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troy_s :praxis_100:

@troy-s.mastodon.art.ap.brid.gy
36 followers 2 following 1.8K posts

Digital colour gadfly. Antihumanist. Antipositivist. Acolyte of moving / static pixel hermeneutics and thaumaturgy. Make creative things matter. [bridged from mastodon.art/@troy_s on the fediverse by fed.brid.gy ]

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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 13/10/2025
Here we could suggest that there is a more or less “continuous” lamina-like form between the pictorial space frustum and the segmented forms “further away”. But what happens if we tweak one of the segmented regions? Here I’ve swapped one of the segmented […] [Original post on mastodon.art]
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 13/10/2025
When we consider the segmentation along z of vision, we can perhaps begin to see how such boundaries might exist, and in doing so, perhaps we can arrive at a model to predict them. Think of a pictorial depiction that includes a segmentation along z of a “green […] [Original post on mastodon.art]
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 13/10/2025
Scott basically constructed spectral energy quantities that match the colourimetric coordinates of a given “adapting” illuminant, and multiplied the results. The intriguing part is the way the projections deform to the classical locus projection. In the […] [Original post on mastodon.art]
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 13/10/2025
This is where I believe stereographic projection could help us. There are some eerie similarities here to Apelle lines and what not as well, I might add. Here, we can think of the additive components of attenuating excitation purity as existing in the upper […] [Original post on mastodon.art]
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 13/10/2025
When we think about the canonical colourimetric diagram, we are deceived by the illustrations. These sorts of bunk diagrams ignore the nature of the integrals of the energy in terms of sensory signal as we move toward the perimeter. That outer horizon line of […] [Original post on mastodon.art]
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 13/10/2025
When we think about integrals of radiometric energy, under the premise that it is these integrals that are transduced to the sensory signals, we can quickly see that a three dimensional Euclidean sort of a colour solid cannot be tenable. If we think about the […] [Original post on mastodon.art]
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 13/10/2025
Multiplication is an intriguing operation as, across varying discrete samples, multiplication will amplify the dominant energy of a given mixed sample.
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 05/10/2025
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 27/09/2025
Does anyone find the "white" band peculiar here?
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 26/09/2025
Anyone who utters any sort of claim around “HDR” ought to be cornered and forced to explain what: 1. Highlight is. 2. Specular is. 3. “White” is. I promise not a soul will be able to do so in any rigorous manner that validates the claims around the BT.2100 […] [Original post on mastodon.art]
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 22/09/2025
Raphael’s “The School of Athens”. Some unique details around the ideas surrounding picture exposure. Specifically the clothing details are depicted as attenuated with respect to excitation purity. The material characteristics we cognize are uniquely […] [Original post on mastodon.art]
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 21/09/2025
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 21/09/2025
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 20/09/2025
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 20/09/2025
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 20/09/2025
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 20/09/2025
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 20/09/2025
Yilmaz H. Perceptual invariance and the psychophysical law. Perception & Psychophysics. 1967;2(11):533-538. doi:10.3758/BF03210261
Does the foregoing thesis imply that, beyond the
peripheral sense organs, the nervous system per-~
forms only linear operations? Neurophysiology has
not as yet obtained a definite answer to that question,
but interesting affirmative evidence has been cited
