Hot answers tagged vision
14
It is not meaningful to talk about your brain processing something as 'right-side up"' or 'upside-down'. The 'images' in your brain are just collections of neural activations, and not actual pictures. Thus they cannot have an orientation. The only meaningful way to test your question is to try flipping the input the brain receives and seeing if it can cope.
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Treisman & Gelade's Feature Integration Theory suggests that we are able to process an entire visual scene in parallel at the level of individual features. For example, in a visual search task, the time required to find a blue circle in a field of red circles is independent of the total number of circles. However, focused attention (typically foveal) is ...
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At least for images (I don't know of such a result tested on videos) for a given resolution, there is an optimal display size (assuming constant viewing distance. otherwise, display size should be measured in angles from the viewers point of view). In a paper from 1989, Peter Barten provided a formula to compute this effect [1]. The gist can be seen in the ...
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The human eye is an interesting device. One of the most amazing things it does is to adjust for the brightness, and it can do so over 10 orders of magnitude.
From a signal processing perspective it can be explained as follows:
There are a few different ways that this is done, but the most basic way is a high pass filter, with a cutoff of about .25-.3 Hz. ...
11
I think you are succumbing to the homunculus argument, the fallacy that there is some sort of image in the brain for someone to view. There is no magical theater in your head where what is incident on your retina is projected. All you have in your brain is complicated patterns of neural activity, there are no images and nothing to view. However, these ...
10
One of the main reasons related to the 'Gestalt principles'
Law of Proximity Objects near each other tend to be grouped together.
Law of Similarity Similar items tend to be grouped together.
Law of Closure Objects grouped together are seen as a whole.
Law of Continuity Lines are seen as following the smoothest path.
Law of Common Region Items in similar ...
10
Your question is referring to display polarity. A positive polar display consists of dark letters on a light background, a negative polar display consists of light letters on a dark background. Polarity by itself is independent of text-to-background contrast, as you rightly state.
Generally, positive polarity facilitates performance (e.g. Buchner & ...
9
People who are unable to perceive stereoscopic depth typically only perceive information from the dominant eye.
Failure to perceive stereoscopic depth is usually caused by conditions where the eyes do not converge properly (e.g., strabismus). If left untreated, it is not possible to develop the necessary correspondance between the two signals from either ...
9
There's a general discussion of speed reading methods on Wikipedia, but let's look at some specific articles and see what they say about reading speed and comprehension.
Bell's review of the reading speed and comprehension literature
In Bell's (2001) review of the empirical literature, he makes a number of points, which seem reasonable to me:
A few ...
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Yes, this scenario is possible, occurring with certain cases of brain lesions in specific areas of the visual cortex, the fusiform, lingual and posterior parahippocampal gyri. These areas are analogous to what is referred to in primates as V4, or the 4th visual cortex, and are known to be involved (at least partly) in the perception of color (though see ...
9
Short answer: there appears to be a whole range of ability at the task of mental visualization. Based on what I have found on the Web, your own level of ability is fairly unusual. Your friend's level of ability, by contrast, seems to be fairly common. Sources I found on this were fairly sparse, though, and my conclusions should not be relied on too heavily.
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A good place to start for a high level understanding of all perception and action is Jaoquin Fuster's perception-action cycle. As he says, it's a "cybernetic cycle linking the organism to its environment". He describes two moieties of the brain, posterior sensation moiety, and the anterior behavioral moiety. Information cycles between perception, ...
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I think part of what makes this question confusing is the use of expressions like "what the eye sees", "what the brain sees" and "what the frog's eye tells the frog's brain". Nobody sees anything except the experiencing subject. When one stops thinking that the brain (or some visual-system part of the brain) observes the image on the retina, then the ...
8
There are two related reasons, I believe for this:
Relationship and connection. When things are aligned, we see then as connected and related. Nature does give us the guidance for things that are related and connected in other ways, but often by a degree of alignment or similarity. In UX terms, we indicate the relationships between items by positioning and ...
