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  • C# Image Deskew

    - by Brett
    Has anyone seen any image deskew algorithms in c#? I have found: http://www.codeproject.com/KB/graphics/Deskew_an_Image.aspx but unfortunately, it doesn't do very much for images without text. I am specifically trying to auto deskew an image of a book with solid edges, but minimal text. Has anyone seen anything that may be able to do this?

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  • Laplacian of Gaussian: how does it work? (opencv)

    - by maximus
    Does anybody know how does it work and how to do it using opencv? Laplacian can be calculated using opencv, but the result is not what I expected. I mean I expect the image to be approximately constant contrast at background regions, but it is black, and edges are white. There are a lot of noise also, even after gauss filter. I filter image using gaussian filter and then apply laplace. I think what I want is done by a different way.

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  • Any task-control algorithms programming practices?

    - by NumberFour
    Hi, I was just wondering if there's any field which concerns the task-control programming (or at least that's the way I call it). For a better explanation of task-control consider the following scenario: An application (master-thread) waits for a command - which might be a particular action or a set of actions the application should perform. When a command is received the master-thread creates a task (= spawns an independent thread which actually does the action) and adds a record in it's task-list - thus keeping track of the time of execution, thread handle, task priority...etc. The master-thread awaits for any other incoming commands while taking care of all the tasks - e.g: kills tasks running too long, prioritizes tasks with higher priorities, kills a task on a request of another task, limits the number of currently running tasks, allows task scheduling, cleans finished tasks (threads) and so on. The model is pretty similar to what we can see in OS dealing with running processes. Are there any good practices programming such task-models or is there some theoretical work done in this field? Maybe my question is too generalized, but at least I wanted to know whether there are any experiences working on such models or if there's a better approach. Thanks for any answers.

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  • Why aren't we programming on the GPU???

    - by Chris
    So I finally took the time to learn CUDA and get it installed and configured on my computer and I have to say, I'm quite impressed! Here's how it does rendering the Mandelbrot set at 1280 x 678 pixels on my home PC with a Q6600 and a GeForce 8800GTS (max of 1000 iterations): Maxing out all 4 CPU cores with OpenMP: 2.23 fps Running the same algorithm on my GPU: 104.7 fps And here's how fast I got it to render the whole set at 8192 x 8192 with a max of 1000 iterations: Serial implemetation on my home PC: 81.2 seconds All 4 CPU cores on my home PC (OpenMP): 24.5 seconds 32 processors on my school's super computer (MPI with master-worker): 1.92 seconds My home GPU (CUDA): 0.310 seconds 4 GPUs on my school's super computer (CUDA with static domain decomposition): 0.0547 seconds So here's my question - if we can get such huge speedups by programming the GPU instead of the CPU, why is nobody doing it??? I can think of so many things we could speed up like this, and yet I don't know of many commercial apps that are actually doing it. Also, what kinds of other speedups have you seen by offloading your computations to the GPU?

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  • How to use gnlcomposition to concatenate video files?

    - by Hardy
    Hi All, I am trying to concatenate two video files with the gnonlin components of the gstreamer. The pipeline I am using is gst-launch-0.10 gnlcomposition { gnlfilesource name="s1" location="/home/s1.mp4" start=0 duration=2000000000 media-start=0 media-duration=2000000000 gnlfilesource name="s2" location="/home/s2.mp4" start=2000000000 duration=2000000000 media-start=0 media-duration=2000000000 } ! queue ! videorate ! progressreport name="Merging Progress" ! ffmpegcolorspace ! ffenc_mpeg4 ! ffmux_mp4 ! filesink location="/home/merge.mp4" As a result I am getting only the second file for the duration specified in the parameters. Tried several things and also searched on google but I could not figure out the problem with the above command. Can anyone point what i am doing wrong? Any other way of concatenating multiple files into one based on time is welcome too. Thanks

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  • OCR for Devanagari (Hindi / Marathi / Sanskrit)

    - by Egon
    Does anybody have any idea about any recent work being done on optical character recognition for Indian scripts using modern Machine Learning techniques ? I know of some research being done at ISI, calcutta, but nothing new has come up in the last 3-4 years to the best of my knowledge, and OCR for Devanagari is sadly lacking!

