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• Render on other render targets starting from one already rendered on

  - by JTulip

  I have to perform a double pass convolution on a texture that is actually the color attachment of another render target, and store it in the color attachment of ANOTHER render target. This must be done multiple time, but using the same texture as starting point What I do now is (a bit abstracted, but what I have abstract is guaranteed to work singularly) renderOnRT(firstTarget); // This is working. for each other RT currRT{ glBindFramebuffer(GL_FRAMEBUFFER, currRT.frameBufferID); programX.use(); glActiveTexture(GL_TEXTURE0); glBindTexture(GL_TEXTURE_2D, firstTarget.colorAttachmentID); programX.setUniform1i("colourTexture",0); glActiveTexture(GL_TEXTURE1); glBindTexture(GL_TEXTURE_2D, firstTarget.depthAttachmentID); programX.setUniform1i("depthTexture",1); glBindBuffer(GL_ARRAY_BUFFER, quadBuffID); // quadBuffID is a VBO for a screen aligned quad. It is fine. programX.vertexAttribPointer(POSITION_ATTRIBUTE, 3, GL_FLOAT, GL_FALSE, 0, (void*)0); glDrawArrays(GL_QUADS,0,4); programY.use(); glActiveTexture(GL_TEXTURE0); glBindTexture(GL_TEXTURE_2D, currRT.colorAttachmentID); // The second pass is done on the previous pass programY.setUniform1i("colourTexture",0); glActiveTexture(GL_TEXTURE1); glBindTexture(GL_TEXTURE_2D, currRT.depthAttachmentID); programY.setUniform1i("depthTexture",1); glBindBuffer(GL_ARRAY_BUFFER, quadBuffID); programY.vertexAttribPointer(POSITION_ATTRIBUTE, 3, GL_FLOAT, GL_FALSE, 0, (void*)0); glDrawArrays(GL_QUADS, 0, 4); } The problem is that I end up with black textures and not the wanted result. The GLSL programs program(X,Y) works fine, already tested on single targets. Is there something stupid I am missing? Even an hint is much appreciated, thanks!

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• Displaying Fourier transforms in OpenCV

  - by Simonw

  Hi, I'm just learning to use OpenCV and am having a problem with using DFT. I've done a signal processing class which used MatLab, so I'm trying to go through some of the exercises we did in that class. I'm trying to get and display the FT of an image, so I can mask some of the frequencies. I'd like to be able to see the FT, so I know how big to make the mask, but when I tried, I got an image like this: rather than like one of these Am I forgetting a step somewhere? I'm loading the image, converting its type to CV_32FC1, getting the matrix of it, getting the DFT, and then getting turning the resulting matrix back into an image. I'll post the code I'm using if it will be of any help? Or if someone has a link to an example of displaying the FT? I could only find ones which used it for the convolution. EDIT: Did I get the Phase of the image?

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• what is the idea behind scaling an image using lanczos?

  - by banister

  Hi, I'm interested in image scaling algorithms and have implemented the bilinear and bicubic methods. However, I have heard of the lanczos and other more sophisticated methods for even higher quality image scaling and I am very curious how they work. Could someone here explain the basic idea behind scaling an image using lanczos (both upscaling and downscaling) and why it results in higher quality? I do have a background in fourier analysis and have done some signal processing stuff in the past, but not with relation to image processing, so don't be afraid to use terms like "frequency response" and such in your answer :) EDIT: I guess what i really want to know is the concept and theory behind using a convolution filter for interpolation. (Note: i have already read the wikipedia article on lanczos resampling but it didn't have nearly enough detail for me) thanks alot!

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• How to write C++ audio processing applications?

  - by cesko82

  Hi everyone, I'm an Electronics and Telecommunications student, next to my graduation. I'm gonna work on a project that involves my knowledge about DSP, music and audio in general. I allready know all the basic mathematic instruments and all the stuff I need to manage it, such as FFT, circular convolution ecc ecc. I want to learn C++ programming basically for one reason: it's very important in the professional world!!! And I think it's one of the most used to write applications working with audio, especially when it's about real time processing. Ok, after this small introduction I would like to know first, which are the most used libraries to work with audio processing in c++?? I was longer looking on the web but i couldn't find a lo of working stuff. (I work under linux with eclipse CDT enviroment). Then I would like to know if there are good sources to learn how to write some working code, such as for example how to write a simple low pass filter. Basically now i will not write real time applications, I would like to start from the processing of a WAV file, or even better an MP3 file, so basically on vectors of samples. Let's say that basically for now I would like to extract the waveform from an audio file, and save it to a thumbnail or to a PNG image. Ok, for now I think it's all I would need. Any ideas, advices, libraries, books, interesting sources about that? Thanks a lot in advance for any kind of answer. Giovanni.

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• What is the name of this geometrical function?

  - by Spike

  In a two dimentional integer space, you have two points, A and B. This function returns an enumeration of the points in the quadrilateral subset bounded by A and B. A = {1,1} B = {2,3} Fn(A,B) = {{1,1},{1,2},{1,3},{2,1},{2,2},{2,3}} I can implement it in a few lines of LINQ. private void UnknownFunction(Point to, Point from, List<Point> list) { var vectorX = Enumerable.Range(Math.Min(to.X, from.X), Math.Abs(to.X - from.Y) + 1); var vectorY = Enumerable.Range(Math.Min(to.Y, from.Y), Math.Abs(to.Y - from.Y) + 1); foreach (var x in vectorX) foreach (var y in vectorY) list.Add(new Point(x, y)); } I'm fairly sure that this is a standard mathematical operation, but I can't think what it is. Feel free to tell me that it's one line of code in your language of choice. Or to give me a cunning implementation with lambdas or some such. But mostly I just want to know what it's called. It's driving me nuts. It feels a little like a convolution, but it's been too long since I was at school for me to be sure.