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As @Gray mentioned, the philosophical problem you are interested in is known as the inverted spectrum. Unfortunately, @Gray's claim about no empirical difference is not exactly true. As @ChuckSherrington pointed out, we can have differences in color perception due to brain lesions, but this is cheating in way. We don't have to go this far, we already have ...
7
The Wikipedia article no longer makes reference to the phenomenon that you quote (to my inspection), so I'm not entirely sure if that assertion was edited out as an inaccuracy on someone's part. I did find some information on visual perception and high frequency flicker that might point to some of the significance of the 60 Hz refresh rate of a monitor.
At ...
7
There is a substantial literature on eye tracking.
Skill acquisition example
One study that I am familiar with and is of some relevance is Study 2 in Lee and Anderson (2000, PDF).
Specifically the study used eye tracking tools to examine how visual attention was allocated over time on an air traffic control simulator.
The broad finding, consistent with ...
7
First, it is not only your intuition - there are many experimental results showing that we first perceive the gist of scenes (for example, is it outdoors or indoors?), then the major parts of it (was there an animal, or a human figure in it?) then more and more details (is that figure male of female? what is her expression?) [1] [2]. Note, however, that it ...
6
One possibility would be to apply those image filters to a live video stream.
Aside from that, you could consider infrared goggles. Not an exact simulation of colorblindness, but it does apparently make red and green into the same color. And if anything, it would let people see the world in differently.
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Not surprisingly, there's a huge load of stuff you need to consider when designing things for users. Here's a good paper written by some perception and vision researchers on the topic that might give you a more detailed introduction that what you have seen so far:
Healey, C.G. & Enns, J.T. (in press). Attention and visual memory in visualization and ...
6
It's essentially shot noise.
In optics, shot noise describes the fluctuations of the number of photons detected (or simply counted in the abstract) due to their occurrence independent of each other. This is therefore another consequence of discretization, in this case of the energy in the electromagnetic field in terms of photons. In the case of photon ...
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The nervous system, especially the cortex, is a distributed system. Asking "where" is not always a sensible question. In reality, different properties of the visual scene are assembled in different areas of cortex. There is no one area where everything is reassembled. All the information we know about a scene is stored all over the visual system. In ...
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From personal observation, the consensus seems to be that the two streams hypothesis is an oversimplification of the truth, albeit a useful one.
The primary reason that this hypothesis is seen as an oversimplification is because there is a lot of cross-talk between the two streams. For example, Zanon et al. (2010) provides evidence for functional ...
5
Bredart (2003) discusses your exact hypothesis and reports the results of a couple of studies. I'd recommend having a read of the article.
The authors acknowledge that in contrast to familiar others the experience of our own face typically comes through self-inspection in mirrors.
They summarise some relevant literature:
Troje and Kersten (1999) ...
5
Until peer-reviewed data on the topic is published, all we have to go on is blog posts from vision and display researchers. The best posts I've seen so far are:
Artal, P. (2012) Is the display resolution of the new iPad adequate for the eye?
Artal, P. (2012) What have in common the Apple “Retina” display and our retina? Probably, only the name.
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Let's begin by being clear about terminology and what is involved in eye movements at a basic level. Saccades are eye movements. Fixations are when your eyes are still. No visual information is gathered during saccades - we are functionally blind when making saccades. The easy way to demonstrate this is to try staring in a mirror and watching your own ...
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Jordan et al. (2010) tested humans that carry the genetic predisposition for having 4 classes of cone receptors. However, only one of their 24 subjects was able to discriminate three color dimensions, thus, demonstrated tetrachromacy.
Jordan G, Deeb SS, Bosten JM, Mollon JD. (2010). The dimensionality of color vision in carriers of anomalous ...
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Consider the colour visual system. Take 3 monochromatic (in the physics sense) light sources of wavelength $420 \; nm$, $534 \; nm$, and $564 \; nm$; i.e. the peaks of spectral sensitivity for cones. Your 3 physical parameters are then 3 knobs $b$, $g$, $r$ that control the intensity of each light source as they shine on the same white surface. If you want ...
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