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  • computing matting Laplacian matrix of an Image

    - by ajith
    hi everyone, i need to compute Laplacian Matrix-L for an image(nXn) in opencv...computing goes as follows.......... dij - 1/|wk|{[1+1/(e/|wk|+s2)][(Ii-µk)*(Ij -µk)]}.... for all(i,j)?wk,summing over k yields (i,j)th element of L. where Here dij is the Kronecker delta,µk and s2k are the mean & variance of intensities in the window wk around k,and |wk| is the number of pixels in this window.wk is 3X3 window... here am not clear about 2 things... 1.what ll be the size of L?nXn or (nXn)X(nXn)?? 2.how to select Ii and Ij separately in 2D image?

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  • Image Recognition (Shape recognition)

    - by mqpasta
    I want to recognize the shapes in the picture by template matching.Is the "ExhaustiveTemplateMatching" is the right option given in Aforge.Net for this purpose.Had anyone tried this class and find it working correctly.How accurate and right choice this class is for achieving my purpose.Suggest any other methods or Alogrithms as well for recognizing shapes by matching template.For example Identifying ComboBox in a picture.

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  • Recognize objects in image

    - by DoomStone
    Hello I am in the process of doing a school project, where we have a robot driving on the ground in between Flamingo plates. We need to create an algorithm that can identify the locations of these plates, so we can create paths around them (We are using A Star for that). So far have we worked with AForged Library and we have created the following class, the only problem with this is that when it create the rectangles dose it not take in account that the plates are not always parallel with the camera border, and it that case will it just create a rectangle that cover the whole plate. So we need to some way find the rotation on the object, or another way to identify this. I have create an image that might help explain this Image the describe the problem: http://img683.imageshack.us/img683/9835/imagerectangle.png Any help on how I can do this would be greatly appreciated. Any other information or ideers are always welcome. public class PasteMap { private Bitmap image; private Bitmap processedImage; private Rectangle[] rectangels; public void initialize(Bitmap image) { this.image = image; } public void process() { processedImage = image; processedImage = applyFilters(processedImage); processedImage = filterWhite(processedImage); rectangels = extractRectangles(processedImage); //rectangels = filterRectangles(rectangels); processedImage = drawRectangelsToImage(processedImage, rectangels); } public Bitmap getProcessedImage { get { return processedImage; } } public Rectangle[] getRectangles { get { return rectangels; } } private Bitmap applyFilters(Bitmap image) { image = new ContrastCorrection(2).Apply(image); image = new GaussianBlur(10, 10).Apply(image); return image; } private Bitmap filterWhite(Bitmap image) { Bitmap test = new Bitmap(image.Width, image.Height); for (int width = 0; width < image.Width; width++) { for (int height = 0; height < image.Height; height++) { if (image.GetPixel(width, height).R > 200 && image.GetPixel(width, height).G > 200 && image.GetPixel(width, height).B > 200) { test.SetPixel(width, height, Color.White); } else test.SetPixel(width, height, Color.Black); } } return test; } private Rectangle[] extractRectangles(Bitmap image) { BlobCounter bc = new BlobCounter(); bc.FilterBlobs = true; bc.MinWidth = 5; bc.MinHeight = 5; // process binary image bc.ProcessImage( image ); Blob[] blobs = bc.GetObjects(image, false); // process blobs List<Rectangle> rects = new List<Rectangle>(); foreach (Blob blob in blobs) { if (blob.Area > 1000) { rects.Add(blob.Rectangle); } } return rects.ToArray(); } private Rectangle[] filterRectangles(Rectangle[] rects) { List<Rectangle> Rectangles = new List<Rectangle>(); foreach (Rectangle rect in rects) { if (rect.Width > 75 && rect.Height > 75) Rectangles.Add(rect); } return Rectangles.ToArray(); } private Bitmap drawRectangelsToImage(Bitmap image, Rectangle[] rects) { BitmapData data = image.LockBits(new Rectangle(0, 0, image.Width, image.Height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb); foreach (Rectangle rect in rects) Drawing.FillRectangle(data, rect, Color.Red); image.UnlockBits(data); return image; } }

