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  • Gradient Mapping in .NET

    - by Otaku
    Is there a way in .NET to perform the same technique Photoshop uses for Gradient Mapping (Image - Adjustments - Gradient Map [Gradient Editor])? Any ideas, links, code, etc. would be welcome.

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  • Files not waiting for each other

    - by Sunny
    I have two batch files as follows in which file2.bat is dependent on file1.bat's output: file1.bat @ECHO OFF setlocal enabledelayedexpansion SET "keystring1=" ( FOR /f "delims=" %%a IN ( Source.txt ) DO ( ECHO %%a|FIND "Appprocess.exe" >NUL IF NOT ERRORLEVEL 1 SET keystring1=%%a FOR %%b IN (App1 App2 App3 App4 App5 App6 ) DO ( ECHO %%a|FIND "%%b" >NUL IF NOT ERRORLEVEL 1 IF DEFINED keystring1 CALL ECHO(%%keystring1%% %%b&SET "keystring1=" )))>result.txt GOTO :EOF file2.bat @echo off setlocal enabledelayedexpansion (for /f "tokens=1,2" %%a in (memory.txt) do ( for /f "tokens=5" %%c in ('find " %%a " ^< result.txt ') do echo %%c %%b ))> new.txt file1.bat usually takes 60 sec to complete its execution. In master.bat file i am calling above two files as: call file1.bat call file2.bat but file2.bat is not waiting for file1.bat to complete its execution. Even , i tried to call file2.bat within file1.bat as below but still its not waiting for file1.bat to get completed: @ECHO OFF setlocal enabledelayedexpansion SET "keystring1=" ( FOR /f "delims=" %%a IN ( Source.txt ) DO ( ECHO %%a|FIND "HsvDataSource.exe" >NUL IF NOT ERRORLEVEL 1 SET keystring1=%%a FOR %%b IN (EUHFMPROD USHFMPROD TL2TEST GSHFMPROD TL2PROD GSARCH1213 TL2FY13) DO ( ECHO %%a|FIND "%%b" >NUL IF NOT ERRORLEVEL 1 IF DEFINED keystring1 CALL ECHO(%%keystring1%% %%b&SET "keystring1=" )))>file2.txt GOTO :EOF call file1.bat I also tried below start option, but no effect.: start file1.bat /wait call file2.bat Not getting ..why its happening..?

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  • CPU Affinity Masks (Putting Threads on different CPUs)

    - by hahuang65
    I have 4 threads, and I am trying to set thread 1 to run on CPU 1, thread 2 on CPU 2, etc. However, when I run my code below, the affinity masks are returning the correct values, but when I do a sched_getcpu() on the threads, they all return that they are running on CPU 4. Anybody know what my problem here is? Thanks in advance! #define _GNU_SOURCE #include <stdio.h> #include <pthread.h> #include <stdlib.h> #include <sched.h> #include <errno.h> void *pthread_Message(char *message) { printf("%s is running on CPU %d\n", message, sched_getcpu()); } int main() { pthread_t thread1, thread2, thread3, thread4; pthread_t threadArray[4]; cpu_set_t cpu1, cpu2, cpu3, cpu4; char *thread1Msg = "Thread 1"; char *thread2Msg = "Thread 2"; char *thread3Msg = "Thread 3"; char *thread4Msg = "Thread 4"; int thread1Create, thread2Create, thread3Create, thread4Create, i, temp; CPU_ZERO(&cpu1); CPU_SET(1, &cpu1); temp = pthread_setaffinity_np(thread1, sizeof(cpu_set_t), &cpu1); printf("Set returned by pthread_getaffinity_np() contained:\n"); for (i = 0; i < CPU_SETSIZE; i++) if (CPU_ISSET(i, &cpu1)) printf("CPU1: CPU %d\n", i); CPU_ZERO(&cpu2); CPU_SET(2, &cpu2); temp = pthread_setaffinity_np(thread2, sizeof(cpu_set_t), &cpu2); for (i = 0; i < CPU_SETSIZE; i++) if (CPU_ISSET(i, &cpu2)) printf("CPU2: CPU %d\n", i); CPU_ZERO(&cpu3); CPU_SET(3, &cpu3); temp = pthread_setaffinity_np(thread3, sizeof(cpu_set_t), &cpu3); for (i = 0; i < CPU_SETSIZE; i++) if (CPU_ISSET(i, &cpu3)) printf("CPU3: CPU %d\n", i); CPU_ZERO(&cpu4); CPU_SET(4, &cpu4); temp = pthread_setaffinity_np(thread4, sizeof(cpu_set_t), &cpu4); for (i = 0; i < CPU_SETSIZE; i++) if (CPU_ISSET(i, &cpu4)) printf("CPU4: CPU %d\n", i); thread1Create = pthread_create(&thread1, NULL, (void *)pthread_Message, thread1Msg); thread2Create = pthread_create(&thread2, NULL, (void *)pthread_Message, thread2Msg); thread3Create = pthread_create(&thread3, NULL, (void *)pthread_Message, thread3Msg); thread4Create = pthread_create(&thread4, NULL, (void *)pthread_Message, thread4Msg); pthread_join(thread1, NULL); pthread_join(thread2, NULL); pthread_join(thread3, NULL); pthread_join(thread4, NULL); return 0; }

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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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  • Are there any well known algorithms to detect the presence of names?

