Mblob
This example uses the Blob module to analyze an image of some nuts and bolts.
Language: C++
Functions used: MappAlloc, MappFree, MblobAlloc, MblobAllocResult, MblobCalculate, MblobControl, MblobDraw, MblobFree, MblobGetResult, MblobSelect, MbufAlloc2d, MbufFree, MbufInquire, MbufRestore, MdispAlloc, MdispControl, MdispFree, MdispSelect, MgraAllocList, MgraFree, MimBinarize, MimClose, MimOpen, MsysAlloc, MsysFree
Categories: Overview, General, Industries, Applications, Counting, Finding/Locating, Modules, Buffer, Display, Graphics, Image Processing, Blob Analysis, What's New, Older
///////////////////////////////////////////////////////////////////////////////
// Aurora Imaging Library
// Filename: MBlob.cpp
//
// Description: This program loads an image of some nuts, bolts and washers,
// determines the number of each of these, finds and marks
// their center of gravity using the Blob analysis module.
//
// (C) 1992-2026 Zebra Technologies Corp. and/or its affiliates
// All Rights Reserved
///////////////////////////////////////////////////////////////////////////////
#include <AIL.h>
// Target image file specifications.
#define IMAGE_FILE M_IMAGE_PATH AIL_TEXT("BoltsNutsWashers.mim")
#define IMAGE_THRESHOLD_VALUE 26L
// Minimum and maximum area of blobs.
#define MIN_BLOB_AREA 50L
#define MAX_BLOB_AREA 50000L
// Radius of the smallest particles to keep.
#define MIN_BLOB_RADIUS 3L
// Minimum hole compactness corresponding to a washer.
#define MIN_COMPACTNESS 1.5
int MosMain(void)
{
AIL_ID AilApplication, // Application identifier.
AilSystem, // System identifier.
AilDisplay, // Display identifier.
AilImage, // Image buffer identifier.
AilGraphicList, // Graphic list identifier.
AilBinImage, // Binary image buffer identifier.
AilBlobResult, // Blob result buffer identifier.
AilBlobContext; // Blob Context identifier.
AIL_INT TotalBlobs, // Total number of blobs.
BlobsWithHoles, // Number of blobs with holes.
BlobsWithRoughHoles, // Number of blobs with rough holes.
n, // Counter.
SizeX, // Size X of the source buffer.
SizeY; // Size Y of the source buffer.
AIL_DOUBLE *CogX, // X coordinate of center of gravity.
*CogY; // Y coordinate of center of gravity.
// Allocate defaults.
MappAllocDefault(M_DEFAULT, &AilApplication, &AilSystem, &AilDisplay, M_NULL, M_NULL);
// Restore source image into image buffer.
MbufRestore(IMAGE_FILE, AilSystem, &AilImage);
// Allocate a graphic list to hold the subpixel annotations to draw.
MgraAllocList(AilSystem, M_DEFAULT, &AilGraphicList);
// Associate the graphic list to the display.
MdispControl(AilDisplay, M_ASSOCIATED_GRAPHIC_LIST_ID, AilGraphicList);
// Display the buffer.
MdispSelect(AilDisplay, AilImage);
// Allocate a binary image buffer for fast processing.
MbufInquire(AilImage, M_SIZE_X, &SizeX);
MbufInquire(AilImage, M_SIZE_Y, &SizeY);
MbufAlloc2d(AilSystem, SizeX, SizeY, 1+M_UNSIGNED, M_IMAGE+M_PROC, &AilBinImage);
// Pause to show the original image.
MosPrintf(AIL_TEXT("\nBLOB ANALYSIS:\n"));
MosPrintf(AIL_TEXT("--------------\n\n"));
MosPrintf(AIL_TEXT("This program determines the number of bolts, nuts and washers\n"));
MosPrintf(AIL_TEXT("in the image and finds their center of gravity.\n"));
MosPrintf(AIL_TEXT("Press any key to continue.\n\n"));
MosGetch();
// Binarize image.
MimBinarize(AilImage, AilBinImage, M_FIXED+M_GREATER_OR_EQUAL,
IMAGE_THRESHOLD_VALUE, M_NULL);
// Remove small particles and then remove small holes.
MimOpen(AilBinImage, AilBinImage, MIN_BLOB_RADIUS, M_BINARY);
MimClose(AilBinImage, AilBinImage, MIN_BLOB_RADIUS, M_BINARY);
// Allocate a context.
MblobAlloc(AilSystem, M_DEFAULT, M_DEFAULT, &AilBlobContext);
// Enable the Center Of Gravity feature calculation.