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  • Finding edge and corner values of an image in matlab

    - by James
    Hi, this problem links to two other questions i've asked on here. I am tracing the outline of an image and plotting this to a dxf file. I would like to use the bwboundaries function to find the coordinates of the edges of the image, find the corner coordinates using the cornermetric function and then remove any edge coordinates that are not a corner. The important thing I need to be able to do is keep the order of the corner elements obtained from bwboundaries, so that the section traces properly. The dxf function I have that draws from the coordinates draws lines between coordinates that are next to each other, so the line has to be drawn "around" the section rather than straight between the corner points. The reason I am doing this is because there are less coordinates obtained this way, so it is easier to amend the dxf file (as there are less points to manipulate). The code I have so far is: %# Shape to be traced bw = zeros(200); bw(20:40,20:180) = 1; bw(20:180,90:110) = 1; bw(140:180,20:185) = 1; %# Boundary Finding Section [Boundary] = bwboundaries(bw); %Traces the boundary of each section figure, imshow(bw); hold on; colors=['b' 'g' 'r' 'c' 'm' 'y']; for k=1:length(Boundary) perim = Boundary{k}; %Obtains perimeter coordinates (as a 2D matrix) from the cell array cidx = mod(k,length(colors))+1;% Obtains colours for the plot plot(perim(:,2), perim(:,1),... colors(cidx),'LineWidth',2); end Coordmat = cell2mat(Boundary) %Converts the traced regions to a matrix X = Coordmat(:,1) Y = Coordmat(:,2) % This gives the edge coordinates in matrix form %% Corner Finding Section (from Jonas' answer to a previous question %# get corners cornerProbability = cornermetric(bw); cornerIdx = find(cornerProbability==max(cornerProbability(:))); %# Label the image. bwlabel puts 1 for the first feature, 2 for the second, etc. %# Since concave corners are placed just outside the feature, grow the features %# a little before labeling bw2 = imdilate(bw,ones(3)); labeledImage = bwlabel(bw2); %# read the feature number associated with the corner cornerLabels = labeledImage(cornerIdx); %# find all corners that are associated with feature 1 corners_1 = cornerIdx(cornerLabels==1) [Xcorners, Ycorners] = ind2sub(200,corners_1) % Convert subscripts The code I have is, to give a matrix Xfin for the final x coordinates (which are on the edge AND at a corner. Xfin = zeros(length(X),1) for i = Xcorners XFin(i) = Xcorners if i~= Xcorners XFin(i) = [] end end However, this does not work correctly, because the values in the solution are sorted into order, and only one of each value remains. As I said, I would like the corner elements to be in the same order as obtained from bwboundaries, to allow the image to trace properly. Thanks

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  • Is there any super fast algorithm for finding LINES on picture?

    - by Ole Jak
    So I have Image like this I need some super fast algorithm for finding all straight lines on it. I want to give to algorithm parameters like min length and max line distortion. I want to get relative to picture pixel coords start and end points of lines. So on this picture to find all lines between dalles and thouse 2 black lines on top. So I need algorithm for super fast finding straight lines of different colors on picture. Is there any such algorithm? (super duper fast=)

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  • C# Monte Carlo Incremental Risk Calculation optimisation, random numbers, parallel execution

