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));
Related
I'm making a labeling tool.
Goal :By drawing a polygon on the picture, you have to export the image inside the polygon to the outside.
example
extract
This is what I drew in the my program.
But I don't know how to extract this region. I want to know how to extract this area.
I have saved the vertices of the picture above in an object. But I don't know how to extract data from the image through these vertices
========================================
So I found this.
https://www.codeproject.com/Articles/703519/Cropping-Particular-Region-In-Image-Using-Csharp
but it is not work
Can't convert Bitmap to IplImage
It doesn't work for the same reason.
In the post, I am going to use opencvsharp 4.x, but the program I am fixing now is .netframework 3.5, so it does not support opencvsharp 4.x.
What should I do?
============================
I made a function referring to the answer, but it doesn't work...
I want to know why.
void CropImage(Bitmap bitmap, Point[] points)
{
Rectangle rect = PaddingImage(points, bitmap);
TextureBrush textureBrush = new TextureBrush(bitmap);
Bitmap bmp1 = new Bitmap(rect.Width, rect.Height);
using (Graphics g = Graphics.FromImage(bmp1))
{
g.FillPolygon(textureBrush, points);
}
string ima_path = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);
bmp1.Save(ima_path + "\\Image.png", ImageFormat.Png);
}
extract Image
original
If you use a small polygon, there is no output at all.
You will notice that the two images are slightly different.
It seems to me that the part where the center point is cut and extracted is different. I don't know if what I was thinking is correct.
You would create a new bitmap, at least as large as the bounding box of your polygon. Create a graphics object from this new bitmap. You can then draw the polygon to this bitmap, using the original image as a texture brush. Note that you might need to apply transform matrix to translate from the full image coordinates to the cropped image coordinates.
Note that it looks like you have radiological images. These are typically 16 bit images, so they will need to be converted to 8bit mono, or 24bit RGB before they can be used. This should already be done in the drawing code if you have access to the source. Or you can do it yourself.
this works for me
private Bitmap CropImage(Bitmap bitmap, List<Point> points)
{
int pminx = 9999, pminy = 9999, pmaxx = 0, pmaxy = 0; System.Drawing.Point[] pcol = new System.Drawing.Point[points.Count]; int i = 0;
foreach (Point pc in points)
{
if (pc.X > pmaxx) pmaxx = (int)pc.X;
if (pc.Y > pmaxy) pmaxy = (int)pc.Y;
if (pc.X < pminx) pminx = (int)pc.X;
if (pc.Y < pminy) pminy = (int)pc.Y;
pcol[i] = new System.Drawing.Point((int)pc.X, (int)pc.Y);
i++;
}
TextureBrush textureBrush = new TextureBrush(bitmap);
Bitmap bmpWrk = new Bitmap(bitmap.Width, bitmap.Height);
using (Graphics g = Graphics.FromImage(bmpWrk))
{
g.FillPolygon(textureBrush, pcol);
}
System.Drawing.Rectangle CropRect = new System.Drawing.Rectangle(pminx, pminy, pmaxx - pminx, pmaxy - pminy);
return bmpWrk.Clone(CropRect, bmpWrk.PixelFormat);
}
Well I am not able to get good accuracy of text detection in tesseract. Please check code and image below.
Mat imgInput = CvInvoke.Imread(#"D:\workspace\raw2\IMG_20200625_194541.jpg", ImreadModes.AnyColor);
int kernel_size = 11;
//Dilation
Mat imgDilatedEdges = new Mat();
CvInvoke.Dilate(
imgInput,
imgDilatedEdges,
CvInvoke.GetStructuringElement(
ElementShape.Rectangle,
new Size(kernel_size, kernel_size),
new Point(1, 1)),
new Point(1, 1),
1,
BorderType.Default,
new MCvScalar(0));
//Blur
Mat imgBlur = new Mat();
CvInvoke.MedianBlur(imgDilatedEdges, imgBlur, kernel_size);
//Abs diff
Mat imgAbsDiff = new Mat();
CvInvoke.AbsDiff(imgInput, imgBlur, imgAbsDiff);
Mat imgNorm = imgAbsDiff;
//Normalize
CvInvoke.Normalize(imgAbsDiff, imgNorm, 0, 255, NormType.MinMax, DepthType.Default);
Mat imgThreshhold = new Mat();
//getting threshhold value
double thresholdval = CvInvoke.Threshold(imgAbsDiff, imgThreshhold, 230, 0, ThresholdType.Trunc);
//Normalize
CvInvoke.Normalize(imgThreshhold, imgThreshhold, 0, 255, NormType.MinMax, DepthType.Default);
imgThreshhold.Save(#"D:\workspace\ocr_images\IMG_20200625_194541.jpg");
//contrast correction
Mat lab = new Mat();
CvInvoke.CvtColor(imgThreshhold, lab, ColorConversion.Bgr2Lab);
VectorOfMat colorChannelB = new VectorOfMat();
CvInvoke.Split(lab, colorChannelB);
CvInvoke.CLAHE(colorChannelB[0], 3.0, new Size(12, 12), colorChannelB[0]);
Mat clahe = new Mat();
//merge
CvInvoke.Merge(colorChannelB, clahe);
Image<Bgr, byte> output = new Image<Bgr, byte>(#"D:\workspace\ocr_images\IMG_20200625_194541.jpg");
Bitmap bmp = output.ToBitmap();
//setting image to 300 dpi since tesseract likes that
bmp.SetResolution(300, 300);
bmp.Save(#"D:\workspace\ocr_images\IMG_20200625_194541.jpg");
I am not getting expected accuracy. Please check how image is converted.