by Sir John Eccles in a recent Ciba Symposium (de
Reuck & Knight, 1966). After describing the conver-
gence of the synapses on pyramidal cells, he concluded
that ''there is no great impediment to the idea that
when all these factors are added up, the transfer
functions across the synaptic mechanism are ap-
proximately linear.'' Professor V. B. Mountcastle
added, '""The interesting point for me here is the
great importance that we must now place upon the
transducer process itself, at the periphery. That is,
the whole functional relationship of the response to the intensity of a stimulus is set at the first stage,
which I believe is a new idea...." Thus it may turn out that the complexion of the problem posed by the neurophysiologists may find itself altered to accord more directly with the notion of simple linear invariances in the central nervous system. The creation of the linear invariances may be the job of the sense organs with their power law
operating characteristics.
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 20/09/2025
For the sake of simplicity, let us consider the cartesian coordinates c,
a, b of a color sample. The coordinates may be regarded as an orthogonal
system. Let boldface ij and iy be vectors (or matrices) representing the
three coordinates of the color sample. In the general case, the trans-
formation of the illuminant may involve more than a simple scale change
of intensity. For example, if a cloud covers the sun, not only does the
intensity of light change, but the spectrum of the illumination also
changes from yellowish sunlight to blue-sky quality. Let L be the trans-
formation in question. We may assume this to be a similarity transforma-
tion, which can always be written as a product L=kU of a number k and
an orthogonal matrix U, Thus
L=kU, UU =1 (12)
where k is the scale change and U is an orthogonal matrix having to do
with the chromatic part of the transformation, U? is the transpose of the
matrix U. (Note: An orthogonal transformation preserves length and im-
plies that the underlying space is metric, Examples are rotation of axes
on a plane, which preserves x2 + »2, and Lorentz transformations, which
preserve c2t2-x2)
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 20/09/2025
Furthermore, pitch and loudness take part in a
multidimensional organization that may be thought
of as speech space, a space in which there are re-
lations and overall relativity requirements. In other
words, because of their relations and transforma-
tions within a multidimensional realm, some variables,
such as pitch, may behave the way prothetic variables
do,
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 20/09/2025
The clear separation of the jnd and Weber's law
from the psychophysical power function leaves us
with the problem of why Weber's law holds, or is at
least approximated, in so many perceptual systems.
We expect that the size of the error, variability,
or noise will increase with the physical magnitude
that is being measured. The same rule applies, at
least roughly, when living organisms are involved.
One of the classical methods for measuring the jnd
is the method of average error. A person is asked
to adjust one stimulus to make it appear equal to
another stimulus. He makes many settings, and the
average deviation from the mean of the settings is
taken as the jnd. When the match is to a small stim-
ulus, the average error is smaller than when the
match is to a large stimulus. In its general form,
Weber's law says simply that the deviation from
the mean will increase linearly with the stimulus
magnitude. This is a principle that is approximated
in much of physics.
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 20/09/2025
Fechner's logarithmic law. We may ask, therefore,
under what circumstances a logarithmic law would
be possible. As spelled out earlier (Yilmaz, 1964),
if additive responses in perception are assumed to
correspond to multiplicative changes in the stimulus,
a derivation similar to that presented above will
lead to a logarithmic law, The difficulty, of course,
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 20/09/2025
The foregoing development has examined two kinds
of relational structures that may obtain in perception
—the one based on ratios, and the other on differ-
ences. In neither case did the derivation lead to
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 20/09/2025
Let iy=i, ip=i+Ai, and similarly s)=s, sp=stAs, and write Eq. 4 as

