What is Images: Definition and 388 Discussions

An image (from Latin: imago) is an artifact that depicts visual perception, such as a photograph or other two-dimensional picture, that resembles a subject—usually a physical object—and thus provides a depiction of it. In the context of signal processing, an image is a distributed amplitude of color(s). A pictorial script is a writing system that employs images as symbols for various semantic entities, rather than the abstract signs used by alphabets.

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  1. Y

    Optimizing Rear-View Mirror Dimensions for Full Rear Window Visibility

    Homework Statement The rear window in a car is approximately a rectangle, 1.3 m wide and 0.30 m high. The inside rear-view mirror is 0.62 m from the driver's eyes, and 1.58 m from the rear window. What are the minimum dimensions for the rear-view mirror if the driver is to be able to see the...
  2. B

    Diffusion eq. with periodic BC using method of images

    Homework Statement Considering the periodic boundary conditions (given below) I am supposed to find the solution T(x,t) with the initial condition T(x,0)=\delta(x) Also I am limited to use method of images so I can't use separation of variables unfortunately. Homework Equations The boundary...
  3. Somefantastik

    Green's Function using method of images

    Homework Statement \Omega = \left{ \left( x,y,z \right) :,0<z<1 \right} Need to find Green's function using the method of images. Homework Equations none The Attempt at a Solution I can see that I will need an infinite sequence of images at each plane z = k, k = 0, +/- 1, +/- 2,... to...
  4. L

    New Images from Mercury Fly-by

    Messenger has sent back new pictures of Mercury. http://www.nasa.gov/mission_pages/messenger/multimedia/index.html The first 4 pictures in the table were relayed back yesterday.
  5. L

    Method of images and spherical shell

    A grounded & conducting spherical shell of outer radius M and inner radius N has a point charge Q inside the shell at a distance r<M from center. Using method of images, find the potential inside the sphere. Could I just use the superposition of charge and point charge? \phi(r) =...
  6. I

    Function Example Ideas: Tips, Suggestions, and Help

    http://answerboard.cramster.com/other-topic-5-311900-0.aspx" I need help getting some ideas for an example of a function. Any help, ideas, suggestions, and/or tips are greatly appreciated. Thanks for looking at this question!
  7. N

    Describing the Image of a Complex Function on the Unit Circle

    How do I describe the image of a function like. f(z) = (z-i)/(z+i) given that the length of z is equal to one. The domain is the unit circle. Is the best way just let z=x+yi and then see what comes out? Or is there a simpler way of doing it.
  8. G

    Global Warming: Emotional Images Beyond Glaciers

    hi am in need of some emotional pictures about global warming other than having images about melting of glaciers
  9. R

    What are some cool and secret Google Earth images?

    I was sitting with my girlfriend yesterday and we were looking at videos of comets and meteorites because I wanted to show her the schumacher levy 9 impacts, that she had never heard of! :bugeye: :cry: Then we kind of did some link following which went a little like this: Comets, meteorites...
  10. S

    Method of Images: Infinite, charged wire above a grounded plate

    Homework Statement Given an infinitely long wire, with charge density \lambda, parallel to and a distance d above an infinite, grounded, conducting sheet, what is the potential, V(x,y,z) above the sheet? What is the induced charge on the sheet? Homework Equations The Attempt at a...
  11. M

    Exploring Mirrors and Reflection: Unanswered Questions in Image Reversal

    I have never understood how images are reflected in mirrors, even now that I am going into my fourth year of university I have some really basic (probably stupid) questions that I need to ask. When an word is reflected in a mirror, why do the letters appear reversed but the word doesn't (the...
  12. S

    Unlocking Hidden Data: How to Save Files as Images on 4chan

    No one thought something useful could be learned on 4chan, until now. http://orz.4chan.org/hr/res/381892.html Apparently renaming a file (such as an .mp3) to .raw and then saving it (using IrfanView or Photoshop) to PNG will allow you to retain the useful information in the image file...
  13. P

    Transmitting Images through a Coherent Fiber Bundle

    A coherent fiber bundle is very useful in transmitting images. Let's say we have a gaussian beam from a laser as our source. Now the acceptance angle(2*alpha) is determined from the location of the beam waist, right? The light ray will then go down the fiber core with the use of a converging...
  14. S

    Differential Geometery: Images of Gauss Maps

    Homework Statement this is a 2 part problem let G: T-----> (Sigma) be the gaus map of the torus T derived from its outward unit normal U. What are the image curves under G of the meridians and parallels of T? What points of (Sigma) are the image of exactly two points of T? And Let...
  15. L

    Formation of Images by lenses

    1. An object is placed in front of a converging lens in such a position that the lens (f = 11.0 cm) creates a real image located 27.0 cm from the lens. Then, with the object remaining in place, the lens is replaced with another converging lens (f = 19.0 cm). A new, real image is formed. What is...
  16. N

    How Does Grounding Affect the Electric Field of a Charged Plate?

    The setup is: Suppose that we have a point charge q held a distance d from an infinite, grounded, conducting plate. Let the plate lie in the xy-plane, and suppose that the point charge is located at coordinates (0, 0, d). What is the scalar potential above the plane? The solution to this...
  17. E

    What is the construction for taking inverse images of subschemes?

