Images Definition and 388 Threads

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. P

    Scanning Electron Microscope Images

    Would the resulting image by a scanning electron microscope be different if it scanned across the y-axis? SEMs have deflecting coils that move the electron beam from left to right (x-axis) rapidly while traversing down the y-axis to cover the entire specimen. Would the image you get after...
  2. EnumaElish

    A Google employee on a camera-equipped tricycle recording images

    So, this is how Google obtains street-view images for its maps: http://www.nytimes.com/imagepages/2010/05/28/technology/28google-inline1.html (I've been wondering.) Why bicycle, though? Wouldn't a motorcycle be faster?
  3. C

    Generate new image from principal components of many images

    1. Homework Statement I'm having a bit of difficulty with a neuroscience course - it's about the primary visual cortex. I have a bunch of image patches (16*16) and I need to generate synthesised images using principal component analysis as a generative model. I reshaped the images to...
  4. F

    Physicists capture first images of atomic spin

    I can't even claim to understand 'spin' as a property (even after reading that big thread about it :P) but I'm sure with the amount of discussion that generated, this could be worth talking about http://www.ohio.edu/research/communications/spin.cfm
  5. L

    What are the ripples in STM images?

    Do they just add waves into demonstrate the probability wave? They could not be detecting the electron in more than one place. Is it because they make so many measurements to generate the image that the amplitudes you see are a collection of each measurement? A good example is the copper...
  6. Q

    Good software for analyzing STM images?

    I've finished a lab with Scanning Tunneling Microscopy in an upper level physics undergrad course, and now I have about 50 ".ezd" files to analyze. They were produced with the Nanosurf easyScan microscope, which I'm told is quite common in very basic applications. I'm looking for some...
  7. E

    Method of images& half a sphere

    Homework Statement http://img532.imageshack.us/img532/3751/39842434.png Find the potential in all space for this configuration. Homework Equations ..basic electrostatics stuff, I guess. The Attempt at a Solution I can easily cancel the whole z=0 plane by placing a charge of -q...
  8. S

    Real Object, Images formed by a single converging or diverging lens

    Homework Statement Starting with a real object, which of the following statements are TRUE about the image formed by a single lens? (Choose ALL correct answers, e.g. B, AC, CDF.) A) For a converging lens an object has to be placed between the focal length and the lens in order to form a...
  9. M

    Retina Image Size: 43 ft Tree vs. 12 in Flower - Eye Distance Comparison

    Homework Statement Which forms the larger image on the retina of your eye: a 43 ft tree seen from a distance of 210 ft, or a 12 in flower viewed from a distance of 2.0 ft? Homework Equations none? The Attempt at a Solution I don't really understand how you would go about working...
  10. R

    Solve 2 Problems - Help Needed with Images Attached

    Hi, Can You Help me solve the these 2 problems? See the images attached. Regards,
  11. K

    Optics - Images with two convave mirrors

    Homework Statement Two concave mirrors of equal focal length f are placed a distance d apart in air. A point source is placed midway between the two mirrors. What should d be so as to get only a single image? Homework Equations Mirror formula (1/f = 1/u + 1/v) The Attempt at a...
  12. G

    Thin Lens & Images: Real, Inverted & Smaller Objects

    Homework Statement Under what conditions will a thin converging lens form: a) a real image, b) an inverted image, and c) an image smaller than the object? Homework Equations none The Attempt at a Solution I have concluded that: a) the object needs to be outside the focal...
  13. L

    Understanding Real and Virtual Images for Beginners

    Im having such a hard time understanding what these types of images even are this is what I've read so far real images "rays from a point of the object meet at a point" im so confused? what? they meet at the principal focus when reflected?? can somone please dumb this down for me in the...
  14. W

    How to Determine Statistical Significance Between Two Image Regions?

    Hi all, I have two images, without any exact spatial correspondence I want to find if the difference between two regions is statistically significant How would I do this?
  15. T

    Method of Images in Electrostatics

    Homework Statement A point charge q is held a distance d > a below the centre of a large spherical conductor of radius a. Show that, if the spherical conductor is earthed, the potential outside the sphere may be found by placing an image charge at a distance c=a2/d from the centre of the...
  16. B

    How Do Refraction and Radii Affect Image Formation in a Glass Rod?

    Homework Statement Hello: I am wondering if someone can help with the following? A rod that is 96 cm long is made of glass with index of refraction of 1.6. The rod has its end ground to convex spherical surfaces with radii of 8 cm and 16 cm. An object is in air on the long axis of the rod...
  17. P

    Is color added to SEM and TEM images in post-processing?

    I saw in some papers SEM colored images. Does anybody have an idea about the software that may be used?? and how? thanks
  18. J

    Help with Images and Optical Instrument Question

    An object is placed two focal lengths from a diverging lens, (a) What kind of image forms? (b) What is the magnification? (c) Where is the image? I am pretty sure the image is virtual, as for (b) and (c) I have no idea what to do.. Looking for some help, thanks in advance.. (a) I am...
  19. B

    What Are Invariant Moments in 2D Images?

