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Search found 2333 results on 94 pages for 'mr pixel'.

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• How to read and modify the colorspace of an image in c#

  - by Matthias

  I'm loading a Bitmap from a jpg file. If the image is not 24bit RGB, I'd like to convert it. The conversion should be fairly fast. The images I'm loading are up to huge (9000*9000 pixel with a compressed size of 40-50MB). How can this be done? Btw: I don't want to use any external libraries if possible. But if you know of an open source utility class performing the most common imaging tasks, I'd be happy to hear about it. Thanks in advance.

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• Video Synthesis - Making waves, patterns, gradients...

  - by Nathan

  I'm writing a program to generate some wild visuals. So far I can paint each pixel with a random blue value: for (y = 0; y < YMAX; y++) { for (x = 0; x < XMAX; x++) { b = rand() % 255; setPixelColor(x,y,r,g,b); } } I'd like to do more than just make blue noise, but I'm not sure where to start (Google isn't helping me much today), so it would be great if you could share anything you know on the subject or some links to related resources.

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• UITableView: moving a row into an empty section

  - by Frank C

  I have a UITableView with some empty sections. I'd like the user to be able to move a row into them using the standard edit mode controls. The only way I can do it so far is to have a dummy row in my "empty" sections and try to hide it by using tableView:heightForRowAtIndexPath: to give the dummy row a height of zero. This seems to leave it as a 1-pixel row. I can probably hide this by making a special type of cell that's just filled with [UIColor groupTableViewBackgroundColor], but is there a better way? This is all in the grouped mode of UITableView UPDATE: Looks like moving rows into empty sections IS possible without any tricks, but the "sensitivity" is bad enough that you DO need tricks in order to make it usable for general users (who won't be patient enough to slowly hover the row around the empty section until things click)

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• In a digital photo, detecting if a mountain is obscured by clouds.

  - by Gavin Brock

  The problem I have a collection of digital photos of a mountain in Japan. However the mountain is often obscured by clouds or fog. What techniques can I use to detect that the mountain is visible in the image? I am currently using Perl with the Imager module, but open to alternatives. All the images are taken from the exact same position - these are some samples. My naïve solution I started by taking several horizontal pixel samples of the mountain cone and comparing the brightness values to other samples from the sky. This worked well for differentiating good image 1 and bad image 2. However in the autumn it snowed and the mountain became brighter than the sky, like image 3, and my simple brightness test started to fail. Image 4 is an example of an edge case. I would classify this as a good image since some of the mountain is clearly visible.

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• On-the-fly lossless image compression

  - by geschema

  I have an embedded application where an image scanner sends out a stream of 16-bit pixels that are later assembled to a grayscale image. As I need to both save this data locally and forward it to a network interface, I'd like to compress the data stream to reduce the required storage space and network bandwidth. Is there a simple algorithm that I can use to losslessly compress the pixel data? I first thought of computing the difference between two consecutive pixels and then encoding this difference with a Huffman code. Unfortunately, the pixels are unsigned 16-bit quantities so the difference can be anywhere in the range -65535 .. +65535 which leads to potentially huge codeword lengths. If a few really long codewords occur in a row, I'll run into buffer overflow problems.

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• image scaling with C

  - by sa125

  Hi - I'm trying to read an image file and scale it by multiplying each byte by a scale its pixel levels by some absolute factor. I'm not sure I'm doing it right, though - void scale_file(char *infile, char *outfile, float scale) { // open files for reading FILE *infile_p = fopen(infile, 'r'); FILE *outfile_p = fopen(outfile, 'w'); // init data holders char *data; char *scaled_data; // read each byte, scale and write back while ( fread(&data, 1, 1, infile_p) != EOF ) { *scaled_data = (*data) * scale; fwrite(&scaled_data, 1, 1, outfile); } // close files fclose(infile_p); fclose(outfile_p); } What gets me is how to do each byte multiplication (scale is 0-1.0 float) - I'm pretty sure I'm either reading it wrong or missing something big. Also, data is assumed to be unsigned (0-255). Please don't judge my poor code :) thanks

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• Cross domain cookie tracking

  - by Jon

  Hi, The company I work for has four domains and I'm trying to set up the cookies, so one cookie can be generated and tracked across all the domains. From reading various posts on here I thought it was possible. I've set up a sub domain on one site, to serve a cookie and 1*1 pixel image to all four sites. But I can't get this working on the other sites. If anyone can clarify that: Its possible? If I'm missing something obvious or a link to a good example? I'm trying to do this server side with PHP. Thanks

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• Image 8-connectivity without excessive branching?