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• Java 2D Resize

  - by jon077

  I have some old Java 2D code I want to reuse, but was wondering, is this the best way to get the highest quality images? public static BufferedImage getScaled(BufferedImage imgSrc, Dimension dim) { // This code ensures that all the pixels in the image are loaded. Image scaled = imgSrc.getScaledInstance( dim.width, dim.height, Image.SCALE_SMOOTH); // This code ensures that all the pixels in the image are loaded. Image temp = new ImageIcon(scaled).getImage(); // Create the buffered image. BufferedImage bufferedImage = new BufferedImage(temp.getWidth(null), temp.getHeight(null), BufferedImage.TYPE_INT_RGB); // Copy image to buffered image. Graphics g = bufferedImage.createGraphics(); // Clear background and paint the image. g.setColor(Color.white); g.fillRect(0, 0, temp.getWidth(null),temp.getHeight(null)); g.drawImage(temp, 0, 0, null); g.dispose(); // j2d's image scaling quality is rather poor, especially when // scaling down an image to a much smaller size. We'll post filter // our images using a trick found at // http://blogs.cocoondev.org/mpo/archives/003584.html // to increase the perceived quality.... float origArea = imgSrc.getWidth() * imgSrc.getHeight(); float newArea = dim.width * dim.height; if (newArea <= (origArea / 2.)) { bufferedImage = blurImg(bufferedImage); } return bufferedImage; } public static BufferedImage blurImg(BufferedImage src) { // soften factor - increase to increase blur strength float softenFactor = 0.010f; // convolution kernel (blur) float[] softenArray = { 0, softenFactor, 0, softenFactor, 1-(softenFactor*4), softenFactor, 0, softenFactor, 0}; Kernel kernel = new Kernel(3, 3, softenArray); ConvolveOp cOp = new ConvolveOp(kernel, ConvolveOp.EDGE_NO_OP, null); return cOp.filter(src, null); }

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• imageconvolution leaves black dot in the upper left corner

  - by Peter O.

  I'm trying to sharp resized images using this code: imageconvolution($imageResource, array( array( -1, -1, -1 ), array( -1, 16, -1 ), array( -1, -1, -1 ), ), 8, 0); When the transparent PNG image is sharpened, using code above, it appears with a black dot in the upper left corner (I have tried different convolution kernels, but the result is the same). After resizing the image looked OK. 1st image is the original one 2nd image is the sharpened one EDIT: What am I going wrong? I'm using the color retrieved from pixel. $color = imagecolorat($imageResource, 0, 0); imageconvolution($imageResource, array( array( -1, -1, -1 ), array( -1, 16, -1 ), array( -1, -1, -1 ), ), 8, 0); imagesetpixel($imageResource, 0, 0, $color); Is imagecolorat the right function? Or is the position correct? EDIT2: I have changed coordinates, but still no luck. I've check the transparency given by imagecolorat (according to this post). This is the dump: array(4) { red => 0 green => 0 blue => 0 alpha => 127 } Alpha 127 = 100% transparent. Those zeroes might cause the problem...

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• function taking in an input image and different kernel size

  - by drifterOcean19

  I have this filtering function that takes an input image, performs convolution using a given kernel, and returns the resulting image. However, I can't seem to work it out how to make it takes different kernel sizes.For example instead of pre-defined 3x3 kernel as below in the code, it could instead take 5x5 or 7x7. and then the user could input the type of kernel/filter they want(Depending on the intended effect). I can't seem to put my head around it. i'm quite new to matlab. function [newImg] = kernelFunc(imgB) img=imread(imgB); figure,imshow(img); img2=zeros(size(img)+2); newImg=zeros(size(img)); for rgb=1:3 for x=1:size(img,1) for y=1:size(img,2) img2(x+1,y+1,rgb)=img(x,y,rgb); end end end for rgb=1:3 for i= 1:size(img2,1)-2 for j=1:size(img2,2)-2 window=zeros(9,1); inc=1; for x=1:3 for y=1:3 window(inc)=img2(i+x-1,j+y-1,rgb); inc=inc+1; end end kernel=[1;2;1;2;4;2;1;2;1]/16; med=window.*kernel; disp(med); med=sum(med); med=floor(med); newImg(i,j,rgb)=med; end end end newImg=uint8(newImg); figure,imshow(newImg); end

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• Can FFT length affect filtering accuracy?

  - by Charles

  Hi, I am designing a fractional delay filter, and my lagrange coefficient of order 5 h(n) have 6 taps in time domain. I have tested to convolute the h(n) with x(n) which is 5000 sampled signal using matlab, and the result seems ok. When I tried to use FFT and IFFT method, the output is totally wrong. Actually my FFT is computed with 8192 data in frequency domain, which is the nearest power of 2 for 5000 signal sample. For the IFFT portion, I convert back the 8192 frequency domain data back to 5000 length data in time domain. So, the problem is, why this thing works in convolution, but not in FFT multiplication. Does converting my 6 taps h(n) to 8192 taps in frequency domain causes this problem? Actually I have tried using overlap-save method, which perform the FFT and multiplication with smaller chunks of x(n) and doing it 5 times separately. The result seems slight better than the previous, and at least I can see the waveform pattern, but still slightly distorted. So, any idea where goes wrong, and what is the solution. Thank you.