source image
converted image
I have posted few images above that you can refer. For first image i am getting garbage data. For last two images i am getting partial data.
Converting image to gray scale and playing with threshold gives better output.
I want to understand that if in case threshold is the key part then how i will be able to get dynamic threshhold value for each new image? It is going to work as service so user will simply pass the image and get the result. My app should be intelligent enough to process and understand image.
Do i have to adjust contrast, threshold more accurately? If yes how i will do that? or image itself is faulty I mean noise causing problem.
Please let me know what i am doing wrong in the algorithm or anything which will help me to understand issue. Any one who is aware of please tell me what should be ideal steps for image preprocessing for OCR?
I am using csharp, emucv and tesseract.
Any suggestion will be highly appreciated.
I have been trying to get the section of an image by giving the coordinates of the image. Here is the code that extracts image from the original image.
private byte[] ExtractImageSection(Bitmap originalMap, ImagePart imgPart)
{
Bitmap imageSection = new Bitmap(imgPart.Width, imgPart.Height);
int top = Math.Min(imgPart.Y1, imgPart.Y2);
int bottom = Math.Max(imgPart.Y1, imgPart.Y2);
int left = Math.Min(imgPart.X1, imgPart.X2);
int right = Math.Max(imgPart.X1, imgPart.X2);
Rectangle cloneRect = Rectangle.FromLTRB(left, top, right, bottom);
Graphics g = Graphics.FromImage(imageSection);
// Draw the given area (section) of the source image
// at location 0,0 on the empty bitmap (imageSection)
//g.DrawImage(originalMap, 0, 0, cloneRect, GraphicsUnit.Pixel);
g.DrawImage(originalMap, cloneRect, 0, 0, imgPart.Width, imgPart.Height, GraphicsUnit.Pixel);
/* Code Commented - Clone Bitmap method
int top = Math.Min(imgPart.Y1, imgPart.Y2);
int bottom = Math.Max(imgPart.Y1, imgPart.Y2);
int left = Math.Min(imgPart.X1, imgPart.X2);
int right = Math.Max(imgPart.X1, imgPart.X2);
Rectangle cloneRect = Rectangle.FromLTRB(left, top, right, bottom);
System.Drawing.Imaging.PixelFormat pixelFormat = originalMap.PixelFormat;
Bitmap imageSection = (Bitmap)originalMap.Clone(cloneRect, pixelFormat);*/
imageSection.Save(pageImageLocation + imgPart.ImagePartName, ImageFormat.Png);
byte[] imageSectionByte = ConvertBitmapIntoByte(imageSection);
return imageSectionByte;
}
The commented code represents the ways that I've used so far to achieve my goal. I used the following stack-overflow link to try to fix the issue but I still did not work. Here is the original image (originalMap)
Above function tries to get the highlighted section. The function gets X1, Y1, X2, Y2, Width, Heigth from front end. To get the required values I am using
imgAreaSelect
Things I have done so far to figure out the issue
I have also debugged the code to verify the coordinates, width, and
height of the extracted part. (they were correct)
Tried variants of DrawImage from Graphics class.
Tried Clone method of Bitmap to clone the original image based on the section coordinates as you can see the commented code.
Here is the image after the extract method.
Can anyone please help me figure out this workaround of the issue?
I'm trying to access image pixels by position i have been use byte array for accessing but it does not give the correct position of x,y like python image[x][y] is there any better way to access pixels?
i have used opencv plugin in unity,visual studio and cannot access them
public texture2D image;
Mat imageMat = new Mat(image.height, image.width, CvType.CV_8UC4);
Utils.texture2DToMat(image, imageMat); // actually converts texture2d to matrix
byte[] imageData = new byte[(int)(imageMat.total() * imageMat.channels())]; // pixel data of image
imageMat.get(0, 0, imageData);// gets pixel data
pixel=imageData[(y * imageMat.cols() + x) * imageMat.channels() + r]
y and x are pixel values in the code and r is the channel but i'm not able to
access a particular value of x and y with that code
There is no usual way to do it because operation is really slow. But some trick to do it is you can make screen texture from 'Camera' class.
After you make texture, you can use texture.GetPixel(x,y)
public class Example : MonoBehaviour
{
// Take a "screenshot" of a camera's Render Texture.
