I have an application that loads an image, so i use:
image1 = imread("Cam_Pic.jpeg", CV_LOAD_IMAGE_COLOR);
And then I do some face detection code and save it to a file to then show it on my windows form. It works perfectly if i only do it once. To give you a little background. This is kinda how my code works:
I "click" button on form
my camera takes pic & saves it as a JPEG image
Picture is read by imread
haar cascade is used to detect face
rectangle is placed around detectedface
THAT image is saved to new JPEG
Form loads the the new JPEG image (with rectangle around face)
This works perfectly if I only do it ONCE. If i press the button again, the camera will take the picture, but my "face_detect" function will gave me an IMREAD error this time saying it can't read the pic taken by the camera, but it is there. Here's my code, or part of it:
void Face_detect()
{
Mat image1;
Mat grayscaleFrame;
//image1 = cam_cap;
//G E T I M A G E
image1 = imread("Cam_Pic.jpeg", CV_LOAD_IMAGE_COLOR);
if (image1.empty())
{
cout << "!!! Failed imread(): image not found" << endl;
}
.
.
.
.
imwrite("Detected_image.jpeg", image1);
}
/////////// W I N D O W S F O R M /////////////////
private: System::Void button3_Click(System::Object^ sender, System::EventArgs^ e)
{
// snap picture
PlaySound(L"Eagle_img_analyzing.wav", NULL, SND_FILENAME | SND_ASYNC);
Eagle.saveImage("Cam_Pic.jpeg");
Face_detect();
PlaySound(L"Eagle_Analysis_complete.wav", NULL, SND_FILENAME | SND_ASYNC);
pictureBox1-> Load("Detected_image.jpeg");
}
Any idea how to troubleshoot this?
Related
Simple problem.
I have a form to which I add a panel and put 1 label with some text. When I look at the saved image, all I see is the panel. I have tried all the solutions I could find. Code below. I get the panel saved but the text box doesn't appear. If I can get that to work, then I can do all that I need.
What am I doing wrong?
int x = SystemInformation.WorkingArea.X;
int y = SystemInformation.WorkingArea.Y;
int width = printPanel.Width;
int height = printPanel.Height;
Rectangle bounds = new Rectangle(x, y, width, height);
using (Bitmap flag = new Bitmap(width, height))
{
printPanel.DrawToBitmap(flag, bounds);
if (Environment.UserName == "grimesr")
{
string saveImage = Path.Combine(fileStore, "./p" + ".png");
flag.Save(saveImage);
}
}
Really not sure where you're going wrong.
Here's a simple test:
private void button1_Click(object sender, EventArgs e)
{
int width = printPanel.Width;
int height = printPanel.Height;
Rectangle bounds = new Rectangle(0, 0, width, height);
Bitmap flag = new Bitmap(width, height);
printPanel.DrawToBitmap(flag, bounds);
pictureBox1.Image = flag;
}
It grabs the entire panel and puts the image into the picturebox to the right:
Thanks for the hints, even if they weren't directly related. The print button helped me figure this out. The button code worked as desired. However, putting the same code where I had it wasn't working. I then noticed a InvalidOperation error was being rasied. So looking at more in detail led me to see what the real issue was.
I must admit I left out 1 tiny piece of information that was critical. I was trying to do this in a thread that was feeding my label printer. Of course, trying to used a UI panel control in the thread threw an Invalid Operation. I moved the code out and all is well now. Cross thread operations are sometimes subtle and difficult to think about how they fail.
Problem solved for me.
I'm working with tesseract ocr.I have done it by console. But during GUI of C++ I faced some problem. In console I have used char array to get input image. But now I'm uploading an image by openFileDialog. I need to convert it in char array. But giving many error. I'm giving my code which is written under a recogition button. How can I solve my problem? I have seen this. It's not helpful for me.
private: System::Void button2_Click(System::Object^ sender, System::EventArgs^ e)
{
char image[256];
//cin>>image;//while I'm taking input in console
image=im;//im is the bitmap image which I have loaded.
PIX *pixs = pixRead(image);
STRING text_out;
api.ProcessPages(image, NULL, 0, &text_out);
//cout<<text_out.string();
ofstream myfile;
myfile.open ("example.txt");
myfile << text_out.string();
myfile.close();
}
I am trying to do the examples in the OpenCV book and I got to the part regarding cvCanny. I am trying to use it, but I keep getting a memory exception error of
Unhandled exception at 0x75d8b760 in Image_Transform.exe: Microsoft C++ exception: cv::Exception at memory location 0x0011e7a4..
