Delphi图像处理 -- 高保真反差
阅读提示：
《Delphi图像处理》系列以效率为侧重点，一般代码为PASCAL，核心代码采用BASM。
《C++图像处理》系列以代码清晰，可读性为主，全部使用C++代码。
尽可能保持二者内容一致，可相互对照。
本文代码必须包括文章《Delphi图像处理 -- 数据类型及公用过程》中的ImageData.pas单元。
图像高保真反差处理很简单，其步骤如下：
1、备份图像原数据；
2、按给定半径对图像进行高斯模糊；
3、用原像素与高斯模糊后的像素相减，形成一个差值；
4、差值加128，完毕。
下面是高保真反差代码，包括高斯模糊代码（关于高斯模糊见文章《Delphi图像处理 -- 高斯模糊》，下面的高斯模糊代码也是从该文拷贝来的）：
procedure CrossBlur(var Dest: TImageData; const Source: TImageData; Weights: Pointer; Radius: Integer);
var
height, srcStride: Integer;
dstOffset, srcOffset: Integer;
asm
push esi
push edi
push ebx
push ecx
mov ecx, [edx].TImageData.Stride
mov srcStride, ecx
call _SetCopyRegs
mov height, edx
mov srcOffset, eax
mov dstOffset, ebx
pop ebx
pxor xmm7, xmm7
push esi // pst = Source.Scan0
push edi
push edx
push ecx
// blur col
mov eax, srcStride
mov edx, eax
shr edx, 2 // width = Source.Width
mov edi, Radius
shl edi, 1
imul edi, eax
add edi, esi // psb = pst + Radius * 2 * Source.Stride
@@cyLoop:
push edx
@@cxLoop:
push esi
push edi
push ebx
mov ecx, Radius
pxor xmm0, xmm0 // sum = 0
@@cblurLoop:
movd xmm1, [esi] // for (i = 0; i < Radius; i ++)
movd xmm2, [edi] // {
punpcklbw xmm1, xmm7
punpcklbw xmm2, xmm7
paddw xmm1, xmm2 // ps = pst + psb
punpcklwd xmm1, xmm7
cvtdq2ps xmm1, xmm1 // pfs (flaot * 4) = ps (int * 4)
mulps xmm1, [ebx] // pfs *= Weights[i]
addps xmm0, xmm1 // sum += pfs
add ebx, 16
add esi, eax // pst += Source.Stride
sub edi, eax // psb -= Source.Stride
loop @@cblurLoop // }
movd xmm1, [esi]
punpcklbw xmm1, xmm7
punpcklwd xmm1, xmm7
cvtdq2ps xmm1, xmm1 // pfs (flaot * 4) = pst (int * 4)
mulps xmm1, [ebx] // pfs *= Weights[Radius]
addps xmm0, xmm1 // sum += pfs
pop ebx
pop edi
pop esi
cvtps2dq xmm0, xmm0 // ps (int * 4) = sum (flaot * 4)
packssdw xmm0, xmm7
packuswb xmm0, xmm7
movd [esi], xmm0 // pst (byte * 4) = ps (int * 4) pask
add esi, 4
add edi, 4
dec edx
jnz @@cxLoop
pop edx
dec height
jnz @@cyLoop
pop edx
pop height
pop edi // pd = Dest.Scan0
pop esi // psl = pst
mov eax, Radius
shl eax, 1+2
add eax, esi // psr = psl + Radius * 2
// blur row
@@ryLoop:
push edx // width = Dest.Width
@@rxLoop:
push esi
push ebx
push eax
mov ecx, Radius
pxor xmm0, xmm0 // sum = 0
@@rblurLoop:
movd xmm1, [esi] // for (i = 0; i < Radius; i ++)
movd xmm2, [eax] // {
punpcklbw xmm1, xmm7
punpcklbw xmm2, xmm7
paddw xmm1, xmm2 // ps = psl + psr
punpcklwd xmm1, xmm7
cvtdq2ps xmm1, xmm1 // pfs (flaot * 4) = ps (int * 4)
mulps xmm1, [ebx] // pfs *= Weights[i]
addps xmm0, xmm1 // sum += pfs
add ebx, 16
add esi, 4 // psl ++
sub eax, 4 // psr --
loop @@rblurLoop // }
