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  • Cropping image with ImageScience

    - by fl00r
    ImageScience is cool and light. I am using it in my sinatra app. But I can't understand how can I crop image with not square form and how can I make thumbnail with two dimensions. As I found on ImageScience site: ImageScience.with_image(file) do |img| img.cropped_thumbnail(100) do |thumb| thumb.save "#{file}_cropped.png" end img.thumbnail(100) do |thumb| thumb.save "#{file}_thumb.png" end img.resize(100, 150) do |img2| img2.save "#{file}_resize.png" end end I can crop thumb and resize thumb only with ONE dimension but I want to use two, as in RMagick. For example I want to crop 100x200px box from image, or I want to make thumbnail with width or height not bigger then 300 (width) or 500 (height) pixels.

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  • scanned image in C#

    - by ahmed fouad
    We wanna a c# solution to correct the scanned image becouse it is rotated and to solve this problem we must detect the rotation angle first then rotate the image.this was our first thinking for our problem then we think image warping will be more accurate as i think it will make the scanned image like our template so we can process it as we know all the coordinates of our template ....... i search for a free SDK or a free solution in c# and helping me in this will be graet work as it is the last task in our working. rally thanxxxx for all.

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  • Matlab - Propagate points orthogonally on to the edge of shape boundaries

    - by Graham
    Hi I have a set of points which I want to propagate on to the edge of shape boundary defined by a binary image. The shape boundary is defined by a 1px wide white edge. I also have the coordinates of these points stored in a 2 row by n column matrix. The shape forms a concave boundary with no holes within itself made of around 2500 points. I want to cast a ray from each point from the set of points in an orthogonal direction and detect at which point it intersects the shape boundary at. What would be the best method to do this? Are there some sort of ray tracing algorithms that could be used? Or would it be a case of taking orthogonal unit vector and multiplying it by a scalar and testing after multiplication if the end point of the vector is outside the shape boundary. When the end point of the unit vector is outside the shape, just find the point of intersection? Thank you very much in advance for any help!

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  • How do you composite an image onto another image with PIL in Python?

    - by Sebastian
    I need to take an image and place it onto a new, generated white background in order for it to be converted into a downloadable desktop wallpaper. So the process would go: 1) Generate new, all white image with 1440x900 dimensions 2) Place existing image on top, centered 3) Save as single image In PIL, I see the ImageDraw object, but nothing indicates it can draw existing image data onto another image. Suggestions or links anyone can recommend?

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  • Perl Parallel::ForkManager wait_all_children() takes excessively long time

    - by zhang18
    I have a script that uses Parallel::ForkManager. However, the wait_all_children() process takes incredibly long time even after all child-processes are completed. The way I know is by printing out some timestamps (see below). Does anyone have any idea what might be causing this (I have 16 CPU cores on my machine)? my $pm = Parallel::ForkManager->new(16) for my $i (1..16) { $pm->start($i) and next; ... do something within the child-process ... print (scalar localtime), " Process $i completed.\n"; $pm->finish(); } print (scalar localtime), " Waiting for some child process to finish.\n"; $pm->wait_all_children(); print (scalar localtime), " All processes finished.\n"; Clearly, I'll get the Waiting for some child process to finish message first, with a timestamp of, say, 7:08:35. Then I'll get a list of Process i completed messages, with the last one at 7:10:30. However, I do not receive the message All Processes finished until 7:16:33(!). Why is that 6-minute delay between 7:10:30 and 7:16:33? Thx!

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  • How to convert a 32bpp image to an indexed format?

