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How can I convert extracted Mat Contours to Bitmap in Opencvsharp?

After I applied the Threshold on the Destination Image
I get a Mat as Reference
then I called the function FindContours()
to extract all existed Contours on the target Image
finally I tried to convert the extracted contours one at a time to Bitmap and here at this point am getting an Error:
System.ArgumentException: "Number of channels must be 1, 3 or 4. Parametername: src" by converting Mat to Bitmap
private void button1_Click(object sender, EventArgs e)
{
OpenFileDialog getImag = new OpenFileDialog();
getImag.Filter = "PNG,JPG|*.png;*.jpg";
DialogResult result = getImag.ShowDialog();
string Source_Logo_Link = string.Empty;
if (result == DialogResult.OK)
{
Source_Logo_Link = getImag.FileName;
System.Drawing.Image image = System.Drawing.Image.FromFile(Source_Logo_Link);
Mat src = new OpenCvSharp.Mat(Source_Logo_Link);
OpenCvSharp.Mat gray = src.CvtColor(ColorConversionCodes.BGR2GRAY);
OpenCvSharp.Mat binary = gray.Threshold(0, 255, ThresholdTypes.Otsu);
OpenCvSharp.Mat[] contoursQuery;
OutputArray hierarchyQ = InputOutputArray.Create(new List<Vec4i>());
binary.FindContours(out contoursQuery, hierarchyQ, RetrievalModes.CComp, ContourApproximationModes.ApproxTC89KCOS);
List<Bitmap> images = new List<Bitmap>();
for (int i = 0; i <= contoursQuery.Length; i++)
images.add(contoursQuery[i].toBitmap());
}
}

sorry this comes a bit late, but I hope this still helps though. Apart from a few other issues (like the counter of the for loop), I guess that your major problem is, that you miss-understood the result of FindContours.
It really just gives you a list of all contour points, which it found in the image, not complete images.
Have a look at the documentation FindContours, it clearly states for the contour parameter:
Each contour is stored as a vector of points
So that means if you wand them "one at a time to Bitmap" you'll need to create these bitmaps first, and then draw the contours into it. To make drawing a bit more easy (and faster) there is the DrawContours command, which you could use for the drawing part.
Over all, in the end, it should look somehow like this:
private void button1_Click(object sender, EventArgs e)
{
OpenFileDialog getImag = new OpenFileDialog();
getImag.Filter = "PNG,JPG|*.png;*.jpg";
DialogResult result = getImag.ShowDialog();
string Source_Logo_Link = string.Empty;
if (result == DialogResult.OK)
{
Source_Logo_Link = getImag.FileName;
System.Drawing.Image image = System.Drawing.Image.FromFile(Source_Logo_Link);
Mat src = new OpenCvSharp.Mat(Source_Logo_Link);
OpenCvSharp.Mat gray = src.CvtColor(ColorConversionCodes.BGR2GRAY);
OpenCvSharp.Mat binary = gray.Threshold(0, 255, ThresholdTypes.Otsu);
// I'd really prefer to work with point lists and HierarchyIndex because
// it's much more descriptive that way
OpenCvSharp.Point[][] contours;
OpenCvSharp.HierarchyIndex[] hierarchyQ;
binary.FindContours(out contours,out hierarchyQ, RetrievalModes.List, ContourApproximationModes.ApproxTC89KCOS);
List<Bitmap> images = new List<Bitmap>();
for (int i = 0; i < contoursQuery.Length; i++){
var singleContour = new OpenCvSharp.Mat(src.Size(), MatType.CV_8U,0);
singleContour.DrawContours(contours,i,Scalar.White);
images.Add(singleContour.ToBitmap());
}
}
}
I also changed the RetrievalMode to "List", since you don't really seem to care about the hierarchical relationships.
Hope that helps ;-)

