/*
*
* https://stackoverflow.com/questions/38336601/ocr-tesseractengine
* /
* public Bitmap ScaleByPercent(Bitmap imgPhoto, int Percent)
* {
* float nPercent = ((float)Percent / 100);
*
* int sourceWidth = imgPhoto.Width;
* int sourceHeight = imgPhoto.Height;
* var destWidth = (int)(sourceWidth * nPercent);
* var destHeight = (int)(sourceHeight * nPercent);
*
* var bmPhoto = new Bitmap(destWidth, destHeight,
* PixelFormat.Format24bppRgb);
* bmPhoto.SetResolution(imgPhoto.HorizontalResolution,
* imgPhoto.VerticalResolution);
*
* Graphics grPhoto = Graphics.FromImage(bmPhoto);
* grPhoto.InterpolationMode = InterpolationMode.HighQualityBicubic;
*
* grPhoto.DrawImage(imgPhoto,
* new System.Drawing.Rectangle(0, 0, destWidth, destHeight),
* new System.Drawing.Rectangle(0, 0, sourceWidth, sourceHeight),
* GraphicsUnit.Pixel);
* bmPhoto.Save(@"D:\Scale.png", System.Drawing.Imaging.ImageFormat.Png);
* grPhoto.Dispose();
* return bmPhoto;
* }
*
* /*
*
* https://stackoverflow.com/questions/38336601/ocr-tesseractengine
* Strickos9 had shown you a partially great way to solve this issue.
* But the point is that if you will have to scan text with the same size,
* but also there would be some letters included, you will get a bad result.
* Also, even with whitelist related only to digits,
* you may expierence some problems while scanning
* (for example 5 scanned as 6), because Tesseract really struggles
* to scan a low quality characters,
* so I would highly recommend you to:
* Enlarge the image by 2-4 times.
* Do some blur if needed to soften the edges of chars.
* Process it with 'threshold' or 'adaptive threshold' algorythms
* (to clear the blurred pixels and that blue color in the background).
* I've answered a similar question HERE, where a person
* was also unsatisfied with results
* while scanning a low quality picture.
* Combined with what Strickos9 offered to you
* (if you are going to scan only digits) should provide you a perfect quality of scanning.
* You can do this image processing with software like OpenCV or
* Matlab (although I've never tried this).
* If you are struggling with this, post in comments your further questions.
*/
Bitmap GrayBitmapSimply(Bitmap b)
{
Bitmap bitmap = (Bitmap)b.Clone();
UnCodebase ud = new UnCodebase(bitmap);
bitmap = ud.GrayByPixels();
bitmap = ud.ReSetBitMap();
return(bitmap);
}
public String OcrBitmap_old_one(Bitmap src)
{
System.Drawing.Bitmap img = src;
UnCodebase ud = new UnCodebase(img);
img = ud.GrayByPixels();
ud.ClearNoise(128, 2);
string str = System.Environment.CurrentDirectory;
Bitmap gryBit = img;
String grybitFileNm = str + "\\gybit" + ".tif";
gryBit.Save(grybitFileNm, System.Drawing.Imaging.ImageFormat.Tiff);
System.Diagnostics.Process exep = new System.Diagnostics.Process();
System.Diagnostics.ProcessStartInfo startInfo = new System.Diagnostics.ProcessStartInfo();
startInfo.FileName = "tesseract.exe";
startInfo.Arguments = "" +
grybitFileNm
+ " output -l fontyp -psm 7";
//MessageBox.Show(startInfo.Arguments);
startInfo.CreateNoWindow = true;
startInfo.UseShellExecute = false;
exep.StartInfo = startInfo;
exep.Start();
exep.WaitForExit();
FileStream fs = File.OpenRead(str + "\\output.txt");
int filelength = 0;
fs.Seek(0, SeekOrigin.Begin);
filelength = (int)fs.Length; //获得文件长度
Byte[] image = new Byte[filelength]; //建立一个字节数组
char[] charData = new char[filelength];
fs.Read(image, 0, filelength); //按字节流读取
Decoder d = Encoding.Default.GetDecoder();
d.GetChars(image, 0, image.Length, charData, 0);
Console.WriteLine(charData);
fs.Close();
String str_res = new String(charData);
return(str_res);
}
public void testOcrTesseract2()
{
TesseractEngine engine = new TesseractEngine(@"../tessdata", "fontyp", EngineMode.TesseractOnly);
Bitmap bit_time = getHHMMSSBit();
Bitmap price_bit_time = this.getGrayPriceBit();
System.Drawing.Bitmap img1 = bit_time;
System.Drawing.Bitmap img2 = price_bit_time;
UnCodebase ud = new UnCodebase(img1);
UnCodebase ud2 = new UnCodebase(img2);
img1 = ud.GrayByPixels();
img2 = ud2.GrayByPixels();
// ud.ClearNoise(128, 2);
string str = System.Environment.CurrentDirectory;
Bitmap gryBit = img1;
String grybitFileNm = str + "\\HHMMSSBit" + DateTime.Now.ToLongDateString() + ".tif";
gryBit.Save(grybitFileNm, System.Drawing.Imaging.ImageFormat.Tiff);
Bitmap gryBit2 = img2;
String grybitFileNm2 = str + "\\price_bit_time" + DateTime.Now.ToLongDateString() + ".tif";
gryBit2.Save(grybitFileNm2, System.Drawing.Imaging.ImageFormat.Tiff);
var img = PixConverter.ToPix(bit_time);
try
{
engine.SetVariable("tessedit_char_whitelist", "0123456789");
//using (var img = Pix.LoadFromFile("../90400.jpg"))
{
using (var page = engine.Process(img))
{
var text = page.GetText();
MessageBox.Show(text);
}
}
}
catch (Exception ex)
{
MessageBox.Show(ex.ToString());
}
}
