Arsip: percepat proses bitmap...
more 17 years ago
yadi
Assalamu'alaikum…
mau nanya ni..gimana untuk mempercepat proses proses perhitungan pada nilai pixel gambar grayscale yaitu dilakukan proses DCT.
Prosesnya agak lama apalagi kalo ukuran gambar sudah agak besar
Seperti 128 x 128 pixel.....
Dan pada saat proses perhitungan formnya juga kaya hang....
Kasih pencerahan ya......
Thanks....... :D
more 17 years ago
yadi
eh.,,lupa..ni..
saya tuangkan rumus DCT itu ke dalam delphi jadinya,,,
banyak loopingnya....
gimana nih biar proses nya cepet ga makan waktu yang lama...
thanks.... :D
more 17 years ago
mat_koder
kode pascal anda sebaiknya pake algoritma Fast DCT
emangnya looping kode DCT anda ada berapa ?
more 17 years ago
mat_koder
berikut saya kopikan code FastDCT yg pernah saya bikin ( bloknya 8x8 pixel)
juga disertakan kode DCT standar - untuk memverifikasi hasil FastDCT
type TBlock = array of Integer;
type PBlock = ^TBlock;
procedure FastDCT8x8(var data:TBlock);
var
row,col:integer;
x0,x1,x2,x3,x4,x5,x6,x7,x8 : integer;
begin
for row:=0 to 7 do
begin
x0:=data[row,0];
x1:=data[row,1];
x2:=data[row,2];
x3:=data[row,3];
x4:=data[row,4];
x5:=data[row,5];
x6:=data[row,6];
x7:=data[row,7];
// Stage 1 /
x8:=x7+x0; x0:=x0-x7; x7:=x1+x6; x1:=x1-x6; x6:=x2+x5; x2:=x2-x5; x5:=x3+x4; x3:=x3-x4;
// Stage 2 /
x4:=x8+x5; x8:=x8-x5; x5:=x7+x6; x7:=x7-x6;
x6:=c1(x1+x2); x2:=(-s1-c1) x2+x6; x1:=(s1-c1)x1+x6;
x6:=c3 (x0+x3); x3:=(-s3-c3)x3+x6; x0:=(s3-c3) x0+x6;
// Stage 3 /
x6:=x4+x5; x4:=x4-x5; x5:=x0+x2; x0:=x0-x2; x2:=x3+x1; x3:=x3-x1;
x1:=r2c6(x7+x8); x7:=(-r2s6-r2c6) x7+x1; x8:=(r2s6-r2c6)x8+x1;
// Stage 4 and output /
data[row,0] := x6; // data[row][0]=x6;
data[row,4] := x4; // data[row][4]=x4;
data[row,2] := x8 div 1024; // data[row][2]=x8>>10;
data[row,6] := x7 div 1024; // data[row][6] = x7>>10;
data[row,7] := (x2-x5) div 1024; // data[row][7]=(x2-x5)>>10;
data[row,1] := (x2+x5) div 1024; // data[row][1]=(x2+x5)>>10;
data[row,3] := (x3 r2) div 131072; // data[row][3]=(x3r2)>>17;
data[row,5] := (x0 r2) div 131072; // data[row][5]=(x0r2)>>17;
end;
for col:=0 to 7 do
begin
x0:=data[0,col];
x1:=data[1,col];
x2:=data[2,col];
x3:=data[3,col];
x4:=data[4,col];
x5:=data[5,col];
x6:=data[6,col];
x7:=data[7,col];
// Stage 1 /
x8:=x7+x0; x0:=x0-x7; x7:=x1+x6; x1:=x1-x6; x6:=x2+x5; x2:=x2-x5; x5:=x3+x4; x3:=x3-x4;
// Stage 2 /
x4:=x8+x5; x8:=x8-x5; x5:=x7+x6; x7:=x7-x6;
x6:=c1 (x1+x2); x2:=(-s1-c1)x2+x6; x1:=(s1-c1) x1+x6;
