探究Delphi的圖形處理 之七 -- 柔化和銳化處理
第三章 基本圖像處理算法
3.1柔化和銳化處理
柔化處理的原理是將圖片中每一個像素都由與其相鄰的n*n個像素的平均值來代替。N的取值決定了其模糊程度。下面是柔化處理的程序。
程序3.1
unit Unit1;
{柔化處理}
Interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, GraphicProcess, StdCtrls, ExtCtrls;
type
TForm1 = class(TForm)
PaintBox1: TPaintBox;
btnExe: TButton;
txtN: TEdit;
Label1: TLabel;
procedure FormCreate(Sender: TObject);
procedure PaintBox1Paint(Sender: TObject);
procedure btnExeClick(Sender: TObject);
procedure FormDestroy(Sender: TObject);
private
Procedure SmoothPicture(const Bit : TBitmap;var n : Integer);
public
{ Public declarations }
end;
procedure WritePixel(Pic: TBitmap; tPix: TPixels);
procedure ReadPixel(Pic: Tbitmap; var tPix: TPixels);
var
Form1: TForm1;
Bits : TBitmap;
implementation
{$R *.dfm}
procedure TForm1.FormCreate(Sender: TObject);
begin
Bits:=TBitmap.Create;
Bits.LoadFromFile(‘Test.Bmp‘);
end;
procedure TForm1.PaintBox1Paint(Sender: TObject);
begin
PaintBox1.Canvas.StretchDraw(Rect(0,0,400,300),Bits);
end;
procedure TForm1.SmoothPicture(const Bit: TBitmap;var n: Integer);
var R,G,B:Integer;
i,j,k,l : Integer;
Pix : TPixels;
nDiv : Integer;
nDivRs : Integer;
jP,jM,ip,im:Integer;
OpCount : Integer;
begin
ReadPixel(Bit,Pix);
if n mod 2 = 0 then n := n +1;
nDiv := n * n;
nDivRs := n div 2;
For i := 0 to Bit.Width-1 do begin
ip:= i + nDivRs;
im := i ;
if im < 0 then im := 0;
if ip > Bit.Width -1 then ip := Bit.Width-1;
For j := 0 to Bit.Height -1 do
begin
R:=0;
G:=0;
B:=0;
jP := j + nDivRs;
jM := j - nDivRs;
if Jp > bit.Height-1 then
jp := Bit.Height-1;
if jm <0 then jm :=0;
OpCount := (ip - im+1) *(jp-jm+1);
For k := im to Ip do begin
For l := jm to jp do
begin
R := R + Pix[k,l].rgbtRed;
G := G + Pix[k,l].rgbtGreen;
B := B + Pix[k,l].rgbtBlue;
end;
end;
Pix[i,j].rgbtBlue := B div opCount;
Pix[i,j].rgbtGreen := G div opCount;
Pix[i,j].rgbtRed := R div opCount;
end;
end;
WritePixel(Bit,Pix);
end;
procedure ReadPixel(Pic: Tbitmap; var tPix: TPixels);
Var PixPtr:PbyteArray;i,j,m:Integer;
begin
SetLength(tPix,Pic.Width,Pic.Height);
Pic.PixelFormat := pf24bit;
Pic.HandleType:=bmDIB;
For i :=0 to pic.Height-1 do begin
PixPtr:=Pic.ScanLine[i];
for j:= 0 to pic.Width-1 do begin
m := j*3;
tPix[j,i].rgbtBlue:=PixPtr[m];
tPix[j,i].rgbtGreen := PixPtr[m+1];
tPix[j,i].rgbtRed := PixPtr[m+2];
end;
end;
end;
procedure WritePixel(Pic: TBitmap; tPix: TPixels);
var PixPtr:PByteArray;i,j,m:Integer;
begin
pic.PixelFormat := pf24bit;
pic.HandleType:=bmDIB;
Pic.Height := High(tPix[0])+1;
Pic.Width:= High(tPix)+1;
For i :=0 to pic.Height-1 do begin
PixPtr:=Pic.ScanLine[i];
for j:= 0 to pic.Width-1 do begin
m := j*3;
PixPtr[M] := tPix[j,i].rgbtBlue;
PixPtr[m+1] := tPix[j,i].rgbtGreen;
PixPtr[m+2] := tPix[j,i].rgbtRed;
end;
end;
end;
procedure TForm1.btnExeClick(Sender: TObject);
var n :Integer;
begin
n := StrToInt(txtN.Text);
Bits.LoadFromFile(‘Test.bmp‘);
SmoothPicture(Bits,n);
PaintBox1.Refresh;
end;
procedure TForm1.FormDestroy(Sender: TObject);
begin
Bits.Free;
end;
end.
