Binarize.otsuAdaptiveThreshold gives bad results about tesseract-android-tools HOT 7 CLOSED

What version of the product are you using? On what operating system?

tessreact-for-android-1.00 (Lastest version from the svn as of 2011-06-14)
used ubuntu32 11.04 in a VirtualBox to build so files
source versions as in readme file
java application compiled using eclipse on Windows 7 64

What steps will reproduce the problem?
See previous Post

What is the expected output? What do you see instead?
I expect a B&W image with the text (foreground) in black and the background in 
white.
I get text in white with a black background, with kind of blocky pixels that is 
non-usable and barely readable.

I managed to fix the problem. It was when converting the 1bpp PIX to the 32 bit 
Android Bitmap.

The problem lies at line 194 of Writefile.cpp.

This line : 
dstx[0] = dstx[1] = dstx[2] = (srcx[0] & (dw % 8)) ? 0xFF : 0x00;
needs to be replaced by: 
dstx[0] = dstx[1] = dstx[2] = (1 << (7 - (dw & 7)) & srcx[0]) ? 0x00 : 0xFF;

The basic problem was that the bitwise AND was comparing srcx[0], an 8 bit 
integer (0-255), with the result of the modulo which is only 3 bits (0-7). 
Needs to compare with decreasing powers of 2 (like 2^(7-0)), so 128, 64, 32 
etc...

Also I inverted the results, to get a black foreground with a white background 
(? 0x00 : 0xFF).

convertTo8 has similiar problem, do you know how to fix it? The following codes 
can not get acceptable result.

Pix p = Convert.convertTo8(ReadFile.readBitmap(bitmap));
baseApi.setImage(p); 

bitmap is from Camera preview frame data processed by:

  public Bitmap renderCroppedGreyscaleBitmap() {
    int width = getWidth();
    int height = getHeight();
    int[] pixels = new int[width * height];
    byte[] yuv = yuvData;
    int inputOffset = top * dataWidth + left;

    for (int y = 0; y < height; y++) {
      int outputOffset = y * width;
      for (int x = 0; x < width; x++) {
        int grey = yuv[inputOffset + x] & 0xff;
        pixels[outputOffset + x] = 0xFF000000 | (grey * 0x00010101);
      }
      inputOffset += dataWidth;
    }

    Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
    bitmap.setPixels(pixels, 0, width, 0, 0, width, height);
    return bitmap;
  }

If I use a bitmap from file, convertTo8 and setImage work fine.

I am searching OCR for Credit Cards and bank Cheques.I found OCR tool for 
Cheques i.e, Clear Check 21 MICR but for the Credit cards  I didn't get any OCR 
tool.Is there any OCR library to support to develop Application for reading 
cheques and cards.If anyone know about this please give me some 
suggestions.............  

hi eric

i have developed OCR application using android tesseract tools. there is a 
binarization using otsu and now im trying to change the binarization method 
using sauvola.

where should i make change?

here is the source of android tesseract that i am using as libarary for the 
application
https://github.com/rmtheis/tess-two

best regards

Thanks Eric. Merged your fix in.