x6:=c3(x0+x3); x3:=(-s3-c3) x3+x6; x0:=(s3-c3)x0+x6;
// Stage 3 /
x6:=x4+x5; x4:=x4-x5; x5:=x0+x2; x0:=x0-x2; x2:=x3+x1; x3:=x3-x1;
x1:=r2c6 (x7+x8); x7:=(-r2s6-r2c6)x7+x1; x8:=(r2s6-r2c6) x8+x1;
// Stage 4 and output /
data[0,col] := (x6+16) div 32; // data[0][col]=(x6+16)>>5;
data[4,col] := (x4+16) div 32; // data[4][col]=(x4+16)>>5;
data[2,col] := (x8+16384) div 32768; // data[2][col]=(x8+16384)>>15;
data[6,col] := (x7+16384) div 32768; // data[6][col]=(x7+16384)>>15;
data[7,col] := (x2-x5+16384) div 32768; // data[7][col]=(x2-x5+16384)>>15;
data[1,col] := (x2+x5+16384) div 32768; // data[1][col]=(x2+x5+16384)>>15;
data[3,col] := ((x3 div 256)r2+8192) div 16384; // data[3][col]=((x3>>8) r2+8192)>>14;
data[5,col] := ((x0 div 256)r2+8192) div 16384; // data[5][col]=((x0>>8) r2+8192)>>14;
end;
end;
end;
// proc berikut ini dipakai untuk men-cek keakuratan procedure fastDCT
procedure Slowdct8x8(var data:TBlock);
var
output : array of double;
i,j,x,y,n,m:integer;
begin
for i:=0 to 7 do
for j:=0 to 7 do
output[i,j]:=0.0;
for y:=0to 7 do
for x:=0 to 7 do
for n:=0 to 7 do
for m:=0 to 7 do
output[y,x] := output[y,x] + data[n,m]
cos(PI x (2 m+1)/16.0) cos(PI y (2 n+1)/16.0);
for y:=0 to 7 do
for x:=0 to 7 do
begin
if(x=0) then output[y][x] := output[y][x]/sqrt(2);
if(y=0) then output[y][x] := output[y][x]/sqrt(2);
data[y][x] := trunc(output[y][x]/16 + 0.5);
end;
end;
more 17 years ago
mat_koder
hmm sorrry... kurang lengkap
procedure FastDCT8x8(var data:TBlock);
var
row,col:integer;
x0,x1,x2,x3,x4,x5,x6,x7,x8 : integer;
temp : array of integer;
begin
for row:=0 to 7 do
begin
x0:=data[row,0];
x1:=data[row,1];
x2:=data[row,2];
x3:=data[row,3];
x4:=data[row,4];
x5:=data[row,5];
x6:=data[row,6];
x7:=data[row,7];
// Stage 1 /
x8:=x7+x0; x0:=x0-x7; x7:=x1+x6; x1:=x1-x6; x6:=x2+x5; x2:=x2-x5; x5:=x3+x4; x3:=x3-x4;
// Stage 2 /
x4:=x8+x5; x8:=x8-x5; x5:=x7+x6; x7:=x7-x6;
x6:=c1(x1+x2); x2:=(-s1-c1) x2+x6; x1:=(s1-c1)x1+x6;
x6:=c3 (x0+x3); x3:=(-s3-c3)x3+x6; x0:=(s3-c3) x0+x6;
// Stage 3 /
x6:=x4+x5; x4:=x4-x5; x5:=x0+x2; x0:=x0-x2; x2:=x3+x1; x3:=x3-x1;
x1:=r2c6(x7+x8); x7:=(-r2s6-r2c6) x7+x1; x8:=(r2s6-r2c6)x8+x1;
// Stage 4 and output /
data[row,0] := x6; // data[row][0]=x6;
data[row,4] := x4; // data[row][4]=x4;
data[row,2] := x8 div 1024; // data[row][2]=x8>>10;
data[row,6] := x7 div 1024; // data[row][6] = x7>>10;
data[row,7] := (x2-x5) div 1024; // data[row][7]=(x2-x5)>>10;
