The spirit, soul or ghost cannot be seen by the mortal people. And they cannot be heard or perceived by people in this life of the World.
Souls or ghosts, on their part, can hear and see us, but we cannot see them, unless following our death, when we will be spriritual beings like them, and then we can hear and see them and speak to them, as will they be able to hear, see and speak to us when we will be souls or ghosts like them.
And we can hear, see and talk with them also during sleep; because during the deep sleep, the soul or the ghost of man separates from his body during sleep, fainting and losing the consciousness.
Some special circumstances:
But during some special circumstances, the spirit or soul of man may be seen: like in some conditions of
photography for example.
When the camera takes a picture in a dark place, and by chance, the flash light of the camera did not work, then the photograph may have the appearacne in the dark on the sensitive film, some manifestation of the spirit world like some branches of some ethereal spirits of the dead trees or the spirit or soul of a dead man appears who was by chance in front of the camera.
And see this information at this link:
http://quran-ayat.com/man/3.htm#Bad_[or_Evil]_Trees_
"Some of Photographers found, in their films, some photographs of trees or branches that were picked by their cameras, by chance and without being aware of them, in places where there were no trees. This may take place when the light given to the film is very little, so that the film comes out devoid of the picture of the man who was in front of the camera, but – in stead – he will find a picture of a tree or one of the branches of a tree in spite of that the place is devoid of trees[v] , but he doesn't know the reason for that, and does not understand that there are ethereal trees which are unseen by the living beings, but that the cameras pick them by chance, in spite of that some of the people are not aware about the existence of the ethereal trees.
A photograph of an ethereal branch has been picked by the camera of a photographer at Hilla [in Iraq], and that was in one of his house rooms. [This photograph is not available now.]"
So here is now a new method of
photography of the ultrasound for some patient tumour, and there appeared a face of man on the scan of the ultrasound.
The explanation can be one of two possibilities:
1- either it is by chance some abnormal shape which is
not realted to anything true like some shapes that appear in the cloud, then will change by the effect of the wind.
2- or it is
due truly to some dead man ghost that by chance happened be before the camera of the scan. And it appeared in this shape when in fact there is a true soul or ghost of a dead man standing or looking in the scan also at the same time: it could be of a dead doctor or the relative of this patient to whom the scan is taken and it concerned that dead relative like his father or grandfather; or could be another man stranger to the patient.