/// <summary>
/// Detects, wrapps and crops out OMR sheet from flattened camera/scanner image.
/// Flattened image is got by using method, private Bitmap flatten(Bitmap bmp, int fillint, int contint);
/// </summary>
/// <param name="bitmap">Bitmap image to process</param>
/// <param name="basicImage">Backup image in case extraction fails</param>
/// <param name="minBlobWidHei">Pre-configured variable, to be queried from XML reader</param>
/// <param name="fillint">Pre-configured int, to be queried from XML reader</param>
/// <param name="contint">Pre-configured int, to be queried from XML reader</param>
/// <param name="OMRSheets">Sheets XML File Address</param>
/// <param name="tb">Textbox to give in'process details on</param>
/// <param name="panel1">Panel to draw in-process changes on.</param>
/// <param name="giveFB">True when In- Process Feedback is required.</param>
/// <param name="sheet">Type of sheet from OMREnums</param>
/// <returns>Cropped OMR sheet (if detected) from camera/scanner image.</returns>
private Bitmap ExtractPaperFromFlattened(Bitmap bitmap, Bitmap basicImage, int minBlobWidHei, int fillint, int contint, string OMRSheets, ref TextBox tb, ref Panel panel1, bool giveFB, XML.OMREnums.OMRSheet sheet)
{
// lock image, Bitmap itself takes much time to be processed
BitmapData bitmapData = bitmap.LockBits(
new Rectangle(0, 0, bitmap.Width, bitmap.Height),
ImageLockMode.ReadWrite, bitmap.PixelFormat);
// step 2 - locating objects
BlobCounter blobCounter = new BlobCounter();
blobCounter.FilterBlobs = true;
blobCounter.MinHeight = minBlobWidHei; // both these variables have to be given when calling the
blobCounter.MinWidth = minBlobWidHei; // method, the can also be queried from the XML reader using OMREnums
blobCounter.ProcessImage(bitmapData);
Blob[] blobs = blobCounter.GetObjectsInformation();
bitmap.UnlockBits(bitmapData);
Graphics g = Graphics.FromImage(bitmap);
Pen yellowPen = new Pen(Color.Yellow, 2); // create pen in case image extraction failes and we need to preview the
//blobs that were detected
Rectangle[] rects = blobCounter.GetObjectsRectangles();
Blob[] blobs2 = blobCounter.GetObjects(bitmap, false);
//Detection of paper lies within the presence of crossmark printed on the corneres of printed sheet.
// First, detect left edge.
System.Drawing.Image compImg = System.Drawing.Image.FromFile("lc.jpg");
// lc.jpg = Mirrored image sample as located on the corner of printed sheet
UnmanagedImage compUMImg = UnmanagedImage.FromManagedImage((Bitmap)compImg);
// this helps filtering out much smaller and much larger blobs depending upon the size of image.
// can be queried from XML Reader
double minbr = XML.OMRSheetReader.getProcessVariableD(OMRSheets, sheet, XML.OMREnums.OMRImageProcessVariables.MinBlobRatio);
double maxbr = XML.OMRSheetReader.getProcessVariableD(OMRSheets, sheet, XML.OMREnums.OMRImageProcessVariables.MaxBlobRatio);
List <IntPoint> quad = new List <IntPoint>(); // Store sheet corner locations (if anyone is detected )
if (giveFB)
{
showTimeStamp("Left edge detection started.", ref tb);
}
try
{
foreach (Blob blob in blobs2)
{
if (
((double)blob.Area) / ((double)bitmap.Width * bitmap.Height) > minbr &&
((double)blob.Area) / ((double)bitmap.Width * bitmap.Height) < maxbr &&
blob.Rectangle.X < (bitmap.Width) / 4) // filters oout very small or very larg blobs
{
if ((double)blob.Rectangle.Width / blob.Rectangle.Height < 1.4 &&
(double)blob.Rectangle.Width / blob.Rectangle.Height > .6) // filters out blobs having insanely wrong aspect ratio
{
compUMImg = UnmanagedImage.FromManagedImage(ImageUtilities.ResizeImage(compImg, blob.Rectangle.Width, blob.Rectangle.Height));
if (isSame(blob.Image, compUMImg))
{
g.DrawRectangle(yellowPen, blob.Rectangle);
quad.Add(new IntPoint((int)blob.CenterOfGravity.X, (int)blob.CenterOfGravity.Y));
}
}
}
}
}
catch (ArgumentException) { MessageBox.Show("No Blobs"); }
if (giveFB)
{
showTimeStamp("Left edge detection finished.", ref tb);
}
try
{ // Sort out the list in right sequence, UpperLeft,LowerLeft,LowerRight,upperRight
if (quad[0].Y > quad[1].Y)
{
