I know this "looks" like a duplicate question, but -- it's not answered in any definitive way that I can see.
In C++, OpenCv operation to init a Mat can be done like so:
float[,] camera = new float[,] {
{ 857.483f, 0.0f, 968.06f },
{ 0.0f, 876.72f, 556.37f },
{ 0.0f, 0.0f, 1.0f }
};
A = Mat(3,3, CV_32FC1, &camera);
Note that the array is 2D.
Now, I want to accomplish the same thing in EMGU, //using managed C#; so Mat is constructed as:
Mat _cameraMatrix = new Mat(3, 3, DepthType.Cv64F, 1);
// and a similar 1D Mat:
Mat _distCoeffs = new Mat(8, 1, DepthType.Cv64F, 1);
// to be passed to the method:
CvInvoke.Undistort(bkgimage, ndimage, _cameraMatrix, _distCoeffs);
Unlike cv::Mat, EMGU Mat's constructor doesn't seem to have an obvious way to get that 2D "camera" data into it. Anyone have any success getting this kind of code to work?
Funnily enough, I came across this question while trying to solve exactly the same problem - camera calibration.
There's an easier but much less elegant method to solve this:
Image<Gray, float> camImage = new Image<Gray, float>(new float[,,]
{
{intrinsics.fx}, {0}, {intrinsics.ppx}},
{ {0}, {intrinsics.fy}, {intrinsics.ppy}},
{ {0}, {0}, {1} }
});
var camMatrix = camImage.Mat;
Image<Gray, float> distImage = new Image<Gray, float>(new float[,,] {{{0},{0},{0},{0}}});
var distCoeffs = distImage.Mat;
Not sure it's the best answer, but it's an answer.
According to the EmguCV documentation, there is a constructor that takes an IntPr as 'data':
see http://www.emgu.com/wiki/files/3.4.3/document/html/c8424736-2d44-c5d6-212f-31dedfe6fb95.htm
The problem is how to get that pointer. Here, maybe this post will help you:
How to get IntPtr from byte[] in C#
Hopefully, this will get you at least started.
Related
Is any one know how i can convert Mat to IplImage ?
to achieve this i have converted Mat to BufferedImage but again not able to find conversion in BufferedImage to IplImage.
is there any way where i can convert Mat to IplImage?
Thanks
I believe you can convert BufferedImage to IplImage as follows.
public static IplImage toIplImage(BufferedImage src) {
Java2DFrameConverter bimConverter = new Java2DFrameConverter();
OpenCVFrameConverter.ToIplImage iplConverter = new OpenCVFrameConverter.ToIplImage();
Frame frame = bimConverter.convert(src);
IplImage img = iplConverter.convert(frame);
IplImage result = img.clone();
img.release();
return result;
}
I got this from this question. Try this for now. I'll check if direct conversion is possible.
UPDATE:
Please have a look at this api docs. I haven't tested the following. Wrote it just now. Please do try and let me know.
public static IplImage toIplImage(Mat src) {
OpenCVFrameConverter.ToIplImage iplConverter = new OpenCVFrameConverter.ToIplImage();
OpenCVFrameConverter.ToMat matConverter = new OpenCVFrameConverter.ToMat();
Frame frame = matConverter.convert(src);
IplImage img = iplConverter.convert(frame);
IplImage result = img.clone();
img.release();
return result;
}
I have Tesseract 3.04 static build and am trying to extract orientation info using the code provided in official samples:
const char* inputfile = "/usr/src/tesseract/testing/eurotext.tif";
tesseract::Orientation orientation;
tesseract::WritingDirection direction;
tesseract::TextlineOrder order;
float deskew_angle;
PIX *image = pixRead(inputfile);
tesseract::TessBaseAPI *api = new tesseract::TessBaseAPI();
api->Init("/usr/src/tesseract/", "eng");
api->SetPageSegMode(tesseract::PSM_AUTO_OSD);
api->SetImage(image);
api->Recognize(0);
tesseract::PageIterator* it = api->AnalyseLayout();
it->Orientation(&orientation, &direction, &order, &deskew_angle);
printf("Orientation: %d;\nWritingDirection: %d\nTextlineOrder: %d\n" \
"Deskew angle: %.4f\n",
orientation, direction, order, deskew_angle);
My application crashes on extraction on the following line:
it->Orientation(&orientation, &direction, &order, &deskew_angle);
What is going wrong in this code?