    - by Rhubarb
    For example, given a string: "Bob went fishing with his friend Jim Smith." Bob and Jim Smith are both names, but bob and smith are both words. Weren't for them being uppercase, there would be less indication of this outside of our knowledge of the sentence. Without doing grammar analysis, are there any well known algorithms for detecting the presence of names, at least Western names?

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  • How to "smart resize" a displayed image to original aspect ratio

    - by Paul Sasik
    I have an application in which end-users can size and position images in a designer. Since the spec calls for the image to be "stretched" to the containing control, the end user can end up with an awkwardly stretched image. To help the user with image sizing I am thinking of implementing a smart resizer function which would allow the the user to easily fix the aspect ratio of the picture so that it no longer appears stretched. The quick way to solve this is to actually provide two options: 1) scale from width 2) scale from height. The user chooses the method and the algorithm adjusts the size of the picture by using the original aspect ratio. For example: A picture is displayed as 200x200 on the designer but the original image is 1024x768 pixels. The user chooses "Smart Size from width" and the new size becomes ~200x150 since the original aspect ratio is ~1.333 That's OK, but how could I make the algorithm smarter and not bother the user by asking which dimension the recalculation should be based on?

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  • HMM for perspective estimation in document image, can't understand the algorithm

    - by maximus
    Hello! Here is a paper, it is about estimating the perspective of binary image containing text and some noise or non text objects. PDF document The algorithm uses the Hidden Markov Model: actually two conditions T - text B - backgrouond (i.e. noise) It is hard to understand the algorithm itself. The question is that I've read about Hidden Markov Models and I know that it uses probabilities that must be known. But in this algorithm I can't understand, if they use HMM, how do they get those probabilities (probability of changing the state from S1 to another state for example S2)? I didn't find anything about training there also in that paper. So, if somebody understands it, please tell me. Also is it possible to use HMM without knowing the state change probabilities?

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  • Rename image file on upload php

    - by blasteralfred
    Hi, I have a form which uploads and re sizes image. The html file file submits data to a php file. The script is as follows; Index.html <form action="resizer.php" method="post" enctype="multipart/form-data"> Image: <input type="file" name="file" /> <input type="submit" name="submit" value="upload" /> </form> Resizer.php <?php require_once('imageresizer.class.php'); $imagename = "myimagename"; //Path To Upload Directory $dirpath = "uploaded/"; //MAX WIDTH AND HEIGHT OF IMAGE $max_height = 100; $max_width = 100; //Create Image Control Object - Parameters(file name, file tmp name, file type, directory path) $resizer = new ImageResizer($_FILES['file']['name'],$_FILES['file']['tmp_name'],$dirpath); //RESIZE IMAGE - Parameteres(max height, max width) $resizer->resizeImage($max_height,$max_width); //Display Image $resizer->showResizedImage(); ?> imageresizer.class.php <?php class ImageResizer{ public $file_name; public $tmp_name; public $dir_path; //Set variables public function __construct($file_name,$tmp_name,$dir_path){ $this->file_name = $file_name; $this->tmp_name = $tmp_name; $this->dir_path = $dir_path; $this->getImageInfo(); $this->moveImage(); } //Move the uploaded image to the new directory and rename public function moveImage(){ if(!is_dir($this->dir_path)){ mkdir($this->dir_path,0777,true); } if(move_uploaded_file($this->tmp_name,$this->dir_path.'_'.$this->file_name)){ $this->setFileName($this->dir_path.'_'.$this->file_name); } } //Define the new filename public function setFileName($file_name){ $this->file_name = $file_name; return $this->file_name; } //Resize the image function with new max height and width public function resizeImage($max_height,$max_width){ $this->max_height = $max_height; $this->max_width = $max_width; if($this->height > $this->width){ $ratio = $this->height / $this->max_height; $new_height = $this->max_height; $new_width = ($this->width / $ratio); } elseif($this->height < $this->width){ $ratio = ($this->width / $this->max_width); $new_width = $this->max_width; $new_height = ($this->height / $ratio); } else{ $new_width = $this->max_width; $new_height = $this->max_height; } $thumb = imagecreatetruecolor($new_width, $new_height); switch($this->file_type){ case 1: $image = imagecreatefromgif($this->file_name); break; case 2: $image = imagecreatefromjpeg($this->file_name); break; case 3: $image = imagecreatefrompng($this->file_name); break; case 4: $image = imagecreatefromwbmp($this->file_name); } imagecopyresampled($thumb, $image, 0, 0, 0, 0, $new_width, $new_height, $this->width, $this->height); switch($this->file_type){ case 1: imagegif($thumb,$this->file_name); break; case 2: imagejpeg($thumb,$this->file_name,100); break; case 3: imagepng($thumb,$this->file_name,0); break; case 4: imagewbmp($thumb,$this->file_name); } imagedestroy($image); imagedestroy($thumb); } public function getImageInfo(){ list($width, $height, $type) = getimagesize($this->tmp_name); $this->width = $width; $this->height = $height; $this->file_type = $type; } public function showResizedImage(){ echo "<img src='".$this->file_name." />"; } public function onSuccess(){ header("location: index.php"); } } ?> Everything is working well. The image will be uploaded in it's original filename and extension with a "_" prefix. But i want to rename the image to "myimagename" on upload, which is a variable in "Resizer.php". How can i make this possible?? Thanks in advance :) blasteralfred

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  • C# .NET : Is using the .NET Image Conversion enough?