IntPoint tp = quad[0];
quad[0] = quad[1];
quad[1] = tp;
}
}
catch
{
}
compImg = System.Drawing.Image.FromFile("rc.jpg");
compUMImg = UnmanagedImage.FromManagedImage((Bitmap)compImg);
if (giveFB)
{
showTimeStamp("Right edge detection started.", ref tb); // jusst like left edge detection
}
try
{
foreach (Blob blob in blobs2)
{
if (
((double)blob.Area) / ((double)bitmap.Width * bitmap.Height) > minbr &&
((double)blob.Area) / ((double)bitmap.Width * bitmap.Height) < maxbr &&
blob.Rectangle.X > (bitmap.Width * 3) / 4)
{
if ((double)blob.Rectangle.Width / blob.Rectangle.Height < 1.4 &&
(double)blob.Rectangle.Width / blob.Rectangle.Height > .6)
{
compUMImg = UnmanagedImage.FromManagedImage(ImageUtilities.ResizeImage(compImg, blob.Rectangle.Width, blob.Rectangle.Height));
if (isSame(blob.Image, compUMImg))
{
g.DrawRectangle(yellowPen, blob.Rectangle);
quad.Add(new IntPoint((int)blob.CenterOfGravity.X, (int)blob.CenterOfGravity.Y));
}
}
}
}
}
catch (ArgumentException) { MessageBox.Show("No Blobs"); }
if (giveFB)
{
showTimeStamp("Right edge detection finished.", ref tb);
}
try
{
if (quad[2].Y < quad[3].Y)
{
IntPoint tp = quad[2];
quad[2] = quad[3];
quad[3] = tp;
}
}
catch
{
}
yellowPen.Dispose();
g.Dispose();
//Again, filter out if wrong blobs pretended to our blobs.
if (quad.Count == 4)
{
if (((double)quad[1].Y - (double)quad[0].Y) / ((double)quad[2].Y - (double)quad[3].Y) < .75 ||
((double)quad[1].Y - (double)quad[0].Y) / ((double)quad[2].Y - (double)quad[3].Y) > 1.25)
{
quad.Clear(); // clear if, both edges have insanely wrong lengths
}
else if (quad[0].X > bitmap.Width / 2 || quad[1].X > bitmap.Width / 2 || quad[2].X < bitmap.Width / 2 || quad[3].X < bitmap.Width / 2)
{
quad.Clear(); // clear if, sides appear to be "wrong sided"
}
}
if (quad.Count != 4) // sheet not detected, reccurrsive call.
{
if (contint <= 60) //try altering the contrast correction on both sides of numberline
{
if (contint >= 0)
{
contint += 5;
contint *= -1;
return(ExtractOMRSheet(basicImage, fillint, contint, OMRSheets, ref panel1, ref tb, giveFB, sheet));
}
else
{
contint *= -1;
contint += 10;
return(ExtractOMRSheet(basicImage, fillint, contint, OMRSheets, ref panel1, ref tb, giveFB, sheet));
}
}
else // contrast correction yeilded no result
{
MessageBox.Show("Extraction Failed.");
return(basicImage);
}
}
else // sheet found
{
IntPoint tp2 = quad[3];
quad[3] = quad[1];
quad[1] = tp2;
//sort the edges for wrap operation
QuadrilateralTransformation wrap = new QuadrilateralTransformation(quad);
wrap.UseInterpolation = false; //perspective wrap only, no binary.
Rectangle sr = XML.OMRSheetReader.GetSheetPropertyLocation(OMRSheets, sheet, XML.OMREnums.OMRProperty.SheetSize);
wrap.AutomaticSizeCalculaton = false;
wrap.NewWidth = sr.Width;
wrap.NewHeight = sr.Height;
wrap.Apply(basicImage).Save("LastImg.jpg", ImageFormat.Jpeg); // creat file backup for future use.
return(wrap.Apply(basicImage)); // wrap
}
}
public Bitmap ExtractPaperFromFlattened(Bitmap bitmap, Bitmap basicImage, int minBlobWidHei, int fillint, int contint)
{
// lock image, Bitmap itself takes much time to be processed
BitmapData bitmapData = bitmap.LockBits(
new Rectangle(0, 0, bitmap.Width, bitmap.Height),
ImageLockMode.ReadWrite, bitmap.PixelFormat);
// step 2 - locating objects
BlobCounter blobCounter = new BlobCounter();
blobCounter.FilterBlobs = true;
blobCounter.MinHeight = minBlobWidHei; // both these variables have to be given when calling the
blobCounter.MinWidth = minBlobWidHei; // method, the can also be queried from the XML reader using OMREnums
blobCounter.ProcessImage(bitmapData);
Blob[] blobs = blobCounter.GetObjectsInformation();
bitmap.UnlockBits(bitmapData);
Graphics g = Graphics.FromImage(bitmap);
// Pen yellowPen = new Pen(Color.Yellow, 2); // create pen in case image extraction failes and we need to preview the
//blobs that were detected
Rectangle[] rects = blobCounter.GetObjectsRectangles();
Blob[] blobs2 = blobCounter.GetObjects(bitmap, false);
//Detection of paper lies within the presence of crossmark printed on the corneres of printed sheet.
// First, detect left edge.