data[row,1] := (x2+x5) div 1024; // data[row][1]=(x2+x5)>>10;
data[row,3] := (x3 r2) div 131072; // data[row][3]=(x3r2)>>17;
data[row,5] := (x0 r2) div 131072; // data[row][5]=(x0r2)>>17;
end;
for col:=0 to 7 do
begin
x0:=data[0,col];
x1:=data[1,col];
x2:=data[2,col];
x3:=data[3,col];
x4:=data[4,col];
x5:=data[5,col];
x6:=data[6,col];
x7:=data[7,col];
// Stage 1 /
x8:=x7+x0; x0:=x0-x7; x7:=x1+x6; x1:=x1-x6; x6:=x2+x5; x2:=x2-x5; x5:=x3+x4; x3:=x3-x4;
// Stage 2 /
x4:=x8+x5; x8:=x8-x5; x5:=x7+x6; x7:=x7-x6;
x6:=c1 (x1+x2); x2:=(-s1-c1)x2+x6; x1:=(s1-c1) x1+x6;
x6:=c3(x0+x3); x3:=(-s3-c3) x3+x6; x0:=(s3-c3)x0+x6;
// Stage 3 /
x6:=x4+x5; x4:=x4-x5; x5:=x0+x2; x0:=x0-x2; x2:=x3+x1; x3:=x3-x1;
x1:=r2c6 (x7+x8); x7:=(-r2s6-r2c6)x7+x1; x8:=(r2s6-r2c6) x8+x1;
// Stage 4 and output /
data[0,col] := (x6+16) div 32; // data[0][col]=(x6+16)>>5;
data[4,col] := (x4+16) div 32; // data[4][col]=(x4+16)>>5;
data[2,col] := (x8+16384) div 32768; // data[2][col]=(x8+16384)>>15;
data[6,col] := (x7+16384) div 32768; // data[6][col]=(x7+16384)>>15;
data[7,col] := (x2-x5+16384) div 32768; // data[7][col]=(x2-x5+16384)>>15;
data[1,col] := (x2+x5+16384) div 32768; // data[1][col]=(x2+x5+16384)>>15;
data[3,col] := ((x3 div 256)r2+8192) div 16384; // data[3][col]=((x3>>8) r2+8192)>>14;
data[5,col] := ((x0 div 256)r2+8192) div 16384; // data[5][col]=((x0>>8) r2+8192)>>14;
end;
// ZIG-ZAG arrangement
Temp[0]:=data[0,0];
Temp[1]:=data[0,1];
Temp[2]:=data[1,0];
Temp[3]:=data[2,0];
Temp[4]:=data[1,1];
Temp[5]:=data[0,2];
Temp[6]:=data[0,3];
Temp[7]:=data[1,2];
Temp[8]:=data[2,1];
Temp[9]:=data[3,0];
Temp[10]:=data[4,0];
Temp[11]:=data[3,1];
Temp[12]:=data[2,2];
Temp[13]:=data[1,3];
Temp[14]:=data[0,4];
Temp[15]:=data[0,5];
Temp[16]:=data[1,4];
Temp[17]:=data[2,3];
Temp[18]:=data[3,2];
Temp[19]:=data[4,1];
Temp[20]:=data[5,0];
Temp[21]:=data[6,0];
Temp[22]:=data[5,1];
Temp[23]:=data[4,2];
Temp[24]:=data[3,3];
Temp[25]:=data[2,4];
Temp[26]:=data[1,5];
Temp[27]:=data[0,6];
Temp[28]:=data[0,7];
Temp[29]:=data[1,6];
Temp[30]:=data[2,5];
Temp[31]:=data[3,4];
Temp[32]:=data[4,3];
Temp[33]:=data[5,2];
Temp[34]:=data[6,1];
Temp[35]:=data[7,0];
Temp[36]:=data[7,1];
Temp[37]:=data[6,2];
Temp[38]:=data[5,3];
Temp[39]:=data[4,4];
Temp[40]:=data[3,5];
Temp[41]:=data[2,6];
Temp[42]:=data[1,7];
Temp[43]:=data[2,7];
Temp[44]:=data[3,6];
Temp[45]:=data[4,5];
Temp[46]:=data[5,4];
Temp[47]:=data[6,3];
Temp[48]:=data[7,2];
Temp[49]:=data[7,3];
Temp[50]:=data[6,4];