linear image stitching using emgu.cv in c#

I have a device that rotates an object and takes a picture of a portion of the object at regular intervals. Currently, I have 30 pictures. To stitch the images into a flat image, I am taking a slice right out of the center of each picture of a fixed width (between 50 and 75 pixels). I am trying to stitch these slices together into a flat image of the original picture using the EMGU CV Stitching library with the sample stitching code that comes with EMGU. I am testing with between 5 and 10 slices at a time. Sometimes, I am getting an error that says "Error, need more images". When I do get a result, it looks terrible with weird curvatures. I don't need any spatial adjustments. I just want to stitch them in a linear fashion from left to right. Any ideas, either using EMGU or other?
Here are a few slices and the result:
Why is the resulting image not the same height as the 4 slices? What must be done just to stitch these together in a linear fashion so that the text is continuous?
Here is the code I am using:
private void selectImagesButton_Click(object sender, EventArgs e)
{
OpenFileDialog dlg = new OpenFileDialog();
dlg.CheckFileExists = true;
dlg.Multiselect = true;
if (dlg.ShowDialog() == System.Windows.Forms.DialogResult.OK)
{
sourceImageDataGridView.Rows.Clear();
Image<Bgr, byte>[] sourceImages = new Image<Bgr, byte>[dlg.FileNames.Length];
for (int i = 0; i < sourceImages.Length; i++)
{
sourceImages[i] = new Image<Bgr, byte>(dlg.FileNames[i]);
using (Image<Bgr, byte> thumbnail = sourceImages[i].Resize(200, 200, Emgu.CV.CvEnum.Inter.Cubic, true))
{
DataGridViewRow row = sourceImageDataGridView.Rows[sourceImageDataGridView.Rows.Add()];
row.Cells["FileNameColumn"].Value = dlg.FileNames[i];
row.Cells["ThumbnailColumn"].Value = thumbnail.ToBitmap();
row.Height = 200;
}
}
try
{
//only use GPU if you have build the native binary from code and enabled "NON_FREE"
using (Stitcher stitcher = new Stitcher(false))
{
using (AKAZEFeaturesFinder finder = new AKAZEFeaturesFinder())
{
stitcher.SetFeaturesFinder(finder);
using (VectorOfMat vm = new VectorOfMat())
{
Mat result = new Mat();
vm.Push(sourceImages);
Stopwatch watch = Stopwatch.StartNew();
this.Text = "Stitching";
Stitcher.Status stitchStatus = stitcher.Stitch(vm, result);
watch.Stop();
if (stitchStatus == Stitcher.Status.Ok)
{
resultImageBox.Image = result;
this.Text = String.Format("Stitched in {0} milliseconds.", watch.ElapsedMilliseconds);
}
else
{
MessageBox.Show(this, String.Format("Stiching Error: {0}", stitchStatus));
resultImageBox.Image = null;
}
}
}
}
}
finally
{
foreach (Image<Bgr, Byte> img in sourceImages)
{
img.Dispose();
}
}
}
}

C# Draw a horizontal line on each stacked column chart

Currently I need to develop a tool with chart as the major component. Chart control is also new for me. I have do a lot of reading, researching to learn and understand the whole picture of the chart control.
After all, I had stuck and question on how to draw a horizontal line (blue & red horizontal line) on stacked column chart as image shown below:
Here what I have done so far:
This is my code so far:
// X-Axis labels settings
chart.ChartAreas[0].AxisX.LabelStyle.Angle = -45;
chart.ChartAreas[0].AxisX.Interval = 1;
// Y-Axis labels settings
//chart.ChartAreas[0].AxisY.Minimum = 100;
chart.ChartAreas[0].AxisY.Minimum = 95;
// Plotting chart
using (YieldEntities context = new YieldEntities())
{
// Extract yield loss list
var yeilds = (
from yeild in context.YeildDatas
group yeild by new { yeild.Loss } into newyeild
select new
{
Loss = newyeild.Key.Loss,
Percentage = newyeild.Sum(p => p.Percentage)
}).OrderByDescending(p => p.Percentage);
//context.YeildDatas.Select(p => new { p.Loss, Percentage = p }).Distinct();
// Create new series
foreach (var yield in yeilds)
{
chart.Series.Add(yield.Loss);
chart.Series[yield.Loss].ChartType = SeriesChartType.StackedColumn100;
}
// Label settings for first series
chart.Series[0].SmartLabelStyle.Enabled = false;
chart.Series[0].LabelAngle = -90;
chart.Series[0].Font = new Font(Font.FontFamily, 15, FontStyle.Bold);
chart.Series[0].IsValueShownAsLabel = true;
var query = context.YeildDatas.ToList();
foreach (var item in query)
{
DataPoint dp = new DataPoint();
dp.SetValueXY(item.DateString, item.Percentage);
chart.Series[item.Loss].Points.Add(dp);
}
// Set empty datapoint for each series
foreach (var yield in yeilds)
{
DataPoint nulldp = new DataPoint();
nulldp.SetValueXY("", 0);
chart.Series[yield.Loss].Points.Insert(1, nulldp);
chart.Series[yield.Loss].Points.Insert(6, nulldp);
chart.Series[yield.Loss].Points.Insert(11, nulldp);
}
chart.Legends["Legend"].IsEquallySpacedItems = true;
chart.Legends["Legend"].IsTextAutoFit = true;
}
I hope to get any expert to guide me to solve this problem.