  - by shoosh

  I'm writing a low level image processing algorithm which needs to do alot of 8-connectivity checks for pixels. For every pixel I often need to check the pixels above it, below it and on its sides and diagonals. On the edges of the image there are special cases where there are only 5 or 3 neighbors instead of 8 neighbors for a pixels. The naive way to do it is for every access to check if the coordinates are in the right range and if not, return some default value. I'm looking for a way to avoid all these checks since they introduce a large overhead to the algorithm. Are there any tricks to avoid it altogether?

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• How to spin an independent dispacher thread for a Silverlight UserControl

  - by ondesertverge

  I am trying to move a lot of different elements by 1 pixel very often and in parallel. Trying to do this on one dispatcher thread means that the elements are visited one after another. The result is that the more elements I have the slower they will all move. In WPF I was able to use a HostVisual as described here to solve this. I can't seem to find anything similar in Silverlight. Is this a drawback of the lightweight framework or is there something I haven't stumbled upon yet? I am using SL4.

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• Margin animate problem with Monitor display settings

  - by Jake

  I have an issue with an animation on a webpage. I have this div with text inside of it that I set the margin using css and when the page is loaded I use jquery to animate the div to a certain part of the page. The problem is it works with my concrete pixel settings, but if I change the properties of the monitor display settings in screen resolution(pixels), the div does not animate to the appropriate spot and it doesn't even start off at the appropriate spot from the css. Sample code: #div{ position:absolute; top:20px; left:50px } $("#div").animate({marginLeft: "250px"},2000); Is there a way to have the settings of the animation margin end at the approriate position no matter what the screen resolution is?

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• Projecting a targetting ring using direct3d

  - by JohnB

  I'm trying to draw a "targetting ring" on the ground below a "unit" in a hobby 3d game I'm working on. Basically I want to project a bright red patterned ring onto the ground terrain below the unit. The only approach I can think of is this - Draw the world once as normal Draw the world a second time but in my vertex shader I have the world x,y,z coordinates of the vertex and I can pass in the coordinates of the highlighted unit - so I can calculate what the u,v coordinates in my project texture should be at that point in the world for that vertex. I'd then use the pixel shader to pick pixels from the target ring texture and blend them into the previously drawn world. I believe that should be easy, and should work but it involves me drawing the whole visible world twice as it's hard to determine exactly which polygons the targetting ring might fall onto. It seems a big overhead to draw the whole world twice, once for the normal lit textured ground, and then again just to draw the targetting ring. Is there a better approach that I'm missing?

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• Altering CSS for nav bar images to accomodate IE

  - by Kim

  My horizontal nav bar is populated with images for the links that are coming from one image that includes all the sub-images; each nav item image is identified by the pixel location within the larger image. This works perfectly fine in Firefox and Safari, but in IE, all of the images are misplaced too low within the nav bar (can only barely see the tops of the words). Two questions: How do I fix this in the css so it is back-compatible with the more recent versions (and current versions) of IE Do I need a separate IE stylesheet? Thanks!

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• 8-direction path finding algorithm

  - by frinkz

  I'm having trouble finding the right pathfinding algorithm for some AI I'm working on. I have players on a pitch, moving around freely (not stuck to a grid), but they are confined to moving in 8 directions (N NE E etc.) I was working on using A*, and a graph for this. But I realised, every node on the graph is equally far apart, and all the edges have the same weight - since the pitch is rectangular. And the number of nodes is enormous (being a large pitch, with them able to move between 1 pixel and another) I figured there must be another algorithm, optimised for this sort of thing?

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• Video Synthesis - Making waves, pattern, gradients...

