We Keep Coding

Copy smaller Mat to larger Mat OpenCv For Unity

I'm trying to take a smaller image mat and copy it into larger mat so I can resize it while keeping the aspect ratio of the image. So, basically this:
So far, this is the code I've written:
private Mat MakeMatFrame(Texture2D image)
{
// Texture must be of right input size
Mat img_mat = new Mat(image.height, image.width, CvType.CV_8UC4, new Scalar(0, 0, 0, 255));
texture2DToMat(image, img_mat);
return img_mat;
}
private void letterBoxImage(Texture2D image)
{
// Get input image as a mat
Mat source = MakeMatFrame(image);
// Create the mat that the source will be put in
int col = source.cols();
int row = source.rows();
int _max = Math.Max(col, row);
Mat resized = Mat.zeros(_max, _max, CvType.CV_8UC4);
// Fill resized
Mat roi = new Mat(resized, new Rect(0, 0, col, row));
source.copyTo(roi);
Texture2D tex2d = new Texture2D(resized.cols(), resized.rows());
matToTexture2D(resized, tex2d);
rawImage.texture = tex2d;
}
Everything I've looked at tells me this is the right approach to take (get a region of interest, fill it in). But instead of getting that third image with the children above the gray region, I just have a gray region.
In other words, the image isn't copying over properly. I've trying using a submat as well, but it failed miserably.
I've been looking for C# code on how to do this sort of thing with OpenCv For Unity, but I can only find C++ code. Which tells me to do exactly this.
Is there some sort of "apply changes" function I'm unaware of for Mats? Am I selecting the region of interest incorrectly? Or is it something else?

sorry for my english,but ur code has a bug.
Mat roi = new Mat(resized, new Rect(0, 0, col, row));
image copied to roi,but this mat not related with resized Mat.so u have to do like this:
Rect roi=new Rect(0,0,width,height);
source.copyto(resized.submat(roi));

threshold depth distance in image opencvsharp c# intel realsense

This maybe a stupid question but how can you make a threshold so that the depth distance of the camera can get changed. Now I am using the Cv2.threshold to to that but with the otsu method the whole picture changes to one color instead of different kinds of a color.
The code used:
var colorizedDepth = colorizer.Process<VideoFrame>(depthFrame).DisposeWith(frames);
Mat testcd = new Mat(colorizedDepth.Height, colorizedDepth.Width, MatType.CV_8UC3, colorizedDepth.Data);
Mat testgd = new Mat();
Cv2.CvtColor(testcd, testgd, ColorConversionCodes.RGBA2GRAY);
Mat testbd = new Mat();
Cv2.Threshold(testgd, testbd, 0, 255, ThresholdTypes.Otsu | ThresholdTypes.Binary);
Cv2.ImShow("camera", testgd);
Cv2.WaitKey(0);
The code to get the colored depth is from the wrapper librealsense:
https://github.com/IntelRealSense/librealsense/tree/master/wrappers/csharp
Does anyone know what I am doing wrong for the threshold so that the depth distances get changed?

EmguCV - Fisheye Calibration

For a school project, I am trying to calibrate a Dahua IP Camera, which has Fisheye distortion.
We need to calibrate the camera to undistort the image, because we need a flat image to do image processing.
So far, we have managed to do the calibration in Python with OpenCV, but the rest of the script is written in C#, so we would like to convert the code to C# using the EmguCV wrapper (OpenCV for .NET)
Correct me if I'm wrong, but so far I have done these steps:
I took 50 pictures of a Chessboard Grid, which is used to find the Corners
I let OpenCV calculate the correct matrices, one called CameraMatrix and the other is the Distortion Coëfficiënts.
With the 2 calculated matrices, we then Undistort an image, and the result is a flat image with no distortion.
In Python, this code works. I get 2 matrices that works to undistort.
I tried to copy these matrices in C#, without doing the rest of the Calibration. Since it's the same camera setup, the Distortion should be the same.
However, when I try to hardcode the matrices, the result is not what I want.
Could it be an issue related to EmguCV (The wrapper of OpenCV for .NET), or is it something related to my code?
Python Code
img = cv2.imread(filename)
K = np.array(...) # removed for brevity
D = np.array(...) # removed for brevity
DIM = (width, height) # image resolution
map1, map2 = cv2.fisheye.initUndistortRectifyMap(K, D, np.eye(3), K, DIM, cv2.CV_16SC2)
undistorted_img = cv2.remap(img, map1, map2, interpolation=cv2.INTER_LINEAR, borderMode=cv2.BORDER_CONSTANT)
C# code
Matrix<double> cameraMatrix = new Matrix<double>(3, 3);
Matrix<double> distortionCoeffs = new Matrix<double>(4, 1);
Mat outputMap1 = new Mat();
Mat outputMap2 = new Mat();
Mat r = new Mat(); // Can be empty, according to the documentation
Mat p = new Mat(); // Can be empty, according to the documentation
Fisheye.InitUndistorRectifyMap(cameraMatrix, distortionCoeffs, r, p, image.Size, DepthType.Cv32F, outputMap1, outputMap2);
CvInvoke.Remap(image, undistorted, outputMap1, outputMap2, Inter.Linear, BorderType.Constant);

