Re: [Bug-ocrad] Library version of OCRAD

[Antonio Diaz Diaz]

Igor Filippov wrote:
> character.h.patch - adds result() function for a single-character
> recognition

This same function with the name "byte_result" is included in ocrad at 
your request since version 0.18-pre3 (2008-08-21). I have found we 
interchanged messages in the past, but it seems none of us remembered 
it. :-)

I see you use ocrad at a low level (Blob), and I see why you do so; 
ocrad does not recognize single characters without surrounding white 
space. Ocrad was designed for full text pages.

As a first step, I have made ocrad recognize such characters.

Now I am wondering about the bitmap/pixmap format to use for 
communication with ocrad. Image format conversion wastes a lot of time, 
and osra seems to do already a lot of conversions.

Internally ocrad uses first a 256 level greymap (page_image.h)
  std::vector< std::vector< unsigned char > > data;
from which it extracts a number of 2 level bitmaps (bitmap.h)
  std::vector< std::vector< unsigned char > > data;

I see osra already uses "struct pixmap" from gocr:
  struct pixmap {
     unsigned char *p;    /* pointer of image buffer (pixmap) */
     int x;               /* xsize */
     int y;               /* ysize */
     int bpp;             /* bytes per pixel:  1=gray 3=rgb */
   };
  typedef struct pixmap pix;

But It may be better one struct per image type, like this:
  struct Ocrad_Bitmap
    {
    int height;
    int width;
    const unsigned char * data;         // 0 = white, 1 = black
    };

  struct Ocrad_Greymap
    {
    int height;
    int width;
    const unsigned char * data;         // 256 level greymap
    };

  struct Ocrad_Colormap
    {
    int height;
    int width;
    const unsigned char * data;         // 3 bytes per pixel RGB
    };


The "struct Ocrad_Greymap" can then be easily built from the values in 
the "struct pixmap".


Best regards,
Antonio.