    - by contactmatt
    I've seen a lot of people try to code their own image conversion techniques. It often seems to be very complicated, and ends up using GDI+ funciton calls, and manipulating bits of the image. This has got me wondering if I am missing something in the simplicity of .NET's image conversion call when saving an image. Here's the code I have Bitmap tempBmp = new Bitmap("c:\temp\img.jpg"); Bitmap bmp = new Bitmap(tempBmp, 800, 600); bmp.Save(c:\temp\img.bmp, //extension depends on format ImageFormat.Bmp) //These are all the ImageFormats I allow conversion to within the program. Ignore the syntax for a second ;) ImageFormat.Gif) //or ImageFormat.Jpeg) //or ImageFormat.Png) //or ImageFormat.Tiff) //or ImageFormat.Wmf) //or ImageFormat.Bmp)//or ); This is all I'm doing in my image conversion. Just setting the location of where the image should be saved, and passing it an ImageFormat type. I've tested it the best I can, but I'm wondering if I am missing anything in this simple format conversion, or if this is suffice?

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  • imagejpeg memory exhaustion

    - by 0plus1
    I'm creating thumbnails cycling through a lot of images, when I find a large image I get: Fatal error: Allowed memory size of 33554432 bytes exhausted (tried to allocate 13056 bytes) Now I already know how to circumvent this with: ini_set('memory_limit', '-1'); What I want to know is why it exhaust the memory! Is there some debug tools that will show me exactly when memory is exhausting? And specifically that will show me if there are variables/arrays that are killing my memory? OR, are there better way to resize images other then: $thumb=imagecreatetruecolor($newwidth,$newheight); $source=imagecreatefromjpeg($imgfile); imagecopyresampled($thumb,$source,0,0,0,0,$newwidth,$newheight,$width,$height); imagejpeg($thumb,$destinationfile,85); ? Thank you very much!

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  • tfidf, am I understanding it right?

    - by alskndalsnd
    Hey everyone, I am interested in doing some document clustering, and right now I am considering using TF-IDF for this. If I am not wrong, TFIDF is particularly used for evaluating the relevance of a document given a query. If I do not have a particular query, how can I apply tfidf to clustering?

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  • Using Cepstrum for PDA

    - by CziX
    Hey, I am currently deleveloping a algorithm to decide wheather or not a frame is voiced or unvoiced. I am trying to use the Cepstrum to discriminate between these two situations. I use MATLAB for my implementation. I have some problems, saying something generally about the frame, but my currently implementation looks like (I'm award of the MATLAB has the function rceps, but this haven't worked for either): ceps = abs(ifft(log10(abs(fft(frame.*window')).^2+eps))); Can anybody give me a small demo, that will convert the frame to the power cepstrum, so a single lollipop at the pitch frequency. For instance use this code to generate the frequency. fs = 8000; timelength = 25e-3; freq = 500; k = 0:1/fs:timelength-(1/fs); s = 0.8*sin(2*pi*freq*k); Thanks.

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  • Steganography Experiment - Trouble hiding message bits in DCT coefficients

