227 lines
9.5 KiB
C
227 lines
9.5 KiB
C
/*******************************************************************************
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License:
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This software was developed at the National Institute of Standards and
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Technology (NIST) by employees of the Federal Government in the course
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of their official duties. Pursuant to title 17 Section 105 of the
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United States Code, this software is not subject to copyright protection
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and is in the public domain. NIST assumes no responsibility whatsoever for
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its use by other parties, and makes no guarantees, expressed or implied,
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about its quality, reliability, or any other characteristic.
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Disclaimer:
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This software was developed to promote biometric standards and biometric
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technology testing for the Federal Government in accordance with the USA
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PATRIOT Act and the Enhanced Border Security and Visa Entry Reform Act.
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Specific hardware and software products identified in this software were used
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in order to perform the software development. In no case does such
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identification imply recommendation or endorsement by the National Institute
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of Standards and Technology, nor does it imply that the products and equipment
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identified are necessarily the best available for the purpose.
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*******************************************************************************/
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/***********************************************************************
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LIBRARY: LFS - NIST Latent Fingerprint System
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FILE: MORPH.C
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AUTHOR: Michael D. Garris
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DATE: 10/04/1999
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UPDATED: 10/26/1999 by MDG
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To avoid indisciminate erosion of pixels along
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the edge of the binary image.
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UPDATED: 03/16/2005 by MDG
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Contains general support image morphology routines required by
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the NIST Latent Fingerprint System (LFS).
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***********************************************************************
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ROUTINES:
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erode_charimage_2()
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dilate_charimage_2()
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get_south8_2()
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get_north8_2()
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get_east8_2()
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get_west8_2()
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***********************************************************************/
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#include <morph.h>
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#include <string.h>
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/*************************************************************************
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**************************************************************************
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#cat: erode_charimage_2 - Erodes an 8-bit image by setting true pixels to zero
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#cat: if any of their 4 neighbors is zero. Allocation of the
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#cat: output image is the responsibility of the caller. The
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#cat: input image remains unchanged. This routine will NOT
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#cat: erode pixels indiscriminately along the image border.
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Input:
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inp - input 8-bit image to be eroded
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iw - width (in pixels) of image
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ih - height (in pixels) of image
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Output:
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out - contains to the resulting eroded image
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**************************************************************************/
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void erode_charimage_2(unsigned char *inp, unsigned char *out,
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const int iw, const int ih)
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{
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int row, col;
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unsigned char *itr = inp, *otr = out;
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memcpy(out, inp, iw*ih);
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/* for true pixels. kill pixel if there is at least one false neighbor */
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for ( row = 0 ; row < ih ; row++ )
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for ( col = 0 ; col < iw ; col++ )
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{
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if (*itr) /* erode only operates on true pixels */
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{
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/* more efficient with C's left to right evaluation of */
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/* conjuctions. E N S functions not executed if W is false */
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if (!(get_west8_2 ((char *)itr, col , 1 ) &&
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get_east8_2 ((char *)itr, col, iw , 1 ) &&
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get_north8_2((char *)itr, row, iw , 1 ) &&
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get_south8_2((char *)itr, row, iw, ih, 1)))
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*otr = 0;
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}
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itr++ ; otr++;
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}
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}
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/*************************************************************************
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**************************************************************************
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#cat: dilate_charimage_2 - Dilates an 8-bit image by setting false pixels to
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#cat: one if any of their 4 neighbors is non-zero. Allocation
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#cat: of the output image is the responsibility of the caller.
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#cat: The input image remains unchanged.