    Hi, As is the case with functions, we can always define the inverse image of a subset. In the case of schemes I was wondering if there is something that could be taken as the inverse image of a subscheme? Example: Let f:X->Y be a scheme morphism. Then if U is an open subscheme of Y, we...
  18. E

    How can I wrap text around images in my LaTeX articles?

    [SOLVED] wrapping text around images I am using the above instructions to put images in my latex articles. However they take up a lot of space. How can I make the text wrap around them?
  19. F

    LaTeX Troubleshooting Image Display Issues in LaTeX

    Hi, I am new to LaTeX and am having trouble putting images up on a document; I am using TeXnicCenter (in it u can use .jpg or .pnp files aprently but not .ps). i use \usepackage(graphicx) ... \insertgraphic(sample.jpg) which I thought should be enough to display the image. compiling...
  20. N

    Getting images out of PDF files?

    I'm doing a presentation for coursework, and would like to include some figures which are in other papers (on my computer in PDF format). What is the best way to get one of these images and include it in my document (latex)? I can just select it and copy/paste to an image file, but is there a...
  21. A

    Forming Images with a Plane Mirror

    [SOLVED] Forming Images with a Plane Mirror Homework Statement (a) How rapidly does the distance between you and your mirror image decrease if you walk directly toward a mirror with a speed of 4.7 m/s? (b) Repeat part (a) for the case in which you walk toward a mirror but at an angle of...
  22. J

    Images Formed by converging mirros

    Homework Statement I need help with this general question. Why is it impossible to focus a virtual image on a screen, ( object is placed between F and lens). Homework Equations this experiment we had a candle on one side, a converging lens in the middle, and at the other end a screen...
  23. K

    Submanifolds as Inverse Images

    Homework Statement Show that there exists no smooth function f : \mathbb{RP}^2 \rightarrow \mathbb{R} \text{ such that } f^{-1}(q) = \mathbb{RP}^1 for some regular value q of f. 2. The attempt at a solution So we can quite simply show that \mathbb{RP}^1 is a submanifold of...
  24. B

    Images - character recognition

    Hi guys, I was just wondering if any of you knew if there have been any programs that have been written by people to perform character recognition in an image file. That is, you have an image of written text and you want to somehow recognise and extract characters. So for example, if you had...
  25. R

    LaTeX Adding Images to LaTeX from PDF Sources

    Hey folks, I plan to use a figure from a paper (Hubble diagram for type 1a supernova demonstrating accelerated expansion).' I'm want to put the image in a \LaTeX document. Of course, I could use the Snapshot tool in Adobe reader and then grab the image and import into photoshop say then...
  26. D

    Fortran Outputting Bitmap Images in Fortran without Record Delimiters

    In Fortran I need to output some data as a bitmap image, to visualise results. Problem is, with every WRITE statement it seems to append some unwanted bytes before and after the data itself. I have found out that these are called record delimiters, but I want to turn these off. How?
  27. K

    Mars Express Images from ESA's Mars spacecraft

    Hello. I would like to share some images taken by the Mars Express spacecraft . Please click on the links below. Thanks. http://www.marsesa.9f.com/slide_show.html Source Image: http://esamultimedia.esa.int/images/marsexpress/306-230906-3253-6-co2-Cydonia_H.jpg
  28. J

    Basic proof about inverse images of sets

    [SOLVED] basic proof about inverse images of sets Homework Statement let f map X onto Y, and let A be a subset of X, B subset of Y 1) Prove that if y is in B, then f^(-1) (y) is in f^(-1) (B)The Attempt at a Solution 1) I think I'm missing some two-line proof, because I'm getting nowhere...
  29. N

    Kernel and images of linear operator, examples

    Homework Statement If I e.g. want to find the kernel and range of the linear opertor on P_3: L(p(x)) = x*p'(x), then we can write this as L(p'(x)) = x*(2ax+b). What, and why, is the kernel and range of this operator? The Attempt at a Solution The kernel must be the x's where L(p'(x))...
  30. J

    Images from Two Parallel Mirrors

    Homework Statement Two parallel mirrors that face each other are placed along and perpendicular to the x-axis at x = +11.00 m and x = -11.00 m. Assume that a point source of light is placed on the axis at x = +2.70 m. In principle, there will be an infinite number of images generated...
  31. J

    Images from Two Parallel Mirrors problem

    Homework Statement Two parallel mirrors that face each other are placed along and perpendicular to the x-axis at x = +11.00 m and x = -11.00 m. Assume that a point source of light is placed on the axis at x = +2.70 m. In principle, there will be an infinite number of images generated...
  32. D

    Mapping Images of Axes Under f(z) = (z+1)/(z-1)

    Homework Statement f(z) = (z+1)/(z-1) What are the images of the x and y axes under f? At what angle do the images intersect? Homework Equations z = x + iy The Attempt at a Solution This is actually a 4 part question and this is the part I don't understand at all really. The...
  33. B. Elliott

    Hunter's images stir Bigfoot debate

    http://news.yahoo.com/s/ap/20071028/ap_on_fe_st/odd_bigfoot_in_pa
  34. G

    Optics: Real vs Virtual Images

    Hi, So, I'm confused about the difference between real and virtual images. Let's use a concave mirror for example. I understand that a real image is formed when the actual light rays reflect off the surface and converge to one point. A virtual image is formed when the rays don't themselves...
  35. K

    LaTeX Maximizing Your Physics Forums Experience: RSS Feeds and LaTeX Images Explained

    I don't know if this is the forum to write this, but I would just like to give firstly some encouragement to the moderators of Physics Forums : you are doing a great job! This is a remarkable resource. I have subscribed to several of the RSS feeds for the forums, which I find very handy...
  36. D

    How does the method of image charges work between two conducting surfaces?