    - by JohnHankinson
    I have an application requiring me to be able to embed loss-less data into an image. As such I've been experimenting with steganography, specifically via modification of DCT coefficients as the method I select, apart from being loss-less must also be relatively resilient against format conversion, scaling/DSP etc. From the research I've done thus far this method seems to be the best candidate. I've seen a number of papers on the subject which all seem to neglect specific details (some neglect to mention modification of 0 coefficients, or modification of AC coefficient etc). After combining the findings and making a few modifications of my own which include: 1) Using a more quantized version of the DCT matrix to ensure we only modify coefficients that would still be present should the image be JPEG'ed further or processed (I'm using this in place of simply following a zig-zag pattern). 2) I'm modifying bit 4 instead of the LSB and then based on what the original bit value was adjusting the lower bits to minimize the difference. 3) I'm only modifying the blue channel as it should be the least visible. This process must modify the actual image and not the DCT values stored in file (like jsteg) as there is no guarantee the file will be a JPEG, it may also be opened and re-saved at a later stage in a different format. For added robustness I've included the message multiple times and use the bits that occur most often, I had considered using a QR code as the message data or simply applying the reed-solomon error correction, but for this simple application and given that the "message" in question is usually going to be between 10-32 bytes I have plenty of room to repeat it which should provide sufficient redundancy to recover the true bits. No matter what I do I don't seem to be able to recover the bits at the decode stage. I've tried including / excluding various checks (even if it degrades image quality for the time being). I've tried using fixed point vs. double arithmetic, moving the bit to encode, I suspect that the message bits are being lost during the IDCT back to image. Any thoughts or suggestions on how to get this working would be hugely appreciated. (PS I am aware that the actual DCT/IDCT could be optimized from it's naive On4 operation using row column algorithm, or an FDCT like AAN, but for now it just needs to work :) ) Reference Papers: http://www.lokminglui.com/dct.pdf http://arxiv.org/ftp/arxiv/papers/1006/1006.1186.pdf Code for the Encode/Decode process in C# below: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Drawing.Imaging; using System.Drawing; namespace ImageKey { public class Encoder { public const int HIDE_BIT_POS = 3; // use bit position 4 (1 << 3). public const int HIDE_COUNT = 16; // Number of times to repeat the message to avoid error. // JPEG Standard Quantization Matrix. // (to get higher quality multiply by (100-quality)/50 .. // for lower than 50 multiply by 50/quality. Then round to integers and clip to ensure only positive integers. public static double[] Q = {16,11,10,16,24,40,51,61, 12,12,14,19,26,58,60,55, 14,13,16,24,40,57,69,56, 14,17,22,29,51,87,80,62, 18,22,37,56,68,109,103,77, 24,35,55,64,81,104,113,92, 49,64,78,87,103,121,120,101, 72,92,95,98,112,100,103,99}; // Maximum qauality quantization matrix (if all 1's doesn't modify coefficients at all). public static double[] Q2 = {1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1}; public static Bitmap Encode(Bitmap b, string key) { Bitmap response = new Bitmap(b.Width, b.Height, PixelFormat.Format32bppArgb); uint imgWidth = ((uint)b.Width) & ~((uint)7); // Maximum usable X resolution (divisible by 8). uint imgHeight = ((uint)b.Height) & ~((uint)7); // Maximum usable Y resolution (divisible by 8). // Start be transferring the unmodified image portions. // As we'll be using slightly less width/height for the encoding process we'll need the edges to be populated. for (int y = 0; y < b.Height; y++) for (int x = 0; x < b.Width; x++) { if( (x >= imgWidth && x < b.Width) || (y>=imgHeight && y < b.Height)) response.SetPixel(x, y, b.GetPixel(x, y)); } // Setup the counters and byte data for the message to encode. StringBuilder sb = new StringBuilder(); for(int i=0;i<HIDE_COUNT;i++) sb.Append(key); byte[] codeBytes = System.Text.Encoding.ASCII.GetBytes(sb.ToString()); int bitofs = 0; // Current bit position we've encoded too. int totalBits = (codeBytes.Length * 8); // Total number of bits to encode. for (int y = 0; y < imgHeight; y += 8) { for (int x = 0; x < imgWidth; x += 8) { int[] redData = GetRedChannelData(b, x, y); int[] greenData = GetGreenChannelData(b, x, y); int[] blueData = GetBlueChannelData(b, x, y); int[] newRedData; int[] newGreenData; int[] newBlueData; if (bitofs < totalBits) { double[] redDCT = DCT(ref redData); double[] greenDCT = DCT(ref greenData); double[] blueDCT = DCT(ref blueData); int[] redDCTI = Quantize(ref redDCT, ref Q2); int[] greenDCTI = Quantize(ref greenDCT, ref Q2); int[] blueDCTI = Quantize(ref blueDCT, ref Q2); int[] blueDCTC = Quantize(ref blueDCT, ref Q); HideBits(ref blueDCTI, ref blueDCTC, ref bitofs, ref totalBits, ref codeBytes); double[] redDCT2 = DeQuantize(ref redDCTI, ref Q2); double[] greenDCT2 = DeQuantize(ref greenDCTI, ref Q2); double[] blueDCT2 = DeQuantize(ref blueDCTI, ref Q2); newRedData = IDCT(ref redDCT2); newGreenData = IDCT(ref greenDCT2); newBlueData = IDCT(ref blueDCT2); } else { newRedData = redData; newGreenData = greenData; newBlueData = blueData; } MapToRGBRange(ref newRedData); MapToRGBRange(ref newGreenData); MapToRGBRange(ref newBlueData); for(int dy=0;dy<8;dy++) { for(int dx=0;dx<8;dx++) { int col = (0xff<<24) + (newRedData[dx+(dy*8)]<<16) + (newGreenData[dx+(dy*8)]<<8) + (newBlueData[dx+(dy*8)]); response.SetPixel(x+dx,y+dy,Color.FromArgb(col)); } } } } if (bitofs < totalBits) throw new Exception("Failed to encode data - insufficient cover image coefficients"); return (response); } public static void HideBits(ref int[] DCTMatrix, ref int[] CMatrix, ref int bitofs, ref int totalBits, ref byte[] codeBytes) { int tempValue = 0; for (int u = 0; u < 8; u++) { for (int v = 0; v < 8; v++) { if ( (u != 0 || v != 0) && CMatrix[v+(u*8)] != 0 && DCTMatrix[v+(u*8)] != 0) { if (bitofs < totalBits) { tempValue = DCTMatrix[v + (u * 8)]; int bytePos = (bitofs) >> 3; int bitPos = (bitofs) % 8; byte mask = (byte)(1 << bitPos); byte value = (byte)((codeBytes[bytePos] & mask) >> bitPos); // 0 or 1. if (value == 0) { int a = DCTMatrix[v + (u * 8)] & (1 << HIDE_BIT_POS); if (a != 0) DCTMatrix[v + (u * 8)] |= (1 << HIDE_BIT_POS) - 1; DCTMatrix[v + (u * 8)] &= ~(1 << HIDE_BIT_POS); } else if (value == 1) { int a = DCTMatrix[v + (u * 8)] & (1 << HIDE_BIT_POS); if (a == 0) DCTMatrix[v + (u * 8)] &= ~((1 << HIDE_BIT_POS) - 1); DCTMatrix[v + (u * 8)] |= (1 << HIDE_BIT_POS); } if (DCTMatrix[v + (u * 8)] != 0) bitofs++; else DCTMatrix[v + (u * 8)] = tempValue; } } } } } public static void MapToRGBRange(ref int[] data) { for(int i=0;i<data.Length;i++) { data[i] += 128; if(data[i] < 0) data[i] = 0; else if(data[i] > 255) data[i] = 255; } } public static int[] GetRedChannelData(Bitmap b, int sx, int sy) { int[] data = new int[8 * 8]; for (int y = sy; y < (sy + 8); y++) { for (int x = sx; x < (sx + 8); x++) { uint col = (uint)b.GetPixel(x,y).ToArgb(); data[(x - sx) + ((y - sy) * 8)] = (int)((col >> 16) & 0xff) - 128; } } return (data); } public static int[] GetGreenChannelData(Bitmap b, int sx, int sy) { int[] data = new int[8 * 8]; for (int y = sy; y < (sy + 8); y++) { for (int x = sx; x < (sx + 8); x++) { uint col = (uint)b.GetPixel(x, y).ToArgb(); data[(x - sx) + ((y - sy) * 8)] = (int)((col >> 8) & 0xff) - 128; } } return (data); } public static int[] GetBlueChannelData(Bitmap b, int sx, int sy) { int[] data = new int[8 * 8]; for (int y = sy; y < (sy + 8); y++) { for (int x = sx; x < (sx + 8); x++) { uint col = (uint)b.GetPixel(x, y).ToArgb(); data[(x - sx) + ((y - sy) * 8)] = (int)((col >> 0) & 0xff) - 128; } } return (data); } public static int[] Quantize(ref double[] DCTMatrix, ref double[] Q) { int[] DCTMatrixOut = new int[8*8]; for (int u = 0; u < 8; u++) { for (int v = 0; v < 8; v++) { DCTMatrixOut[v + (u * 8)] = (int)Math.Round(DCTMatrix[v + (u * 8)] / Q[v + (u * 8)]); } } return(DCTMatrixOut); } public static double[] DeQuantize(ref int[] DCTMatrix, ref double[] Q) { double[] DCTMatrixOut = new double[8*8]; for (int u = 0; u < 8; u++) { for (int v = 0; v < 8; v++) { DCTMatrixOut[v + (u * 8)] = (double)DCTMatrix[v + (u * 8)] * Q[v + (u * 8)]; } } return(DCTMatrixOut); } public static double[] DCT(ref int[] data) { double[] DCTMatrix = new double[8 * 8]; for (int v = 0; v < 8; v++) { for (int u = 0; u < 8; u++) { double cu = 1; if (u == 0) cu = (1.0 / Math.Sqrt(2.0)); double cv = 1; if (v == 0) cv = (1.0 / Math.Sqrt(2.0)); double sum = 0.0; for (int y = 0; y < 8; y++) { for (int x = 0; x < 8; x++) { double s = data[x + (y * 8)]; double dctVal = Math.Cos((2 * y + 1) * v * Math.PI / 16) * Math.Cos((2 * x + 1) * u * Math.PI / 16); sum += s * dctVal; } } DCTMatrix[u + (v * 8)] = (0.25 * cu * cv * sum); } } return (DCTMatrix); } public static int[] IDCT(ref double[] DCTMatrix) { int[] Matrix = new int[8 * 8]; for (int y = 0; y < 8; y++) { for (int x = 0; x < 8; x++) { double sum = 0; for (int v = 0; v < 8; v++) { for (int u = 0; u < 8; u++) { double cu = 1; if (u == 0) cu = (1.0 / Math.Sqrt(2.0)); double cv = 1; if (v == 0) cv = (1.0 / Math.Sqrt(2.0)); double idctVal = (cu * cv) / 4.0 * Math.Cos((2 * y + 1) * v * Math.PI / 16) * Math.Cos((2 * x + 1) * u * Math.PI / 16); sum += (DCTMatrix[u + (v * 8)] * idctVal); } } Matrix[x + (y * 8)] = (int)Math.Round(sum); } } return (Matrix); } } public class Decoder { public static string Decode(Bitmap b, int expectedLength) { expectedLength *= Encoder.HIDE_COUNT; uint imgWidth = ((uint)b.Width) & ~((uint)7); // Maximum usable X resolution (divisible by 8). uint imgHeight = ((uint)b.Height) & ~((uint)7); // Maximum usable Y resolution (divisible by 8). // Setup the counters and byte data for the message to decode. byte[] codeBytes = new byte[expectedLength]; byte[] outBytes = new byte[expectedLength / Encoder.HIDE_COUNT]; int bitofs = 0; // Current bit position we've decoded too. int totalBits = (codeBytes.Length * 8); // Total number of bits to decode. for (int y = 0; y < imgHeight; y += 8) { for (int x = 0; x < imgWidth; x += 8) { int[] blueData = ImageKey.Encoder.GetBlueChannelData(b, x, y); double[] blueDCT = ImageKey.Encoder.DCT(ref blueData); int[] blueDCTI = ImageKey.Encoder.Quantize(ref blueDCT, ref Encoder.Q2); int[] blueDCTC = ImageKey.Encoder.Quantize(ref blueDCT, ref Encoder.Q); if (bitofs < totalBits) GetBits(ref blueDCTI, ref blueDCTC, ref bitofs, ref totalBits, ref codeBytes); } } bitofs = 0; for (int i = 0; i < (expectedLength / Encoder.HIDE_COUNT) * 8; i++) { int bytePos = (bitofs) >> 3; int bitPos = (bitofs) % 8; byte mask = (byte)(1 << bitPos); List<int> values = new List<int>(); int zeroCount = 0; int oneCount = 0; for (int j = 0; j < Encoder.HIDE_COUNT; j++) { int val = (codeBytes[bytePos + ((expectedLength / Encoder.HIDE_COUNT) * j)] & mask) >> bitPos; values.Add(val); if (val == 0) zeroCount++; else oneCount++; } if (oneCount >= zeroCount) outBytes[bytePos] |= mask; bitofs++; values.Clear(); } return (System.Text.Encoding.ASCII.GetString(outBytes)); } public static void GetBits(ref int[] DCTMatrix, ref int[] CMatrix, ref int bitofs, ref int totalBits, ref byte[] codeBytes) { for (int u = 0; u < 8; u++) { for (int v = 0; v < 8; v++) { if ((u != 0 || v != 0) && CMatrix[v + (u * 8)] != 0 && DCTMatrix[v + (u * 8)] != 0) { if (bitofs < totalBits) { int bytePos = (bitofs) >> 3; int bitPos = (bitofs) % 8; byte mask = (byte)(1 << bitPos); int value = DCTMatrix[v + (u * 8)] & (1 << Encoder.HIDE_BIT_POS); if (value != 0) codeBytes[bytePos] |= mask; bitofs++; } } } } } } } UPDATE: By switching to using a QR Code as the source message and swapping a pair of coefficients in each block instead of bit manipulation I've been able to get the message to survive the transform. However to get the message to come through without corruption I have to adjust both coefficients as well as swap them. For example swapping (3,4) and (4,3) in the DCT matrix and then respectively adding 8 and subtracting 8 as an arbitrary constant seems to work. This survives a re-JPEG'ing of 96 but any form of scaling/cropping destroys the message again. I was hoping that by operating on mid to low frequency values that the message would be preserved even under some light image manipulation.

