Image Definition and 996 Threads

I am reading Munkres book, "Topology" (Second Edition). I need help with an aspect of Theorem 18.2 Part (f) concerning the inverse image of a set under the restriction of a function ... Theorem 18.2 Part f reads as follows: In the above text we read: " ... ... Let $$V$$ be an open set in...

What does f(x,y) in the 2D CT image account for? If for density, then which material is considered as a reference for that density? If for atomic number, then again which is the reference substance?

Homework Statement At what distance from an object must a 55mm camera lens be placed if the image is to be the same size as the object? Homework Equations 1/u + 1/v = 1/f m = v/u do/di = ho/hiThe Attempt at a Solution My thinking is that (m) needs to equal 0 therefore v/u needs to equal...

Homework Statement Two converging lenses having focal lengths of f1 = 12.5 cm and f2 = 19.5 cm are placed a distance d = 49.0 cm apart as shown in the figure below. The image due to light passing through both lenses is to be located between the lenses at the position x = 33.0 cm indicated. (a)...

Hello, I have heard many times that red lighting is good for imaging applications where the effect of ambient light needs to be reduced to a minimum. What is the theory behind this? Why does red light (vs. other colors) reduce the effect of ambient light? Thank you.

That is, take the virtual image as the object for a second lens?

Hi everybody, The situation is the classic one: a point charge q+ in a distance d above a conductor plane grounded: The conductor is grounded so V = 0, for z = 0. Also, far away from the system (x2 + y2 + z2 >> d) V --> 0 The argument to replace it for a q- charge seems perfect to me. What I...

Homework Statement I know this stuff isn't complicated but the definitions of my book are very formal and confusing. I have to find the image and the kernel of these two matrices: A= \begin{bmatrix}1&2&3\end{bmatrix} B= \begin{bmatrix}2&3\\6&9\end{bmatrix} The Attempt at a Solution my book...

I am trying to make a term for a function equipped on an image sensor. The term is to express "the upper limit of fluctuation allowance in image size which is specified in %" The value of percentage does not express the ratio of the enlarged image size compared to the original image size, so...

Homework Statement Consider a 2x2 matrix A with A2=A. If vector w is in the image of A, what is the relationship between w and Aw? Homework Equations Linear transformation T(x)=Ax Image of a matrix is the span of its column vectors The Attempt at a Solution I know that vector w is one of the...

Hi, I'm working on a project to determine the distance a pedestrian is away from a single digital camera but having never done optics before I'm struggling to find the right equation to use. I'd really appreciate any help! The method I am trying to use assumes you know the height of the camera...

1. The problem: A plane mirror of length 2m is kept along the line y=-x as shown in the figure. An insect having velocity of 4 cm/s is moving along x-axis from far away. The time span for which the insect can see its image will be:A)50 sec B)25 sec C)25√2 sec D)50√2 sec 2.The answer...

i just wanted to get this cleared that a beam falling on a diffraction grating with a shape gives the Fourier images of the grating object which can be reobtained by placing a biconvex lens that would converge the rays and form a focussed Fourier image at its focal length and the image of the...

Hi, Well I hope it's not a thread that already is in the storage here. I want to understand the image of a matrix. not only calculating it but also why I'm doing that. Here are my questions: 1) They say d = Lx has a solution if d ∈ ImL. I know that the image of a matrix is calculated by Lx = x...

like a person with a background and just the background really fast, like a strobe effect. If you cycle back and forth fast enough would the person appear like normal or 50% see through?

$\textbf{Problem}$ Let $\textbf{b} = \begin{bmatrix}\begin{array}{r} 8 \\ 7 \\ 5 \\ -3 \end{array}\end{bmatrix}$ and let $A = \begin{bmatrix} 2 & 3 & 5 & - 5 \\ -7 & 7 & 0 & 0 \\ -3 & 4 & 1 & 3 \\ -9 & 3 & -6 & -4 \end{bmatrix}$ Is $\textbf{b}$ in the range of the transformation $\textbf{x}...

How do you call of the digital image processing that simplifies an image by reducing the amount of pixels? I thought of the word “thinning”. But according to ”Fundamentals of Digital Image Processing” by Anil K. Jain, “Thinning algorithm transforms an object to a set of simple digital arcs...

Homework Statement Harris stands at point A and wants to take a picture of bird located at point B. Because there is wall, he has to direct his camera to mirror located 3.7 m to the north from his position. What is the focal length of his camera so that he can take a clear picture of the...

Hello! (Wave) Theorem: No set is equinumerous with its power set. Proof: Let $A$ be a set. We want to show that if $f: A \to \mathcal{P}A$ (a random function) then $f$ is not surjective.We define the set $D=\{ x \in A: x \notin f(x)\}$ and obviously $D \in \mathcal{P}A$. We assume that there...

so virtual image is my image on the mirror? If that was true, then what is a virtual object? (with examples please)

Diapl is the program based on DIA by Dr. P. Wazniak to do image subtraction. I use diapl2 to reduce my CCD data. When my CCD images' fwhm is about 5 pixels, the results are good, but when the fwhm is 15 pixels (my scale is about 0."28/pixel), the subtracted images are bad. I know that I must...

I am currently pursuing a Master's degree in physics with optics as my major and my interests are fiber optics and biosensors. I have also worked on a couple of projects in the past that dealt with a lot of image processing. I will soon begin working on my Master's thesis and want to decide a...

How do I put my image on the top right corner of my web page? In HTML or CSS.

Homework Statement Find Kernel, Image, Rank and Nullity of the matrix 1 −1 1 1  | 1 2 −1 1 | 0 3 -2 0 Homework EquationsThe Attempt at a Solution I have reduced the matrix into rref of 3 0 1 3 0 3-2 0...