    Hi there I'm thinking about using the rotation invarient moments by Hu/Flusser (http://en.wikipedia.org/wiki/Image_moment#Rotation_invariant_moments). I'm a physicist by trade, with exceptionally poor math..! I'm not comfortable with exactly what these invariants are. The wikipedia link...
  20. T

    Physics Geniuses: Mirrors;How many images Produced?

    Homework Statement In the following diagram, why not 6 images are produced? Explain thoroughly. And mention the amount of images produced. Problem Image: http://img691.imageshack.us/img691/8315/imageproduced.jpg or http://file15.9q9q.net/preview/92743229/Image-Produced.jpg.htmlPlease...
  21. K

    Linear Algebra- Kernel and images of a matrix

    Homework Statement Consider a square matrix A: a. What is the relationship between ker(A) and ker(A^2)? Are they necessarily equal? Is one of them necessarily contained in the other? More generally, What can you say about ker(A), ker(A^2), ker(A^3), ker(A^4),...? b. What can you say...
  22. N

    Amount of light needed to capture images

    Hi all, I'm working in application where a camera needs to see in a dark closed area. Imagine a small box, say 8"x8" and there is a camera trying to record inside. In order to get images, we need some light. The problem is how to determine how much light is needed without being too little...
  23. W

    Method of images for two charges and two planes

    Homework Statement Consider two charges, +q each, placed between two grounded plates at a distance d along the z-axis from each plate. thus, the potential V(x,y,-d) = 0 and V(x,y,d) = 0 and the charges are placed at (+R/2,0,0) and (-R/2,0,0) being a distance R apart. Draw the location and...
  24. J

    How to Invert Pixels in a Specific Window of an Image Using MATLAB?

    Homework Statement 1.invert all pixel of a 20x20 window around I(X,Y) 2.set all pixel aroud the in the inverted images Homework Equations cant make work right way. Please help me to solve problem. Thanks, The Attempt at a Solution I=imread('test7.jpg'); % Load the image file and...
  25. J

    Unveiling the Beauty of the Universe: Hubble's Latest Images in High Definition

    New Images just released from Nasa- So happy we still have Hubble! They're everywhere on online, though You can find them on Youtube, at "Hubble Spectacular First Light Images in HD". cheers, joono
  26. A

    Understanding Real and Virtual Images: Definition and Doubts Explored

    What is the exact definition of a real/virtual image? This is what gave rise to the doubt. Suppose we have a pair of plane mirrors inclined at any angle. A point object lies on the angle bisector of the two mirrors. Now,the object sends out 2 rays,one towards each mirror. These will...
  27. J

    Distance Between Woman and Mirrored Images in Reflection Experiment

    two plane mirrors facing each other are 10m apart. A woman stands 3 m from one of the mirrors and looks at the mirror and sees two distinct images. How far are these images from the woman? this one is a bit confusing.. can somebody knows how to solve it?
  28. P

    Method of Images: How does the uniqueness theorem apply?

    [b]1. Point charge in the presence of a grounded conducting sphere given the boundary conditions phi(x)=0 at r=a (V=0) and at r=infinity (V=0) [b]2. The equation I used phi(x)= (q/abs(x-y))+(q'/abs(x-y))=(q/abs(x*nhatsubx-y'nhatsuby))+ (q'/abs(x'*nhatsubx-y'*nhatsuby') [b]3. The...
  29. R

    LaTeX Incorporating LaTeX into Word documents as images

    I'm sorry if this is covered in a tutorial somewhere on here, but I couldn't find it. What I want to be able and do, is write in LaTeX code, and then export the product as an image. I've tried to do it on my own, but I just got bogged down by all sorts of sophisticated programs. I've...
  30. R

    Extracting data from copyrighted images in a paper ?

    I am using quite a few images from other neuroscience papers or medical books in my paper. I went through the recommended procedure of writing to the authors and copyright owners about six weeks ago. All the authors wrote back right away and said ok to use. The copyright owners: journals and...
  31. W

    Calculating Image Position and Size Using Convex Mirrors

    1. Shiny lawn spheres placed on pedestals are convex mirrors. One such sphere has a diameter of 40 cm. A 12 cm robin sits in a tree 1.5 m from the sphere. a) Where is the image of the robin? b) How long is the robin's image? 2. 1/f = 1/do + 1/di 3. a. 1/f = 1/do + 1/di...
  32. R

    Can conjugate images be used in place of dark field filters?