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  • Basic image resizing in Ruby on Rails

    - by Koning Baard XIV
    I'm creating a little photo sharing site for our home's intranet, and I have an upload feature, which uploads the photo at original size into the database. However, I also want to save the photo in four other sizes: W=1024, W=512, W=256 and W=128, but only the sizes smaller than the original size (e.g. if the original width is 511, only generate 256 and 128). How can I implement this? I already have this code to upload the photo: pic.rb <-- model def image_file=(input_data) self.filename = input_data.original_filename self.content_type = input_data.content_type.chomp self.binary_data = input_data.read # here it should generate the smaller sizes #+and save them to self.binary_data_1024, etc... end new.rb <-- view <h1>New pic</h1> <% form_for(@pic, :html => {:multipart => true}) do |f| %> <%= f.error_messages %> <p> <%= f.label :title %><br /> <%= f.text_field :title %> </p> <p> <%= f.label :description %><br /> <%= f.text_field :description %> </p> <p> <%= f.label :image_file %><br /> <%= f.file_field :image_file %> </p> <p> <%= f.submit 'Create' %> </p> <% end %> <%= link_to 'Back', pics_path %> Thanks

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  • Django-imagekit: how to reduce image quality with a preprocessor_spec ?

    - by pierre-guillaume-degans
    Hi, please excuse me for my ugly english :p I've created this simple model class, with a Preprocessor to reduce my photos'quality (the photos'extension is .JPG): from django.db import models from imagekit.models import ImageModel from imagekit.specs import ImageSpec from imagekit import processors class Preprocessor(ImageSpec): quality = 50 processors = [processors.Format] class Picture(ImageModel): image = models.ImageField(upload_to='pictures') class IKOptions: preprocessor_spec = Preprocessor The problem : pictures'quality are not reduced. :( Any idea to fix it ? Thank you very much ;)

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  • Java Imaging Framework

    - by Prabhakar
    Is there any Open source or Commercial Java frameworks for doing image operations such as converting the images from one format to other and scaling the images etc. There should be no installation.Set of jars that are in classpath that will do the job. I have looked into the java-image-scaling library but it is having issues. Thanks in advance.

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  • MPIexec.exe Access denide

    - by shake
    I have installed microsoft compute cluster and MPI.net, now i have trouble to run program using mpiexec.exe on cluster. When i try to run it on console i get message: "Access Denied", and pop up: "mpiexec.exe is not valid win32 application". I tried google it, but found nothing. Pls help. :)

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  • WPF WriteableBitmap

    - by Sam
    I'm using WriteableBitmap on an image of type Bgra32 to change the pixel value of certain pixels. I'm setting the value to 0x77CCCCCC. After calling WritePixels, the pixels I set to 0x77CCCCCC show up with a value of 0x77FFFFFF. Why does this happen? How do I make the pixels have the correct value?

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  • Number of threads and thread numbers in Grand Central Dispatch

    - by raphgott
    I am using C and Grand Central Dispatch to parallelize some heavy computations. How can I get the number of threads used by GCD? Also is it possible to know on which thread a piece of code is currently running on? Basically I'd like to use sprng (parallel random numbers) with multiple streams and for that I need to know what stream id to use (and therefore what thread is being used).