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• Parallelize or vectorize all-against-all operation on a large number of matrices?

  - by reve_etrange

  I have approximately 5,000 matrices with the same number of rows and varying numbers of columns (20 x ~200). Each of these matrices must be compared against every other in a dynamic programming algorithm. In this question, I asked how to perform the comparison quickly and was given an excellent answer involving a 2D convolution. Serially, iteratively applying that method, like so list = who('data_matrix_prefix*') H = cell(numel(list),numel(list)); for i=1:numel(list) for j=1:numel(list) if i ~= j eval([ 'H{i,j} = compare(' char(list(i)) ',' char(list(j)) ');']); end end end is fast for small subsets of the data (e.g. for 9 matrices, 9*9 - 9 = 72 calls are made in ~1 s). However, operating on all the data requires almost 25 million calls. I have also tried using deal() to make a cell array composed entirely of the next element in data, so I could use cellfun() in a single loop: # who(), load() and struct2cell() calls place k data matrices in a 1D cell array called data. nextData = cell(k,1); for i=1:k [nextData{:}] = deal(data{i}); H{:,i} = cellfun(@compare,data,nextData,'UniformOutput',false); end Unfortunately, this is not really any faster, because all the time is in compare(). Both of these code examples seem ill-suited for parallelization. I'm having trouble figuring out how to make my variables sliced. compare() is totally vectorized; it uses matrix multiplication and conv2() exclusively (I am under the impression that all of these operations, including the cellfun(), should be multithreaded in MATLAB?). Does anyone see a (explicitly) parallelized solution or better vectorization of the problem?

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• Filter design for audio signal.

  - by beanyblue

  What I am trying to do is simple. I have a few .wav files. I want to remove noise and filter out specific frequencies. I don't have matlab and I intend to write my own code for all the filters. Right now, I have a way to read the .wav file and dump out the structure into a text file. My questions are the following: Can I directly apply the digital filters on this sampled data?{ ie, can I directly do a convolution between my input samples and h(n) for the filter function that i choose?). How do I choose the number of coefficients for the Window function? I have octave, so if someone can point me to anything that gives me some idea on how to process the .wav file using octave, that would be great too. I want to be able to filter out the frequency and then listen to the sound again. Is this possible with octave? I'm just a beginner with these kinds of things, so please bear with me if my questions are too naive. Any help will be great.

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• How can I speed-up this loop (in C)?

  - by splicer

  Hi! I'm trying to parallelize a convolution function in C. Here's the original function which convolves two arrays of 64-bit floats: void convolve(const Float64 *in1, UInt32 in1Len, const Float64 *in2, UInt32 in2Len, Float64 *results) { UInt32 i, j; for (i = 0; i < in1Len; i++) { for (j = 0; j < in2Len; j++) { results[i+j] += in1[i] * in2[j]; } } } In order to allow for concurrency (without semaphores), I created a function that computes the result for a particular position in the results array: void convolveHelper(const Float64 *in1, UInt32 in1Len, const Float64 *in2, UInt32 in2Len, Float64 *result, UInt32 outPosition) { UInt32 i, j; for (i = 0; i < in1Len; i++) { if (i > outPosition) break; j = outPosition - i; if (j >= in2Len) continue; *result += in1[i] * in2[j]; } } The problem is, using convolveHelper slows down the code about 3.5 times (when running on a single thread). Any ideas on how I can speed-up convolveHelper, while maintaining thread safety?

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• Why not .NET-style delegates rather than closures in Java?

  - by h2g2java

  OK, this is going to be my beating a dying horse for the 3rd time. However, this question is different from my earlier two about closures/delegates, which asks about plans for delegates and what are the projected specs and implementation for closures. This question is about - why is the Java community struggling to define 3 different types of closures when we could simply steal the whole concept of delegates lock, stock and barrel from our beloved and friendly neighbour - Microsoft. There are two non-technical conclusions I would be very tempted to jump into: The Java community should hold up its pride, at the cost of needing to go thro convoluted efforts, by not succumbing to borrowing any Microsoft concepts or otherwise vindicate Microsoft's brilliance. Delegates is a Microsoft patented technology. Alright, besides the above two possibilities, Q1. Is there any weakness or inadequacy in msft-styled delegates that the three (or more) forms of closures would be addressing? Q2. I am asking this while shifting between java and c# and it intrigues me that c# delegates does exactly what I needed. Are there features that would be implemented in closures that are not currently available in C# delegates? If so what are they because I cannot see what I need more than what C# delegates has adequately provided me? Q3. I know that one of the concerns about implementing closures/delegates in java is the reduction of orthogonality of the language, where more than one way is exposed to perform a particular task. Is it worth the level convolution and time spent to avoid delegates just to ensure java retains its level of orthogonality? In SQL, we know that it is advisable to break orthogonality by frequently adequately satisfying only the 2nd normal form. Why can't java be subjected to reduction of orthogonality and OO-ness for the sake of simplicity? Q4. The architecture of JVM is technically constrained from implementing .NET-styled delegates. If this reason WERE (subjunctive to emphasize unlikelihood) true, then why can't the three closures proposals be hidden behind a simple delegate keyword or annotation: if we don't like to use @delegate, we could use @method. I cannot see how delegate statement format is more complex than the three closure proposals.