I have also looked at another post that was similar to this question, but it did not help for me as I got the same error each time. Any help is greatly appreciated and the source code for the function is located below.
void example2_4(IplImage* img)
{
// Create windows to show input and ouput images
cvNamedWindow("Example 2-4 IN", CV_WINDOW_AUTOSIZE);
cvNamedWindow("Example 2-4 OUT", CV_WINDOW_AUTOSIZE);
// Display out input image
cvShowImage("Example 2-4 IN", img);
// Create an image to hold our modified input image
IplImage* out = cvCreateImage(cvGetSize(img), IPL_DEPTH_8U, 3);
// Do some smoothing
//cvSmooth(img, out, CV_GAUSSIAN, 3, 3);
// Do some Edge detection
cvCanny(img, out, 10, 20, 3);
// Show the results
cvShowImage("Example 2-4 OUT", out);
// Release the memory used by the transformed image
cvReleaseImage(&out);
// Wait for user to hit a key then clean up the windows
cvWaitKey(0);
cvDestroyWindow("Example 2-4 IN");
cvDestroyWindow("Example 2-4 OUT");
}
int main()
{
// Load in an image
IplImage* img = cvLoadImage("images/00000038.jpg");
// Run the transform
example2_4(img);
// clean the image from memory
cvReleaseImage(&img);
return 0;
}
You forgot to say if you are able to see the original image being displayed on the screen.
I never get tired of telling people that checking the return of functions is a must!
Consider IplImage* img = cvLoadImage("images/00000038.jpg"); , how can you tell if this function succeeded or not? As far as I can tell, the error you are having might be from a function failing prior to cvCanny() being called.
Anyway, I recently posted a code that uses cvCanny to improve circle detection. You can check that code and see what you are doing differently.
EDIT:
Your problem in this case is that you are passing to cvCanny input and output as a 3 channel image, when it takes only a single channel image. Check the docs:
void cvCanny(const CvArr* image, CvArr* edges, double threshold1, double threshold2, int aperture_size=3)
Implements the Canny algorithm for edge detection.
Parameters:
* image – Single-channel input image
* edges – Single-channel image to store the edges found by the function
* threshold1 – The first threshold
* threshold2 – The second threshold
* aperture_size – Aperture parameter for the Sobel operator (see Sobel)
So, change your code to:
// Create an image to hold our modified input image
IplImage* out = cvCreateImage(cvGetSize(img), IPL_DEPTH_8U, 1);
// Do some smoothing
//cvSmooth(img, out, CV_GAUSSIAN, 3, 3);
IplImage* gray = cvCreateImage(cvGetSize(img), IPL_DEPTH_8U, 1);
cvCvtColor(img, gray, CV_BGR2GRAY);
// Do some Edge detection
cvCanny(gray, out, 10, 20, 3);
I'm new to OpenCV and image processing and I'M not sure how to solve my problem.
I have a photo of document made in iPhone and I want to convert that document to black and white. I tried to use threshold but the text was not so good (a little blurry and unreadable). I'd like to text looks same as on the original image, only black, and background will be white. What can I do?
P.S. When I made a photo of part of the document, where text is quite big, then result is ok.
I will be grateful for any help.
Here are the example image I use and the result:
My attemp, maybe a little more readable than yours:
IplImage * pRGBImg = 0;
pRGBImg = cvLoadImage(input_file.c_str(), CV_LOAD_IMAGE_UNCHANGED);
if(!pRGBImg)
{
std::cout << "ERROR: Failed to load input image" << std::endl;
return -1;
}
// Allocate the grayscale image
IplImage * pGrayImg = 0;
pGrayImg = cvCreateImage(cvSize(pRGBImg->width, pRGBImg->height), pRGBImg->depth, 1);
// Convert it to grayscale
cvCvtColor(pRGBImg, pGrayImg, CV_RGB2GRAY);
// Dilate
cvDilate(pGrayImg, pGrayImg, 0, 0.2);
cvThreshold(pGrayImg, pGrayImg, 30, 255, CV_THRESH_BINARY | CV_THRESH_OTSU);
cvSmooth(pGrayImg, pGrayImg, CV_BLUR, 2, 2);
cvSaveImage("out.png", pGrayImg);
Threshold image is used for different purposes.
If u just want to convert it to b/w image just do this. USing openCV 2.2
cv::Mat image_name = cv::imread("fileName", 0);
the second parameter 0 tells to read a color image as b/w image.
And if you want to save as a b/w image file.
code this
cv::Mat image_name = cv::imread("fileName", 0);
cv::imwrite(image_name, "bw_filename.jpg");
Using Adaptive Gaussian Thresholding is a good idea here. This will also enhance the quality of text written in the image.