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

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

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  • Training sets for AdaBoost algorithm

    - by palau1
    How do you find the negative and positive training data sets of Haar features for the AdaBoost algorithm? So say you have a certain type of blob that you want to locate in an image and there are several of them in your entire array - how do you go about training it? I'd appreciate a nontechnical explanation as much as possible. I'm new to this. Thanks.

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  • libpng cannot read an image properly

    - by jonathanasdf
    Here is my function... I don't know why it's not working. The resulting image looks nothing like what the .png looks like. But there's no errors either. bool Bullet::read_png(std::string file_name, int pos) { png_structp png_ptr; png_infop info_ptr; FILE *fp; if ((fp = fopen(file_name.c_str(), "rb")) == NULL) { return false; } png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL); if (png_ptr == NULL) { fclose(fp); return false; } info_ptr = png_create_info_struct(png_ptr); if (info_ptr == NULL) { fclose(fp); png_destroy_read_struct(&png_ptr, NULL, NULL); return false; } if (setjmp(png_jmpbuf(png_ptr))) { png_destroy_read_struct(&png_ptr, &info_ptr, NULL); fclose(fp); return false; } png_init_io(png_ptr, fp); png_read_png(png_ptr, info_ptr, PNG_TRANSFORM_STRIP_16 | PNG_TRANSFORM_SWAP_ALPHA | PNG_TRANSFORM_EXPAND, NULL); png_uint_32 width = png_get_image_width(png_ptr, info_ptr); png_uint_32 height = png_get_image_height(png_ptr, info_ptr); imageData[pos].width = width; imageData[pos].height = height; png_bytepp row_pointers; row_pointers = png_get_rows(png_ptr, info_ptr); imageData[pos].data = new unsigned int[width*height]; for (unsigned int i=0; i < height; ++i) { memcpy(&imageData[pos].data[i*width], &row_pointers[i], width*sizeof(unsigned int)); } png_destroy_read_struct(&png_ptr, &info_ptr, NULL); fclose(fp); for (unsigned int i=0; i < height; ++i) { for (unsigned int j=0; j < width; ++j) { unsigned int val = imageData[pos].data[i*width+j]; if (val != 0) { unsigned int a = ((val >> 24)); unsigned int r = (((val - (a << 24)) >> 16)); unsigned int g = (((val - (a << 24) - (r << 16)) >> 8)); unsigned int b = (((val - (a << 24) - (r << 16) - (g << 8)))); // for debugging std::string s(AS3_StringValue(AS3_Int(i*width+j))); s += " "; s += AS3_StringValue(AS3_Int(val)); s += " "; s += AS3_StringValue(AS3_Int(a)); s += " "; s += AS3_StringValue(AS3_Int(r)); s += " "; s += AS3_StringValue(AS3_Int(g)); s += " "; s += AS3_StringValue(AS3_Int(b)); AS3_Trace(AS3_String(s.c_str())); } } } return true; } ImageData is just a simple struct to keep x, y, width, and height, and imageData is an array of that struct. struct ImageData { int x; int y; int width; int height; unsigned int* data; }; Here is a side by side screenshot of the input and output graphics (something I made in a minute for testing), and this was after setting alpha to 255 in order to make it show up (because the alpha I was getting back was 1). Left side is original, right side is what happened after reading it through this function. Scaled up 400% for visibility. Here is a log of the traces: 0 16855328 1 1 49 32 1 16855424 1 1 49 128 2 16855456 1 1 49 160 3 16855488 1 1 49 192 4 16855520 1 1 49 224 5 16855552 1 1 50 0 6 16855584 1 1 50 32 7 16855616 1 1 50 64 8 16855424 1 1 49 128 9 16855456 1 1 49 160 10 16855488 1 1 49 192 11 16855520 1 1 49 224 12 16855552 1 1 50 0 13 16855584 1 1 50 32 14 16855616 1 1 50 64 15 16855648 1 1 50 96 16 16855456 1 1 49 160 17 16855488 1 1 49 192 18 16855520 1 1 49 224 19 16855552 1 1 50 0 20 16855584 1 1 50 32 21 16855616 1 1 50 64 22 16855648 1 1 50 96 23 16855680 1 1 50 128 24 16855488 1 1 49 192 25 16855520 1 1 49 224 26 16855552 1 1 50 0 27 16855584 1 1 50 32 28 16855616 1 1 50 64 29 16855648 1 1 50 96 30 16855680 1 1 50 128 31 16855712 1 1 50 160 32 16855520 1 1 49 224 33 16855552 1 1 50 0 34 16855584 1 1 50 32 35 16855616 1 1 50 64 36 16855648 1 1 50 96 37 