movd xmm1, [esi]
punpcklbw xmm1, xmm7
punpcklwd xmm1, xmm7
cvtdq2ps xmm1, xmm1 // pfs (flaot * 4) = psl (int * 4)
mulps xmm1, [ebx] // pfs *= Weights[Radius]
addps xmm0, xmm1 // sum += pfs
cvtps2dq xmm0, xmm0 // ps (int * 4) = sum (flaot * 4)
packssdw xmm0, xmm7
packuswb xmm0, xmm7
movd [edi], xmm0 // pd (byte * 4) = ps (int * 4) pask
pop eax
pop ebx
pop esi
add eax, 4
add esi, 4
add edi, 4
dec edx
jnz @@rxLoop
add eax, srcOffset
add esi, srcOffset
add edi, dstOffset
pop edx
dec height
jnz @@ryLoop
pop ebx
pop edi
pop esi
end;
// --> st x
// <-- st e**x = 2**(x*log2(e))
function _Expon: Extended;
asm
fldl2e // y = x*log2e
fmul
fld st(0) // i = round(y)
frndint
fsub st(1), st // f = y - i
fxch st(1) // z = 2**f
f2xm1
fld1
fadd
fscale // result = z * 2**i
fstp st(1)
end;
function GetWeights(var Buffer, Weights: Pointer; Q: Single; Radius: Integer): Integer;
const
_fcd1: Single = 0.1;
_fc1: Single = 1.0;
_fc2: Single = 2.0;
_fc250: Single = 250.0;
_fc255: Single = 255.0;
var
R: Integer;
v, QQ2: double;
asm
mov R, ecx
mov ecx, eax
fld Q
fabs
fcom _fcd1
fstsw ax
sahf
jae @@1
fld _fcd1
fstp st(1) // if (Q < 0.1) Q = 0.1
jmp @@2
@@1:
fcom _fc250
fstsw ax
sahf
jbe @@2
fld _fc250
fstp st(1) // if (Q > 250) Q = 250
@@2:
fst Q
fmul Q
fmul _fc2
fstp QQ2 // QQ2 = 2 * Q * Q
fwait
mov eax, R
test eax, eax
jg @@10
push eax // if (radius <= 0)
fld1 // {
fadd Q // radius = Abs(Q) + 1
fistp [esp].Integer
fwait
pop eax
@@testRadius: // while (TRUE)
mov R, eax // {
fldz // sum = 0
@@testLoop: // for (R = radius; R > 0; R ++)
fild R // {
fld st(0)
fmulp st(1), st
fdiv QQ2
fchs
call _Expon // tmp = Exp(-(R * R) / (2.0 * Q * Q));
cmp R, eax
jne @@3
fst v // if (R == radius) v = tmp
@@3:
faddp st(1), st(0) // sum += tmp
dec R
jnz @@testLoop // }
fmul _fc2 // sum *= 2
fadd _fc1 // sum += 1
fdivr v
fmul _fc255
fistp R
cmp R, 0
je @@4 // if ((INT)(v / sum * 255 + 0.5) = 0) break
inc eax // radius ++
jmp @@testRadius // }
@@4:
dec eax
jnz @@5
inc eax
@@5:
mov R, eax // }
@@10:
inc eax
shl eax, 4
add eax, 12
push edx
push ecx
mov edx, eax
mov eax, GHND
call GlobalAllocPtr
pop ecx
pop edx
test eax, eax
jz @@Exit
mov [ecx], eax // buffer = GlobalAllocPtr(GHND, (Radius + 1) * 16 + 12)
add eax, 12
and eax, -16
mov [edx], eax // weights = ((char* )buffer + 12) & 0xfffffff0
mov ecx, R // ecx = radius
mov edx, eax // edx = weights
fldz // for (i = radius, sum = 0; i > 0; i --)
@@clacLoop: // {
fild R
fld st(0)
fmulp st(1), st
fdiv QQ2
fchs
call _Expon
fstp [edx].Double // weights[i] = Expon(-(i * i) / (2 * Q * Q))