    - by m3ntat
    My current task is to optimise a Monte Carlo Simulation that calculates Capital Adequacy figures by region for a set of Obligors. It is running about 10 x too slow for where it will need to be in production and number or daily runs required. Additionally the granularity of the result figures will need to be improved down to desk possibly book level at some stage, the code I've been given is basically a prototype which is used by business units in a semi production capacity. The application is currently single threaded so I'll need to make it multi-threaded, may look at System.Threading.ThreadPool or the Microsoft Parallel Extensions library but I'm constrained to .NET 2 on the server at this bank so I may have to consider this guy's port, http://www.codeproject.com/KB/cs/aforge_parallel.aspx. I am trying my best to get them to upgrade to .NET 3.5 SP1 but it's a major exercise in an organisation of this size and might not be possible in my contract time frames. I've profiled the application using the trial of dotTrace (http://www.jetbrains.com/profiler). What other good profilers exist? Free ones? A lot of the execution time is spent generating uniform random numbers and then translating this to a normally distributed random number. They are using a C# Mersenne twister implementation. I am not sure where they got it or if it's the best way to go about this (or best implementation) to generate the uniform random numbers. Then this is translated to a normally distributed version for use in the calculation (I haven't delved into the translation code yet). Also what is the experience using the following? http://quantlib.org http://www.qlnet.org (C# port of quantlib) or http://www.boost.org Any alternatives you know of? I'm a C# developer so would prefer C#, but a wrapper to C++ shouldn't be a problem, should it? Maybe even faster leveraging the C++ implementations. I am thinking some of these libraries will have the fastest method to directly generate normally distributed random numbers, without the translation step. Also they may have some other functions that will be helpful in the subsequent calculations. Also the computer this is on is a quad core Opteron 275, 8 GB memory but Windows Server 2003 Enterprise 32 bit. Should I advise them to upgrade to a 64 bit OS? Any links to articles supporting this decision would really be appreciated. Anyway, any advice and help you may have is really appreciated.

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  • Float PPM image file format?

    - by Luca
    I've found a PPM image with the header starting with PF. The resolution number is stored in floating point (-1.000). No comments are inserted to get how it was produced. From the resolution, each pixel is composed by 12 bytes (4 bytes per component)... I suppose they are float or integer numbers. The problem is that I cannot get a clear image. Someone has already found this kind of images?

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  • JPEG artifacts removal in C#

    - by Arcturus
    Hi all I am building a website for a club that is part of a mother organisation. I am downloading (leeching ;) ) the images that where put on profile pages of the mother organisation to show on my own page. But their website has a nice white background, and my website has a nice gray gradient on the background. This does not match nicely. So my idea was to edit the images before saving them to my server. I am using GDI+ to enhance my images, and when I use the method MakeTransparent of Bitmap, it does work, and it does do what its supposed to do, but I still have these white jpeg artifacts all over the place. The artifacts makes the image so bad, I am better off not making the image transparent and just leaving it white, but thats really ugly on my own website. I can always at a nice border with a white background of course, but I rather change the background to transparent. So I was wondering if and how I can remove some simple JPEG artifacts in C#. Has anyone ever done this before? Thanks for your time. Example image: Transformed image:

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  • Programming for Multi core Processors

    - by Chathuranga Chandrasekara
    As far as I know, the multi-core architecture in a processor does not effect the program. The actual instruction execution is handled in a lower layer. my question is, Given that you have a multicore environment, Can I use any programming practices to utilize the available resources more effectively? How should I change my code to gain more performance in multicore environments?

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  • Acordex Image viewer throws out of memory exception in CITRIX environment

    - by neha
    We have a .net 2.0 application. In the .aspx page we are calling the java applet using . This applet is calling the Acordex Image viewer. In the production environment users are facing "out of memory" or "insufficient memory" issues when users try to open the image or magnify an image in Acordex viewer. Strangely when the users logout and login again they are able to see the same image without any errors. The website is hosted in a CITRIX environment. We have access to this environment but we are not able to reproduce this issue on the test servers or the local machines. We dont know what is causing this issue. What should we do to troubleshoot the issue? Do we have to increase the memory allotted to the users in CITRIX? The RAM is around 4 gb. Number of simultaneous users - 10-13. image size is max 2 mb Following is the code used to call Acordex image viewer:

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  • fft understanding

    - by maximus
    Can somebody give a good explanation of FFT image transform How the FFT transformed image and it's Re^2+Im^2 image can be analyzed? I just want to understand something when loiking to the image and it's frequency.

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  • Crystal Reports Programmatic Image Resizing... Scale?

