HOMEWORK 2Windows thread programming

GOAL

Implement a simple image sharpening program on Windows

Use multithread programming to make your program faster

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IMAGE SHARPENING

Asharp = A + k(A – Ablur) k = const.

Origin signal Blurred signal

Sharpened signal

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Unsharp mask

Origin signal

FILTERINGImage origin

mask

y

x

Image f(x,y)

m(-1,-1) m(-1,0) m(-1,1)

m(0,-1) m(0,0) m(0,1)

m(1,-1) m(1,0) m(1,1)

Mask coefficient showing coordinate

arrangement

f(x-1,y-1) f(x-1,y) f(x-1,y+1)

f(x,y-1) f(x,y) f(x,y+1)

f(x+1,y-1) f(x+1,y) f(x+1,y+1)

Pixels of image section under

mask

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SMOOTHING FILTER

1 1 1

1 1 1

1 1 1

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ORIGINAL IMAGE

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SHARPENED IMAGE

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IMAGE CONTENT

imgWidth, imgHeight Unsigned char Pic_in[x] array Each pixel is represented by three values R G B R G B….. Accessing the ith row, jth col pixel :

pic_in[(i*imgWidth+j)*3+color] color = 0,1,2

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……………..R G B R G B BPic_in

imgWidth*imgHeight*3

REQUIREMENT

We will give you an example code of smoothing and sharpening filter, and you need to modify it.

You can only write your own image processing code between the timing function (of course you can declare global variables or local variables anywhere) QueryPerformanceFrequency(&ticksPerSecond); QueryPerformanceCounter(&start_tick); //your code… QueryPerformanceCounter(&end_tick);

elapsed = ((double) (end_tick.QuadPart - start_tick.QuadPart) / ticksPerSecond.QuadPart); 9

REQUIREMENT

You can only use our library to read the input image (24bit uncompressed BMP file)

The format of the mask file: 1st line : FILTER SIZE (3x3 5x5 …) 2nd line : filtering times for smoothing 3rd line: mask number start from upper left (but

all of them will be 1)

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REQUIREMENT

You must use more than 1 thread You can get basic score if your program is

faster than the example The man who can write the fastest program,

will get the highest score in this project! The demo computer spec: Intel Core i5, 4GB

ram, windows7 32bit ……

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REQUIREMENT

Test the program in different number of threads

Make a line chart of “Elapsed Time” and “Number of Threads” in your report

Upload your code and report to the FTP

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CREATE THREAD AND SYNCHRONIZATION FUNCTIONS IN WINDOWS Windows thread programming

CREATE THREAD AND SYNCHRONIZATION FUNCTIONS IN WINDOWS

#include <windows.h> #include <process.h>

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CREATE THREAD IN WINDOWS

HANDLE WINAPI CreateThread( __in_opt LPSECURITY_ATTRIBUTES lpThreadAttributes, __in SIZE_T dwStackSize, __in LPTHREAD_START_ROUTINE lpStartAddress, __in_opt LPVOID lpParameter, __in DWORD dwCreationFlags, __out_opt LPDWORD lpThreadId );

EX: to create a thread to execute function ABCCreateThread( NULL, 0, (LPTHREAD_START_ROUTINE)ABC,

NULL, 0, &ThreadID );15

SYNCHRONIZATION FUNCTIONSIN WINDOWS

HANDLE WINAPI CreateSemaphore (__in_opt LPSECURITY_ATTRIBUTES lpSemaphoreAttributes,__in LONG lInitialCount,__in LONG lMaximumCount,__in_opt LPCTSTR lpName );

EX ： The max value for the semaphore Sem is 5, and its initial value is 0

HANDLE Sem;Sem = CreateSemaphore( NULL, 0, 5, NULL ); 16

SYNCHRONIZATION FUNCTIONSIN WINDOWS

DWORD WINAPI WaitForSingleObject (__in HANDLE hHandle,__in DWORD dwMilliseconds );

EX ： to wait for a semaphoreWaitForSingleObject( Sem, INFINITE );

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SYNCHRONIZATION FUNCTIONSIN WINDOWS

DWORD WINAPI WaitForMultipleObject ( __in DWORD nCount,

__in const HANDLE *lpHandles, __in BOOL bWaitAll,

__in DWORD dwMilliseconds );

EX ： to wait for two threadsHANDLE Thread[2];WaitForMultipleObject( 2, Thread, TRUE, INFINITE );18

SYNCHRONIZATION FUNCTIONSIN WINDOWS

BOOL WINAPI ReleaseSemaphore (__in HANDLE hSemaphore,__in LONG lReleaseCount,__out_opt LPLONG lpPreviousCount );

EX ： to signal a semaphoreReleaseSemaphore( Sem, 1, NULL );

WaitForSingleObject( Sem, INFINITE );19

EX:HW1 IN WINDOWSint main(void){

top = down = 0;full = CreateSemaphore( NULL, 0, 5, NULL );empty = CreateSemaphore( NULL, 5, 5, NULL );int j, *tid_arg;srand((int)time(0)); printf("start\n");tid_arg = (int *) malloc(sizeof(int));*tid_arg = 1;DWORD tid;HANDLE Thread[2];Thread[0] = CreateThread( NULL, 0, (LPTHREAD_START_ROUTINE)producer, (void*)tid_arg, 0, &tid );Thread[1] = CreateThread( NULL, 0, (LPTHREAD_START_ROUTINE)consumer, (void*)tid_arg, 0, &tid );WaitForMultipleObjects(2, Thread, TRUE, INFINITE);printf("finish\n");system("pause");return 0;

}

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//global variablesint top, down;int buf[5];HANDLE full, empty;

void * producer(void *arg)

{

printf("p_in\n");

int i, input, in_data;

input = *((int *) arg);

for (i=0; i<12; i++) {

WaitForSingleObject( empty, INFINITE );

Sleep(rand()%5);

in_data = rand()%256;

printf(">>p(%d) =(%d),buf[%d]\n", i, in_data, top);

buf[top] = in_data;

top = (top+1)%5;

ReleaseSemaphore(full, 1, NULL);

}

return 0;

}21

EX:HW1 IN WINDOWS

void * consumer(void *arg)

{

printf("c_in\n");

int i, input, out_data;

input = *((int *) arg);

for (i=0;i<12;i++){

WaitForSingleObject( full, INFINITE );

Sleep(rand()%10);

out_data = buf[down];

printf(">>c(%d) =(%d),buf[%d]\n", i, out_data, down);

down = (down+1)%5;

ReleaseSemaphore(empty, 1, NULL);

}

return 0;

}22

EX:HW1 IN WINDOWS