Develop Reference

Image stitching with opencvsharp

I want to make image stitching with openCvSharp but something goes wrong. Since I do not get the right output of 2 image stitched together.
I was fallowing the tutorial in python link and converting it in to C# code.
Here are 2 photo examples
The output where image should be stitched I get wrong result. It looks the same as image 2.
I gues something goes wrong in line, or somewhere after the line
Cv2.WarpPerspective(trainImg, result, H, new OpenCvSharp.Size(width, height));
Here is the full code.
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
bool debugImages = true;
string locationFolder = "";
OpenFileDialog dlg = new OpenFileDialog();
dlg.CheckFileExists = true;
dlg.Multiselect = true;
if (dlg.ShowDialog() == System.Windows.Forms.DialogResult.OK)
{
locationFolder = Path.GetDirectoryName(dlg.FileNames[0]) + "\\output\\";
List<Mat> imagesMat = new List<Mat>();
for (var i = 0; i < dlg.FileNames.Length; i++)
{
using (Bitmap fromFile = new Bitmap(dlg.FileNames[i]))
{
Mat source = BitmapConverter.ToMat(fromFile);
imagesMat.Add(source);
}
}
if (imagesMat.Count != 2)
throw new Exception("Select only 2 images!!!");
int imageCounter = 0;
Mat trainImg = imagesMat[0];
Mat queryImg = imagesMat[1];
Mat trainImg_gray = new Mat();
Mat queryImg_gray = new Mat();
Cv2.CvtColor(trainImg, trainImg_gray, ColorConversionCodes.BGRA2GRAY);
Cv2.CvtColor(queryImg, queryImg_gray, ColorConversionCodes.BGRA2GRAY);
// detecting keypoints
// FastFeatureDetector, StarDetector, SIFT, SURF, ORB, BRISK, MSER, GFTTDetector, DenseFeatureDetector, SimpleBlobDetector
string method = "SURF";
string feature_matching = "bf"; //bf, knn
var descriptor = SURF.Create(500, 4, 2, true);
Mat descriptors1 = new Mat();
Mat descriptors2 = new Mat();
KeyPoint[] kpsA;
KeyPoint[] kpsB;
descriptor.DetectAndCompute(trainImg_gray, null, out kpsA, descriptors1);
descriptor.DetectAndCompute(queryImg_gray, null, out kpsB, descriptors2);
// Match descriptor vectors
//var flannMatcher = new FlannBasedMatcher();
DMatch[] matches;
if (feature_matching == "bf")
matches = matchKeyPointsBF(descriptors1, descriptors2, method);
else
matches = matchKeyPointsKNN(descriptors1, descriptors2, 0.75, method);
var bfView = new Mat();
Cv2.DrawMatches(trainImg, kpsA, queryImg, kpsB, matches, bfView, null, flags: DrawMatchesFlags.NotDrawSinglePoints);
if (debugImages)
{
using (Bitmap resultBitmap = BitmapConverter.ToBitmap(bfView))
resultBitmap.Save(locationFolder + (imageCounter++).ToString().PadLeft(3, '0') + ".png", ImageFormat.Png); //1
}
Mat H = getHomography(kpsA, kpsB, descriptors1, descriptors2, matches, 4);
if (H == null)
throw new Exception("No Homography!!!");
//for (var i = 0; i < H.Cols; i++)
//{
// for (var j = 0; j < H.Rows; j++)
// Console.Write(H.At<float>(i, j) + " ");
// Console.WriteLine("");
//}
double width = trainImg.Size().Width + queryImg.Size().Width;
double height = trainImg.Size().Height + queryImg.Size().Height;
Mat result = new Mat();
Cv2.WarpPerspective(trainImg, result, H, new OpenCvSharp.Size(width, height));
if (debugImages)
{
using (Bitmap resultBitmap = BitmapConverter.ToBitmap(result))
resultBitmap.Save(locationFolder + (imageCounter++).ToString().PadLeft(3, '0') + ".png", ImageFormat.Png); //1
}
result[new Rect(new OpenCvSharp.Point(0, 0), new OpenCvSharp.Size(queryImg.Size().Width, queryImg.Size().Height))] = queryImg;
if (debugImages)
{
using (Bitmap resultBitmap = BitmapConverter.ToBitmap(result))
resultBitmap.Save(locationFolder + (imageCounter++).ToString().PadLeft(3, '0') + ".png", ImageFormat.Png); //2
}
//# transform the panorama image to grayscale and threshold it