    - by Ed Swangren
    So here are the details (I am using C# BTW): I receive a 32bpp image (JPEG compressed) from a server. At some point, I would like to use the Palette property of a bitmap to color over-saturated pixels (brightness 240) red. To do so, I need to get the image into an indexed format. I have tried converting the image to a GIF, but I get quality loss. I have tried creating a new bitmap in an index format by these methods: // causes a "Parameter not valid" error Bitmap indexed = new Bitmap(orig.Width, orig.Height, PixelFormat.Indexed) // no error, but the resulting image is black due to information loss I assume Bitmap indexed = new Bitmap(orig.Width, orig.Height, PixelFormat.Format8bppIndexed) I am at a loss now. The data in this image is changed constantly by the user, so I don't want to manually set pixels that have a brightness 240 if I can avoid it. If I can set the palette once when the image is created, my work is done. If I am going about this the wrong way to begin with please let me know. EDIT: Thanks guys, here is some more detail on what I am attempting to accomplish. We are scanning a tissue slide at high resolution (pathology application). I write the interface to the actual scanner. We use a line-scan camera. To test the line rate of the camera, the user scans a very small portion and looks at the image. The image is displayed next to a track bar. When the user moves the track bar (adjusting line rate), I change the overall intensity of the image in an attempt to model what it would look like at the new line rate. I do this using an ImageAttributes and ColorMatrix object currently. When the user adjusts the track bar, I adjust the matrix. This does not give me per pixel information, but the performance is very nice. I could use LockBits and some unsafe code here, but I would rather not rewrite it if possible. When the new image is created, I would like for all pixels with a brightness value of 240 to be colored red. I was thinking that defining a palette for the bitmap up front would be a clean way of doing this.

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  • "Unsupported Image Type" exception in only few images...

    - by Nitz
    In my java-swing project. I have one frame in which user can drop the images and save that images in database. Now this work perfectly but their are some images which is not showing. This are images Image 1 , Images 2 which is not supporting .. this are some images which are not reading... and its showing me exception, like javax.imageio.IIOException: Unsupported Image Type Can i check that, is the image which user had dropped is supported or not? And can i convert that file which is not supported into supported file in java?

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  • Removing the transparency from image while keeping the actual image

    - by KPL
    Hello people, I have three images,and , they are not square or rectangular in shape. They are just like face of anyone. So, basically, my images are in the size 196x196 or anything like that, but complete square or rectangle with the face in the middle and transperant background in the rest of the portion. Now, I want to remove the transperant background too and just keep the faces. Don't know if this is possible and mind you, this isn't a programming question.

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  • Java 1.5.0_16 corrupted colours when saving jpg image

    - by Coder
    Hi, i have a loaded image from disk (stored as a BufferedImage), which i display correctly on a JPanel but when i try to re-save this image using the command below, the image is saved in a reddish hue. ImageIO.write(image, "jpg", fileName); Note! image is a BufferedImage and fileName is a File object pointing to the filename that will be saved which end in ".jpg". I have read that there were problems with ImageIO methods in earlier JDKs but i'm not on one of those versions as far as i could find. What i am looking for is a way to fix this issue without updating the JDK, however having said that i would still like to know in what JDK this issue was fixed in (if it indeed is still a bug with the JDK i'm using). Thanks.

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  • How do you go about finding out whether an idea you've had has already been patented?

    - by Iain Fraser
    I have an idea for image copy-protection that I'm in the process of coding up and plan on selling to one of my clients who sells images online. If successful I think there would be a lot of people in a similar situation to my client who would be interested in the code also. I think this is a fairly unique idea that could be packaged into a saleable product - but if I did do this, I wouldn't want some big corporation decending on me with their lawyers after all my hard work. So before I put too much work into this I'd really like to know how I'd go about finding if this idea has been patented already and whether I'd get in trouble if I sold my product and if it would be worthwhile patenting the idea myself. Although I find the idea of software patenting abhorrent, it would be more to protect myself from the usual suspects than to stop fellow-developers from using the idea (if it is in fact a worthwhile one). I live in Australia, so an idea of who to go and see and a ball park figure of how much money I'd be looking at having to pay would be fantastic (in orders of a magnitude: 100s, 1000s, 10s of thousands of dollars, etc). Cheers Iain

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  • Parallelism in Python

    - by fmark
    What are the options for achieving parallelism in Python? I want to perform a bunch of CPU bound calculations over some very large rasters, and would like to parallelise them. Coming from a C background, I am familiar with three approaches to parallelism: Message passing processes, possibly distributed across a cluster, e.g. MPI. Explicit shared memory parallelism, either using pthreads or fork(), pipe(), et. al Implicit shared memory parallelism, using OpenMP. Deciding on an approach to use is an exercise in trade-offs. In Python, what approaches are available and what are their characteristics? Is there a clusterable MPI clone? What are the preferred ways of achieving shared memory parallelism? I have heard reference to problems with the GIL, as well as references to tasklets. In short, what do I need to know about the different parallelization strategies in Python before choosing between them?