This is only sample, you can start from there:
// Data point to pixel
var pixelX = this.chart1.ChartAreas[0].AxisX.ValueToPixelPosition(dataPointX);
var pixelY = this.chart1.ChartAreas[0].AxisY.ValueToPixelPosition(dataPointY);
// Pixel to data point
var dataPointX = this.chart1.ChartAreas[0].AxisX.PixelPositionToValue(pixelX);
var dataPointY = this.chart1.ChartAreas[0].AxisY.PixelPositionToValue(pixelY);
// Use event Paint to draw your line
private void chart1_Paint(object sender, PaintEventArgs e)
{
// Convert dataPoint to pixel
var dataPointX = this.chart1.Series[0].Points[0].XValue;
var dataPointY = this.chart1.Series[0].Points[0].YValues[0];
var pixelX = this.chart1.ChartAreas[0].AxisX.ValueToPixelPosition(dataPointX);
var pixelY = this.chart1.ChartAreas[0].AxisY.ValueToPixelPosition(dataPointY);
// Only sample, pen should be initialized outside Paint method
Pen pen = new Pen(Brushes.Red);
// Example of drawing line with width=100 pixel
e.Graphics.DrawLine(pen, pixelX, pixelY, pixelX + 100, pixelY);
}

AForge.NET -> AVIWriter Adding Images as Frames

I want to make a video from images, and each image should stay for one second.
The AVIWriter has 25 frames rate, so i have to add one image 25 times to make it stay for one second.
I tried changing the frame-rate, but it is not working.
Can anyone suggest a workaround?
The following is the code for writing frames into video:
private void writeVideo()
{
// instantiate AVI writer, use WMV3 codec
AVIWriter writer = new AVIWriter("wmv3");
// create new AVI file and open it
writer.Open(fileName, 320, 240);
// create frame image
Bitmap image = new Bitmap(320, 240);
var cubit = new AForge.Imaging.Filters.ResizeBilinear(320, 240);
string[] files = Directory.GetFiles(imagesFolder);
writer.FrameRate = 25;
int index = 0;
int failed = 0;
foreach (var item in files)
{
index++;
try
{
image = Image.FromFile(item) as Bitmap;
//image = cubit.Apply(image);
for (int i = 0; i < 25; i++)
{
writer.AddFrame(image);
}
}
catch
{
failed++;
}
this.Text = index + " of " + files.Length + ". Failed: " + failed;
}
writer.Close();
}

Hello I had the same problem and saw this topic read it all and no comment for
http://www.aforgenet.com/framework/docs/html/bc8345f8-8e09-c1a4-4834-8330e5e85605.htm
There is a note like that "The property should be set befor opening new file to take effect."

The solution of Hakan is working, if you use this code:
AVIWriter videoWriter;
videoWriter = new AVIWriter("wmv3");
videoWriter.FrameRate = 1;
videoWriter.Open("test.avi", 320, 240);
videoWriter.AddFrame(bitmap1);
videoWriter.AddFrame(bitmap2);
videoWriter.AddFrame(bitmap3);
videoWriter.Close();
There is well one bitmap displayed per second.
(just for giving a directly working piece of code).

The default frame rate for AVIWriter is 25. As you have no option to specify dropped or otherwise skipped frames, why wouldn't you set AVIWriter::FrameRate property to 1 before you start populating your writer with frames?

Creating numerous PictureBoxes by code - only one is visible

I am trying to draw lots of instances of an image using the following code:
PictureBox[] sprites = new PictureBox[100];
private void Game_Load(object sender, EventArgs e)
{
PictureBox mainSprite = new PictureBox();
Bitmap img = new Bitmap(SpriteTest.Properties.Resources.Image); //Load a png image
mainSprite.Size = new Size(16, 16);
mainSprite.Image = img;
for(var i = 0; i < sprites.Length; i++)
{
sprites[i] = mainSprite;
//Keeping it simple for now with a single row of sprites
sprites[i].Location = new Point(i * 16, 8);
}
Game.ActiveForm.Controls.AddRange(sprites);
}
When it comes to running the code, only the last image is shown. While debugging the code, everything seems to be working as expected. I can also verify that the location is in fact being updated.
I have also tried adding the controls differently using the following code in the for loop (with no luck);
this.Controls.Add(sprites[i]);
I have had this problem many times, especially when I tried to create many GroupBoxes in a similar fashion. For the hours that I searched online as I tried to find a solution, nothing has ever fixed it.

You're only actually creating one instance of PictureBox:
PictureBox mainSprite = new PictureBox();
...
for(var i = 0; i < sprites.Length; i++)
{
sprites[i] = mainSprite;
Your array will have lots of reference to the same object. You should create a new PictureBox on each iteration of the loop:
for(var i = 0; i < sprites.Length; i++)
{
PictureBox mainSprite = new PictureBox();
mainSprite.Size = new Size(16, 16);
mainSprite.Image = img;
sprites[i] = mainSprite;
...
}