  - by Nathan

  I'm writing a program to generate some trippy visuals. My code paints each pixel with a random blue value which loops at 0.04 second intervals. for (y = 0; y < 5.5; y += 0.2) { for (x = 0; x < 7.5; x += 0.2) { b = rand() / ((double) RAND_MAX); setPixelColor(x,y,r,g,b); } } I'd like to do more than just make blue noise... but my maths is a bit rusty, and Google isn't helping me much today, so it would be great if you could share anything you know about making waves, patterns, gradient animations, etc or links to such material.

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• SSRS: Report loading external images, image not found, can I hide the image control

  - by Nauman

  My SSRS report loads logo images for each customer from a customer number specific folder on the report server. I write an expression, to form my URL to the image based on th customer number. ..."http://localhost/images/" + iCustomerNumber.ToString() + "/logo.gif" I am able to get this working, but the problem I face is, when a particular customer doesn't has an image, then my report shows a red X mark in place of the logo. In this case, I expect to hide the image control itself. Any thoughts???? The other dirty solution will be to ensure that each customer specific folder has the designated image! even if there is no logo for a customer, I'll place a blank.gif or a spacer.gif of probably a square pixel in dimension!.

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• Why use multiple OpenGL context

  - by Luca

  For rendering I have a current GL context, associated to a window. In the case the application render multiple scenes (for example using accumulation or different viewports) I think it is ok to reuse the same context. My question, indeed, is: why should I use multiple GL context? I red on ARB_framebuffer_object extension spec that MakeCurrent call could be expansive, and in the case the ARB_framebuffer_object extension is present I can render on a generic buffer without using MakeCurrent. Apparently the only reason to use multiple GL context is to avoid to setup context state (pixel store, transfer, point size, polygon stipple...) or to have avaialable multiple render buffers configuration (one context with accumulation, another without). How to determine when is better an alternative context instead of setting context state? Thankyou all!

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• Three vertically stacked DIVs with scrolling middle

  - by Dave

  Is it possible to stack three DIVs vertically and have just the middle div scroll vertically? I don't want to use pixel heights, though, because the DIVs are inside of a dialog box that is resizeable. Something like this (pardon my lousy ASCII art): +-----------+ | Header | +-----------+ | ^| | || | Scroll || | || | v| +-----------+ | Footer | +-----------+ The goal is to have the header and and footer fixed and, as the dialog grows, the middle div would grow vertically. Maybe I'm just being stupid, but I've been fighting this for the last few hours and can't seem to get it right. The three DIVs probably need to be inside "another" DIV but when I do that, and set the height to 100%, it grows as the middle DIV grows. Again, it's probably something silly I'm not accounting for. I've also tried using a TABLE to no avail. Thanks for any help.

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• Is there any simple way to test two PNGs for equality?

  - by Mason Wheeler

  I've got a bunch of PNG images, and I'm looking for a way to identify duplicates. By duplicates I mean, specifically, two PNG files whose uncompressed image data are identical, not necessarily whose files are identical. This means I can't do something simple like compare CRC hash values. I figure this can actually be done reliably since PNGs use lossless compression, but I'm worried about speed. I know I can winnow things down a little by testing for equal dimensions first, but when it comes time to actually compare the images against each other, is there any way to do it reasonably efficiently? (ie. faster than the "double-for-loop checking pixel values against each other" brute-force method?)

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• OpenCV in Python can't scan through pixels

  - by Marco L.

  Hi everyone, I'm stuck with a problem of the python wrapper for OpenCv. I have this function that returns 1 if the number of black pixels is greater than treshold def checkBlackPixels( img, threshold ): width = img.width height = img.height nchannels = img.nChannels step = img.widthStep dimtot = width * height data = img.imageData black = 0 for i in range( 0, height ): for j in range( 0, width ): r = data[i*step + j*nchannels + 0] g = data[i*step + j*nchannels + 1] b = data[i*step + j*nchannels + 2] if r == 0 and g == 0 and b == 0: black = black + 1 if black >= threshold * dimtot: return 1 else: return 0 The loop (scan each pixel of a given image) works good when the input is an RGB image...but if the input is a single channel image I get this error: for j in range( width ): TypeError: Nested sequences should have 2 or 3 dimensions The input single channel image (called 'rg' in the next example) is taken from an RGB image called 'src' processed with cvSplit and then cvAbsDiff cvSplit( src, r, g, b, 'NULL' ) rg = cvCreateImage( cvGetSize(src), src.depth, 1 ) # R - G cvAbsDiff( r, g, rg ) I've also already noticed that the problem comes from the difference image got from cvSplit... Anyone can help me? Thank you