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  • How to display part of an image for the specific width and height?

    - by Brady Chu
    Recently I participated in a web project which has a huge large of images to handle and display on web page, we know that the width and height of images end users uploaded cannot be control easily and then they are hard to display. At first, I attempted to zoom in/out the images to rearch an appropriate presentation, and I made it, but my boss is still not satisfied with my solution, the following is my way: var autoResizeImage = function(maxWidth, maxHeight, objImg) { var img = new Image(); img.src = objImg.src; img.onload = function() { var hRatio; var wRatio; var Ratio = 1; var w = img.width; var h = img.height; wRatio = maxWidth / w; hRatio = maxHeight / h; if (maxWidth == 0 && maxHeight == 0) { Ratio = 1; } else if (maxWidth == 0) { if (hRatio < 1) { Ratio = hRatio; } } else if (maxHeight == 0) { if (wRatio < 1) { Ratio = wRatio; } } else if (wRatio < 1 || hRatio < 1) { Ratio = (wRatio <= hRatio ? wRatio : hRatio); } if (Ratio < 1) { w = w * Ratio; h = h * Ratio; } w = w <= 0 ? 250 : w; h = h <= 0 ? 370 : h; objImg.height = h; objImg.width = w; }; }; This way is only intended to limit the max width and height for the image so that every image in album still has different width and height which are still very urgly. And right at this minute, I know we can create a DIV and use the image as its background image, this way is too complicated and not direct I don't want to take. So I's wondering whether there is a better way to display images with the fixed width and height without presentation distortion? Thanks.

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  • Arduino wireless options

    - by user541597
    I am currently working on a wireless solution for my arduino and computer. I am trying to connect a Transmitter to my computer and a receiver to my arduino. I have seen a lot of examples with arduino to arduino communication but none for computer to arduino. What would I need to interface the transmitter with my computer, PIC? If anyone can provide any insight or any links it would be greatly appreciated. Thanks,

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  • Sending series of images to display like a movie on iPhone

    - by unknownthreat
    Allow me to elaborate more. On the server, we will have a program that will take data from iPhone and process that data and produce series of images. Each time an image is generated, it will be send back to display on iPhone. I have done all of the things above using UDP, OpenGL, and such. It works. The images are transferred to iPhone and can be displayed, but it is slow. The image's resolution is around 320 x 420 and we send the image pixels by pixels. This naive implementation leads to a slow framerate. I can see around 2-3 frames per second. There are also some UDP packets dropped, and this is expected. Are there any sort of compression method available for something like this? Are there any other method that can make this better? NOTE: please don't just write "compression" as an answer, because we are aware that we will need to do it in some ways.

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  • How to Use Calculated Color Values with ColorMatrix?

    - by Otaku
    I am changing color values of each pixel in an image based on a calculation. The problem is that this takes over 5 seconds on my machine with a 1000x1333 image and I'm looking for a way to optimize it to be much faster. I think ColorMatrix may be an option, but I'm having a difficult time figure out how I would get a set of pixel RGB values, use that to calculate and then set the new pixel value. I can see how this can be done if I was just modifying (multiplying, subtracting, etc.) the original value with ColorMatrix, but now how I can use the pixels returned value to use it to calculate and new value. For example: Sub DarkenPicture() Dim clrTestFolderPath = "C:\Users\Me\Desktop\ColorTest\" Dim originalPicture = "original.jpg" Dim Luminance As Single Dim bitmapOriginal As Bitmap = Image.FromFile(clrTestFolderPath + originalPicture) Dim Clr As Color Dim newR As Byte Dim newG As Byte Dim newB As Byte For x = 0 To bitmapOriginal.Width - 1 For y = 0 To bitmapOriginal.Height - 1 Clr = bitmapOriginal.GetPixel(x, y) Luminance = ((0.21 * (Clr.R) + (0.72 * (Clr.G)) + (0.07 * (Clr.B))/ 255 newR = Clr.R * Luminance newG = Clr.G * Luminance newB = Clr.B * Luminance bitmapOriginal.SetPixel(x, y, Color.FromArgb(newR, newG, newB)) Next Next bitmapOriginal.Save(clrTestFolderPath + "colorized.jpg", ImageFormat.Jpeg) End Sub The Luminance value is the calculated one. I know I can set ColorMatrix's M00, M11, M22 to 0, 0, 0 respectively and then put a new value in M40, M41, M42, but that new value is calculated based of a value multiplication and addition of that pixel's components (((0.21 * (Clr.R) + (0.72 * (Clr.G)) + (0.07 * (Clr.B)) and the result of that - Luminance - is multiplied by the color component). Is this even possible with ColorMatrix?

