f-number equivalent between m43 and FF

Started Mar 25, 2014 | Discussions thread
Detail Man
Detail Man Forum Pro • Posts: 16,681
Re: Perhaps simple if and when we perceive so ...

Detail Man wrote:

Detail Man wrote:

In a monochromatic example, compare perceptual response to the output of the Java applet here:

http://www.fizyka.umk.pl/~duch/ref/demos/Szum-obraz

(when set to a Delay Time equal to 16 mSec) with a Noise Level of 120 (as opposed to one of 40).

For some background on the above-linked Java applet, it previously existed on the web-page linked to below describing the work of Enrico Simonotto and collegues on visual Stochastic Resonance:

http://www.umsl.edu/~neurodyn/Projects/vsr.html

The paper linked-to at the above-linked web-page:

http://www.umsl.edu/~neurodyn/files/pdfs/VisualSR.pdf

... indicates that Simonotto and collegues' investigations (and the Java applet previously linked-to) relate to stationary images to which temporal noise has been added to the existing image data:

Here we report the results of a psychophysics experiment which show that the brain can consistently and quantitatively interpret detail in a stationary image obscured with time varying noise and that both the noise intensity and its temporal characteristics strongly determine the perceived image quality.

As bobn2 has previously pointed out on this thread, it is (in the case of recorded still images, as opposed to video) spatial as opposed to temporal noise that is the relevant subject of concern.

My conceptual linking of Simonotto and collegues' Java applet image to my previous statement:

If one pre-ceives the sky to be of a blue-ish hue, the means by which per-ception arises - whether via periodic/random processes - are arguably secondary to one's own given sensory expectations.

... being off-base, there may exist some potential merit where purely spatial noise is concerned.

Without denying the complexity of the combinations of various elements of image-sensor color-filtering, any RAW-level weighting of RGB channels, as well as any and all RGB weightings that may exist in the course of (in-camera or other) image-processing to follow, ...

... it seems to me that when a viewer looks at a processed image of a patch of blue sky, it may be likely that contributions of blue-filtered photosite image-data - where random/periodic noise-sources have combined in some manner prior to subsequent combination with red or green-filtered photosite image-data in image-processing to follow - may possibly appear to be less objectionable than are contributions of similar red or green-filtered image-data (with their own associated noise-sources added) to the viewer, ...

... because a blue-ish hue is what our "mind's eyes" tend to "pre-ceive", and thus expect to see.

My previous statement:

Perhaps the metaphor "signal" relates primarily to what we expect to be, and/or are pleased by, perceiving - and the metaphor "noise" arises as conceptualizations regarding any various remainders.

... attempts to qualify what may likely be potential differences between what we are able to differentiate (in terms of "signal" and "noise") within image-capturing instrumentation and subsequent image-processing, and our net (subjective) visual perceptions experienced upon viewing the results.

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