程序的運行結果如下圖所示。
原圖
柔化系數=21
銳化處理的原理是把每一像素的值與該像素斜上方的像素值之差乘以一個系數再加上該像素原來的顏色值。
如果記圖像中任意一個像素(x,y) (x∈[1,圖像寬度-1],y∈[1,圖像高度-1])修改前的RGB分值分別為OldRed, OldGreen, OldBlue, 修改後的RGB分值分別為NewR,NewG,NewB,有：
newR = (oldR - (x-1,y-1)的Red分值)×待定系數 + OldRed
newG = (oldG - (x-1,y-1)的Green分值)×待定系數 + OldGreen
newB = (oldB - (x-1,y-1)的Blue分值)×待定系數 + OldBlue
根據這個公式，我們的程序如下：
程序3.12
unit Sharp;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, ExtCtrls;
type
TPixels = Array of Array of TRGBTriple;
TfrmMain = class(TForm)
PaintBox1: TPaintBox;
btnExecute: TButton;
lblCap: TLabel;
txtS: TEdit;
procedure FormCreate(Sender: TObject);
procedure FormDestroy(Sender: TObject);
procedure btnExecuteClick(Sender: TObject);
procedure PaintBox1Paint(Sender: TObject);
private
Procedure SharpPic(Bit : TBitmap; n : Single);
public
{ Public declarations }
end;
procedure WritePixel(Pic: TBitmap; tPix: TPixels);
procedure ReadPixel(Pic: Tbitmap; var tPix: TPixels);
var
frmMain: TfrmMain;
Bits : TBitmap;
implementation
{$R *.dfm}
procedure TfrmMain.FormCreate(Sender: TObject);
begin
Bits := TBitmap.Create;
Bits.LoadFromFile(‘Test.bmp‘);
end;
procedure TfrmMain.FormDestroy(Sender: TObject);
begin
Bits.Free;
end;
procedure TfrmMain.btnExecuteClick(Sender: TObject);
var n : Single;c : Integer;
begin
Bits.LoadFromFile(‘Test.BMP‘);
Val(txtS.Text,n,c);
SharpPic(Bits,n);
PaintBox1.Refresh;
end;
procedure ReadPixel(Pic: Tbitmap; var tPix: TPixels);
Var PixPtr:PbyteArray;i,j,m:Integer;
begin
SetLength(tPix,Pic.Width,Pic.Height);
Pic.PixelFormat := pf24bit;
Pic.HandleType:=bmDIB;
For i :=0 to pic.Height-1 do begin
PixPtr:=Pic.ScanLine[i];
for j:= 0 to pic.Width-1 do begin
m := j*3;
tPix[j,i].rgbtBlue:=PixPtr[m];
tPix[j,i].rgbtGreen := PixPtr[m+1];
tPix[j,i].rgbtRed := PixPtr[m+2];
end;
end;
end;
procedure WritePixel(Pic: TBitmap; tPix: TPixels);
var PixPtr:PByteArray;i,j,m:Integer;
begin
pic.PixelFormat := pf24bit;
pic.HandleType:=bmDIB;
Pic.Height := High(tPix[0])+1;
Pic.Width:= High(tPix)+1;
For i :=0 to pic.Height-1 do begin
PixPtr:=Pic.ScanLine[i];
for j:= 0 to pic.Width-1 do begin
m := j*3;
PixPtr[M] := tPix[j,i].rgbtBlue;
PixPtr[m+1] := tPix[j,i].rgbtGreen;
PixPtr[m+2] := tPix[j,i].rgbtRed;
end;
end;
end;
procedure TfrmMain.SharpPic(Bit: TBitmap; n: Single);
var R, G, B : Integer;
i,j:Integer;
Pix : TPixels;
im,jm : Integer;
begin
ReadPixel(Bit,Pix);
For i := 1 to Bit.Width-1 do begin
im := i-1;
For j := 1 to Bit.Height-1 do begin
jm := j-1;
R := Pix[i,j].rgbtRed + Round((Pix[i,j].rgbtRed-Pix[im,jm].rgbtRed)*n);
G := Pix[i,j].rgbtGreen + Round((Pix[i,j].rgbtGreen-Pix[im,jm].rgbtGreen)*n);
B := Pix[i,j].rgbtBlue + Round((Pix[i,j].rgbtBlue-Pix[im,jm].rgbtBlue)*n);
if R > 255 then R := 255;
If R <0 then R := 0;
if G > 255 then G := 255;
If G <0 then G := 0;
if B > 255 then B := 255;
If B <0 then B := 0;
Pix[i,j].rgbtRed := R;
Pix[i,j].rgbtGreen := G;
Pix[i,j].rgbtBlue := B;
end;
end;
WritePixel(Bit,Pix);
end;
procedure TfrmMain.PaintBox1Paint(Sender: TObject);
begin
PaintBox1.Canvas.StretchDraw(Rect(0,0,400,300),Bits);
end;
end.