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• Using fft2 with reshaping for an RGB filter

  - by Mahmoud Aladdin

  I want to apply a filter on an image, for example, blurring filter [[1/9.0, 1/9.0, 1/9.0], [1/9.0, 1/9.0, 1/9.0], [1/9.0, 1/9.0, 1/9.0]]. Also, I'd like to use the approach that convolution in Spatial domain is equivalent to multiplication in Frequency domain. So, my algorithm will be like. Load Image. Create Filter. convert both Filter & Image to Frequency domains. multiply both. reconvert the output to Spatial Domain and that should be the required output. The following is the basic code I use, the image is loaded and displayed as cv.cvmat object. Image is a class of my creation, it has a member image which is an object of scipy.matrix and toFrequencyDomain(size = None) uses spf.fftshift(spf.fft2(self.image, size)) where spf is scipy.fftpack and dotMultiply(img) uses scipy.multiply(self.image, image) f = Image.fromMatrix([[1/9.0, 1/9.0, 1/9.0], [1/9.0, 1/9.0, 1/9.0], [1/9.0, 1/9.0, 1/9.0]]) lena = Image.fromFile("Test/images/lena.jpg") print lena.image.shape lenaf = lena.toFrequencyDomain(lena.image.shape) ff = f.toFrequencyDomain(lena.image.shape) lenafm = lenaf.dotMultiplyImage(ff) lenaff = lenafm.toTimeDomain() lena.display() lenaff.display() So, the previous code works pretty well, if I told OpenCV to load the image via GRAY_SCALE. However, if I let the image to be loaded in color ... lena.image.shape will be (512, 512, 3) .. so, it gives me an error when using scipy.fttpack.ftt2 saying "When given, Shape and Axes should be of same length". What I tried next was converted my filter to 3-D .. as [[[1/9.0, 1/9.0, 1/9.0], [1/9.0, 1/9.0, 1/9.0], [1/9.0, 1/9.0, 1/9.0]], [[1/9.0, 1/9.0, 1/9.0], [1/9.0, 1/9.0, 1/9.0], [1/9.0, 1/9.0, 1/9.0]], [[1/9.0, 1/9.0, 1/9.0], [1/9.0, 1/9.0, 1/9.0], [1/9.0, 1/9.0, 1/9.0]]] And, not knowing what the axes argument do, I added it with random numbers as (-2, -1, -1), (-1, -1, -2), .. etc. until it gave me the correct filter output shape for the dotMultiply to work. But, of course it wasn't the correct value. Things were totally worse. My final trial, was using fft2 function on each of the components 2-D matrices, and then re-making the 3-D one, using the following code. # Spiltting the 3-D matrix to three 2-D matrices. for i, row in enumerate(self.image): r.append(list()) g.append(list()) b.append(list()) for pixel in row: r[i].append(pixel[0]) g[i].append(pixel[1]) b[i].append(pixel[2]) rfft = spf.fftshift(spf.fft2(r, size)) gfft = spf.fftshift(spf.fft2(g, size)) bfft = spf.fftshift(spf.fft2(b, size)) newImage.image = sp.asarray([[[rfft[i][j], gfft[i][j], bfft[i][j]] for j in xrange(len(rfft[i]))] for i in xrange(len(rfft))] ) return newImage Any help on what I made wrong, or how can I achieve that for both GreyScale and Coloured pictures.

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• Lightning talk: Coderetreat