MblobControl(AilBlobContext, M_CENTER_OF_GRAVITY + M_BINARY, M_ENABLE);
// Allocate a blob result buffer.
MblobAllocResult(AilSystem, M_DEFAULT, M_DEFAULT, &AilBlobResult);
// Calculate selected features for each blob.
MblobCalculate(AilBlobContext, AilBinImage, M_NULL, AilBlobResult);
// Exclude blobs whose area is too small.
MblobSelect(AilBlobResult, M_EXCLUDE, M_AREA, M_LESS_OR_EQUAL,
MIN_BLOB_AREA, M_NULL);
// Get the total number of selected blobs.
MblobGetResult(AilBlobResult, M_DEFAULT, M_NUMBER + M_TYPE_AIL_INT, &TotalBlobs);
MosPrintf(AIL_TEXT("There are %d objects "), (int) TotalBlobs);
// Read and print the blob's center of gravity.
if ((CogX = new AIL_DOUBLE[TotalBlobs]) &&
(CogY = new AIL_DOUBLE[TotalBlobs]))
{
// Get the results.
MblobGetResult(AilBlobResult, M_DEFAULT, M_CENTER_OF_GRAVITY_X + M_BINARY, CogX);
MblobGetResult(AilBlobResult, M_DEFAULT, M_CENTER_OF_GRAVITY_Y + M_BINARY, CogY);
// Print the center of gravity of each blob.
MosPrintf(AIL_TEXT("and their centers of gravity are:\n"));
for(n=0; n < TotalBlobs; n++)
MosPrintf(AIL_TEXT("Blob #%d: X=%5.1f, Y=%5.1f\n"), (int) n, CogX[n], CogY[n]);
delete [] CogX; CogX = NULL;
delete [] CogY; CogY = NULL;
}
else
MosPrintf(AIL_TEXT("\nError: Not enough memory.\n"));
// Draw a cross at the center of gravity of each blob.
MgraControl(M_DEFAULT, M_COLOR, M_COLOR_RED);
MblobDraw(M_DEFAULT, AilBlobResult, AilGraphicList, M_DRAW_CENTER_OF_GRAVITY,
M_INCLUDED_BLOBS, M_DEFAULT);
// Reverse what is considered to be the background so that
// holes are seen as being blobs.
MblobControl(AilBlobContext, M_FOREGROUND_VALUE, M_ZERO);
// Add a feature to distinguish between types of holes. Since area
// has already been added to the context, and the processing
// mode has been changed, all blobs will be re-included and the area
// of holes will be calculated automatically.
MblobControl(AilBlobContext, M_COMPACTNESS, M_ENABLE);
// Calculate selected features for each blob.
MblobCalculate(AilBlobContext, AilBinImage, M_NULL, AilBlobResult);
// Exclude small holes and large (the area around objects) holes.
MblobSelect(AilBlobResult, M_EXCLUDE, M_AREA, M_OUT_RANGE,
MIN_BLOB_AREA, MAX_BLOB_AREA);
// Get the number of blobs with holes.
MblobGetResult(AilBlobResult, M_DEFAULT, M_NUMBER + M_TYPE_AIL_INT, &BlobsWithHoles);
// Exclude blobs whose holes are compact (i.e. nuts).
MblobSelect(AilBlobResult, M_EXCLUDE, M_COMPACTNESS, M_LESS_OR_EQUAL,
MIN_COMPACTNESS, M_NULL);
// Get the number of blobs with holes that are NOT compact.
MblobGetResult(AilBlobResult, M_DEFAULT, M_NUMBER + M_TYPE_AIL_INT, &BlobsWithRoughHoles);
// Print results.
MosPrintf(AIL_TEXT("\nIdentified objects:\n"));
MosPrintf(AIL_TEXT("%d bolts\n"), (int) (TotalBlobs-BlobsWithHoles));
MosPrintf(AIL_TEXT("%d nuts\n"), (int) (BlobsWithHoles - BlobsWithRoughHoles));
MosPrintf(AIL_TEXT("%d washers\n\n"), (int) (BlobsWithRoughHoles));
MosPrintf(AIL_TEXT("Press any key to end.\n\n"));
MosGetch();
// Free all allocations.
MgraFree(AilGraphicList);
MblobFree(AilBlobResult);
MblobFree(AilBlobContext);
MbufFree(AilBinImage);
MbufFree(AilImage);
MappFreeDefault(AilApplication, AilSystem, AilDisplay, M_NULL, M_NULL);
return 0;
}