    I'm reading about the method of image charges at http://en.wikipedia.org/wiki/Method_of_image_charges The page describes a charge located above a single conducting surface. What happens if the charge is between two conducting surfaces? Does the bottom plate, along with the imaginary...
  37. T

    Dependent vectors and their images

    Homework Statement Prove that if T is a linear transform, and vectors v1,..., vn are linearly dependent, then Tv1,...,Tvn are linearly dependent Homework Equations The Attempt at a Solution I tried this: Assume A1v1 + ... + Anvn = 0, where all Ai are scalars. Taking the...
  38. W

    E&M Method of Images: Amplitude Adjustment?

    The method of images exploits the fact any linear combination of solutions to a differential equation is also a solution, and the fields and potentials from a point source satisfy all relevant diff eq's, assuming the boundary conditions are met. However, a scalar multiple of any solution is...
  39. J

    Are the kernel and image the same for a matrix and its reduced row echelon form?

    Consider a matrix A, and let B = rref(A). Is ker(A) necesarily equal to ker(B), and is im(A) necessarily equal to im(B)? I want to say that the answer to both questions are yes because A and B are the same matrix, i.e. there are a finite number of elementary operations that can change A to...
  40. P

    Method of images to solve green's function problems

    How does the method of images work? I can see why it works (by going back to the form of the Green function and differentiating) but don't see how useful it is to solve problems. At the moment I am basically memorising the different images for each boundary condition which I am sure is not the...
  41. ?

    Object Must Be Placed at 15cm from Convex Mirror for Half Size Image

    A virtual image is formed by a convex mirror that has a 30cm focal length. Where must the object be placed if the image is to be half the size of the object? I know that since the mirror is convex F is negative (F is the focal length). Useful equations are 1/Do + 1/Di = 1/F, where Do is...
  42. G

    Calculating Number of Images in Mirrors

    I need some help guys with this one. Say you have two mirrors like in the image below, with some angle phi between them. The question is how many images would be formed if the angle between them changed to 20, 30, 40, 60, 90, or 0 degress. Is there some sort of equation that will give you this...
  43. V

    How Does the Method of Images Solve Poisson's Equation in All of Space?

    Dear all, I have some difficulties in understanding to use the method of images to solve Poisson's/Laplace's equation with boundary values. I understand that the Uniqueness theorem(s) enables this method. In this method we use image charges and setup a different configuration without...
  44. T

    Kernels & Images: Matrix A vs. Matrix B

    Homework Statement Consider a matrix A, and let B = rref(A) (a) Is ker(A) necessarily equal to ker(B)? Explain. (b) Is im(A) necessarily equal to im(B)? Explain. Homework Equations The Attempt at a Solution I feel confident saying yes for (a) and no for (b), and what I can...
  45. T

    LaTeX Preview option and LaTex images

    When I want to see how \LaTeX image displays by the preview option,the image can't be generated (no matter if I reload page or not). Why?
  46. S

    Method of images and charges

    Homework Statement To conducting planes are placed at an angle 60 degrees to each other. A point charge q is placed on the line bisecting this angle at a distance a/2 fro each plane. Find the image charges and the resulting potnetial Homework Equations V(0,0) = 0 V(x,0) = 0...
  47. DaveC426913

    S/w to turn still images into movie

    I've got a sequence of illustrated images that I want to run as an animation. What is an easy shareware way to do this? (It is a simple cell animation sequence that I once did.) I've got a gif animator program but my images are large and plentiful (say, 320x240 x 100 frames).
  48. S

    Method of images and infinite conducting sheet

    Homework Statement An infinite conducting sheet has a hemispherical bubble of radius a. (Refer to the diagram) 2. The attempt at a solution ok i know the boundary conditions should be (Phi refresents the potential) And we are working in CGS units... units with which i am not entire...
  49. Z

    Mathematica Generating Mathematical Images?

    Hey, I was wondering what's the best way to generate mathematical images? I was really hoping of creating a few really high resolution ones and popping down to the print shop to have them printed out. But I have a couple of problems: 1) How do I go about generating a mathematical image...
  50. S

    Electromagnetics - Method of Images ?

    Electromagnetics - Method of Images ? Hello all, I am in the process of preparing for a entrance examination. In the course of studying I came across this problem that I just can not figure out. Here it is: A perfectly conducting plane is located in free space at x=4, and a uniform inifinte...
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