  - by Michael Williamson

  In the spirit of trying to encourage more deliberate practice amongst coders in Red Gate, Lauri Pesonen had the idea of running a coderetreat in Red Gate. Lauri and I ran the first one a few weeks ago: given that neither of us hadn’t even been to a coderetreat before, let alone run one, I think it turned out quite well. The participants gave positive feedback, saying that they enjoyed the day, wrote some thought-provoking code and would do it again. Sam Blackburn was one of the attendees, and gave a lightning talk to the other developers in one of our regular lightning talk sessions: In case you can’t watch the video, I’ve transcribed the talk below, although I’d recommend watching the video if you can — I didn’t have much time to do the transcribing! So, what is a coderetreat? So it’s not just something in Red Gate, there’s a website and everything, although it’s not a very big website. It calls itself a community network. The basic ideas behind coderetreat are: you’ve got one day, and you split it into one hour sections. You spend three quarters of that coding, and do a little retrospective at the end. You’re supposed to start fresh each, we were told to delete our code after every session. We were in pairs, swapping after each session, and we did the same task every time. In fact, Conway’s Game of Life is the only task mentioned anywhere that I find for coderetreat. So I don’t know what we’ll do next time, or if we’re meant to do the same thing again. There are some guiding principles which felt to us like restrictions, that you have to code in crazy ways to encourage better code. Final thing is that it’s supposed to be free for outsiders to join. It’s meant to be a kind of networking thing, where you link up with people from other companies. We had a pilot day with Michael and Lauri. Since it was basically the first time any of us had done anything like this, everybody was from Red Gate. We didn’t chat to anybody else for the initial one. The task was Conway’s Game of Life, which most of you have probably heard of it, all but one of us knew about it when did the coderetreat. I won’t got into the details of what it is, but it felt like the right size of task, basically one or two groups actually produced something working by the end of the day, and of course that doesn’t mean it’s necessarily a day’s work to produce that because we were starting again every hour. The task really drives you more than trying to create good code, I found. It was really tempting to try and get it working rather than stick to the rules. But it’s really good to stop and try again because there are so many what-ifs when you’ve finished writing something, “what if I’d done it this way?”. You can answer all those questions at a coderetreat because it’s not about getting a product out the door, it’s about learning and playing with ideas. So we had all these different practices we were trying. I’ll try and go through most of these. Single responsibility is this idea that everything should do just one thing. It was the very first session, we were still trying to figure out how do you go about the Game of Life? So by the end of forty-five minutes hadn’t produced very much for that first session. We were still thinking, “Do we start with a board, how do we represent all these squares? It can be infinitely big, help, this is getting really difficult!”. So, most of us didn’t really get anywhere on the first one. Although it was interesting that some people started with the board, one group started with the FateDecider class that decides whether things live or die. A sort of god class, but in a good way. They managed to implement all of the rules without even defining how the squares were arranged or anything like that. Another thing we tried was TDD (test-driven development). I’m sure most of you know what TDD is: Watch a test, watch it fail for the right reason Write code to pass the test, watch it pass Refactor, check the test still passes Repeat! It basically worked, we were able to produce code, but we often found the tests defined the direction that code went, which is obviously the idea of TDD. But you tend to find that by the time you’ve even written your first assertion, which is supposed to be the very first thing you write, because you write your tests backwards from the assertions back to the initial conditions, you’ve already constrained the logic of the code in some way by the time you’ve done that. You then get to this situation of, “Well, we actually want to go in a slightly different direction. Can we do this?”. Can we write tests that don’t constrain the architecture? Wrapping up all primitives: it’s kind of turtles all the way down. We had a Size, which has a Width and Height, which both derive from Dimension. You’ve got pages of code before you’ve even done anything. No getters and setters (use tell don’t ask instead): mocks and stubs for tests are required if you want to assert that your results are what you think they should be. You can’t just check the internal state of the code. And people found that really challenging and it made them think in a different way which I think is really good. Not having mutable state: that was kind of confusing because we weren’t quite sure what fitted within that rule and what didn’t, and I think we were trying too hard to follow the rule rather than the guideline. No if-statements: supposed to use polymorphism instead, but polymorphism still requires a factory with conditional behaviour. We did something really crazy to get around this: public T If(bool condition, Func<T> left, Func<T> right) { var dict = new Dictionary<bool, Func<T>> {{true, left}, {false, right}}; return dict[condition].Invoke(); } That is not really polymorphism, is it? For-loops: you can always replace a for-loop with recursion, but it doesn’t tend to make it any more readable unless it’s the kind of task that really lends itself to that. So it was interesting, it was good practice, but it wouldn’t make it easier it’s the kind of tree-structure algorithm where that would help. Having a limit on the number of levels of indentation: again, I think it does produce very nice, clean code, but it wasn’t actually a challenge because you just extract methods. That’s quite a useful thing because you can apply that to real code and say, “Okay, should this method really be going crazy like this?” No talking: we hated that. It’s like there’s two of you at a computer, and one of you is doing the typing, what does the other guy do if they’re not allowed to talk. The answer is TDD ping-pong – one person writes the tests, and then the other person writes the code to pass the test. And that creates communication without actually having to have discussion about things which is kind of cool. No code comments: just makes no difference to anything. It’s a forty-five minute exercise, so what are you going to put comments in code for? Finally, this is my fault. I discovered an entertaining way of doing the calculation that was kind of cool (using convolutions over the state of the board). Unfortunately, it turns out to be really hard to implement in C#, so didn’t even manage to work out how to do that convolution in C#. It’s trivial in some high-level languages, but you need something matrix-orientated for it to really work. That’s most of it, really. The thoughts that people went away with: we put down our answers to questions like “What have you learnt?” and “What surprised you?”, “How are you going to do things differently?”, and most people said redoing the problem is really, really good for understanding it properly. People hate having a massive legacy codebase that they can’t change, so being able to attack something three different ways in an environment where the end-product isn’t important: that’s something people really enjoyed. Pair-programming: also people said that they wanted to do more of that, especially with TDD ping-pong, where you write the test and somebody else writes the code. Various people thought different things about immutables, but most people thought they were good, they promote functional programming. And TDD people found really hard. “Tell, don’t ask” people found really, really hard and really, really, really hard to do well. And the recursion just made things trickier to debug. But most people agreed that coderetreats are really cool, and we should do more of them.