You can do that by simply giving the command:
AdaptiveThreshold(src_Mat, dst_Mat, Max_value, Adaptive_Thresholding_Method, Thresholding_type, blocksize, C);
Firstly: apologies if this is a duplicate post. Things got a bit confusing as I'm trying to post/register at same time.
I started investigating running UCI chess engines from a simple WPF window, got the hang of having the chess engine running onf a different thread to the interface, and have created a reasonably servcieable text-based front end.
I'm getting a bit more ambitious now, and would like to start building a GUI with chess pieces on it that will feed the player's moves to the chess engine, and represent the engine's moves on the board as well. I'm aiming for draggable pieces rather than clicking squares.
My current attempts involve using draggable user controls for the pieces on a <canvas> element. I'd be really interested to hear how other, more experienced WPF/.NET programmers would approach this, as I'm not entirely convinced I'm on the right track.
For example: would it be better to use a uniform grid and drag piece data between child elements? Should I create an abstract 'piece' class from which pieces such as pawns could derive? That kind of thing.
Any thoughts? This isn't a homework assignment or anything, just something I'm noodling around with in my spare time as an exercise.
I have implemented a chess board for my Silverlight Online Chess system.
Here is how I did it.
I made a seperate user control for the chess board
I added a grid 8x8 onto the control
I then added 64 Borders shading each one a different color (dark squares and light squares) Make sure to name each one. Each of the borders were placed on the grid using the Grid.Row and Grid.Col properties.
Within each Border I added an Image that will hold the chess piece image.
You will have to code some methods around setting the image to the correct chess piece based on your current game state.
Each of the Images received the same event (this is important), all 64 call the same piece of code:
MouseLeftButtonDown="Image_MouseLeftButtonDown"
MouseMove="Image_MouseMove"
MouseLeftButtonUp="Image_MouseLeftButtonUp"
The idea behind these 3 events is that we record when I click on the image (MouseLeftButtonDown) that gets me the origin of the click, then I call the event as the mouse is moving, that allows me to update the screen as the piece is moving, and the last event I record when I let go of the mouse button (MouseLeftButtonUp), this allows me to get the destination and send the move to my chess engine. Once the move is recorded by the chess engine I just redraw the chess board.
private void Image_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
Image image = (Image)sender;
Border border = (Border)image.Parent;
image.CaptureMouse();
isMouseCapture = true;
mouseXOffset = e.GetPosition(border).X;
mouseYOffset = e.GetPosition(border).Y;
var chessPiece = (Image) sender;
var chessSquare = (Border) chessPiece.Parent;
var row = (byte) (Grid.GetRow(chessSquare));
var column = (byte) (Grid.GetColumn(chessSquare) - 1);
if (engine.HumanPlayer == ChessPieceColor.White)
{
SelectionChanged(row, column, false);
}
else
{
SelectionChanged((byte)(7 - row), (byte)(7 - column), false);
}
}
SelectionChanged is my own method for recording what source square the user selected.
isMouseCapture is also my own variable for recording when the user started draging the piece.
private void Image_MouseMove(object sender, MouseEventArgs e)
{
Image image = (Image)sender;
Border border = (Border)image.Parent;
if (!currentSource.Selected)
{
image.ReleaseMouseCapture();
isMouseCapture = false;
translateTransform = new TranslateTransform();
translateTransform.X = 0;
translateTransform.Y = 0;
mouseXOffset = 0;
mouseYOffset = 0;
}
if (isMouseCapture)
{
translateTransform = new TranslateTransform();
translateTransform.X = e.GetPosition(border).X - mouseXOffset;
translateTransform.Y = e.GetPosition(border).Y - mouseYOffset;
image.RenderTransform = translateTransform;
CalculateSquareSelected((int)translateTransform.X, (int)translateTransform.Y, false);
}
}
In the above CalculareSquareSelected converts the pixels moved to where I think the piece is moving to in the 8x8 chess board. For example say I moved 100 pixels and the chess board square is only 50 pixels than I moved 2 chess board squares.
private void Image_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
if (translateTransform == null)
{
return;
}
Image image = (Image)sender;
image.ReleaseMouseCapture();
isMouseCapture = false;
if (translateTransform.X > 10 || translateTransform.Y > 10 || translateTransform.X < -10 || translateTransform.Y < -10)
{
CalculateSquareSelected((int)translateTransform.X, (int)translateTransform.Y, true);
}
translateTransform = new TranslateTransform();
translateTransform.X = 0;
translateTransform.Y = 0;
mouseXOffset = 0;
mouseYOffset = 0;
image.RenderTransform = translateTransform;
}
If you have any questions feel free to contact me.