Mat gray = result.Clone();
Cv2.CvtColor(result, gray, ColorConversionCodes.BGR2GRAY);
Mat thresh = new Mat();
double thresh2 = Cv2.Threshold(gray, thresh, 0, 255, ThresholdTypes.Binary);
//# Finds contours from the binary image
OpenCvSharp.Point[][] cnts;
HierarchyIndex[] hierarchy;
Cv2.FindContours(thresh, out cnts, out hierarchy, RetrievalModes.External, ContourApproximationModes.ApproxSimple);
OpenCvSharp.Point[] cnts2 = new OpenCvSharp.Point[cnts[0].Length];
for (var k = 0; k < cnts[0].Length; k++)
cnts2[k] = cnts[0][k];
//InputArray ptsA = InputArray.Create(cnts2);
//var c = Cv2.ContourArea(ptsA, true);
OpenCvSharp.Rect xywh = Cv2.BoundingRect(cnts2);
result = result[new Rect(new OpenCvSharp.Point(xywh.X, xywh.Y), new OpenCvSharp.Size(xywh.Width, xywh.Height))];
//result = result[new Rect(new OpenCvSharp.Point(0, 0), new OpenCvSharp.Size(256, 256))];
Bitmap endResultBitmap = BitmapConverter.ToBitmap(result);
endResultBitmap.Save(locationFolder + (imageCounter++).ToString().PadLeft(3, '0') + ".png", ImageFormat.Png); //4
Environment.Exit(-1);
}
}
private BFMatcher createMatcher(string method, bool crossCheck)
{
//"Create and return a Matcher Object"
if (method == "SURF" || method == "SIFT")
return new BFMatcher(NormTypes.L2, crossCheck);
else //if (method == "ORB" || method == "BRISK")
return new BFMatcher(NormTypes.Hamming, crossCheck);
}
private DMatch[] matchKeyPointsBF(Mat featuresA, Mat featuresB, string method)
{
BFMatcher bf = createMatcher(method, crossCheck: true);
// # Match descriptors.
DMatch[] bfMatches = bf.Match(featuresA, featuresB);
//# Sort the features in order of distance.
//# The points with small distance (more similarity) are ordered first in the vector
DMatch[] rawMatches = bfMatches.OrderBy(a => a.Distance).ToArray();
if (rawMatches.Length > 100)
Array.Resize(ref rawMatches, 100);
return rawMatches;
}
private DMatch[] matchKeyPointsKNN(Mat featuresA, Mat featuresB, double ratio, string method)
{
BFMatcher bf = createMatcher(method, crossCheck: false);
// # compute the raw matches and initialize the list of actual matches
DMatch[][] rawMatches = bf.KnnMatch(featuresA, featuresB, 2);
List<DMatch> rawMatches2 = new List<DMatch>();
//# loop over the raw matches
DMatch prevmatchN = rawMatches[0][0];
rawMatches2.Add(prevmatchN);
for (int m = 0; m < rawMatches.Length; m++)
{
for (int n = 0; n < rawMatches[m].Length; n++)
{
//# ensure the distance is within a certain ratio of each
//# other (i.e. Lowe's ratio test)
DMatch matchN = rawMatches[m][n];
if (n == 0)
prevmatchN = matchN;
if (prevmatchN.Distance < matchN.Distance * (ratio))
rawMatches2.Add(matchN);
if (rawMatches2.Count >= 100)
break;
}
}
return rawMatches2.ToArray();
}
private Mat getHomography(KeyPoint[] kpsA, KeyPoint[] kpsB, Mat featuresA, Mat featuresB, DMatch[] matches, int reprojThresh)
{
//# convert the keypoints to numpy arrays
Point2f[] PtA = new Point2f[matches.Length];
Point2f[] PtB = new Point2f[matches.Length];
for (int i = 0; i < matches.Length; i++)
{
KeyPoint kpsAI = kpsA[matches[i].QueryIdx];
KeyPoint kpsBI = kpsB[matches[i].TrainIdx];
PtA[i] = new Point2f(kpsAI.Pt.X, kpsAI.Pt.Y);
PtB[i] = new Point2f(kpsBI.Pt.X, kpsBI.Pt.Y);
}
InputArray ptsA = InputArray.Create(PtA);
InputArray ptsB = InputArray.Create(PtB);
if (matches.Length > 4)
{
//You get the homography matrix usin
Mat H = Cv2.FindHomography(ptsA, ptsB, HomographyMethods.Ransac, reprojThresh);
//and then to get any point on the target picture from the original picture:
//Mat targetPoint = new Mat();
//Cv2.PerspectiveTransform(ptsA, targetPoint, H);
return H;
}
else
return null;
}
}