程序的運行結果如下圖所示。
原圖
銳化系數 = 0.95
探究Delphi的圖形處理 之八 -- 圖像混合(透明度)效果
圖像混合(透明度)效果
這種效果經常用在動畫的轉場過度上。這是一個由圖像A逐漸變化為圖像B的中間效果。就像向圖像B以變量N為透明度覆蓋在圖像B一樣。下圖展示了這種效果。
透明度 = 100%
透明度 = 50%
透明度 = 0%
圖像過渡效果的原理是，如果記透明度為A，那麼在確保圖像A和圖像B同等大小的情況下，創建一個與圖像A或B等大的圖像C，對於圖像C中每一個像素點P(x,y)，它的顏色值為：
R = 圖像A的像素點(x,y).R +(圖像B的像素點(x,y).R-圖像A的像素點(x,y).R)×A
G = 圖像A的像素點(x,y).G +(圖像B的像素點(x,y).G-圖像A的像素點(x,y).G)×A
B = 圖像A的像素點(x,y).B +(圖像B的像素點(x,y).B-圖像A的像素點(x,y).B)×A
根據公式，有下面的程序：
程序3.2
unit AlphaBlending;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, ComCtrls, StdCtrls, ExtCtrls;
type
TPixels = Array of array of TRGBTriple;
TForm1 = class(TForm)
PaintBox1: TPaintBox;
Label1: TLabel;
scA: TTrackBar;
lblPos: TLabel;
Bevel1: TBevel;
procedure FormCreate(Sender: TObject);
procedure PaintBox1Paint(Sender: TObject);
procedure FormDestroy(Sender: TObject);
procedure scAChange(Sender: TObject);
private
public
{ Public declarations }
end;
Procedure GraphicFading(PicA, PicB: TPixels; const PicR: tBitmap; Percent: Byte);
procedure WritePixel(Pic: TBitmap; tPix: TPixels);
procedure ReadPixel(Pic: Tbitmap; var tPix: TPixels);
var
Form1: TForm1;
BitA,BitB:TBitmap;
Bits: TBitmap;
PixA,PixB:TPixels;
implementation
{$R *.dfm}
procedure TForm1.FormCreate(Sender: TObject);
begin
BitA := TBitmap.create;
BitB := TBitmap.Create;
Bits := TBitmap.Create;
BitA.LoadFromFile(‘PicA.bmp‘);
BitB.LoadFromFile(‘PicB.bmp‘);
Bits.Assign(BitA); //這個語句可以把BitA中的內容復制到Bits中
Bits.PixelFormat := pf24Bit;
ReadPixel(BitA,PixA);
ReadPixel(BitB,PixB);
end;
procedure TForm1.PaintBox1Paint(Sender: TObject);
begin
PaintBox1.Canvas.Draw(0,0,Bits);
end;
Procedure GraphicFading(PicA, PicB: TPixels;
const PicR: tBitmap; Percent: Byte);//Make a Fading Picture From
var //PicA to PicB
MidR,MidG,MidB : Byte;
i,j : integer; m:Integer;
pixPtrA,pixPtrB,pixPtrR : PByteArray;
Position : Single;rPos,gPos:Integer;
PicRWidth:Integer;
begin
Position := Percent / 100;
PicRWidth:=PicR.Width-1;
for i := 0 to picR.Height -1 do begin
PixPtrR := picR.ScanLine[i];
for j := 0 to picRWidth do Begin
m:=j*3;
rPos:=m+2;
gPos:=m+1;
midR := PicA[j,i].RGBTRed+Round((PicB[j,i].RGBTRed-PicA[j,i].RGBTRed)*Position);
