My understanding is that this works because in each 14x14 set of pixels for one microlens, the same pixel position will correspond to a particular u value, so if we just take that particular pixel from each microimage, we'll get a sub-aperture image. But I don't understand how we are sure that the same pixel position will correspond to a particular u value in every single microimage. Won't the angle that each ray hits the microlens, which then gets refracted through the lens and onto a particular pixel, be different for each microlens, even when all the rays have the same u?
My understanding is that this works because in each 14x14 set of pixels for one microlens, the same pixel position will correspond to a particular u value, so if we just take that particular pixel from each microimage, we'll get a sub-aperture image. But I don't understand how we are sure that the same pixel position will correspond to a particular u value in every single microimage. Won't the angle that each ray hits the microlens, which then gets refracted through the lens and onto a particular pixel, be different for each microlens, even when all the rays have the same u?