    - by C. Griffin
    I'm working with a Crystal Reports object in Visual Studio 2008 (C#). The report is building fine and the data is binding correctly. However, when I try to resize an IBlobFieldObject from within the source, the scale is getting skewed. Two notes about this scenario. Source image is 1024x768, my max width and height are 720x576. My math should be correct that my new image size will be 720x540 (to fit within the max width and height guidelines). The ratio is wrong when I do this though: img = Image.FromFile(path); newWidth = img.Size.Width; newHeight = img.Size.Height; if ((img.Size.Width > 720) || (img.Size.Height > 576)) { double ratio = Convert.ToDouble(img.Size.Width) / Convert.ToDouble(img.Size.Height); if (ratio > 1.25) // Adjust width to 720, height will fall within range { newWidth = 720; newHeight = Convert.ToInt32(Convert.ToDouble(img.Size.Height) * 720.0 / Convert.ToDouble(img.Size.Width)); } else // Adjust height to 576, width will fall within range { newHeight = 576; newWidth = Convert.ToInt32(Convert.ToDouble(img.Size.Width) * 576.0 / Convert.ToDouble(img.Size.Height)); } imgRpt.Section3.ReportObjects["image"].Height = newHeight; imgRpt.Section3.ReportObjects["image"].Width = newWidth; } I've stepped through the code to make sure that the values are correct from the math, and I've even saved the image file out to make sure that the aspect ratio is correct (it was). No matter what I try though, the image is squashed--almost as if the Scale values are off in the Crystal Reports designer (they're not). Thanks in advance for any help!

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  • asp.net image aspect ratio help

    - by StealthRT
    Hey all, i am in need of some help with keeping an image aspect ratio in check. This is the aspx code that i have to resize and upload an image the user selects. <%@ Page Trace="False" Language="vb" aspcompat="false" debug="true" validateRequest="false"%> <%@ Import Namespace=System.Drawing %> <%@ Import Namespace=System.Drawing.Imaging %> <%@ Import Namespace=System %> <%@ Import Namespace=System.Web %> <SCRIPT LANGUAGE="VBScript" runat="server"> const Lx = 500 ' max width for thumbnails const Ly = 60 ' max height for thumbnails const upload_dir = "/uptest/" ' directory to upload file const upload_original = "sample" ' filename to save original as (suffix added by script) const upload_thumb = "thumb" ' filename to save thumbnail as (suffix added by script) const upload_max_size = 512 ' max size of the upload (KB) note: this doesn't override any server upload limits dim fileExt ' used to store the file extension (saves finding it mulitple times) dim newWidth, newHeight as integer ' new width/height for the thumbnail dim l2 ' temp variable used when calculating new size dim fileFld as HTTPPostedFile ' used to grab the file upload from the form Dim originalimg As System.Drawing.Image ' used to hold the original image dim msg ' display results dim upload_ok as boolean ' did the upload work ? </script> <% randomize() ' used to help the cache-busting on the preview images upload_ok = false if lcase(Request.ServerVariables("REQUEST_METHOD"))="post" then fileFld = request.files(0) ' get the first file uploaded from the form (note:- you can use this to itterate through more than one image) if fileFld.ContentLength > upload_max_size * 1024 then msg = "Sorry, the image must be less than " & upload_max_size & "Kb" else try originalImg = System.Drawing.Image.FromStream(fileFld.InputStream) ' work out the width/height for the thumbnail. Preserve aspect ratio and honour max width/height ' Note: if the original is smaller than the thumbnail size it will be scaled up If (originalImg.Width/Lx) > (originalImg.Width/Ly) Then L2 = originalImg.Width newWidth = Lx newHeight = originalImg.Height * (Lx / L2) if newHeight > Ly then newWidth = newWidth * (Ly / newHeight) newHeight = Ly end if Else L2 = originalImg.Height newHeight = Ly newWidth = originalImg.Width * (Ly / L2) if newWidth > Lx then newHeight = newHeight * (Lx / newWidth) newWidth = Lx end if End If Dim thumb As New Bitmap(newWidth, newHeight) 'Create a graphics object Dim gr_dest As Graphics = Graphics.FromImage(thumb) ' just in case it's a transparent GIF force the bg to white dim sb = new SolidBrush(System.Drawing.Color.White) gr_dest.FillRectangle(sb, 0, 0, thumb.Width, thumb.Height) 'Re-draw the image to the specified height and width gr_dest.DrawImage(originalImg, 0, 0, thumb.Width, thumb.Height) try fileExt = System.IO.Path.GetExtension(fileFld.FileName).ToLower() originalImg.save(Server.MapPath(upload_dir & upload_original & fileExt), originalImg.rawformat) thumb.save(Server.MapPath(upload_dir & upload_thumb & fileExt), originalImg.rawformat) msg = "Uploaded " & fileFld.FileName & " to " & Server.MapPath(upload_dir & upload_original & fileExt) upload_ok = true catch msg = "Sorry, there was a problem saving the image." end try ' Housekeeping for the generated thumbnail if not thumb is nothing then thumb.Dispose() thumb = nothing end if catch msg = "Sorry, that was not an image we could process." end try end if ' House Keeping ! if not originalImg is nothing then originalImg.Dispose() originalImg = nothing end if end if %> What i am looking for is a way to just have it go by the height of what i set it: const Ly = 60 ' max height for thumbnails And have the code for the width just be whatever. So if i had an image... say 600 x 120 (w h) and i used photoshop to change just the height, it would keep it in ratio and have it 300 x 60 (w x h). Thats what i am looking to do with this code here. However, i can not think of a way to do this (or to just leave a wildcard for the width setting. Any help would be great :o) David