PDFStamper not working for newer versions of iTextSharp

The latest version of iTextSharp is 5.5.11.
When I run the exact same code against 5.5.0 it works.
It's a pretty simple request - use iTextSharp to set a watermark on an existing PDF in-memory.
Here's the offending code:
private static Stream Watermark(Stream inStream, WatermarkRequest request)
{
using (var outStream = new MemoryStream((int)(inStream.Length + 4096)))
{
using (var reader = new PdfReader(inStream))
using (var stamper = new PdfStamper(reader, outStream))
{
var opacity = request.Opacity.HasValue ? request.Opacity.Value : 0.75f;
var angle = request.Angle.HasValue ? request.Angle.Value : 45;
var size = request.Size.HasValue ? request.Size.Value : 72f;
var color = new BaseColor(1f, 0f, 0f, 0f);
if (!String.IsNullOrEmpty(request.Color))
{
var rgba = PDF.Lib.RGBA.convert(request.Color);
color = new BaseColor((float)rgba.R, (float)rgba.G, (float)rgba.B, 0f);
}
for (var n = 1; n <= reader.NumberOfPages; n++)
{
var pcb = stamper.GetOverContent(n);
var gstate = new PdfGState() { FillOpacity = opacity, StrokeOpacity = opacity };
pcb.SaveState();
pcb.SetGState(gstate);
pcb.SetColorFill(color);
pcb.BeginText();
pcb.SetFontAndSize(BaseFont.CreateFont(BaseFont.HELVETICA, Encoding.Default.WebName, true), size);
var ps = reader.GetPageSize(n);
var x = (ps.Right + ps.Left) / 2;
var y = (ps.Bottom + ps.Top) / 2;
pcb.ShowTextAligned(Element.ALIGN_CENTER, request.Text, x, y, angle);
pcb.EndText();
pcb.RestoreState();
}
}
return new MemoryStream(outStream.ToArray());
}
}

