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L_EdgeDetectStatisticalBitmap

Summary

Detects edges by examining the variation of colors in all directions using statistical indices.

Syntax

#include "l_bitmap.h"

L_LTIMGEFX_API L_INT L_EdgeDetectStatisticalBitmap(pBitmap, uDim, nThreshold, crEdgeColor, crBkColor, uFlags)

Parameters

pBITMAPHANDLE pBitmap

Pointer to the bitmap handle that references the bitmap in which the edge detector is applied.

L_UINT uDim

Dimensions of the neighborhood used to detect edges (uDim x uDim), in pixels.

L_INT nThreshold

Threshold value used to determine which pixels are edge pixels. If the difference determined by the edge detector algorithm for a pixel is greater than this value, the pixel is an edge pixel.

COLORREF crEdgeColor

The COLORREF value that specifies the edge color. You can specify a COLORREF value, such as the return value of the Windows RGB macro, or you can use the PALETTEINDEX macro to specify a palette color.

COLORREF crBkColor

The COLORREF value that specifies the non edge color. You can specify a COLORREF value, such as the return value of the Windows RGB macro, or you can use the PALETTEINDEX macro to specify a palette color.

L_UINT32 uFlags

Reserved for future use. Must be 0.

Returns

Value	Meaning
SUCCESS	The function was successful.
< 1	An error occurred. Refer to Return Codes.

Comments

The edges are detected by applying a statistical filter that analyzes the variations of colors in all directions around each pixel.

To update a status bar or detect a user interrupt during execution of this function, refer to L_SetStatusCallback.

This function supports 12 and 16-bit grayscale and 48 and 64-bit color images. Support for 12 and 16-bit grayscale and 48 and 64-bit color images is available in the Document and Medical Imaging toolkits.

This function does not support 32-bit grayscale images. It returns the error code ERROR_GRAY32_UNSUPPORTED if a 32-bit grayscale image is passed to this function.

The threshold range for 16, 48 and 64-bit images is from 0 to 65535 for unsigned images, and from –32768 to +32767 for signed images. For 12-bit images, the threshold range is from 0 to 4095 for unsigned images, and from –2048 to +2047 for signed images. Otherwise, it is from 0 to 255. The threshold is applied to channels separately.

Edge Detect Statistical Function - Before

Edge Detect Statistical Function - After

View additional platform support for this Edge Detect Statistical function.

Required DLLs and Libraries

LTIMGEFX
For a listing of the exact DLLs and Libraries needed, based on the toolkit version, refer to Files To Be Included With Your Application.

Platforms

Win32, x64, Linux.

Example

The following example loads a bitmap and applies an edge detector statistical function

L_INT EdgeDetectStatisticalBitmapExample(L_VOID) 
{ 
   L_INT nRet; 
   BITMAPHANDLE LeadBitmap;   /* Bitmap handle to hold the loaded image. */ 
 
   /* Load the bitmap, keeping the bits per pixel of the file */ 
   nRet = L_LoadBitmap(MAKE_IMAGE_PATH(TEXT("NaturalFruits.jpg")), &LeadBitmap, sizeof(BITMAPHANDLE), 0, ORDER_BGR, NULL, NULL); 
   if (nRet != SUCCESS) 
      return nRet; 
 
   /* Apply an edge detector statistical function */ 
   nRet = L_EdgeDetectStatisticalBitmap(&LeadBitmap, 15, 128, RGB(255, 255, 255), RGB(0, 0, 0), 0); 
   if (nRet != SUCCESS) 
      return nRet; 
 
   //free Bitmap 
   if (LeadBitmap.Flags.Allocated) 
      L_FreeBitmap(&LeadBitmap); 
 
   return SUCCESS; 
}