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. M

    Deblurring Images: Can Blur be Reversed?

    Everyone always says that there is nothing that can ever remove blur from images. Correct me if I'm wrong, but here's some thoughts: Blur is a distinct mathematical transformation involving however many parameters. Which would mean that no information is lost in the image(except where the blur...
  2. C

    Why do funny mirrors produce distorted images?

    Homework Statement why is it that when one stands outside a cafe in front of its glass wall he can see his own reflection but not the people inside the cafe, and yet the people inside the cafe can see him from the inside?
  3. B

    Converting jpg images to movies

    Dear All I'm looking for free software for converting 100 jpg images to movie without loosing the quality. Kindly advice. Many Thanks Balaji
  4. M

    Why virtual images in telescopes & microscopes?

    Why in telescopes and microscopes the ocular distance is such that it creates virtual images instead of real images?
  5. N

    Why SPECT produces images with higher contrast

    Homework Statement Why does SPECT produce images with higher contrast compared with its alternatives such as PET? The Attempt at a Solution I HAVE NO IDEA! I honestly researched everywhere, they only say that it has a higher contrast. I think its something to do with the hardness...
  6. S

    Looking for HIV virus electron microscope images

    Hi, I am looking for some detailed electron microscop images of HIV virus itself. I need it bigger and more detailed then this: http://www.allvoices.com/contributed-news/9114517/image/80168820-hiv-virus-electron-micro-graph I would like to have some picture, not computer render or...
  7. D

    How Do Curved Mirrors Form Clear Images?

    My Optics text shows how the light rays reflecting off a spherical mirror appear to have been emitted from a single point, hence producing a well-formed image. The text then says that this is true "for any mirror whose curvature is gentle enough and that is symmetric with respect to rotation...
  8. A

    Conformal mapping of images

    Hi everybody, I was looking at the following link: http://www.dimensions-math.org/Dim_CH5_E.htm The section 6 deals with conformal mapping of the image for different kinds of transformations. I tried to reproduce them in mathematica for the transformation z \rightarrow z^2. I followed the...
  9. R

    Revising simple lenses - magnified, and diminished images

    Basically, I'm trying to revise lenses and the one thing I never really understood was how to tell whether an image is magnified or diminished. http://store.aqa.org.uk/qual/gce/pdf/AQA-2450-W-TRB-OGA.PDF pages 6 and 7 has the diagrams to show what I mean I can do the geometry of an object...
  10. QuarkCharmer

    Real Quasar Image: Gamma Radiation Burst on Science Channel Program

    I saw a real image of a quasar bursting out gamma radiation on a science channel program and I am having trouble finding the image, or any like it on the internet. All I can find are CG rendered things, and IR/UV images. The photo that I am referring to looked a bit like the Hubble deep field...
  11. cobalt124

    Texniccenter/eps/pdf and transparent images

    I'm looking for a way to add eps images with a transparent background to a pdf generated by texniccenter (Windows environment). Can this be done?
  12. A

    Theory of Images, or Gauss's Law?

    Homework Statement Two conducting spheres are concentric, the radius of the inner being a and the outer being b. One sphere is grounded & the other is at a potential V0. Find the charge on each when the grounded sphere is a) the outer, b) the inner. 2. The attempt at a solution Is this...
  13. R

    A dielectric + an infinite line of charge = use method of images

    Hi everyone, first time poster, long time reader (only because you're all so clever and I feel my contribution wouldn't be all that helpful haha). Homework Statement A dielectric (homogeneous, isotropic, with relative permativity \epsilon_{r}) is located in the region x<0. An infinite line...
  14. A

    Multi Lens/Mirror problems and virtual real images

    Hey everyone, So I'm wondering whether or not a virtual object can make a real image, essentially. Let's say a real object is passed through a diverging lens, and thus creates a virtual image. This image is then bounced off a concave mirror. Now the concave mirror, if given a real object...
  15. S

    How Are Nebular Images Composed?

    I'm hoping that someone can answer a question that has been bothering me for sometime now and I can't seem to find the answer anywhere. We've all seen the fantastic pictures of nebular like e.g. the helix nebular, since the nebular I believe is approx 700 light years across, and that Light...
  16. B

    Calculate Reflection & Transmission of Candle Flame Images in Glass Sphere

    A fortune-teller’s crystal ball is a sphere of diameter 200 mm, made of glass with refractive index 1.70. A candle flame of height 10 mm is placed 1.00 metre away from the surface of the ball. Calculate the position and size of the two images of the flame: (i) reflected in the ball’s...
  17. A

    Project light visibly on glass to create images?

