I have an algorithm in created in c++ to make background subtraction, and i want to call it from c# with an argument "IplImage" using dll(extern). The problem that i acquire the camera stream in c# and i have the frame as image (bitmap).
How could i convert the bitmap to IplImage to send it in c++ and vice versa to retrieve the frame treated?
Many thanks.
Using Emgucv, you can try
Bitmap bitmap = ....
Emgu.CV.Image<Bgr, Byte> img = new Image<Bgr, byte>(bitmap);
Emgu.CV.Structure.MIplImage = img.MIplImage;
to send it in C++ method you can pass it as IntPtr object
IntPtr r = IntPtr.Zero;
System.Runtime.InteropServices.Marshal.StructureToPtr(img, r, false);
// call your c++ method
...
also see detail about Marshal
Related
Suppose we have the following color:
const Scalar TRANSPARENT2 = Scalar(255, 0, 255,0);
which is magenta but fully transparent: alpha = 0 (to be fully opaque is 255).
Now I made the following test based on:
http://blogs.msdn.com/b/lucian/archive/2015/12/04/opencv-first-version-up-on-nuget.aspx
WriteableBitmap^ Grabcut::TestTransparent()
{
Mat res(400,400, CV_8UC4);
res.setTo(TRANSPARENT2);
WriteableBitmap^ wbmp = ref new WriteableBitmap(res.cols, res.rows);
IBuffer^ buffer = wbmp->PixelBuffer;
unsigned char* dstPixels;
ComPtr<IBufferByteAccess> pBufferByteAccess;
ComPtr<IInspectable> pBuffer((IInspectable*)buffer);
pBuffer.As(&pBufferByteAccess);
pBufferByteAccess->Buffer(&dstPixels);
memcpy(dstPixels, res.data, res.step.buf[1] * res.cols * res.rows);
return wbmp;
}
The issue I have is that the image created is not fully transparent, it has a bit of alpha:
I understand there is a fila in the memcpy data, but I am not really sure about how to solve this. any idea to get it to alpha 0?
more details
To see I saving the image could then read and test if it works, I saw that the imwrite contains an snippet about transparency like in the image, but well imwrite is not implemented yet. But the transparency method is not working neither.
Any light with this snippet?
Thanks.
Finally I did the conversion in the C# code, first avoid calling CreateAlphaMat.
Then what I did is use a BitmapEncoder to convert data:
WriteableBitmap wb = new WriteableBitmap(bitmap.PixelWidth, bitmap.PixelHeight);
using (IRandomAccessStream stream = new InMemoryRandomAccessStream())
{
BitmapEncoder encoder = await BitmapEncoder.CreateAsync(BitmapEncoder.PngEncoderId, stream);
Stream pixelStream = bitmap.PixelBuffer.AsStream();
byte[] pixels = new byte[pixelStream.Length];
await pixelStream.ReadAsync(pixels, 0, pixels.Length);
encoder.SetPixelData(BitmapPixelFormat.Bgra8, BitmapAlphaMode.Premultiplied,
(uint)bitmap.PixelWidth, (uint)bitmap.PixelHeight, 96.0, 96.0, pixels);
await encoder.FlushAsync();
wb.SetSource(stream);
}
this.MainImage.Source = wb;
where bitmap is the WriteableBitmap from the OpenCV result. And now the image is fully transparent.
NOTE: Do not use MemoryStream and then .AsRandomAccessStream because it won't FlushAsync
I need to process images which i get from OpenCV.
