Added documentation for high-level adaptive binarization functions

src/adaptmap.c

@@ -35,6 +35,7 @@
  *     adaptmap.c:    local adaptive; mostly gray-to-gray in preparation
  *                    for binarization
  *     binarize.c:    special binarization methods, locally adaptive.
+ *     pageseg.c:     locally adaptive cleaning operation with several options
  *
  *  -------------------------------------------------------------------
  *
@@ -134,6 +135,15 @@
  *      useful for improving the appearance of pages with very light
  *      foreground or very dark background, and where the local TRC
  *      function doesn't change rapidly with position.
+ *
+ *  Adaptive binarization is done in two steps:
+ *    (1) Background normalization by some method
+ *    (2) Global thresholding with a value appropriate to the normalization.
+ *  There are several high-level functions in leptonica for doing adaptive
+ *  binarization on grayscale and color images, such as:
+ *    * pixAdaptThresholdToBinary()   (in grayquant.c)
+ *    * pixConvertTo1Adaptive()       (in pixconv.c)
+ *    * pixCleanImage()               (in pageseg.c)
  * </pre>
  */
 

src/grayquant.c

@@ -702,6 +702,8 @@ PIX       *pixd;
  *      (1) This is a simple convenience function for doing adaptive
  *          thresholding on a grayscale image with variable background.
  *          It uses default parameters appropriate for typical text images.
+ *          Other high-level adaptive thresholding functions are
+ *          pixConvertTo1Adaptive() and pixCleanImage().
  *      (2) %pixm is a 1 bpp mask over "image" regions, which are not
  *          expected to have a white background.  The mask inhibits
  *          background finding under the fg pixels of the mask.  For

src/pixconv.c

@@ -2889,6 +2889,8 @@ PIX       *pixs, *pixd;
  *      (1) This is a top-level function, that uses default values for
  *          adaptive thresholding, if necessary.  Otherwise, it is the same as
  *          pixConvertTo1(), which uses a global threshold for binarization.
+ *      (2) Other high-level adaptive thresholding functions are
+ *          pixAdaptThresholdToBinary() and pixCleanImage().
  * </pre>
  */
 PIX *