Release memory consumed by images with Twain

Twain scan images to memory and it consumes too much memory. So I scanned images in batch, and compress images in memory. So source images should be released. how can I do it?
protected void OnTwainTransferReady()
{
if (TwainTransferReady == null)
return; // not likely..
List<ImageSource> imageSources = new List<ImageSource>();
ArrayList pics = tw.TransferPictures();
tw.CloseSrc();
EndingScan();
picnumber++;
for (int i = 0; i < pics.Count; i++) {
IntPtr imgHandle = (IntPtr)pics[i];
/*if (i == 0) { // first image only
imageSources.Add(DibToBitmap.FormHDib(imgHandle));
//Refresh(image1); // force a redraw
}*/
ImageSource src = DibToBitmap.FormHDib(imgHandle);
ImageSource temp = ImageHelper.compressImage(src);
src = null;
imageSources.Add(temp);
Win32.GlobalFree(imgHandle);
}
// for some reason the main window does not refresh properly - resizing of the window solves the proble.
// happens only with the Canon LIDE Scanner
// Suspected: some messages where eaten by Twain
TwainTransferReady(this, imageSources);
}
Generate the BitSource
public static BitmapSource FormHDib(IntPtr dibHandle)
{
BitmapSource bs = null;
IntPtr bmpPtr = IntPtr.Zero;
bool flip = true; // vertivcally flip the image
try {
bmpPtr = Win32.GlobalLock(dibHandle);
Win32.BITMAPINFOHEADER bmi = new Win32.BITMAPINFOHEADER();
Marshal.PtrToStructure(bmpPtr, bmi);
if (bmi.biSizeImage == 0)
bmi.biSizeImage = (uint)(((((bmi.biWidth * bmi.biBitCount) + 31) & ~31) >> 3) * bmi.biHeight);
int palettSize = 0;
if (bmi.biClrUsed != 0)
throw new NotSupportedException("DibToBitmap: DIB with pallet is not supported");
// pointer to the beginning of the bitmap bits
IntPtr pixptr = (IntPtr)((int)bmpPtr + bmi.biSize + palettSize);
// Define parameters used to create the BitmapSource.
PixelFormat pf = PixelFormats.Default;
switch (bmi.biBitCount) {
case 32:
pf = PixelFormats.Bgr32;
break;
case 24:
pf = PixelFormats.Bgr24;
break;
case 8:
pf = PixelFormats.Gray8;
break;
case 1:
pf = PixelFormats.BlackWhite;
break;
default: // not supported
throw new NotSupportedException("DibToBitmap: Can't determine picture format (biBitCount=" + bmi.biBitCount + ")");
// break;
}
int width = bmi.biWidth;
int height = bmi.biHeight;
int stride = (int)(bmi.biSizeImage / height);
byte[] imageBytes = new byte[stride * height];
//Debug: Initialize the image with random data.
//Random value = new Random();
//value.NextBytes(rawImage);
if (flip) {
for (int i = 0, j = 0, k = (height - 1) * stride; i < height; i++, j += stride, k -= stride)
Marshal.Copy(((IntPtr)((int)pixptr + j)), imageBytes, k, stride);
} else {
Marshal.Copy(pixptr, imageBytes, 0, imageBytes.Length);
}
int xDpi = (int)Math.Round(bmi.biXPelsPerMeter * 2.54 / 100); // pels per meter to dots per inch
int yDpi = (int)Math.Round(bmi.biYPelsPerMeter * 2.54 / 100);
// Create a BitmapSource.
bs = BitmapSource.Create(width, height, xDpi, yDpi, pf, null, imageBytes, stride);
Win32.GlobalUnlock(pixptr);
Win32.GlobalFree(pixptr);
} catch (Exception ex) {
string msg = ex.Message;
}
finally {
// cleanup
if (bmpPtr != IntPtr.Zero) { // locked sucsessfully
Win32.GlobalUnlock(dibHandle);
}
}
Win32.GlobalUnlock(bmpPtr);
Win32.GlobalFree(bmpPtr);
return bs;
}
Compress Image in Memory
internal static System.Windows.Media.ImageSource compressImage(System.Windows.Media.ImageSource ims)
{
using (MemoryStream stream = new MemoryStream())
{
using (MemoryStream outS = new MemoryStream())
{
BitmapSource bs = ims as BitmapSource;
JpegBitmapEncoder encoder = new JpegBitmapEncoder();
BitmapFrame bf = BitmapFrame.Create(bs);
//encoder.Frames.Add(BitmapFrame.Create(image1.Source));
encoder.Frames.Add(bf);
encoder.Save(stream);
stream.Flush();
try
{
// Read first frame of gif image
using (MagickImage image = new MagickImage(stream))
{
image.Quality = 75;
image.Resize(new Percentage(0.65));
image.Density = new Density(200, DensityUnit.PixelsPerInch);
image.Write(outS);
image.Dispose();
}
stream.Close();
stream.Dispose();
BitmapImage bitmap = new BitmapImage();
bitmap.BeginInit();
bitmap.CacheOption = BitmapCacheOption.OnLoad;
outS.Position = 0;
bitmap.StreamSource = outS;
//
bitmap.EndInit();
//bitmap.Freeze();
outS.Flush();
outS.Close();
outS.Dispose();
ims = null;
return bitmap;
}
catch (Exception e)
{
return null;
}
}
}
}