    I was working on some dark field filters and I was wondering if you could substitute the black spot in the centre of a dark field filter for a completely black filter with a light passing hole in the middle. Sort of an inverted dark field filter. I seem to remember reading something like this...
  33. K

    Finding the map between two images

    Homework Statement Let D* be the parallelogram with vertices at (-1,3), (0,0), (2,-1), and (1,2), and let D be the rectangle D = [0,1] X [0,1]. Find a T such that D is the image set of D8 under T. Homework Equations Not much to say other than T(D*) = D The Attempt at a Solution...
  34. S

    Diffusion Equation by Method of Images

    Homework Statement I need help in solving a problem I was assigned from Numerical Methods for Physics, 2nd Ed., by Garcia. We are asked to create a solution, by hand, for the diffusion equation, using the method of images. In particular, we have a 1-dimensional bar, centered at x = 0, of...
  35. U

    Method of Images (Electrostatics)

    Homework Statement A grounded spherical shell has inner radius of 1m. and outer radius of 2m. Q1=1 Coul. is located at x=0.5m and Q2=-2 Coul. is located at x=4m, respectively. Homework Equations Find the charge system to find the potential outside the shell. Find the charge system to find...
  36. marcus

    BH Mergers: 8 Images & Computer Simulations

    http://www.stsci.edu/institute/conference/blackholemergers Eight images. Four on the left appear to be stills from a computer simulation of a merger, calculated step by step using numerical GR methods. The four on the right seem to be actual photographs, some with false color showing...
  37. S

    Method of Images - Need a hint

    Homework Statement A conducting sphere of charge Q and radius A is located at a distance D from the sphere's center to an infinite, grounded, conducting plane. Ultimately, I would like to find the capacitance, but that is simple once I find the potential. So the question is:How does one...
  38. P

    Method of Images Question (Concave Geometries)

    I've been working with image charges for a while now, and I have noticed that I haven't been able to find a single discussion on the use of image charges for concave geometries (i.e. a charge on the "inside" of a catenary shaped curved conducting plate, see attached picture). Has anyone worked...
  39. R

    Finding Images of a Red Ball at Point A: Location & Number

    Homework Statement A red ball is placed at point A in the figure. (Intro 1 figure) : figure attached How many images are seen by an observer at point O? Where is each image seen by an observer located? Enter your answers as an ordered pairs (x, y) separated with comma(s), where x and...
  40. V

    Why does the method of images use a distance of 2x instead of just x?

    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 a...
  41. N

    Images in the frequency domain

    Hi, I've been trying to understand more on frequency plots of images. 1. Assuming a 1d example of just a strip of an image; in the frequency map there are 'same' no. of frequencies as there are pixels. What is the reason for this? Does this have something to do with the Nyquist theorom...
  42. L

    LaTeX Having Trouble Including Images in LaTex?

    Hi I am trying to include pictures in my physics course work but come up with these errors . I am using MikTex and writing in WinEdit. Thanks David
  43. K

    Method of images in Griffiths' text

    In Griffiths' text "Introduction to electrodynamics", p.125, how does the author get (3.15) and (3.16)? I try for an hour to deduce the relation with geometry, but still can't get that.
  44. W

    Method of images with infinite, earthed, conducting plane

    Hello guys, I'm having some trouble getting my head around the method of images, partly due to confusing notes and things. If I have a charge +q at a fixed point (0,0,a) above a conducting plane that is held at zero potential, it is said that the plane can be replaced with a charge of -q...
  45. Shackleford

    Understanding Inverted Images: Calculating M and f Ratios

    How do I know the image is inverted? Reporter photographs an actress. The ratio of the actual height of the actress to the height of the image on the film is M = hi/ho = .00471 f = .220
  46. Jonathan Scott

    LaTeX LaTeX showing old images in preview

    I've been trying to use LaTeX in a response, but the preview keeps showing images of different LaTeX expressions which I used in previous responses. This happens even for the most trivial case such as just a single letter X, both in ITEX and TEX tags. Is there something I need to do to reset...
  47. C

    Gallery of high-magnification images, including Nanobama

    http://www.boston.com/bigpicture/2008/11/peering_into_the_micro_world.html" (Including the usual, potentially disturbing, giant monster dust mite images but lots of other cool ones too.)
  48. D

    How can I project images onto a mirror for a painting project?

    Hi. I am an artist and currently working on a project using mirrors. I need to transfer an image (portrait photo) onto a mirror so I can trace directly on the mirror surface so I have the guides to then paint over it. I would like to be able to use an overhead projector but of course the light...
  49. T

    LaTeX Improving Latex Image Quality: Can Anti-Aliasing and Text Size Increase Help?

    Hi! Is there possible to improve the quality of the images generated by latex code? It should be good if anti aliasing could be turned on, which would produce smooth and fine images. Now, the text looks a little bit awkward in my opinion, since it it all edged, and the small text is hard to read.
  50. G

    Real Images and Thin Lenses: Can You Explain the Postulation?

    I was reading a bit on thin lenses when a postulation was made that the image formed from the first surface would be the object for the second. The postulation made sense for when the first image is virtual, but I don't see how it works when the first image is real? Can anyone provide me the...
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