Emgu CV to Detect Circular Cookies on a Baking Sheet

I'm fairly new to image processing and that being said, I was hoping someone could tell me if I am on the right track and if not, point me in the right direction and/or provide some code samples.
The requirements I am working on:
Detect the number of cookies on a baking sheet.
The cookies can be any color.
The cookies may be covered in chocolate (white or black) in which case they will have a mess of chocolate around each cookies meaning doing a simple contrast check probably won't work.
The cookies will not overlap but they may touch one another.
I am trying to use the Emgu CV library with HoughCirlces but I am getting mixed results. Here is my code using winforms and C# in which I load an image of cookies on a baking sheet and run it on (I am not confident in my values).
Am I on the right track? Any ideas? Code samples?
Below are some test images:
http://imgur.com/a/dJmU6, followed by my code
private int GetHoughCircles(Image image)
{
Bitmap bitmap = new Bitmap(image);
Image<Bgr, Byte> img = new Image<Bgr, byte>(bitmap).Resize(466, 345, Emgu.CV.CvEnum.INTER.CV_INTER_CUBIC);
//Get and sharpen gray image (don't remember where I found this code; prob here on SO)
Image<Gray, Byte> graySoft = img.Convert<Gray, Byte>().PyrDown().PyrUp();
Image<Gray, Byte> gray = graySoft.SmoothGaussian(3);
gray = gray.AddWeighted(graySoft, 1.5, -0.5, 0);
Image<Gray, Byte> bin = gray.ThresholdBinary(new Gray(149), new Gray(255));
Gray cannyThreshold = new Gray(150);
Gray cannyThresholdLinking = new Gray(120);
Gray circleAccumulatorThreshold = new Gray(50);
Image<Gray, Byte> cannyEdges = bin.Canny(cannyThreshold.Intensity, cannyThresholdLinking.Intensity);
//Image<Gray, Byte> cannyEdges = bin.Canny(cannyThreshold, cannyThresholdLinking);
//Circles
CircleF[] circles = cannyEdges.HoughCircles(
cannyThreshold,
circleAccumulatorThreshold,
3.0, //Resolution of the accumulator used to detect centers of the circles
50.0, //min distance
20, //min radius
30 //max radius
)[0]; //Get the circles from the first channel
//draw circles (on original image)
foreach (CircleF circle in circles)
{
img.Draw(circle, new Bgr(Color.Brown), 2);
}
pictureBox1.Image = new Bitmap(img.ToBitmap());
return circles.Count();
}

OCR Line detecting

I am trying to detectect the bounding box of sentences in an Image. I am using Emgu OpenCV in C# using HougLinesP method to extract lines, but I am obviously doing something wrong. I have looked at many examples and estimate the skew level with houghLines is pretty much what I am trying to do.
Using that sample image I do some pre-processing (Thresholding, canny, ect) and end up with http://snag.gy/sWCuO.jpg, but then when I do HoughLines and draw the lines on the original image, I get http://snag.gy/ESKmR.jpg .
Here is an extract of my code:
using (MemStorage stor = new MemStorage())
{
Image<Hsv, byte> imgHSV = new Image<Hsv, byte>(bitmap);
Image<Gray, Byte> gray = imgHSV.Convert<Gray, Byte>().PyrDown().PyrUp();
CvInvoke.cvCanny(gray, EdgeMap, 100, 400, 3);
IntPtr lines = CvInvoke.cvHoughLines2(EdgeMap, stor,
Emgu.CV.CvEnum.HOUGH_TYPE.CV_HOUGH_PROBABILISTIC, 1, Math.PI / 360, 10,
gray.Width / 4, 20);
Seq<LineSegment2D> segments = new Seq<LineSegment2D>(lines, stor);
ar = segments.ToArray();
}
Graphics g = Graphics.FromImage(OriginalImage);
foreach (LineSegment2D line in ar)
{
g.DrawLine(new Pen(Color.Blue),
new Point(line.P1.X, line.P1.Y),
new Point(line.P2.X, line.P2.Y));
}
g.Save();
Any help would be appreciated.

You can try two approaches:
1- Utilize the frequency domain. Example here
2- After pre-processing, extract the contours, collect all the points (or at least collect all points that are not black); find the minimum bounding rectangle with its angle. Example here