Print multiple pages using PrintDocument

I have an issue regarding printing multiple pages using the code below. It always prints only the last page. Can you guys please help me?
using (var rasterizer = new PdfRasterizer(pdfInputPdf))
{
// Create a JpegImageFormat object.
var jpegImageFormat = new JpegImageFormat(100);
// Create a FixedImageSize object with required width and height.
var imageSize = new PercentageImageSize(400);
// Save the image.
var imageData = rasterizer.Draw(jpegImageFormat, imageSize);
using (var pd = new PrintDocument())
{
var margins = new Margins(0, 40, 0, 40);
pd.DefaultPageSettings.Margins = margins;
pd.DefaultPageSettings.Color = true;
pd.DefaultPageSettings.Landscape = false;
pd.PrintPage += (sender, args) =>
{
PrintPage(text1, text2, imageData, pd, args);
};
pd.Print();
}
}
And this class:
private static int counter = 0;
private static void PrintPage(string text1, string text2, byte[][] imageData, PrintPageEventArgs args)
{
foreach (var b in imageData)
{
using (var stream = new MemoryStream(b))
{
var i = Image.FromStream(stream);
CreateNotApprovedWatermark(i, text1, text2);
if (args.PageSettings.PrinterSettings.CanDuplex)
{
args.PageSettings.PrinterSettings.Duplex = Duplex.Horizontal;
}
var m = args.MarginBounds;
if (i.Width / (double)i.Height > m.Width / (double)m.Height) // image is wider
{
m.Height = (int)(i.Height / (double)i.Width * m.Width);
}
else
{
m.Width = (int)(i.Width / (double)i.Height * m.Height);
}
args.Graphics.DrawImage(i, m);
if (counter <= 2)
{
counter++;
args.HasMorePages = true;
}
else
{
args.HasMorePages = false;
}
}
}
}

I found a easy solution to my problem after quit some trial and error:
using (var rasterizer = new PdfRasterizer(new Foxit.PDF.Rasterizer.InputPdf(pdfData)))
{
// Create a JpegImageFormat object.
var jpegImageFormat = new JpegImageFormat(100);
// Create a FixedImageSize object with required width and height.
var imageSize = new PercentageImageSize(400);
// Save the image.
var imagePages = rasterizer.Draw(jpegImageFormat, imageSize);
using (var pd = new PrintDocument())
{
var margins = new Margins(0, 40, 0, 40);
pd.DefaultPageSettings.Margins = margins;
pd.DefaultPageSettings.Color = true;
pd.DefaultPageSettings.Landscape = false;
var pageNumber = 0;
pd.PrintPage += (sender, args) =>
{
PrintPage(pageNumber, text1, text2, imagePages[pageNumber], args);
if (pageNumber < imagePages.Count())
{
pageNumber++;
args.HasMorePages = pageNumber != imagePages.Count();
}
};
pd.Print();
}
}
The problem was placement of the HasMorePages property.

WPF Leak when adding multiple items to a canvas and rendering using RenderBitmapTarget

