Recent content by u0362565

Ah ha yes that makes perfect sense to me now! i just couldn't visualise how this was done despite having seen the standard error formula that gives the localisation precision. Thanks for the explanation.

Hi all, If a camera images a fluorescent molecule gaussian function with diameter roughly 300nm and each image pixel represents 160x160nm how could you say with higher precision where the molecule is located within that pixel. For instance if the localisation precision turns out to be 40nm how...

Ok thanks for the comments, i think that's clearer. I found it hard to decipher electric potential and how this is created in a battery.

Hi all, For some reason I'm really struggling to understand how batteries store energy and how this relates to electric potential. Can I just think of a battery as two separate plates one accumulating positive charges the other negative. The positive and negative charges are attracted but they...

This is pretty cool! http://beforeitsnews.com/space/2015/11/acoustic-holograms-that-levitate-particles-video-2494258.html

I am interested to know what governs whether an object in the path of a sound wave will feel force. For instance will low frequency sound have more of an effect than high frequency? What difference does the material or shape of the object have on whether it would feel any force from the...

Related to this question, would an explosion create a vacuum as the air is forced away from the epicentre? At least very temporarily at least.

I see that's interesting, I have never heard of phase, signal or group velocity of light. If there's no general rule it does seem higher energy em radiation slows down to a greater extent, so is there no explanation for why this happens? Can light transmission through a medium be thought of...

Hi all, I've read that when light undergoes refraction into a medium with higher refractive index it changes speed and this is explained by the electrons of the medium absorbing the photon energy, they hold onto it then eventually re-emit the light if the frequency of light doesn't match the...

Thanks for that, I'm still not clear though why the OTF has considerable support along the s-axis

Hi all, I am wondering in the 3D optical transfer function as shown below: http://www.purplebark.net/mra/research/votf/otf-sliced-volume.png The m and n axes represent support of lateral spatial frequencies and the s axes axial. If we were talking about a microscope then it has what's called...

Ok thanks, i think that's all i need to know.

Hi guys, What i know is that to produce the Fourier transform you're essentially breaking the image up into its component sinusoids (variations in intensity in space). These are then mapped to 2d axes. Where as you say the origin represents the zero frequency and increasing spatial...

Hi all, I have a somewhat qualitative understanding of image Fourier transforms and what they represent which for the most part is sufficient for me. However i am interested to know how when i use an image analysis program to produce the Fourier transform of a real image, what is actually...

thanks andy that all makes sense. I had fairly simple lens and ray diagrams in my head so in this over-simplified example the focal length and the working distance are basically the same i think.. If you can create an image only with the objective lens then the light does eventually converge...