Homework Statement Find the Geometric image of; 1. ## | z - 2 | - | z + 2| < 2; ## 2. ## 0 < Re(iz) < 1 ## Homework EquationsThe Attempt at a Solution In both cases i really am struggling to begin these questions, complex numbers are not my best field. There are problems before this one...

Hi Guy, My name is John Dolan and I am an Irish student studying Astronomy in the university of Groningen in the Netherlands. I have been interested in Physics and Astronomy since I was knee high to a grasshopper and I look forward to asking questions, finding out new ideas and new ways of...

In texts on geometrical optics I have read that an image is formed where light rays converge -- without an explanation of why. Thus I ask, why are images formed where light rays converge? In particular, what is the answer to this question in terms of the wave theory of light (Electrodynamics)...

as to manipulate its possition?

Homework Statement [/B] Two parallel mirrors that face each other are placed along and perpendicular to the x-axis at x = +7.40 m and x = -7.40 m. Assume that a point source of light is placed on the axis at x = +3.30 m. In principle, there will be an infinite number of images generated...

After watching these videos about Computational photography: and lensless image sensors: was wondering if it is at least theoretically possible to calculate the light of the surroundings of a white surface just from the light information on that surface. For instance taking a picture of a...

Homework Statement Two point charges of equal value are placed a distance 2b from one another. In the middle, there is a grounded conducting sphere. What is the minimum radius of the sphere required to cancel out the repelling force between the two charges? (Solve using Image Charge Method)...

Hi all What if instead of charges and a surface, we were given a set of charges and image charges and have to find the surface, how would you do that? This is actually part of my homework but I'm pretty sure he doesn't want us to prove it mathematically (the case is obviously a sphere) so I...

So on my first course of Algebra in university I have been asked to find the image of the following function: f : Z x Z -> Z, f(x, y) = x2 - y2 In high school I worked only with single variable functions and I could have found the image by drawing its graph, using limits or using some specific...

hi guys, my professor told me in the class that when we would like to determine green function there are two general method i.e using image charge and using orthonormal eigen function. However I don't understand what are the specific differences between them. Anybody can help me? Moreover in the...

Homework Statement Write an expression for the Dirichlet Green's function of the part of the space bounded by two infinite conducting plates parallel each other and separated by distance of d. Use Image charge method Homework Equations G (at z=0) =0, G (at z=d) =0 I guess The Attempt at a...

how image is formed on a plane mirror , when light bulb is switched on, photon strikes a point on an object ( for ex.a ball) and from their the photon strikes the mirror and form incident angle and reflective angle , my question is does the photon carry the image with it ? or does it act like a...

Homework Statement How do I add image to my web page? Homework Equations None. The Attempt at a Solution I know that the img element is <img src="logo.png" alt="My Logo"> but I don't know what to type between the 2 quotation marks for "logo.png" and "My Logo". I put logo.png and My Logo...

I understand obviously that the image and light will be kept but it will become a little bit green. But what happen in a very specific way especially about absorption??

Hi all, I'm dealing with a homework connected to the magnetic field. But I can't image how these things are generated. I can image that for the electric field, one can generate it by just applying a voltage different across two plates and you will get an electric field pointing from one plate...

Greetings, I don't have a magnifying glass/convex lens otherwise I would try to confirm this by experiment. Maybe I'll get one soon but to get things started. Let's say you have an object, with its own light source, and a convex lens with focal point f. The object is beyond 2f away from the...

So for BiConvex Lenses, increasing the lens radius (by making the lens fatter) brings the image and focus closer to the lens, thus making it smaller given constant object position. As demonstrated in this demo http://micro.magnet.fsu.edu/primer/java/lenses/lensvariations/index.htmlYet for the...

I'm interested in learning how to solve a relatively general sort of problem that comes up a lot in my problem sets and will presumably come up in future exams. I'm asked to give an example of a matrix or linear transformation that has a given image or kernel. Here are some examples...

How the brain creates 3 dimensional image (what you see) from information that photons carry to your eyes? Photons travel with constant speed so your brain can't calculate how far object is from their velocities. I know stereoscopic vision helps to calculate distance from objects but even when...

Homework Statement Three thin lenses, each with a focal length of 40.0 cm, are aligned on a common axis; adjacent lenses are separated by 52.0 cm. Find the position of the image of a small object on the axis, 80.0 cm to the left of the first lens. Homework Equations 1/s + 1/s' = 1/f The...

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...

I know that for a given signal, the sampling frequency Fs must be twice or more than maximum frequency of the signal Fm. It is easy to understand the concept for a 1D signal. But I don't know how to calculate sampling frequency or Nyquist rate for a 2D image. Also what is effect of...

Hey! I'm new here and I just wanted to ask a question and maybe I'll come back here once I have started college in a week or so. :P But firstly I must say, at first I thought the confirmation question for signing up was a science question about acid and I was totally stumped. But that's PH... I...

Homework Statement A sphere of radius 12.0cm has refractive index of 1.33. A speck is 4.0cm from the centre of the sphere is viewed along the diameter that passes thru the speck. Find the position of image when the speck is viewed from the nearer side? the ans is -7.2cm Homework Equations...

I need to do something for a project. Basically, I need to be able to project a clear image onto a mirror while still being able to use the mirror when the projector is not in use. Is there a way to do this/a cheap coating I can put on a mirror to accomplish this? Thank you!

Hey all, As the title suggests, I've found some recurring structure on an SEM image and I can't for the life of me figure out what it is. I took the image this morning. Here she is: http://i.imgur.com/nFuBsW2.png Here's a larger, more zoomed out and higher res version. A few more of...