PO +85 = 101 +5) ©)

with boundary condition P(1)=f(1). Expanding by Taylor’s series and

keeping only the first-order terms (which is appropriate if Ai and As are
small compared to 7 and 5),

POY + PME =p) + rE ©
where P'(1) and f'(1) are derivatives evaluated at sp=s1 and i=i] and
therefore constants. By using the boundary condition and integrating,
we obtain

s=Ai% a=f'(D/P'(1) ™
which is the power law of Stevens.
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 18/09/2025
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 16/09/2025
This is someone's book shelf. Seriously.
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 16/09/2025
So it sadly seems Zoom and other streaming platforms have embraced Assembled Statistical Sequencing software. I'm suffering through a stream with wobbly lines and moshed regions that have no "texture". This is likely in the service of cutting costs on the […] [Original post on mastodon.art]
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 13/09/2025
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 11/09/2025
pictorial view frustum. But can we imagine *another* form, that is not spatially curved away from the pictorial frustum, where a modification of the excitation purity might not have a probability of being cognized as “bringing toward the frustum”? How would […] [Original post on mastodon.art]
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 11/09/2025
Why do I keep hammering on how our conscious constructed space seems to matter at a superimportance level? Because there is an almost ubiquitous and subconscious component of spatial constriction implicit in all pictorial analysis. (Arguably all of visual […] [Original post on mastodon.art]
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 11/09/2025
If we put a “spatial thinking first” hat on, we can look at examples and discuss how the gradient relationships relate to our conscious, multistable, and computed constructions of space. This example from @petrikas is damn brilliant, and really should have more […] [Original post on mastodon.art]
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 11/09/2025
Marlow PJ, Mooney SWJ, Anderson BL. Photogeometric Cues to Perceived Surface Shading. Current Biology. 2019;29(2):306-311.e3. doi:10.1016/j.cub.2018.11.041
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 10/09/2025
It is rather amazing that I followed this exact train of thought and arrived at a rather similar formulation.
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 10/09/2025
It is amazing how one can “sniff” something. Turns out my sniffing might be related. My head just exploded. So I have farted with scaling the XYZ functionals, and know the α β patterns can be gleaned from the colourimetric projection. Anyone recognize Yilmaz’ plot?
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 10/09/2025
Wow. Gilchrist’s “Eye as Photometer” myth, conveyed decades prior by Yilmaz.
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 10/09/2025
Yilmaz, Huseyin. “On Color Perception.” The Bulletin of Mathematical Biophysics 24, no. 1 (March 1962): 5–29. doi.org/10.1007/BF02477863.
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 08/09/2025
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 06/09/2025
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 06/09/2025
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 04/09/2025
Notice how the bread and butter of our potential heuristic information to deduce the “colour” of the depicted “shape” increases significantly by chasing the local polarity inversions of this form? Not only do we have the obvious Apelle line, but now we have an […] [Original post on mastodon.art]
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 04/09/2025
If we imagine the first column of the Briggs’ picture as samples from some spatial 3D shape depiction, instead of a basic columnar arrangement of “plane”, what would we cognize the colour of the shape as being? My hunch is that I suspect we’d lean toward that […] [Original post on mastodon.art]
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 04/09/2025
What is intriguing here is that we can cognize a “filter” cognition in *both* cases, but the emergent cognition of “white” seems to be predicated on a polarity inversion relationship within the segmented form. Arguably we might have some sort of “swatch […] [Original post on mastodon.art]
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 04/09/2025
What is intriguing here are the different cognitions that emerge! If we applied a closer to physical emulation of filtration, the upper range would be scaled down in emission, multiplied by the filtration attenuation. We’d likely cognize “all red”, including […] [Original post on mastodon.art]
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 04/09/2025
What I find rather fascinating about Briggs’ example is that he didn’t emulate a pure filtration, but rather substituted out the ground. A more reasonable “filtration emulation” would always lead to a decrement orientation across the range. Instead, with the […] [Original post on mastodon.art]
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 04/09/2025
For folks who might not be aware, the Apelle Line is an idea taught to illustrators and painters. It is the depth boundary line in a cognized shape, often amodally completed as it is often “contour completed” by following the fuzzy boundary of the “shadow”. In […] [Original post on mastodon.art]
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 04/09/2025
And for reference, here is the newer Briggs illustration. Only look at the first column and think about "lightness". Notice the pattern that emerges with specific attention to "lightness"?
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 04/09/2025
Here's a "chromatic filter" variation that is vaguely similar to Briggs example. Pay close attention to how the "lightness" scale is wildly different in the two example cases!
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 04/09/2025
Here's the gradient at the boundary relative to the segmented "ground". As visually striking as the "lightness" example is, the gradient at the boundary is almost entirely elusive unless one knows to think about it.
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 04/09/2025
The "glaringly obvious part if you happen to have a PhD in computational vision science" is that the segmented "ground" determines a sort of "fulcrum". That is, within the segmented region of each "rectangle", we have a local gamut, and the "ground" seems to be […] [Original post on mastodon.art]
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troy_s :praxis_100: @troy-s.mastodon.art.ap.brid.gy · 04/09/2025
As you may have guessed, yes the discs are all identical tristimuli emissions in each disc. The sole difference is the segmented "ground". Now if your name isn't Vladusich, you probably aren't quite aware of the glaringly obvious pattern in the picture. Can you spot it?
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