Temp[51]:=data[5,5];
Temp[52]:=data[4,6];
Temp[53]:=data[3,7];
Temp[54]:=data[4,7];
Temp[55]:=data[5,6];
Temp[56]:=data[6,5];
Temp[57]:=data[7,4];
Temp[58]:=data[7,5];
Temp[59]:=data[6,6];
Temp[60]:=data[5,7];
Temp[61]:=data[6,7];
Temp[62]:=data[7,6];
Temp[63]:=data[7,7];
MoveMemory(@data[0,0],@temp[0],64);
end;
more 17 years ago
yadi
thank's ya...mas @mat_koder
wah banyak nih..dapet hal2 yang baru...
btw ini dah hasil ku wat DCT in delphi.....he..he..
ada comment ga nih..
ta tunggu ya....
unit UnitDCT2;
interface
uses Unitutama,Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, ExtCtrls, ComCtrls, Buttons, StdCtrls, ExtDlgs;
function HDCT(A : PMatrik): PMatrik;
implementation
function HDCT(A : PMatrik): PMatrik;
var
u,v,x,y,baris,kolom : integer;
c1, c2, jumlah : real;
DCT : PMatrik;
begin
setlength(DCT,length(A),length(A[0]));
for u := 0 to length(A) - 1 do
begin
for v := 0 to length(A[0])-1 do
begin
DCT[u,v] := 0;
end;
end;
baris := length(A);
kolom := length(A[0]);
jumlah := 0;
for u := 0 to baris -1 do
begin
for v := 0 to kolom - 1 do
begin
for x := 0 to baris - 1 do
begin
for y := 0 to kolom - 1 do
begin
if u = 0 then
begin
c1 := 1/sqrt(baris)
end
else
begin
c1 := sqrt(2/baris);
end ;
if v = 0 then
begin
c2 := 1/sqrt(kolom)
end
else
begin
c2 := sqrt(2/kolom);
end;
jumlah:=jumlah + c1c2 A[x,y]cos((2 x+1)pi u/(2baris)) cos((2y+1) piv/(2 kolom));
end;
end;
DCT[u,v] := jumlah;
jumlah := 0;
end;
end;
HDCT := DCT;
end;
end.
more 17 years ago
mat_koder
-
pantesan waktu eksekusi anda lama......... pake kode yg diturunin langsung dari rumus matematik sih...
coba baca-baca artikel mengenai Fast DCT .
Kelebihan Fast DCT terhadap standar DCT dalam hal kecepatan eksekusi adalah :
- Fast DCT menggunakan integer operation sedangkan DCt menggunakan floating point.
- Fast DCT mengeliminasi banyaknya looping yg diperlukan ( banyak operasi simetris dapat direduksi menjadi lebih sedikit).
more 17 years ago
yadi
mas @mat_koder boleh nanya lagi nih,,
kalo untuk optimasi atao untuk mempercepat proses dari fungsi DCT2 diatas itu biar ga banyak looping tapi hasilnya akhirnya benar
bisa ga???
atau ada ga cara lain untuk mempercepat proses eksekusinya...maklum aku newbie sih..
mohon pencerahannya ya...
di tunggu nih..
thanks.......
more 17 years ago
mat_koder
cari di rumah Oom Google artikel mengenai optimasi DCT...
tapi emang banyaknya dlm bhs Inggris sih...
more ...
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