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• FLTK Image Array Manipulation

  - by Cenoc

  Hello, I was wondering if anyone knew how to redraw after altering the pixel array in fltk, basically, I have: UI.OnlyBlue=false; for(int i=0; i!=jpg.h()*jpg.w(); i++){ ((uchar*)jpg.array)[3*i+1]=0; ((uchar*)jpg.array)[3*i+2]=0; } UI.ImageBox-set_changed(); UI.ImageBox-redraw(); I'm trying to only get the blue color to show up. I know that this change is registering, because when I do the desaturation, it gets darker when I first run it through this. Any tips would be much appreciated! Thanks.

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• How to work with BufferedImage and YCbCr colorspace?

  - by Onlyx

  Hi everyone! I need to translate colors in bitmap loaded to BufferedImage from RGB to YCbCr (luminance and 2 channels chrominance) and back after process. I made it with functions used like rgb2ycbcr() in main method for each pixel, but it isn't so smart solution. I should use ColorSpace and ColorModel classes to get BufferedImage with correct color space. It would be more flexible method, but I don't know how to do that. I'm lost and I need some tips. Can somebody help me?

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• How to use Haar wavelet to detect LINES on an image?

  - by Ole Jak

  So I have Image like this I want to get something like this (I hevent drawn all lines I want but I hope you can get my idea) I want to use SURF ( (Speeded Up Robust Features) is a robust image descriptor, first presented by Herbert Bay et al. in 2006 ) or something that is based on sums of 2D Haar wavelet responses and makes an efficient use of integral images for finding all straight lines on image. I want to get relative to picture pixel coords start and end points of lines. So on this picture to find all lines between tiles and thouse 2 black lines on top. Is there any such Code Example (with lines search capability) to start from? I love C and C++ but any other readable code will probably work for me=)

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• Programming related name for a kitten? [closed]

  - by andrhamm

  I am a programmer and I just got my first kitten. A Google search for nerdy/geeky cat names was unimpressive. She's a little black kitten with a very courageous and adventurous attitude! She has a little light gray spot on her chest which might turn white with time. Here she is on my Flickr Which name would you suggest? Which of these do you like? It should be something short that has a couple contrasting sounds so it stands out a bit when you say it. PHP is my favorite scripting language but it makes for a lousy name :P Java Pixel Perl Ruby Gizmo Mocha Thanks for the help!

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• Advantage of using a static member function instead of an equivalent non-static member function?

  - by jonathanasdf

  I was wondering whether there's any advantages to using a static member function when there is a non-static equivalent. Will it result in faster execution (because of not having to care about all of the member variables), or maybe less use of memory (because of not being included in all instances)? Basically, the function I'm looking at is an utility function to rotate an integer array representing pixel colours an arbitrary number of degrees around an arbitrary centre point. It is placed in my abstract Bullet base class, since only the bullets will be using it and I didn't want the overhead of calling it in some utility class. It's a bit too long and used in every single derived bullet class, making it probably not a good idea to inline. How would you suggest I define this function? As a static member function of Bullet, of a non-static member function of Bullet, or maybe not as a member of Bullet but defined outside of the class in Bullet.h? What are the advantages and disadvantages of each?

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• Slow motion tween text isn't smooth

  - by Alex

  Hi! i have to create a movie where a text string move in horizontal. the problem is that in the movie (800px wide) the text should go from right to left in about 7 seconds (so it have to go about 400px to the left in 7 sec). i created a motion-tween with ease for my "text" and the tween is long (at 30fps) 30*7=210 frames. the result is that the text DON'T MOVE FLUID... it's not a uniform movement... it's too visible the fact that it moves X pixel each x frames. it's the exact opposite of SMOOTH MOVEMENT. How can i obtain a smooth slow-motion text movement?

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