midG := PicA[j,i].RGBTgREEN+Round((PicB[j,i].RGBTgREEN-PicA[j,i].RGBTgREEN)*Position);
midB := PicA[j,i].RGBTBlue+Round((PicB[j,i].RGBTBlue-PicA[j,i].RGBTBlue)*Position);
pixPtrR[m] := midB;
pixPtrR[gPos] := midG;
pixPtrR[rPos] := MidR;
end;
end;
end;
procedure ReadPixel(Pic: Tbitmap; var tPix: TPixels);
Var PixPtr:PbyteArray;i,j,m:Integer;
begin
SetLength(tPix,Pic.Width,Pic.Height);
Pic.PixelFormat := pf24bit;
Pic.HandleType:=bmDIB;
For i :=0 to pic.Height-1 do begin
PixPtr:=Pic.ScanLine[i];
for j:= 0 to pic.Width-1 do begin
m := j*3;
tPix[j,i].rgbtBlue:=PixPtr[m];
tPix[j,i].rgbtGreen := PixPtr[m+1];
tPix[j,i].rgbtRed := PixPtr[m+2];
end;
end;
end;
procedure WritePixel(Pic: TBitmap; tPix: TPixels);
var PixPtr:PByteArray;i,j,m:Integer;
begin
pic.PixelFormat := pf24bit;
pic.HandleType:=bmDIB;
Pic.Height := High(tPix[0])+1;
Pic.Width:= High(tPix)+1;
For i :=0 to pic.Height-1 do begin
PixPtr:=Pic.ScanLine[i];
for j:= 0 to pic.Width-1 do begin
m := j*3;
PixPtr[M] := tPix[j,i].rgbtBlue;
PixPtr[m+1] := tPix[j,i].rgbtGreen;
PixPtr[m+2] := tPix[j,i].rgbtRed;
end;
end;
end;
procedure TForm1.FormDestroy(Sender: TObject);
begin
BitB.Free;
BitA.Free;
BitS.Free;
end;
procedure TForm1.scAChange(Sender: TObject);
begin
GraphicFading(PixA,PixB,Bits,scA.Position);
paintBox1.Canvas.Draw(0,0,Bits);
lblPos.Caption := IntToStr(scA.Position) + ‘ %‘;
lblPos.Refresh;
end;
end.
探究Delphi的圖形處理 之九 -- 轉為灰度圖像
作者:何詠 發布日期:(2005-4-12 20:56:06
轉為灰度圖像
將圖像轉為灰度的算法非常簡單，把圖像中每一個像素的R、G、B分值都設置為該像素R、G、B分值的平均值即可。這是因為，在RGB編碼中，如果一個像素的R、G、B分值相等，那麼這就是一個灰色的像素。例如RGB(i,i,i) (i∈[0,255])可以表示不同灰度等級的灰色。當i = 255時，該像素為白色，當 i = 0時，該像素為白色。下面的程序段給出了灰度圖像的算法。這一次，我們使用PRGBTriple類型作為ScanLine的指針類型，大家可以參考一下。
程序3.3
Function GraphicToGray(const Pic: Tbitmap): Integer;
var
i,j : integer;
pixPtr : PRGBTriple;
picH : integer;
picW : Integer;
GrayVal : Byte;
Begin
Pic.PixelFormat := pf24Bit;
Pic.HandleType := bmDIB;
picH := pic.Height;
picW := pic.Width;
for i := 0 to picH -1 do begin
pixPtr := pic.ScanLine[i];
for j := 0 to picW -1 do begin
GrayVal := Round((pixPtr^.rgbtBlue + pixPtr^.rgbtRed +pixptr^.rgbtGreen)/3);
pixPtr^.rgbtBlue := grayVal;
pixptr^.rgbtGreen := grayval;
pixptr^.rgbtRed := grayval;
inc(pixPtr);
end;
end;
end;