// lc.jpg = Mirrored image sample as located on the corner of printed sheet
// this helps filtering out much smaller and much larger blobs depending upon the size of image.
// can be queried from XML Reader
List <IntPoint> quad = new List <IntPoint>(); // Store sheet corner locations (if anyone is detected )
if (blobs2.GetLength(0) < 4 && contint == 0)
{
lExtractResult = ExtractResults.FAILED;
return(basicImage);
}
try
{
foreach (Blob blob in blobs2)
{
if (
((double)blob.Area) / ((double)bitmap.Width * bitmap.Height) > minbr &&
((double)blob.Area) / ((double)bitmap.Width * bitmap.Height) < maxbr &&
blob.Rectangle.X < (bitmap.Width) / 4) // filters oout very small or very larg blobs
{
if ((double)blob.Rectangle.Width / blob.Rectangle.Height < 1.4 &&
(double)blob.Rectangle.Width / blob.Rectangle.Height > .6) // filters out blobs having insanely wrong aspect ratio
{
cb1 = UnmanagedImage.FromManagedImage(ImageUtilities.ResizeImage(iMarkLeft, blob.Rectangle.Width, blob.Rectangle.Height));
if (isSame(blob.Image, cb1))
{
quad.Add(new IntPoint((int)blob.CenterOfGravity.X, (int)blob.CenterOfGravity.Y));
}
}
}
}
}
catch (ArgumentException) { lExtractResult = ExtractResults.NOBLOB; }
try
{ // Sort out the list in right sequence, UpperLeft,LowerLeft,LowerRight,upperRight
if (quad[0].Y > quad[1].Y)
{
IntPoint tp = quad[0];
quad[0] = quad[1];
quad[1] = tp;
}
}
catch
{
}
try
{
foreach (Blob blob in blobs2)
{
if (
((double)blob.Area) / ((double)bitmap.Width * bitmap.Height) > minbr &&
((double)blob.Area) / ((double)bitmap.Width * bitmap.Height) < maxbr &&
blob.Rectangle.X > (bitmap.Width * 3) / 4)
{
if ((double)blob.Rectangle.Width / blob.Rectangle.Height < 1.4 &&
(double)blob.Rectangle.Width / blob.Rectangle.Height > .6)
{
cb2 = UnmanagedImage.FromManagedImage(ImageUtilities.ResizeImage(iMarkRight, blob.Rectangle.Width, blob.Rectangle.Height));
if (isSame(blob.Image, cb2))
{
quad.Add(new IntPoint((int)blob.CenterOfGravity.X, (int)blob.CenterOfGravity.Y));
}
}
}
}
}
catch (ArgumentException) { lExtractResult = ExtractResults.NOBLOB; }
try
{
if (quad[2].Y < quad[3].Y)
{
IntPoint tp = quad[2];
quad[2] = quad[3];
quad[3] = tp;
}
}
catch
{
}
g.Dispose();
//Again, filter out if wrong blobs pretended to our blobs.
if (quad.Count == 4)
{
if (((double)quad[1].Y - (double)quad[0].Y) / ((double)quad[2].Y - (double)quad[3].Y) < .75 ||
((double)quad[1].Y - (double)quad[0].Y) / ((double)quad[2].Y - (double)quad[3].Y) > 1.25)
{
quad.Clear(); // clear if, both edges have insanely wrong lengths
}
else if (quad[0].X > bitmap.Width / 2 || quad[1].X > bitmap.Width / 2 || quad[2].X < bitmap.Width / 2 || quad[3].X < bitmap.Width / 2)
{
quad.Clear(); // clear if, sides appear to be "wrong sided"
}
}
if (quad.Count != 4) // sheet not detected, reccurrsive call.
{
if (contint <= 60) //try altering the contrast correction on both sides of numberline
{
if (contint >= 0)
{
contint += 5;
contint *= -1;
return(ExtractOMRSheet(basicImage, fillint, contint));
}
else
{
contint *= -1;
contint += 10;
return(ExtractOMRSheet(basicImage, fillint, contint));
}
}
else // contrast correction yeilded no result
{
lExtractResult = ExtractResults.FAILED;
return(basicImage);
}
}
else // sheet found
{
IntPoint tp2 = quad[3];
quad[3] = quad[1];
quad[1] = tp2;
if (!CheckSheetAR(quad))
{
lExtractResult = ExtractResults.INVALIDAR;
return(basicImage);
}
//sort the edges for wrap operation
QuadrilateralTransformation wrap = new QuadrilateralTransformation(quad);
wrap.UseInterpolation = false; //perspective wrap only, no binary.
wrap.AutomaticSizeCalculaton = false;
wrap.NewWidth = tSheetSize.Width;
wrap.NewHeight = tSheetSize.Height;
lExtractResult = ExtractResults.OK;
//wrap.Apply(basicImage);//.Save("LastImg.jpg", ImageFormat.Jpeg); // creat file backup for future use.
return(wrap.Apply(basicImage)); // wrap
}
}