I wrote so far:
IplImage* img=0;
img=cvLoadImage("paket2.tif");
api.SetRectangle(0,0,img->width, img->height);
api.SetImage((uchar*)img->imageData,img->width,img->height,img->depth/8,img->width*(img->depth/8));
//i tried also below line
//api.SetImage((uchar*)img->imageData,img->width,img->height,img->depth/8,img->widthStep);
int left,top,right,bottom;
left=0;top=0;right=0;bottom=0;
api.Recognize(NULL);
tesseract::ResultIterator *ri=api.GetIterator();
char * sonuc=(*ri).GetUTF8Text(tesseract::RIL_SYMBOL);
if((*ri).BoundingBox(tesseract::RIL_SYMBOL,&left,&top,&right,&bottom))
{printf("bb dogru\n");printf("%d,%d,%d,%d",left,top,right,bottom);}
printf("sonuc:%s",sonuc);
if i pass IplImage->widthStep to bytes perline, i have "wrong" boundingBox in left and right values and can not read all the text in the image.
if i pass IplImage->width*(IplImage->depth/8), boundingBox function returns false.
I hope you have some idea.
Thanks in advance.
Copy your submatrix to a new IplImage. Create a tesseract image header with the correct info(width, height, step). Link the tesseract data pointer to the iplImage data pointer.
I can't remember how to access tesseract pointer, but for opencv is image->data.ptr
This code here worked for me:
tesseract::TessBaseAPI tess;
tess.Init(argv[0], "eng", tesseract::OEM_DEFAULT);
cv::Mat image = cv::imread("...");
tess.SetImage((uchar*)image .data, image.size().width, image.size().height, image.channels(), image.step1());
tess.Recognize(0);
const char* out = tess.GetUTF8Text();
Suppose i have an animated GIF image name test.GIF added to my project in BlackBerry JDE to be used in AnimatedGIFField class. and now i need to convert it to Encoded image.
In the reference it is given to create encoded image the following function
public static EncodedImage createEncodedImage(byte[] data,
int offset,
int length)
Plz give me the code to convert test.GIF to encoded image????
use this code
EncodedImage encImg = GIFEncodedImage.getEncodedImageResource("test.gif");
if you need GIFEncodedImage then cast encImg to GIFEncodedImage.
GIFEncodedImage img = (GIFEncodedImage) encImg;
By the way, casting EncodedImage to GIFEncodedImage fails on OS7. You have to rename your gif extension to .agif to make it work.
I simply want to convert an Emgu.Cv.Image<,> from a pointer, I am using the following code:
Size img = CvInvoke.cvGetSize(frame);
Image<Bgr, Byte> tImg = new Image<Bgr, byte>(img.Width, img.Height, 0, frame);
I don't know what value to give in 3rd parameter of Image<,> constructor that takes a pointer. It says Size of aligned image row in bytes what does that mean?
Note that image width has to be a multiple of 4 since some OpenCV code optimization is based on this assumption when CVImage is constructed from a memory 1D array.
I have a pointer to image:
IplImage *img;
which has been converted to Mat
Mat mt(img);
Then, the Mat is sent to a function that gets a reference to Mat as input void f(Mat &m);
f(mt);
Now I want to copy back the Mat data to the original image.
Do you have any suggestion?
Best
Ali
Your answer can be found in the documentation here: http://opencv.willowgarage.com/documentation/cpp/c++_cheatsheet.html
Edit:
The first half of the first code area indeed talks about the copy constructor which you already have.
The second half of the first code area answers your question. Reproduced below for clarity.
//Convert to IplImage or CvMat, no data copying
IplImage ipl_img = img;
CvMat cvmat = img; // convert cv::Mat -> CvMat
For the following case:
double algorithm(IplImage* imgin)
{
//blabla
return erg;
}
I use the following way to call the function:
cv::Mat image = cv::imread("image.bmp");
double erg = algorithm(&image.operator IplImage());
I have made some tests and how it looks the image object will manage the memory. The operator IplImage() will only construct the header for IplImage. Maybe this could be useful?
You can use this form:
Your Code:
plImage *img;
Mat mt(img);
f(mt);
Now copy back the Mat data to the original image.
img->imageData = (char *) mt.data;
You can also copy the data instead of pointer:
memcpy(mt.data, img->imageData, (mt.rows*mt.cols));
(mt.rows*mt.cols) is the size that you should use for copy all data the mt to img.
Hope I helped