How does visual perception work?

The visual perception works so naturally, that one is hardly aware of the individual steps. However, as soon as you be careful, one observes that in a relaxed perception – i.e. without concentrating on something, but looking at a point – only a small circle of the perceptual field can be seen sharply. Around this, the forms are blurred soon to be colored surfaces.

But if you concentrate on an object, e.B. a wide shelf, the eye movements scan this object and it is composed in the head, so to speak: a glance alone can the entire shelf may not capture. The result of several glances
is then pulled together in consciousness to create an overall picture.
A knowledge of shelves is useful: the scanning view can only quickly find the right and important parts of the construction if you know that the boards are usually straight and along the wall. Therefore, the perception of
children who have not yet stored so much knowledge in which
rule slower. Now, if I want to perceive the wooden parts of the shelf, other items, such as the books on the shelf or the carpet before that, neglected and not seen at all. Perception is now geared to this aspect, the shape of the shelf. In this respect, the “sharp” area in the visual field is not constant, but subject-bound. There are items that are even cannot be captured “at a glance”.

From a longer distance, the picture can be build-up, but to become aware of only a small detail resolution. If the viewer concentrates on one detail, on a crossflow, only this is seen and the previously total perceived cathedral blurs with the blurred and spotty background.

Thus, there are two types of setting to distinguish when detecting objects. Perception can be global, i.e. a complex structure is first recognized as an overall meaning and from there, the perception of the details progresses. In the other case, perception can first capture details and then later to absorb the overall meaning (local perception). If the taking meaning once difficulties, one notices, how the overall meaning of a scene is captured only after individual details are detected.

So it is not a single “sharpness plane” which one sees, but rather an object that is separated from the field of perception, which is sharp and in its entirety, the shape becomes visually conscious with more or less detail.

Even when looking at an image, the perception of progress from detail to whole or from whole to detail. People who have never seen a photograph sometimes recognize only individual objects, a horn or a hoof, in order to get to the meaning “beef”. The experience when visiting a flea market, this distinction can be further illustrated. The buyer is looking for the displays of the stands in a local “preset” on objects of interest, but at the same time hardly gets an overall impression of the scene of stalls and sellers.
All this may be possible as a result of a limited processing capacity
be understood.

There can only be a limited number of lines and angles of seen structures that are related to each other so that a selection must take place (visual short-term memory). It can be either an overall shape or a detail so that
that a conscious recognition (perception) is achieved. A second distinction helps. The analysis can be both visual stimuli (data-driven) and stored terms (concept-driven). The selection of the shape that is analyzed is not only based on the visual appeal but – as was already evident with the example of the shelf according to internal presets.

The perception of the cup, which is well known, can serve as a demonstration for us: If the viewer concentrates on the cup, he sees only this one; if he concentrates on seeing two profiles set against each other, the cup is “suppressed”. An expectation to see something picks out one aspect of the image. So seeing does not arise from the object alone, but from a combination of the visual information and expectation.