    I'm not sure which category of physics best suits light rays and what not so I just stuck this under general physics, many thanks to anyone who can help me with my problem! I want to project some words onto glass with a projector... What projector do I need? I was assuming something with...
  18. P

    A question about mirrors and images

    If two mirrors are placed at such an angle so that when 360 degree is divided by that angle the result is a fraction.then if an object is placed between the two mirrors how many images of that object will be formed? Proof is needed.
  19. FtlIsAwesome

    Artistic or CG astronomy images

    I would like to start a thread where we can post artistic or computer generated images of planets, stars, etc. This is mainly for artistic merit and not neccesarily realism in the photos. If you want, you can also post real astronomy images. Be sure to not break any copyrights. If you are...
  20. B

    Method of Images: Find Minimum Energy for Electron to Escape Metal Surface

    Homework Statement A point charge +q is initially at distance x from a conducting plane of infinite extent and held at zero potential. Find the work done in moving the charge to an infinite distance from the plane. Hence find the minimum energy an electron must have in order to escape from...
  21. H

    LaTeX Problem with previewing Latex images

    This forum has a problem with Latex for a long time. Please try it yourself: Start writing a new post Write down a Latex text in it (with "[latex ]...[/latex ]" tags) Preview your Latex output (press the "Preview Post" button - No problem until now) Now change your Latex text and press the...
  22. M

    MATLAB MATLAB subplot: how to have 1 colorbar for both images?

    Title says it all. I have two matrices representing 2D surfaces, and I am using subplot to compare them in the same plat area, however, each has its own colorbar so comparison is not so easy to do by eye. I'm pretty weak at figure handles, can someone give me a hint to do this? Thanks...
  23. E

    "Intersection Equality iff Function is Injective

    Homework Statement Let A, B be sets, C,D\subset A and f:A\longrightarrow B be a function between them. Then f(C\cap D)=f(C)\cap f(D) if and only if f is injective. Homework Equations Another proposition, that I have proven that for any function f(C\cap D)\subset f(C)\cap f(D), and the...
  24. Simfish

    Where is a good place to find scientific images w/o violating copyright?

    Okay, so I'm thinking about creating a website about astronomy. One thing I'd like to do is to include a lot of figures from journal articles. But I fear that including these diagrams will violate copyright. Are there certain journals that pretty much allow anyone to post figures without...
  25. A

    Can Non-Live Images Be Captured on a Screen?

    I don't understand what's meant by 'images can be caught or cannot be caught on a screen?'. Can we catch the pictures which are not live only?
  26. G

    A question concerning lenses and the resulting images

    Imagine a situation where an object is placed infinitely far away from a convex, converging lens such that the light rays that come from the object are parallel to the principal axis. The real image forms at the focal point. In this situation, the magnification is 0, so if a screen was placed at...
  27. P

    Two Point Charge Force Calculation on Left Side

    Homework Statement Two point charges sit on either side of large grounded conducting plane. Give an expression for the force experienced by the charge on the left hand side. There is a neg charge on one side and positive charge on the other side. Homework Equations The electric...
  28. M

    News UK's Tuition Fee Protest (Images)

    Thanks to the Boston Globe for uploading these. Viewer discretion advised (blood, violence, etc) http://www.boston.com/bigpicture/2010/12/london_tuition_fee_protest.html Here is one sample:
  29. W

    Inserting images into blogs etc.

    [Mentor's note: this thread was split off from a thread in the "Forum Feedback and Announcements" forum: https://www.physicsforums.com/showthread.php?t=449867 ] OK. I understand. I'm actually writing a blog for another website. I'm writing the blog using Microsoft Word with insertions. Is...
  30. J

    LaTeX Learn How to Easily Insert Images on LaTeX | Helpful Tips and Tricks

    Hi, I know this isn't a general math problem but I didn't really know where else to post. I'm trying to insert an image into a text I'm wrtting on LaTeX, the file is saved in .gif format in My Documents. I've read a little on the web about how I should insert the image into my text but I can't...
  31. nukeman

    Stargazing Looking for images of same object, but with different telescope sizes?

    Hey guys, Iv been looking for this, but can't seem to put it together. Mainly I am looking for images of the same object, like Jupiter or andromeda, with various sizes of telescopes, showing the difference in image of small telescopes to large ones. Like, a small dob, to a 6, to a 8...
  32. O

    Deriving Solutions with Method of Images

    Apply the method of images to derive the solution \displaystyle \phi(x,y,z) = \frac{z}{2 \pi} \int_{- \infty}^{\infty} \int_{- \infty}^{\infty} \frac{f(x_0, y_0)}{((x - x_0)^2 + (y - y_0)^2 + z^2)^{\frac{3}{2}}} dx_0 dy_0 from \displaystyle \bigtriangledown^2 \phi (x,y,z) = 0 \phi(x,y,0)...
  33. N

    Google images - Is there something wrong with it?

