/*
* Description:
* Locates the characters of the license plate
* - Warp image (Rectify)
* - Segment characters
* - Remove blobs which are to small (Lines between characters)
* Input:
* //Original image
* RGB888Image plateImage
* //Segmented license plate
* Int32Image binaryPlateImage
* Output:
* //Image containing binary six characters
* ref Int32Image binaryCharacterImage
* Return:
* //Function executed successfully
* bool
*/
public static bool FindCharacters(RGB888Image plateImage, Int32Image binaryPlateImage, ref Int32Image binaryCharacterImage)
{
try
{
//Constants
const int c_height = 100;
const int c_width = 470;
const int c_remove_blobs_min = 1;
const int c_remove_blobs_max = 450;
XYCoord leftTop = new XYCoord();
XYCoord rightTop = new XYCoord();
XYCoord leftBottom = new XYCoord();
XYCoord rightBottom = new XYCoord();
//Find licenseplate
VisionLab.FindCornersRectangle(binaryPlateImage, Connected.EightConnected, 0.5, Orientation.Landscape, leftTop, rightTop, leftBottom, rightBottom);
if (!VisionLab.WarpCoordsValid(new Coord2D(leftTop), new Coord2D(rightTop), new Coord2D(leftBottom), new Coord2D(rightBottom)))
{
VisionLab.FindCornersRectangleSq(binaryPlateImage, Connected.EightConnected, leftTop, rightTop, leftBottom, rightBottom);
if (!VisionLab.WarpCoordsValid(new Coord2D(leftTop), new Coord2D(rightTop), new Coord2D(leftBottom), new Coord2D(rightBottom)))
{
return(false);
}
}
Int32Image plateImageGray = new Int32Image();
VisionLab.Convert(plateImage, plateImageGray);
//Rectify plate
VisionLab.Warp(plateImageGray, binaryCharacterImage, TransformDirection.ForwardT, new Coord2D(leftTop), new Coord2D(rightTop), new Coord2D(leftBottom), new Coord2D(rightBottom), c_height, c_width, 0);
plateImageGray.Dispose();
//*******************************//
//** Exercise: **//
//** adjust licenseplate **//
//** segmentation **//
//*******************************//
//Find dark text on bright licenseplate using ThresholdISOData
VisionLab.ThresholdIsoData(binaryCharacterImage, ObjectBrightness.DarkObject);
//Remove small blobs and noise
Int32Image binaryCharacterImageCopy = new Int32Image(binaryCharacterImage);
VisionLab.Opening(binaryCharacterImageCopy, binaryCharacterImage, new Mask_Int32(5, 1, 1));
//Remove blobs connected to the border
VisionLab.RemoveBorderBlobs(binaryCharacterImage, Connected.EightConnected, Border.AllBorders);
//Remove small blobs
VisionLab.RemoveBlobs(binaryCharacterImage, Connected.EightConnected, BlobAnalyse.BA_Area, c_remove_blobs_min, c_remove_blobs_max);
leftTop.Dispose();
rightTop.Dispose();
leftBottom.Dispose();
rightBottom.Dispose();
return(true);
}
catch (System.Exception ex)
{
throw new Exception("FindCharacters: " + ex.Message);
}
}