Texture2D RTImage(Camera camera)
{
// The Render Texture in RenderTexture.active is the one
// that will be read by ReadPixels.
var currentRT = RenderTexture.active;
RenderTexture.active = camera.targetTexture;
// Render the camera's view.
camera.Render();
// Make a new texture and read the active Render Texture into it.
Texture2D image = new Texture2D(camera.targetTexture.width, camera.targetTexture.height);
image.ReadPixels(new Rect(0, 0, camera.targetTexture.width, camera.targetTexture.height), 0, 0);
image.Apply();
// Replace the original active Render Texture.
RenderTexture.active = currentRT;
return image;
}
}
Hi I have the issue that when I use ScaleTransform(zoomFactor,zoomFactor) the image saved on disk is the original version always, while on screen in the picturebox the image is distorted in proportion to the zoomFactor.
Why this could be happening ? Shouldn't I have the final result as applied from e.Graphics on disk written image ?
My code is the following which is a version with matrix. but the instead of matrix I have used the ScaleTransform as well. Result is always the same:
g=e.Graphics;//inside picturebox_paint()
g.ScaleTransform(ratio * zoomFac, ratio * zoomFac);
e.Graphics.DrawImage((Bitmap)bmp, 0, 0);
int seed = Convert.ToInt32(Regex.Match(Guid.NewGuid().ToString(), #"\d+").Value);
String destinationFile = #"C:\tmp\photoid\" + new Random(seed).Next() + "_conv.jpg";
//Here I get always the original image back!!!!
bmp.Save(destinationFile);
I have used as well the following idiom but with same results:
//Matrix matrix = new Matrix();
//matrix.Scale(zoomFac, zoomFac);
//e.Graphics.Transform = matrix;
You need to make the PictureBox draw the things it shows on screen into a new Bitmap, which you then can save!
As it is the Image will be saved in the original form and nothing you did in the Paint event, which actually painst onto the surface of the PictureBox will be saved.
So to save everything, i.e. The Image, possibly a BackgroundImage and all you draw in the Paint event you would call DrawToBitmap somehwere.
Somewhere means somewhere else, not in the Paint event, as it will call the Paint event to create the new Bitmap, causing an endless loop..
To call it you would do something like this:
Bitmap bmpSave = new Bitmap(pictureBox1.ClientSize.Width, pictureBox1.ClientSize.Height);
pictureBox1.DrawToBitmap(bmpSave, pictureBox1.ClientRectangle);
But maybe this is not really what you want? Maybe you actually want to modify the Image? In that case do not use the Paint event at all!
Instead do something like this:
Bitmap bmpSave = new Bitmap(yourNewWidth, yourNewHeight);
using (Graphics g = Graphics.FromImage(bmpSave))
{
g.ScaleTransform(ratio * zoomFac, ratio * zoomFac);
g.DrawImage((Bitmap)pictureBox1.Image, 0, 0); //
pictureBox1.Image = bmpSave;
bmpSave.Save(...);
}
You could call this from somewhere where the scaling is being triggered from.
Note that doing the scaling repeatedly and each time from the previoulsy scaled version will degrade the quality rather fast. For this always scale from a saved version of the original!!
Btw: Using a Matrix for scaling doesn't really make a difference over ScaleTransform.
But if you want to do a direct scaling why not use the DrawImage overload which takes two Rectangles? This is the most common solution if all you want to to scale and maybe draw other stuff additionally..:
int newWidth = 100; int newHeight = 100; string yourFileName = "D:\\xyz123.jpg";
Bitmap bmpSave = new Bitmap(pictureBox1.ClientSize.Width, pictureBox1.ClientSize.Height);
Rectangle newRectangle = new Rectangle(0, 0, newWidth, newHeight);
Rectangle oldRectangle = new Rectangle(Point.Empty, pictureBox1.Image.Size);
using (Graphics g = Graphics.FromImage(bmpSave))
{
g.DrawImage((Bitmap)pictureBox1.Image, newRectangle, oldRectangle, GraphicsUnit.Pixel);
bmpSave.Save(yourFileName, ImageFormat.Jpeg);
}
And there there is the scaling Bitmap constructor:
Bitmap bmp = new Bitmap(pictureBox1.Image, newWidth, newHeight);
Which I would recommend if all you want is to scale the Image. As the other solutions it will not change the Image displayed until you assign it back into the PictureBox..:
pictureBox1.Image = bmp ;
Don't forget to dispose of the old Image..
Been a while since I messed with GDI but I think you need to copy back to the Bitmap here.
g.DrawImage(bmp, scaledwidth, scaledheight);
Try something like that before bmp.Save
Edit
Apologies for not seeing that you were copying back to the bitmap. Perhaps the overload which specifies the output rectangle is what you need. Try a DrawImage overload which has the destination Rect. https://msdn.microsoft.com/en-us/library/ms142040(v=vs.110).aspx