Thanks!
If you are interesting in orientation info you can use leptonica instead. IMO it should be faster. See example
I found orientation in tesserect by below code and it returns 0,1(=90),2(=180),3(=270) orientated sides
#include <osdetect.h>
#include <baseapi.h>
#include <allheaders.h>
int main()
{
TessBaseAPI *tessBaseAPI = new TessBaseAPI();
tessBaseAPI ->Init("/tessdataPath/", "eng"))
Pix *image = pixRead(imagePath);
tessBaseAPI->SetImage(image);
//orientation
OSResults os_results;
tessBaseAPI->DetectOS(&os_results);
int orientationType=os_results.best_result.orientation_id
pixDestroy(&image);
return 0;
}
I'm working on a project where I want to track a dice with the Microsoft Kinect using the AForge.NET-Library.
The project itself contains only the fundamentals such as initializing the Kinect, obtaining a Colorframe and applying one color filter but there already the problem occurs.
So here is the main part of the program:
void ColorFrameReady(object sender, ColorImageFrameReadyEventArgs e)
{
using (ColorImageFrame colorFrame = e.OpenColorImageFrame())
{
if (colorFrame != null)
{
colorFrameManager.Update(colorFrame);
BitmapSource thresholdedImage =
diceDetector.GetThresholdedImage(colorFrameManager.Bitmap);
if (thresholdedImage != null)
{
Display.Source = thresholdedImage;
}
}
}
}
The 'Update'-method of the 'colorFrameManager'-object looks like this:
public void Update(ColorImageFrame colorFrame)
{
byte[] colorData = new byte[colorFrame.PixelDataLength];
colorFrame.CopyPixelDataTo(colorData);
if (Bitmap == null)
{
Bitmap = new WriteableBitmap(colorFrame.Width, colorFrame.Height,
96, 96, PixelFormats.Bgr32, null);
}
int stride = Bitmap.PixelWidth * Bitmap.Format.BitsPerPixel / 8;
imageRect.X = 0;
imageRect.Y = 0;
imageRect.Width = colorFrame.Width;
imageRect.Height = colorFrame.Height;
Bitmap.WritePixels(imageRect, colorData, stride, 0);
}
And the 'getThresholdedImage'-method looks like this:
public BitmapSource GetThresholdedImage(WriteableBitmap colorImage)
{
BitmapSource thresholdedImage = null;
if (colorImage != null)
{
try
{
Bitmap bitmap = BitmapConverter.ToBitmap(colorImage);
HSLFiltering filter = new HSLFiltering();
filter.Hue = new IntRange(335, 0);
filter.Saturation = new Range(0.6f, 1.0f);
filter.Luminance = new Range(0.1f, 1.0f);
filter.ApplyInPlace(bitmap);
thresholdedImage = BitmapConverter.ToBitmapSource(bitmap);
}
catch (Exception ex)
{
System.Console.WriteLine(ex.Message);
}
}
return thresholdedImage;
}
Now the program slows down a lot/ doesn't respond when this line is executed:
filter.ApplyInPlace(bitmap);
So I already read this thread (C# image processing on Kinect video using AForge) and I tried EMGU but I couldn't get it to work because of inner exceptions and as the thread-starter wasn't online since four months my question to have a look at his working code wasn't answered.
Now firstly I'm intereseted in how the reason for the slow execution can be
filter.ApplyInPlace(bitmap);
Is this image processing really so complex? Or could this be a problem with my enviroment?
Secondly I would like to ask if skipping frames is a good solution? Or is it better to use polling and open frames only every - for instance - 500 milliseconds.
Thank you very much!
The HSL filter would not slow down the computation, is not an complex Filter.
Im utilizing it in 320x240 images with 30 fps without problems.
The problem may be in the resolution of the computed image or in a too high frame rate!