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  • Solid FFmpeg wrapper for C#/.NET

    - by Lillemanden
    I have been searching the web for some time for a solid FFmpeg wrapper for C#/.NET. But I have yet to come up with something useful. I have found the following three projects, but all of them apears to be dead in early alpha stage. FFmpeg.NET ffmpeg-sharp FFLIB.NET So my question is if anyone knows of a wrapper project that is more mature? I am not looking for a full transcoding engine with job queues and more. Just a simple wrapper so I do not have to make a command line call and then parse the console output, but can make method calls and use eventlisteners for progress. And please feel free to mention any active projects, even if they are stil in the early stages.

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  • Best practice for writing ARRAYS

    - by Douglas
    I've got an array with about 250 entries in it, each their own array of values. Each entry is a point on a map, and each array holds info for: name, another array for points this point can connect to, latitude, longitude, short for of name, a boolean, and another boolean The array has been written by another developer in my team, and he has written it as such: names[0]=new Array; names[0][0]="Campus Ice Centre"; names[0][1]= new Array(0,1,2); names[0][2]=43.95081811364498; names[0][3]=-78.89848709106445; names[0][4]="CIC"; names[0][5]=false; names[0][6]=false; names[1]=new Array; names[1][0]="Shagwell's"; names[1][1]= new Array(0,1); names[1][2]=43.95090307839151; names[1][3]=-78.89815986156464; names[1][4]="shg"; names[1][5]=false; names[1][6]=false; Where I would probably have personally written it like this: var names = [] names[0] = new Array("Campus Ice Centre", new Array[0,1,2], 43.95081811364498, -78.89848709106445, "CIC", false, false); names[1] = new Array("Shagwell's", new Array[0,1], 43.95090307839151, -78.89815986156464, 'shg", false, false); They both work perfectly fine of course, but what I'm wondering is: 1) does one take longer than the other to actually process? 2) am I incorrect in assuming there is a benefit to the compactness of my version of the same thing? I'm just a little worried about his 3000 lines of code versus my 3-400 to get the same result. Thanks in advance for any guidance.

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  • Is there an existing solution to the multithreaded data structure problem?

    - by thr
    I've had the need for a multi-threaded data structure that supports these claims: Allows multiple concurrent readers and writers Is sorted Is easy to reason about Fulfilling multiple readers and one writer is a lot easier, but I really would wan't to allow multiple writers. I've been doing research into this area, and I'm aware of ConcurrentSkipList (by Lea based on work by Fraser and Harris) as it's implemented in Java SE 6. I've also implemented my own version of a concurrent Skip List based on A Provably Correct Scalable Concurrent Skip List by Herlihy, Lev, Luchangco and Shavit. These two implementations are developed by people that are light years smarter then me, but I still (somewhat ashamed, because it is amazing work) have to ask the question if these are the two only viable implementations of a concurrent multi reader/writer data structures available today?

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  • How to Profile R Code that Includes SNOW Cluster

    - by James
    Hi, I have a nested loop that I'm using foreach, DoSNOW, and a SNOW socket cluster to solve for. How should I go about profiling the code to make sure I'm not doing something grossly inefficient. Also is there anyway to measure the data flows going between the master and nodes in a Snow cluster? Thanks, James

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  • Difference in amplitude from the same source using FFT

    - by Anders
    Hi, I have a question regarding use of FFT. Using function getBand(int i) with Minim i can extract the amplitude of a specific frequency and do pretty maps of it. Works great. However, this is a more of a curiosity question. When i look at the values extracted from playing the same song two twice using the same frequency (so the amplitude should be identical) but i get very different values - why is this? 0.0,0.0,0.0,0.0,0.0,0.08706585,0.23708777,0.83046436,0.74603105,0.30447206 0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.08706585,0.4790409,0.9608221,0.83046436,0.74603105

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