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 - Before

Edge Detect Statistical Function - After

Edge Detect Statistical Function - After

View additional platform support for this Edge Detect Statistical function.

Required DLLs and Libraries

Platforms

Win32, x64, Linux.

See Also

Functions

Topics

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; 
} 

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