fadd [edx].Double // sum += weights[i]
add edx, 16
dec R
jnz @@clacLoop // }
fmul _fc2 // sum *= 2
fld1
fstp [edx].Double // weights[radius] = 1
fadd [edx].Double // sum += weights[radius]
push ecx
inc ecx
@@divLoop: // for (i = 0; i <= Radius; i ++)
fld st(0) // weights[i] = Round(weights[i] / sum)
fdivr [eax].Double
fst [eax].Single
fst [eax+4].Single
fst [eax+8].Single
fstp [eax+12].Single
add eax, 16
loop @@divLoop
ffree st(0)
fwait
pop eax // return Radius
@@Exit:
end;
// 高斯模糊。
procedure ImageGaussiabBlur(var Data: TImageData; Q: Single; Radius: Integer);
var
Buffer, Weights: Pointer;
src: TImageData;
begin
Radius := GetWeights(Buffer, Weights, Q, Radius);
if Radius = 0 then Exit;
if Data.AlphaFlag then
ArgbConvertPArgb(Data);
src := _GetExpandData(Data, Radius);
CrossBlur(Data, src, Weights, Radius);
FreeImageData(src);
GlobalFreePtr(Buffer);
if Data.AlphaFlag then
PArgbConvertArgb(Data);
end;
procedure DoHighPass(var Dest: TImageData; const Source: TImageData);
asm
push esi
push edi
push ebx
pxor mm7, mm7
mov ecx, 128
movd mm6, ecx
pshufw mm6, mm6, 0
call _SetCopyRegs
@@yLoop:
push ecx
@@xLoop:
movd mm0, [esi] // mm0 = 原像素
movd mm1, [edi] // mm1 = 高斯模糊后像素
punpcklbw mm0, mm7
punpcklbw mm1, mm7
psubw mm0, mm1
paddw mm0, mm6 // mm0 = mm0 - mm1 + 128
packuswb mm0, mm7
movd [edi], mm0
add esi, 3
add edi, 3
movsb
loop @@xLoop
pop ecx
add esi, eax
add edi, ebx
dec edx
jnz @@yLoop
pop ebx
pop edi
pop esi
emms
end;
// 高保真反差
procedure ImageHighPass(var Data: TImageData; Radius: Single);
procedure CopyData(var Dest: TImageData; const Source: TImageData);
asm
push esi
push edi
mov ecx, [eax].TImageData.Width
imul ecx, [eax].TImageData.Height
mov edi, [eax].TImageData.Scan0
mov esi, [edx].TImageData.Scan0
rep movsd
pop edi
pop esi
end;
var
IsInvertScan0: Boolean;
Src: TImageData;
begin
// 备份图像数据
Src := NewImageData(Data.Width, Data.Height);
IsInvertScan0 := Data.Stride < 0;
if IsInvertScan0 then
_InvertScan0(Data);
CopyData(Src, Data);
// 图像数据作高斯模糊
ImageGaussiabBlur(Data, Radius, 0);
// 用备份图像数据和高斯模糊图像数据作高保真反差
DoHighPass(Data, Src);
FreeImageData(Src);
if IsInvertScan0 then
_InvertScan0(Data);
end;
简单例子：
procedure TForm1.Button2Click(Sender: TObject);
var
bmp: TBitmap;
data: TImageData;
begin
bmp := TBitmap.Create;
bmp.LoadFromFile('d:\source.bmp');
data := GetBitmapData(bmp);
ImageHighPass(Data, 3);
Canvas.Draw(0, 0, bmp);
bmp.Free;
end;
下面是原图以及例子运行界面截图：
《Delphi图像处理》系列使用GDI+单元下载地址和说明见文章《GDI+ for VCL基础 -- GDI+ 与 VCL》。
因水平有限，错误在所难免，欢迎指正和指导。邮箱地址：[email protected]
这里可访问《Delphi图像处理 -- 文章索引》。