    Or is it just my end? The top half of the images don't load for me.
  34. O

    Method of Images - Green's Function

    Use the method of images to find a Green's function for the problem in the attached image. Demonstrate the functions satisfies the homogenous boundary condition.
  35. D

    Images and Monotone Functions

    Homework Statement Included in the pdf Homework Equations Included in the pdf The Attempt at a Solution Please take a look at pdf for my attempted solution. I would like to know how if it makes logical sense or if I should change something. Thanks!
  36. U

    Proof work - Topology Images and Inverse Images

    1. Let f:X->Y be a function and let U be a subset of X and V a subset of X. Prove that f(U) - f(v) is a subset of f(U-v). 3. The Attempt at a Solution Suppose x belongs to f(U-v), then f(x) belongs to U-V and then f(x) does not belong to V so f(x) belongs to U. Then it holds that...
  37. B

    Question about images of measurable functions

    I want to prove the following. Statement: Given that f is measurable, let B = {y \in ℝ : μ{f^(-1)(y)} > 0}. I want to prove that B is a countable set. (to clarify the f^(-1)(y) is the inverse image of y; also μ stands for measure) Please set me in the right direction. I would greatly...
  38. B

    Brightness of real images from converging lens

    Hi, Have a question about images from a converging lens. I assume that the brightness of the (real) image projected on a screen depends upon the amount of light rays going through the lens - more rays -> brighter. So a larger lens should bring about a brighter image. Ok, now let's go the...
  39. D

    Solving Prisms and Images: Find Location and Size of Image

    Homework Statement (2) For the combination of one prism and 2 lenses shown (Fig. 1), find the location and size of the final image when the object, length 1 cm, is located as shown in the figure. [Hint: Treat the prism as a mirror, but you have to take into account the image shift caused by...
  40. N

    Inverse Images and Sets (union & intersection)

    Homework Statement Suppose f is a function with sets A and B. 1. Show that: I_{f} \left(A \cap B\right) = I_{f} \left(A\right) \cap I_{f} \left(B\right) Inverse Image of F (A intersects B) = Inverse Image of F (A) intersects Inverse Image of B. 2. Show by giving a counter example that...
  41. T

    NASA Explanation needed: unknown objects orbiting our sun in NASA images

    Greetings, I've stumbled upon some peculiar images of our sun that appear to have extremely large objects in orbit which don't appear to be planets. The images are from the following NASA database. Each image is taken every ~10 minutes...
  42. P

    What are Direct and Inverse Images in Mathematics?

    Homework Statement The problem is attached and my attempt for direct image is also attached. I seek help in inverse image. Homework Equations The Attempt at a Solution
  43. B

    Infinite Plane with Point Charge Above - Method of Images - Uniqueness Dogma

    Homework Statement You have point charge a distance "d" above infinite conducting plane held at V = 0. What is the potential when you remove charge to infinity? Homework Equations The Attempt at a Solution I think I incorrectly used Coulomb's law between the charge (+q...
  44. B

    MATLAB Acquiring images and plotting graphs using Matlab

    I want to create a Matlab script which takes images and plots a graph of image intensity versus position. Currently created a script like this: %Create video input object vid = videoinput('winvideo',1,'RGB24_640x480'); % Set video input object properties for this application. % Note...
  45. Z

    What is the Difference Between Real and Virtual Images Formed by Mirrors?

    concave mirror make real and inverted image which means that the image can be obtained on the screen and on the contrary convex mirror makes virtual and erect image and it can't be obtained on screen..i can see that the images made by them are inverted and erect respectively but both the images...
  46. L

    Could we realistically see ancient images of the earth from reflected light?

    Could we realistically see ancient images of the Earth from reflected light? We know the speed of light and we know the distance of the Earth from the sun. Do we have the knowledge to predict the movements of light that we could take a reflection off the Earth that shines on a distant object...
  47. E

    Max theoretical resolution of scanned images.

    May seem like a bizarre question but I was wondering what the maximum possible resolution of a scanned A4 image would be. A4 paper is 0.297m x 0.21m, average resolution of light is 200nm. So I get, (0.297m / 200x10^-9m) x (0.21m / 200x10^-9m) = 1.56 terapixels Is this about right...
  48. T

    Ye garments and ye images of ye garments

    All right, drop the lab coats and headgear, because it's time to get a bit fashionable! Show off your favourite or recently attained clothing, or simply torture us with your horrid sense of fashion! I've recently attained something of an affection for denim jackets, personally. These are two...
  49. I

    Calculation of size from images at unknown distance

    Here is the problem I've been trying to solve for a couple of weeks. I have taken 2 pictures of an object of an unknown size with a camera. The first picture of the object was 1162 pixels across. I moved 419.1 mm closer and took a second picture, which was 1429 pixels across. Can I calculate...
  50. E

    Producing images with telescopes

    Homework Statement A telescope has a mirror with a focal length of +3 meters and the distance from the mirror the the eyepiece is 3.5 meter. If the eyepiece is 3.5 meter. a. If the eye piece has a focal length of 50 cm, where would the image produced by the eyepiece be? Could the image be...
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