I've been having a whale of a time diagnosing a leak in a service which is rendering multiple images to a canvas and then pushing out a bitmap or PNG at the end (and doing this multiple times). On start up the service will rocket up to 600MB+ and then keep on increasing until it's taken almost all that it can get hold of. It will never decrease once started.
I've instrumented and run the service using the VS2012 perf mon and seen that there are large amounts of Byte arrays laying about after processing has been completed. I've tried a GC clear to see if it would wipe them out to no avail. Looking into it using WinDbg I can see that the byte array is being held onto by a long chain of items (mostly WPF objects) which is keeping the image in ram.
I've had a look over MSDN for all the objects that are being used and can't find anything that points out a problem with the way the code is running.
I've put together some sample code that closely follows the service (some bits reduced for bevity). This is called off a thread (set to STA). The only other differece is the service code uses MemoryStreams to load images sourced from a DB rather than the URIs I am using. The streams are disposed of:
public static void TestThread()
{
const int rounds = 50;
const int innerRounds = 50;
var randomiser = new Random(DateTime.Now.Millisecond);
// Simulating some live values
const float scaling = 2.67F;
const int pageWidth = 363;
const int pageHeight = 516;
const int dpi = 96;
// To simulate the live system using multiple images
// This is an list of images of different sizes etc
var imageList = new List<ImageData>
{
new ImageData{Uri = new Uri(#"..."), Height = 2592},
new ImageData{Uri = new Uri(#"..."), Height = 1339},
new ImageData{Uri = new Uri(#"..."), Height = 386},
new ImageData{Uri = new Uri(#"..."), Height = 968},
new ImageData{Uri = new Uri(#"..."), Height = 1952},
new ImageData{Uri = new Uri(#"..."), Height = 1024},
};
var proc = Process.GetCurrentProcess();
for (var i = 0; i < rounds; ++i)
{
var canvas = new Canvas();
canvas.BeginInit();
canvas.SnapsToDevicePixels = false;
canvas.UseLayoutRounding = false;
canvas.Width = pageWidth;
canvas.Height = pageHeight;
canvas.Background = Brushes.White;
for (var j = 0; j < innerRounds; ++j)
{
var img = new Image {Stretch = Stretch.Fill};
var bitmapImage = new BitmapImage();
bitmapImage.BeginInit();
bitmapImage.CacheOption = BitmapCacheOption.OnLoad;
var imageNo = randomiser.Next(0, imageList.Count - 1);
bitmapImage.UriSource = imageList[imageNo].Uri;
int imageHeight = imageList[imageNo].Height;
bitmapImage.DecodePixelHeight = (int) (imageHeight * scaling * 1.8);
bitmapImage.EndInit();
if (bitmapImage.CanFreeze)
{
bitmapImage.Freeze();
}
var opacityMask = new ImageBrush();
var opactityBitmap = new BitmapImage();
opactityBitmap.BeginInit();
opactityBitmap.CacheOption = BitmapCacheOption.OnLoad;
imageNo = randomiser.Next(0, imageList.Count - 1);
opactityBitmap.UriSource = imageList[imageNo].Uri;
int opacityImageHeight = imageList[imageNo].Height; ;
opactityBitmap.DecodePixelHeight = (int)(opacityImageHeight * scaling * 1.8);
opactityBitmap.EndInit();
if (opactityBitmap.CanFreeze)
{
opactityBitmap.Freeze();
}
opacityMask.ImageSource = opactityBitmap;
img.OpacityMask = opacityMask;
img.Source = bitmapImage;
img.Width = pageWidth * scaling;
img.Height = pageHeight * scaling;
Canvas.SetLeft(img, 0);
Canvas.SetTop(img, 0);
canvas.Children.Add(img);
img.Opacity = 50F;
}
canvas.LayoutTransform = null;
var size = new Size(Math.Max(canvas.Width, 5), Math.Max(canvas.Height, 5));
canvas.Measure(size);
canvas.Arrange(new Rect(size));
canvas.EndInit();
var renderTargetBitmap = new RenderTargetBitmap(pageWidth, pageHeight, dpi, dpi, PixelFormats.Default); //xxx
renderTargetBitmap.Render(canvas);
if (renderTargetBitmap.CanFreeze)
{
renderTargetBitmap.Freeze();
}
System.Drawing.Image imageData;
using (var ms = new MemoryStream())
{
var image = new PngBitmapEncoder();
image.Frames.Add(BitmapFrame.Create(renderTargetBitmap));
image.Save(ms);
imageData = System.Drawing.Image.FromStream(ms);
}
var encoder = Encoder.Quality;
var encoderParams = new EncoderParameters(1);
encoderParams.Param[0] = new EncoderParameter(encoder, 100L);
ImageCodecInfo[] codecs = ImageCodecInfo.GetImageDecoders();
var codecInfo = codecs.FirstOrDefault(x => x.FormatID == ImageFormat.Png.Guid);
Byte[] bitmapArray;
using (var ms = new MemoryStream())
{
imageData.Save(ms, codecInfo, encoderParams);
bitmapArray = ms.GetBuffer();
}
var filepath = string.Format(#"C:\temp\{0}.png", i);
imageData.Save(filepath, ImageFormat.Png);
var gcMemory = GC.GetTotalMemory(false) / 1024;
Console.WriteLine("Proc mem = {0}KB, GC = {1}KB", (proc.PrivateMemorySize64 / 1024), gcMemory);
}
Console.WriteLine("Exiting");
}
I'm hoping it's something obvious I'm missing here. Thanks for all your help!