performance questions

  • Thread starter Thread starter Jeroen CEuppens
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Jeroen CEuppens

Hi,

I need to make conclusions for a thesis.

I work with WinCE .NET 4.2 and write the program in C# with a Advantech
board wit 64MBRAM and 300Mhz

The calculations for image processing seems to be very poor

here code that takes about 2500 millisenconds
output=new double[H,W];

double[,] doublepixeldata=new doublepixeldata[320,480];

//code to fill doublepixeldata





double [,] filter=new double[FR,FK]; //FR= filter rij FK = filter kolom

//[320,480];

double term=Convert.ToDouble(this.Parameter[4].SName);

//double term=(double)0.04;


for (int i=0;i<FR;i++)

{

for(int j=0;j<FK;j++)

{

filter[i,j]=filterdata[i*FR+j];

}

}

double NewVal;

int a,b,c,r;

int r0,r1,c0,c1;

for(r=FK/2;r<H-FK/2;r++)

{

r0=r-FK/2;

r1=r0+FK;

for(c=FR/2;c<W-FR/2;c++)

{

c0=c-FR/2;

c1=c0+FR;

NewVal = 0;

for(a=r0;a<r1;a++)

{

for(b=c0;b<c1;b++)

NewVal+=doublepixeldata[a,b] *
filter[b-c0,a-r0];//NewVal+=input[b,a] * filter[b-c0,a-r0];

}

output[r,c]=NewVal;//output[r,c]=Math.Abs(NewVal);

}

}

}


Other question, what about the graphics performance, is it possible to view
smooth video with the standard drivers?


Greetz Jeroen
 
Some general observations on the performance of the code below:

1) Most embedded devices have fairly poor floating-point performance
because they lack an FPU. If your application has the flexibility, a
fixed-point algorithm based on 32-bit ints would give the best performance.

2) Multi-dimensional arrays are not the most efficient construct in the
Compact Framework. Since your code belows relies quite heavily on array
accesses, you could probably get a noticeable performance improvement by
using a one-dimensional array and only logically dividing it into rows and
columns afterwards. An array of arrays (double[][]) would also have better
performance than a multi-dimensional array (double[,]) in most
circumstances, though perhaps not as good as a one-dimensional array.

--------------------
From: "Jeroen CEuppens" <[email protected]>
Subject: performance questions
Date: Thu, 22 Apr 2004 13:27:47 +0100

Hi,

I need to make conclusions for a thesis.

I work with WinCE .NET 4.2 and write the program in C# with a Advantech
board wit 64MBRAM and 300Mhz

The calculations for image processing seems to be very poor

here code that takes about 2500 millisenconds
output=new double[H,W];

double[,] doublepixeldata=new doublepixeldata[320,480];

//code to fill doublepixeldata





double [,] filter=new double[FR,FK]; //FR= filter rij FK = filter kolom

//[320,480];

double term=Convert.ToDouble(this.Parameter[4].SName);

//double term=(double)0.04;


for (int i=0;i<FR;i++)

{

for(int j=0;j<FK;j++)

{

filter[i,j]=filterdata[i*FR+j];

}

}

double NewVal;

int a,b,c,r;

int r0,r1,c0,c1;

for(r=FK/2;r<H-FK/2;r++)

{

r0=r-FK/2;

r1=r0+FK;

for(c=FR/2;c<W-FR/2;c++)

{

c0=c-FR/2;

c1=c0+FR;

NewVal = 0;

for(a=r0;a<r1;a++)

{

for(b=c0;b<c1;b++)

NewVal+=doublepixeldata[a,b] *
filter[b-c0,a-r0];//NewVal+=input[b,a] * filter[b-c0,a-r0];

}

output[r,c]=NewVal;//output[r,c]=Math.Abs(NewVal);

}

}

}


Other question, what about the graphics performance, is it possible to view
smooth video with the standard drivers?


Greetz Jeroen
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