alanr0

As Erik said, diffraction by a circular aperture broadens the angular spread of light by an amount proportional to the ratio of wavelength to aperture diameter. More specifically, the angular ...

Don't you mean kibibyte ? :-D

Sure. I have attempted to highlight the approximations and assumptions in this approach, and suggested some resources for Jack to follow up. The Shannon Hartley theorem is widely used to estimate ...

Jack, I don't claim to be an expert, but this Wikipedia page offers a useful overview, https://en.wikipedia.org/wiki/Shannon%E2%80%93Hartley_theorem. In particular, the historical development secti ...

That is essentially what I did to get the factor 1/3. If you treat the square root of the electron count as the signal, noise variance is approximately constant with mean square value 1/4.  That ...

Let's take a closer look at the information rate ( not the data rate), using the pointers provided by bobn2 and Jack .  Assume The Shannon Hartley theorem tells us that for an analogue channel ...

At the risk of derailing - or is it re-railing the discourse ... We don't seem to have a good definition of microcontrast, but there is an IEEE standard for texture blur. Is this the same thing? CPIQ ...

<snip> That is rather the point. The second moment is the " Unique blur measure ". But where? Is there a truncation radius which "does not make a visible difference" for a useful range of ...

Line spread function is the intensity profile measured normal to an extended line source. Step response (also referred to as Edge Spread Function) is the convolution of the line spread function ...

<snip> Let's look at intensities in the neighbourhood of point, line and step sources, against an ideal black background. Fig. 5. Point and line spread functions plus step response for ...

You mentioned a missing paragraph here , which was a reply to my post with the graphs, in which I quoted the first three paragraphs from your earlier post , in reply to AiryDiscus. The only ...

For the record, I started with a normalised analytic representation. I began with an ideal Gaussian blur, with unit standard deviation sigma_x = sigma_y = 1 G(x,y) = exp( -(x*x + y*y)/2 ) I scaled ...

Agreed. Let's compare your observations with some simple Fresnel diffraction predictions. Here is an ideal diffraction-limited circular pupil PSF (Airy disk), compared with a Gaussian Fig. 1. ...

The derivation of the proof may be correct, but a key starting assumption is an unjustified leap of faith. I suggested elsewhere that this is invalid for diffraction-limited images. More generally ...

Given that diffraction sometimes contributes to lack of sharpness in photographic imaging, some discussion of the relevance of this approach in such cases would have been helpful too. A jinc² blur ...

As you say, their thesis seems to be (1) A Gaussian point spread function has convenient mathematical properties. (2) If the PSF ...

Jim, This is certainly how photographic sensors are typically specified, but it is worth bearing in mind that this convention is not adopted in other fields. In optical telecommunications, optical ...

Well, if solving the Navier-Stokes equations for convective mixing in a teacup is too simple , you could choose a shorter mid-IR wavelength and have your super-hero combine heating with laser cutting,

Definitely the wrong instrument to use. Photometric units are weighted by the photopic spectral luminous efficiency function V(λ). A properly calibrated lux meter has zero sensitivity for ...

Well size is number of electrons capacity. Base ISO is a measure of how many photons are needed to fill the well with electrons. So there are two ways to reduce base ISO. (1) Increase the size of the ...