If the resolution of the image is high, i suggest to resize it before any filter application.
And i think a framerate of 20 (and maybe less) is enough to tracking a dice.
I am trying to save an OpenCV image to the hard drive.
Here is what I tried:
public void SaveImage (Mat mat) {
Mat mIntermediateMat = new Mat();
Imgproc.cvtColor(mRgba, mIntermediateMat, Imgproc.COLOR_RGBA2BGR, 3);
File path =
Environment.getExternalStoragePublicDirectory(
Environment.DIRECTORY_PICTURES);
String filename = "barry.png";
File file = new File(path, filename);
Boolean bool = null;
filename = file.toString();
bool = Highgui.imwrite(filename, mIntermediateMat);
if (bool == true)
Log.d(TAG, "SUCCESS writing image to external storage");
else
Log.d(TAG, "Fail writing image to external storage");
}
}
Can any one show how to save that image with OpenCV 2.4.3?
Your question is a bit confusing, as your question is concerning OpenCV on the desktop, but your code is for Android, and you ask about IplImage, but your posted code is using C++ and Mat. Assuming you're on the desktop using C++, you can do something along the lines of:
cv::Mat image;
std::string image_path;
//load/generate your image and set your output file path/name
//...
//write your Mat to disk as an image
cv::imwrite(image_path, image);
...Or for a more complete example:
void SaveImage(cv::Mat mat)
{
cv::Mat img;
cv::cvtColor(...); //not sure where the variables in your example come from
std::string store_path("..."); //put your output path here
bool write_success = cv::imwrite(store_path, img);
//do your logging...
}
The image format is chosen based on the supplied filename, e.g. if your store_path string was "output_image.png", then imwrite would save it was a PNG image. You can see the list of valid extensions at the OpenCV docs.
One caveat to be aware of when writing images to disk with OpenCV is that the scaling will differ depending on the Mat type; that is, for floats the images are expected to be within the range [0, 1], while for say, unsigned chars they'll be from [0, 256).
For IplImages, I'd advise just switching to use Mat, as the old C-interface is deprecated. You can convert an IplImage to a Mat via cvarrToMat then use the Mat, e.g.
IplImage* oldC0 = cvCreateImage(cvSize(320,240),16,1);
Mat newC = cvarrToMat(oldC0);
//now can use cv::imwrite with newC
alternately, you can convert an IplImage to a Mat just with
Mat newC(oldC0); //where newC is a Mat and oldC0 is your IplImage
Also I just noticed this tutorial at the OpenCV website, which gives you a walk-though on loading and saving images in a (desktop) environment.
I want to implement bag of words in opencv. after detector->detect(img, keypoint); detects keypoints, when i want to clean keypoints using keypoint.clear(); or when the function wants to return the following error will be appeared.
"Unhandled exception at 0x011f45bb in BOW.exe: 0xC0000005: Access violation reading location 0x42ebe098."
and also detected keypoints have bizarre points coordinates like cv::Point_ pt{x=-1.5883997e+038y=-1.5883997e+038 }
Part of the code
Ptr<DescriptorMatcher> matcher = DescriptorMatcher::create("FlannBased");
Ptr<DescriptorExtractor> extractor = new SurfDescriptorExtractor();
Ptr<FeatureDetector> detector = new SurfFeatureDetector(2000);
void extractTrainingVocabulary() {
IplImage *img;
int i,j;
CvSeq *imageKeypoints = 0;
for(j=1;j<=60;j++)
for(i=1;i<=60;i++){
sprintf( ch,"%d%s%d%s",j," (",i,").jpg");
const char* imageName = ch;
Mat img = imread(ch);
vector<KeyPoint> keypoint;
detector->detect(img, keypoint);
Mat features;
extractor->compute(img, keypoint, features);
bowTrainer.add(features);
keypoint.clear();//problem
}
return;
}
I noticed something about your code, on extractTrainingVocabulary() you declare IplImage* img; and inside the loop you declare another variable with the same name (but different type): Mat img = imread(ch);.
Even though that might not be the problem, it's certainly not good practice. I would fix that immediately and update the code on your question.