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Input:
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inp - input 8-bit image to be dilated
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iw - width (in pixels) of image
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ih - height (in pixels) of image
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Output:
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out - contains to the resulting dilated image
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**************************************************************************/
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void dilate_charimage_2(unsigned char *inp, unsigned char *out,
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const int iw, const int ih)
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{
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int row, col;
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unsigned char *itr = inp, *otr = out;
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memcpy(out, inp, iw*ih);
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/* for all pixels. set pixel if there is at least one true neighbor */
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for ( row = 0 ; row < ih ; row++ )
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for ( col = 0 ; col < iw ; col++ )
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{
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if (!*itr) /* pixel is already true, neighbors irrelevant */
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{
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/* more efficient with C's left to right evaluation of */
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/* conjuctions. E N S functions not executed if W is false */
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if (get_west8_2 ((char *)itr, col , 0) ||
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get_east8_2 ((char *)itr, col, iw , 0) ||
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get_north8_2((char *)itr, row, iw , 0) ||
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get_south8_2((char *)itr, row, iw, ih, 0))
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*otr = 1;
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}
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itr++ ; otr++;
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}
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}
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/*************************************************************************
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**************************************************************************
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#cat: get_south8_2 - Returns the value of the 8-bit image pixel 1 below the
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#cat: current pixel if defined else it returns (char)0.
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Input:
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ptr - points to current pixel in image
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row - y-coord of current pixel
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iw - width (in pixels) of image
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ih - height (in pixels) of image
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failcode - return value if desired pixel does not exist
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Return Code:
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Zero - if neighboring pixel is undefined
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(outside of image boundaries)
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Pixel - otherwise, value of neighboring pixel
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**************************************************************************/
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char get_south8_2(char *ptr, const int row, const int iw, const int ih,
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const int failcode)
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{
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if (row >= ih-1) /* catch case where image is undefined southwards */
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return failcode; /* use plane geometry and return code. */
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return *(ptr+iw);
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}
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/*************************************************************************
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**************************************************************************
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#cat: get_north8_2 - Returns the value of the 8-bit image pixel 1 above the
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#cat: current pixel if defined else it returns (char)0.
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Input:
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ptr - points to current pixel in image
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row - y-coord of current pixel
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iw - width (in pixels) of image
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failcode - return value if desired pixel does not exist
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Return Code:
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Zero - if neighboring pixel is undefined
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(outside of image boundaries)
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Pixel - otherwise, value of neighboring pixel
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**************************************************************************/
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char get_north8_2(char *ptr, const int row, const int iw,
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const int failcode)
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{
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if (row < 1) /* catch case where image is undefined northwards */
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return failcode; /* use plane geometry and return code. */
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return *(ptr-iw);
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}
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/*************************************************************************
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**************************************************************************
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#cat: get_east8_2 - Returns the value of the 8-bit image pixel 1 right of the
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#cat: current pixel if defined else it returns (char)0.
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Input:
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ptr - points to current pixel in image
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col - x-coord of current pixel
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iw - width (in pixels) of image
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failcode - return value if desired pixel does not exist
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Return Code:
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Zero - if neighboring pixel is undefined
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(outside of image boundaries)
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Pixel - otherwise, value of neighboring pixel
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**************************************************************************/
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char get_east8_2(char *ptr, const int col, const int iw,
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const int failcode)
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{
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if (col >= iw-1) /* catch case where image is undefined eastwards */
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return failcode; /* use plane geometry and return code. */
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return *(ptr+ 1);
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}
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/*************************************************************************
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**************************************************************************
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#cat: get_west8_2 - Returns the value of the 8-bit image pixel 1 left of the
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#cat: current pixel if defined else it returns (char)0.
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Input:
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ptr - points to current pixel in image
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col - x-coord of current pixel
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failcode - return value if desired pixel does not exist
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Return Code:
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Zero - if neighboring pixel is undefined
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(outside of image boundaries)
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Pixel - otherwise, value of neighboring pixel
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**************************************************************************/
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char get_west8_2(char *ptr, const int col, const int failcode)
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{
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if (col < 1) /* catch case where image is undefined westwards */
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return failcode; /* use plane geometry and return code. */
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return *(ptr- 1);
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}
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