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  • Issue with WIC image resizing on ASP.NET MVC 2

    - by Dave
    I am attempting to implement image resizing on user uploads in ASP.NET MVC 2 using a version of the method found: here on asp.net. This works great on my dev machine, but as soon as I put it on my production machine, I start getting the error 'Exception from HRESULT: 0x88982F60' which is supposed to mean that there is an issue decoding the image. However, when I use WICExplorer to open the image, it looks ok. I've also tried this with dozens of images of various sources and still get the error (though possible, I doubt all of them are corrupted). Here is the relevant code (with my debugging statements in there): MVC Controller [Authorize, HttpPost] public ActionResult Upload(string file) { //Check file extension string fx = file.Substring(file.LastIndexOf('.')).ToLowerInvariant(); string key; if (ConfigurationManager.AppSettings["ImageExtensions"].Contains(fx)) { key = Guid.NewGuid().ToString() + fx; } else { return Json("extension not found"); } //Check file size if (Request.ContentLength <= Convert.ToInt32(ConfigurationManager.AppSettings["MinImageSize"]) || Request.ContentLength >= Convert.ToInt32(ConfigurationManager.AppSettings["MaxImageSize"])) { return Json("content length out of bounds: " + Request.ContentLength); } ImageResizerResult irr, irr2; //Check if this image is coming from FF, Chrome or Safari (XHR) HttpPostedFileBase hpf = null; if (Request.Files.Count <= 0) { //Scale and encode image and thumbnail irr = ImageResizer.CreateMaxSizeImage(Request.InputStream); irr2 = ImageResizer.CreateThumbnail(Request.InputStream); } //Or IE else { hpf = Request.Files[0] as HttpPostedFileBase; if (hpf.ContentLength == 0) return Json("hpf.length = 0"); //Scale and encode image and thumbnail irr = ImageResizer.CreateMaxSizeImage(hpf.InputStream); irr2 = ImageResizer.CreateThumbnail(hpf.InputStream); } //Check if image and thumbnail encoded and scaled correctly if (irr == null || irr.output == null || irr2 == null || irr2.output == null) { if (irr != null && irr.output != null) irr.output.Dispose(); if (irr2 != null && irr2.output != null) irr2.output.Dispose(); if(irr == null) return Json("irr null"); if (irr2 == null) return Json("irr2 null"); if (irr.output == null) return Json("irr.output null. irr.error = " + irr.error); if (irr2.output == null) return Json("irr2.output null. irr2.error = " + irr2.error); } if (irr.output.Length > Convert.ToInt32(ConfigurationManager.AppSettings["MaxImageSize"]) || irr2.output.Length > Convert.ToInt32(ConfigurationManager.AppSettings["MaxImageSize"])) { if(irr.output.Length > Convert.ToInt32(ConfigurationManager.AppSettings["MaxImageSize"])) return Json("irr.output.Length > maximage size. irr.output.Length = " + irr.output.Length + ", irr.error = " + irr.error); return Json("irr2.output.Length > maximage size. irr2.output.Length = " + irr2.output.Length + ", irr2.error = " + irr2.error); } //Store scaled and encoded image and thumbnail .... return Json("success"); } The code is always failing when checking if the output stream is null (i.e. irr.output == null is true). ImageResizerResult and ImageResizer public class ImageResizerResult : IDisposable { public MemoryIStream output; public