sufficiently powerful tools where we can now start going back through history and trying to answer some really interesting long-standing Mysteries throughout history and that's
sort of an exciting U Avenue to use these modern day tools to go back you know through through the decad to try to understand certain things I think if you're going to make claims that something is fake you you can't just say something looks wrong I that's sort of the whole point is that you've got to bring more rational reasoning to these types of things I think that's what these forensics tools can do