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• CodePlex Daily Summary for Thursday, February 17, 2011

  CodePlex Daily Summary for Thursday, February 17, 2011Popular ReleasesMarr DataMapper: Marr Datamapper 2.7 beta: - Changed QueryToGraph relationship rules: 1) Any parent entity (entity with children) must have at least one PK specified or an exception will be thrown 2) All 1-M relationship entities must have at least one PK specified or an exception will be thrown Only 1-1 entities with no children are allowed to have 0 PKs specified. - fixed AutoQueryToGraph bug (columns in graph children were being included in the select statement)datajs - JavaScript Library for data-centric web applications: datajs version 0.0.2: This release adds support for parsing DateTime and DateTimeOffset properties into javascript Date objects and serialize them back.thinktecture WSCF.blue: WSCF.blue V1 Update (1.0.11): Features Added a new option that allows properties on data contract types to be marked as virtual. Bug Fixes Fixed a bug caused by certain project properties not being available on Web Service Software Factory projects. Fixed a bug that could result in the WrapperName value of the MessageContractAttribute being incorrect when the Adjust Casing option is used. The menu item code now caters for CommandBar instances that are not available. For example the Web Item CommandBar does not exist ...Document.Editor: 2011.5: Whats new for Document.Editor 2011.5: New export to email New export to image New document background color Improved Tooltips Minor Bug Fix's, improvements and speed upsTerminals: Version 2 - RC1: The "Clean Install" will overwrite your log4net configuration (if you have one). If you run in a Portable Environment, you can use the "Clean Install" and target your portable folder. Tested and it works fine. Changes for this release: Re-worked on the Toolstip settings are done, just to avoid the vs.net clash with auto-generating files for .settings files. renamed it to .settings.config Packged both log4net and ToolStripSettings files into the installer Upgraded the version inform...Export Test Cases From TFS: Test Case Export to Excel 1.0: Team Foundation Server (TFS) 2010 enables the users to manage test cases as Work Item(s). The complete description of the test case along with steps can be managed as single Work Item in TFS 2010. Before migrating to TFS 2010 many test teams will be using MS Excel to manage the test cases (or test scripts). However, after migrating to TFS 2010, test teams can manage the test cases in the server but there may be need to get the test cases into excel sheet like approval from Business Analysts ...WriteableBitmapEx: WriteableBitmapEx 0.9.7.0: Fixed many bugs. Added the Rotate method which rotates the bitmap in 90° steps clockwise and returns a new rotated WriteableBitmap. Added a Flip method with support for FlipMode.Vertical and FlipMode.Horizontal. Added a new Filter extension file with a convolution method and some kernel templates (Gaussian, Sharpen). Added the GetBrightness method, which returns the brightness / luminance of the pixel at the x, y coordinate as byte. Added the ColorKeying BlendMode. Added boundary ...AllNewsManager.NET: AllNewsManager.NET 1.3: AllNewsManager.NET 1.3. This new version provide several new features, improvements and bug fixes. Some new features: Online Users. Avatars. Copy function (to create a new article from another one). SEO improvements (friendly urls). New admin buttons. And more...Facebook Graph Toolkit: Facebook Graph Toolkit 0.8: Version 0.8 (15 Feb 2011)moved to Beta stage publish photo feature "email" field of User object added new Graph Api object: Group, Event new Graph Api connection: likes, groups, eventsDJME - The jQuery extensions for ASP.NET MVC: DJME2 -The jQuery extensions for ASP.NET MVC beta2: The source code and runtime library for DJME2. For more product info you can goto http://www.dotnetage.com/djme.html What is new ?The Grid extension added The ModelBinder added which helping you create Bindable data Action. The DnaFor() control factory added that enabled Model bindable extensions. Enhance the ListBox , ComboBox data binding.Jint - Javascript Interpreter for .NET: Jint - 0.9.0: New CLR interoperability features Many bugfixesBuild Version Increment Add-In Visual Studio: Build Version Increment v2.4.11046.2045: v2.4.11046.2045 Fixes and/or Improvements:Major: Added complete support for VC projects including .vcxproj & .vcproj. All padding issues fixed. A project's assembly versions are only changed if the project has been modified. Minor Order of versioning style values is now according to their respective positions in the attributes i.e. Major, Minor, Build, Revision. Fixed issue with global variable storage with some projects. Fixed issue where if a project item's file does not exist, a ...Coding4Fun Tools: Coding4Fun.Phone.Toolkit v1.1: Coding4Fun.Phone.Toolkit v1.1 release. Bug fixes and minor feature requests addedTV4Home - The all-in-one TV solution!: 0.1.0.0 Preview: This is the beta preview release of the TV4Home software.Finestra Virtual Desktops: 1.2: Fixes a few minor issues with 1.1 including the broken per-desktop backgrounds Further improves the speed of switching desktops A few UI performance improvements Added donations linksNuGet: NuGet 1.1: NuGet is a free, open source developer focused package management system for the .NET platform intent on simplifying the process of incorporating third party libraries into a .NET application during development. This release is a Visual Studio 2010 extension and contains the the Package Manager Console and the Add Package Dialog. The URL to the package OData feed is: http://go.microsoft.com/fwlink/?LinkID=206669 To see the list of issues fixed in this release, visit this our issues listEnhSim: EnhSim 2.4.0: 2.4.0This release supports WoW patch 4.06 at level 85 To use this release, you must have the Microsoft Visual C++ 2010 Redistributable Package installed. This can be downloaded from http://www.microsoft.com/downloads/en/details.aspx?FamilyID=A7B7A05E-6DE6-4D3A-A423-37BF0912DB84 To use the GUI you must have the .NET 4.0 Framework installed. This can be downloaded