int width; public int height; public string error; public void Dispose() { output.Dispose(); } } public static class ImageResizer { private static Object thislock = new Object(); public static ImageResizerResult CreateMaxSizeImage(Stream input) { uint maxSize = Convert.ToUInt32(ConfigurationManager.AppSettings["MaxImageDimension"]); try { lock (thislock) { // Read the source image var photo = ByteArrayFromStream(input); var factory = (IWICComponentFactory)new WICImagingFactory(); var inputStream = factory.CreateStream(); inputStream.InitializeFromMemory(photo, (uint)photo.Length); var decoder = factory.CreateDecoderFromStream(inputStream, null, WICDecodeOptions.WICDecodeMetadataCacheOnDemand); var frame = decoder.GetFrame(0); // Compute target size uint width, height, outWidth, outHeight; frame.GetSize(out width, out height); if (width > height) { //Check if width is greater than maxSize if (width > maxSize) { outWidth = maxSize; outHeight = height * maxSize / width; } //Width is less than maxSize, so use existing dimensions else { outWidth = width; outHeight = height; } } else { //Check if height is greater than maxSize if (height > maxSize) { outWidth = width * maxSize / height; outHeight = maxSize; } //Height is less than maxSize, so use existing dimensions else { outWidth = width; outHeight = height; } } // Prepare output stream to cache file var outputStream = new MemoryIStream(); // Prepare JPG encoder var encoder = factory.CreateEncoder(Consts.GUID_ContainerFormatJpeg, null); encoder.Initialize(outputStream, WICBitmapEncoderCacheOption.WICBitmapEncoderNoCache); // Prepare output frame IWICBitmapFrameEncode outputFrame; var arg = new IPropertyBag2[1]; encoder.CreateNewFrame(out outputFrame, arg); var propBag = arg[0]; var propertyBagOption = new PROPBAG2[1]; propertyBagOption[0].pstrName = "ImageQuality"; propBag.Write(1, propertyBagOption, new object[] { 0.85F }); outputFrame.Initialize(propBag); outputFrame.SetResolution(96, 96); outputFrame.SetSize(outWidth, outHeight); // Prepare scaler var scaler = factory.CreateBitmapScaler(); scaler.Initialize(frame, outWidth, outHeight, WICBitmapInterpolationMode.WICBitmapInterpolationModeFant); // Write the scaled source to the output frame outputFrame.WriteSource(scaler, new WICRect { X = 0, Y = 0, Width = (int)outWidth, Height = (int)outHeight }); outputFrame.Commit(); encoder.Commit(); return new ImageResizerResult { output = outputStream, height = (int)outHeight, width = (int)outWidth }; } } catch (Exception e) { return new ImageResizerResult { error = "Create maxsizeimage = " + e.Message }; } } } Thoughts on where this is going wrong? Thanks in advance for the effort.

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  • Laplacian of gaussian filter use

    - by maximus
    This is a formula for LoG filtering: Also in applications with LoG filtering I see that function is called with only one parameter: sigma(s). I want to try LoG filtering using that formula (previous attempt was by gaussian filter and then laplacian filter with some filter-window size ) But looking at that formula I can't understand how the size of filter is connected with this formula, does it mean that the filter size is fixed? Can you explain how to use it?

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