16855680 1 1 50 128 38 16855712 1 1 50 160 39 16855744 1 1 50 192 40 16855552 1 1 50 0 41 16855584 1 1 50 32 42 16855616 1 1 50 64 43 16855648 1 1 50 96 44 16855680 1 1 50 128 45 16855712 1 1 50 160 46 16855744 1 1 50 192 47 16855776 1 1 50 224 48 16855584 1 1 50 32 49 16855616 1 1 50 64 50 16855648 1 1 50 96 51 16855680 1 1 50 128 52 16855712 1 1 50 160 53 16855744 1 1 50 192 54 16855776 1 1 50 224 55 16855808 1 1 51 0 56 16855616 1 1 50 64 57 16855648 1 1 50 96 58 16855680 1 1 50 128 59 16855712 1 1 50 160 60 16855744 1 1 50 192 61 16855776 1 1 50 224 62 16855808 1 1 51 0 63 16855840 1 1 51 32 64 16855648 1 1 50 96 65 16855680 1 1 50 128 66 16855712 1 1 50 160 67 16855744 1 1 50 192 68 16855776 1 1 50 224 69 16855808 1 1 51 0 70 16855840 1 1 51 32 71 16855872 1 1 51 64 72 16855680 1 1 50 128 73 16855712 1 1 50 160 74 16855744 1 1 50 192 75 16855776 1 1 50 224 76 16855808 1 1 51 0 77 16855840 1 1 51 32 78 16855872 1 1 51 64 79 16855904 1 1 51 96 80 16855712 1 1 50 160 81 16855744 1 1 50 192 82 16855776 1 1 50 224 83 16855808 1 1 51 0 84 16855840 1 1 51 32 85 16855872 1 1 51 64 86 16855904 1 1 51 96 87 16855936 1 1 51 128 88 16855744 1 1 50 192 89 16855776 1 1 50 224 90 16855808 1 1 51 0 91 16855840 1 1 51 32 92 16855872 1 1 51 64 93 16855904 1 1 51 96 94 16855936 1 1 51 128 95 16855968 1 1 51 160 96 16855776 1 1 50 224 97 16855808 1 1 51 0 98 16855840 1 1 51 32 99 16855872 1 1 51 64 100 16855904 1 1 51 96 101 16855936 1 1 51 128 102 16855968 1 1 51 160 103 16856000 1 1 51 192 104 16855808 1 1 51 0 105 16855840 1 1 51 32 106 16855872 1 1 51 64 107 16855904 1 1 51 96 108 16855936 1 1 51 128 109 16855968 1 1 51 160 110 16856000 1 1 51 192 111 16856032 1 1 51 224 112 16855840 1 1 51 32 113 16855872 1 1 51 64 114 16855904 1 1 51 96 115 16855936 1 1 51 128 116 16855968 1 1 51 160 117 16856000 1 1 51 192 118 16856032 1 1 51 224 119 16856064 1 1 52 0 120 16855872 1 1 51 64 121 16855904 1 1 51 96 122 16855936 1 1 51 128 123 16855968 1 1 51 160 124 16856000 1 1 51 192 125 16856032 1 1 51 224 126 16856064 1 1 52 0 127 16856096 1 1 52 32 128 16855904 1 1 51 96 129 16855936 1 1 51 128 130 16855968 1 1 51 160 131 16856000 1 1 51 192 132 16856032 1 1 51 224 133 16856064 1 1 52 0 134 16856096 1 1 52 32 135 16856128 1 1 52 64 136 16855936 1 1 51 128 137 16855968 1 1 51 160 138 16856000 1 1 51 192 139 16856032 1 1 51 224 140 16856064 1 1 52 0 141 16856096 1 1 52 32 142 16856128 1 1 52 64 143 16856160 1 1 52 96 144 16855968 1 1 51 160 145 16856000 1 1 51 192 146 16856032 1 1 51 224 147 16856064 1 1 52 0 148 16856096 1 1 52 32 149 16856128 1 1 52 64 150 16856160 1 1 52 96 151 16856192 1 1 52 128 152 16856000 1 1 51 192 153 16856032 1 1 51 224 154 16856064 1 1 52 0 155 16856096 1 1 52 32 156 16856128 1 1 52 64 157 16856160 1 1 52 96 158 16856192 1 1 52 128 159 16856224 1 1 52 160 160 16856032 1 1 51 224 161 16856064 1 1 52 0 162 16856096 1 1 52 32 163 16856128 1 1 52 64 164 16856160 1 1 52 96 165 16856192 1 1 52 128 166 16856224 1 1 52 160 167 16856256 1 1 52 192 168 16856064 1 1 52 0 169 16856096 1 1 52 32 170 16856128 1 1 52 64 171 16856160 1 1 52 96 172 16856192 1 1 52 128 173 16856224 1 1 52 160 174 16856256 1 1 52 192 175 16856288 1 1 52 224 176 16856096 1 1 52 32 177 16856128 1 1 52 64 178 16856160 1 1 52 96 179 16856192 1 1 52 128 180 16856224 1 1 52 160 181 16856256 1 1 52 192 182 16856288 1 1 52 224 183 16856320 1 1 53 0 184 16856128 1 1 52 64 185 16856160 1 1 52 96 186 16856192 1 1 52 128 187 16856224 1 1 52 160 188 16856256 1 1 52 192 189 16856288 1 1 52 224 190 16856320 1 1 53 0 192 16856160 1 1 52 96 193 16856192 1 1 52 128 194 16856224 1 1 52 160 195 16856256 1 1 52 192 196 16856288 1 1 52 224 197 16856320 1 1 53 0 200 16856192 1 1 52 128 201 16856224 1 1 52 160 202 16856256 1 1 52 192 203 16856288 1 1 52 224 204 16856320 1 1 53 0 208 16856224 1 1 52 160 209 16856256 1 1 52 192 210 16856288 1 1 52 224 211 16856320 1 1 53 0 216 16856256 1 1 52 192 217 16856288 1 1 52 224 218 16856320 1 1 53 0 224 16856288 1 1 52 224 225 16856320 1 1 53 0 232 16856320 1 1 53 0 Was stuck on this for a couple of days.

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