from http://www.microsoft.com/downloads/en/details.aspx?FamilyID=9cfb2d51-5ff4-4491-b0e5-b386f32c0992 Changes since 2.3.0 - Upd...Sterling Isolated Storage Database with LINQ for Silverlight and Windows Phone 7: Sterling OODB v1.0: Note: use this changeset to download the source example that has been extended to show database generation, backup, and restore in the desktop example. Welcome to the Sterling 1.0 RTM. This version is not backwards-compatible with previous versions of Sterling. Sterling is also available via NuGet. This product has been used and tested in many applications and contains a full suite of unit tests. You can refer to the User's Guide for complete documentation, and use the unit tests as guide...PDF Rider: PDF Rider 0.5.1: Changes from the previous version * Use dynamic layout to better fit text in other languages * Includes French and Spanish localizations Prerequisites * Microsoft Windows Operating Systems (XP - Vista - 7) * Microsoft .NET Framework 3.5 runtime * A PDF rendering software (i.e. Adobe Reader) that can be opened inside Internet Explorer. Installation instructionsChoose one of the following methods: 1. Download and run the "pdfRider0.5.1-setup.exe" (reccomended) 2. Down...Snoop, the WPF Spy Utility: Snoop 2.6.1: This release is a bug fixing release. Most importantly, issues have been seen around WPF 4.0 applications not always showing up in the app chooser. Hopefully, they are fixed now. I thought this issue warranted a minor release since more and more people are going WPF 4.0 and I don't want anyone to have any problems. Dan Hanan also contributes again with several usability features. Thanks Dan! Happy Snooping! p.s. By request, I am also attaching a .zip file ... so that people can install it ...New ProjectsAlpe d'HuZes: This project contains the source for Alpe d'HuZes, an organization that fights the cancer disease, by giving people the chance to ride the Alpe d'Hues, a mountain in france. By climbing this mountain, money is collected which is entirely donated to the "kankerbestrijding".AstroLib: Astronomical libraryDevon: Devon_Projectearthquake predictor: This project is attempt to create earthquake prediction application , which can help save lives. It is based on theory that number of lost pets, before earthquake, growing up. This statistics can be obtained from free news papers, boards, forums... Technology : C#, ASPX, .NET 4FCNS.Calendar: FCNS.Calendar ??? MonoCalendar(?????????) ?.NET??????????，??????Mac???????????????iCal?????。???????????.??????????.?????????????????.????????????????. FlashRelease [O-GO.ru edition]: FlashRelease it's a tool for easy create description of new video\music\game torrent releases. Developed in Delphi.Forms based authentication for SharePoint2010: Forms based authentication Management features for SharePoint 2010. <a href="http://www.softwarediscipline.com/post/2011/01/03/Forms-based-authentication-feature-SharePoint-2010.aspx" alt="SharePoint 2010 FBA management feature">SharePoint 2010 FBA feature</a>ITune.LittleTools: Reads your ITune library and copy your track rating in ITune on to your file in windows.MingleProject: Just a simple project that showcases the power of ASP.NET and Visual StudioMvcContrib UI Extensions - Themed Grid & Menu: UI Extensions to the MvcContrib Project - Themed Grid & MenuNDOS Azure: Windows Azure projects developed at the "Open Source and Interoperability Development Nucleous" (http://ndos.codeplex.com/) at Universidade Federal do Rio Grande do Sul (http://www.ufrgs.br).ObjectDumper: ObjectDumper takes a normal .NET object and dumps it to a string, TextWriter, or file. Handy for debugging purposes.Open Analytic: Open Analytic is an open source business intelligence framework that believes in simplicity. The framework is developed with .NET language and can be easily integrated in custom product development.Pomodoro.Oob Expression Blend Example App: This is a non-functional Silverlight 4 Out-of-Browser app to demonstrate functionality in Expression Blend and to accompany user group talks and presentations on Blend.Senior Design: Uconn senior design project!Service Monitors - A services health monitoring tool: The idea behind this project is simple, I want to know when a service related to my application is not available. Our first intent to get a tool to generete the necessary data to be compliant with the Availability SLA of our systems. SGO: OrganizerSina Weibo QReminder: A handy utility that display remind message in the browser title for sina weibo.System Center Configuration Manager Integration Pack Extention: This integration pack adds some additional integration points for Opalis to System Center Configuration Manager. These functions are used in my User Self imaging workflow that will be demoed at MMS 2011.TwittaFox: TwittaFox ist ein kleiner Twitter-Client welcher direkt aus dem Tray angesprochen werden kann.Ultralight Markup: Ultralight Markup makes it easier for webmasters to allow safe user comments. It features a stripped-down intermediate markup language meant to bridge the gap between text entry and HTML. And the project includes an ASP.NET MVC implementation with a Javascript editor.Unit Conversion Library: Unit Conversion Library is a .Net 2.0 based library, containing static methods for all the Units Set present in Windows 7 calculator. "Angle", "Area", "Energy", "Length", "Power", "Pressure", "Temperature",Time", "Velocity", "Volume", "Weight/Mass".UTB-PFIII-TermProj-Team DeLaFuente, Vasquez, Morales, Dartez: This is the group project for UTB-PFIII Team project. Authors include David De La Fuente, Louis Dartez, Juan Vasquez and Froylan Morales.Version History to InfoPath Custom List Form: The ability to add a button to view the version history of an item when the display form is modified in InfoPath allows a user easy access to view versioning information. Out of the box, SharePoint does not allow this ability. This is a sandboxed solution.WeatherCN - ????: WeatherCN - ????WinformsPOCMVP: This is a simple, and small proof of concept for the Model View Presenter UI design pattern with C# WinForms.worldbestwebsites: Customer Connecting Websites A website development for customer connecting

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• Autocorrelation returns random results with mic input (using a high pass filter)

  - by Niall

  Hello, Sorry to ask a similar question to the one i asked before (FFT Problem (Returns random results)), but i've looked up pitch detection and autocorrelation and have found some code for pitch detection using autocorrelation. Im trying to do pitch detection of a users singing. Problem is, it keeps returning random results. I've got some code from http://code.google.com/p/yaalp/ which i've converted to C++ and modified (below). My sample rate is 2048, and data size is 1024. I'm detecting pitch of both a sine wave and mic input. The frequency of the sine wave is 726.0, and its detecting it to be 722.950820 (which im ok with), but its detecting the pitch of the mic as a random number from around 100 to around 1050. I'm now using a High pass filter to remove the DC offset, but it's not working. Am i doing it right, and if so, what else can i do to fix it? Any help would be greatly appreciated! double* doHighPassFilter(short *buffer) { // Do FFT: int bufferLength = 1024; float *real = malloc(bufferLength*sizeof(float)); float *real2 = malloc(bufferLength*sizeof(float)); for(int x=0;x<bufferLength;x++) { real[x] = buffer[x]; } fft(real, bufferLength); for(int x=0;x<bufferLength;x+=2) { real2[x] = real[x]; } for (int i=0; i < 30; i++) //Set freqs lower than 30hz to zero to attenuate the low frequencies real2[i] = 0; // Do inverse FFT: inversefft(real2,bufferLength); double* real3 = (double*)real2; return real3; } double DetectPitch(short* data) { int sampleRate = 2048; //Create sine wave double *buffer = malloc(1024*sizeof(short)); double amplitude = 0.25 * 32768; //0.25 * max length of short double frequency = 726.0; for (int n = 0; n < 1024; n++) { buffer[n] = (short)(amplitude * sin((2 * 3.14159265 * n * frequency) / sampleRate)); } doHighPassFilter(data); printf("Pitch from sine wave: %f\n",detectPitchCalculation(buffer, 50.0, 1000.0, 1, 1)); printf("Pitch from mic: %f\n",detectPitchCalculation(data, 50.0, 1000.0, 1, 1)); return 0; } // These work by shifting the signal until it seems to correlate with itself. // In other words if the signal looks very similar to (signal shifted 200 data) than the fundamental period is probably 200 data // Note that the algorithm only works well when there's only one prominent fundamental. // This could be optimized by looking at the rate of change to determine a maximum without testing all periods. double detectPitchCalculation(double* data, double minHz, double maxHz, int nCandidates, int nResolution) { //-------------------------1-------------------------// // note that higher frequency means lower period int nLowPeriodInSamples = hzToPeriodInSamples(maxHz, 2048); int nHiPeriodInSamples = hzToPeriodInSamples(minHz, 2048); if (nHiPeriodInSamples <= nLowPeriodInSamples) printf("Bad range for pitch detection."); if (1024 < nHiPeriodInSamples) printf("Not enough data."); double *results = new double[nHiPeriodInSamples - nLowPeriodInSamples]; //-------------------------2-------------------------// for (int period = nLowPeriodInSamples; period < nHiPeriodInSamples; period += nResolution) { double sum = 0; // for each sample, find correlation. (If they are far apart, small) for (int i = 0; i < 1024 - period; i++) sum += data[i] * data[i + period]; double mean = sum / 1024.0; results[period - nLowPeriodInSamples] = mean; } //-------------------------3-------------------------// // find the best indices int *bestIndices = findBestCandidates(nCandidates, results, nHiPeriodInSamples - nLowPeriodInSamples - 1); //note findBestCandidates modifies parameter // convert back to Hz double *res = new double[nCandidates]; for (int i=0; i < nCandidates;i++) res[i] = periodInSamplesToHz(bestIndices[i]+nLowPeriodInSamples, 2048); double pitch2 = res[0]; free(res); free(results); return pitch2; } /// Finds n "best" values from an array. Returns the indices of the best parts. /// (One way to do this would be to sort the array, but that could take too long. /// Warning: Changes the contents of the array!!! Do not use result array afterwards. int* findBestCandidates(int n, double* inputs,int length) { //int length = inputs.Length; if (length < n) printf("Length of inputs is not long enough."); int *res = new int[n]; double minValue = 0; for (int c = 0; c < n; c++) { // find the highest. double fBestValue = minValue; int nBestIndex = -1; for (int i = 0; i < length; i++) { if (inputs[i] > fBestValue) { nBestIndex = i; fBestValue = inputs[i]; } } // record this highest value res[c] = nBestIndex; // now blank out that index. if(nBestIndex!=-1) inputs[nBestIndex] = minValue; } return res; } int hzToPeriodInSamples(double hz, int sampleRate) { return (int)(1 / (hz / (double)sampleRate)); } double periodInSamplesToHz(int period, int sampleRate) { return 1 / (period / (double)sampleRate); } Thanks, Niall. Edit: Changed the code to implement a high pass filter with a cutoff of 30hz (from What Are High-Pass and Low-Pass Filters?, can anyone tell me how to convert the low-pass filter using convolution to a high-pass one?) but it's still returning random results. Plugging it into a VST host and using VST plugins to compare spectrums isn't an option to me unfortunately.

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