目前我没有太多时间,但你可以从以下内容开始:
blur the image a bit (remove noise)
simple convolution will do for example few times with matrix
0.0 0.1 0.0
0.1 0.6 0.1
0.0 0.1 0.0
do color derivation by y axis
derivate pixel color along y
axis... for example I used this for each pixel of input image:
pixel(x,y)=pixel(x,y)-pixel(x,y-1)
beware the result is signed so you can normalize by some bias or use abs
value or handle as signed values ... In my example I used bias so the gray area is zero derivation ... black is most negative and white is most positive
blur the image a bit (remove noise)
enhance dynamic range
Simply find in image the min color c0
and max color c1
and rescale all pixels to predefined range <low,high>
. This will make the tresholding much more stable across different images...
pixel(x,y)=low + ((pixel(x,y)-c0)*(high-low)/(c1-c0)
so for example you can use low=0
and high=255
treshold all pixels which are bigger then treshold
缩小/重新着色区域,以留下每个 x
坐标上的中点
最顶部的点是红色的,底部是绿色的。
picture pic0,pic1,pic2; // pic0 is your input image, pic1,pic2 are output images
int x,y;
int tr0=Form1->sb_treshold0->Position; // treshold from scrollbar (=100)
// [prepare image]
pic1=pic0; // copy input image pic0 to output pic1 (upper)
pic1.pixel_format(_pf_s); // convert to grayscale intensity <0,765> (handle as signed numbers)
pic2=pic0; // copy input image pic0 to output pic2 (lower)
pic1.smooth(5); // blur 5 times
pic1.derivey(); // derive colros by y
pic1.smooth(5); // blur 5 times
pic1.enhance_range(); // maximize range
for (x=0;x<pic1.xs;x++) // loop all pixels
for (y=0;y<pic1.ys;y++)
if (pic1.p[y][x].i>=tr0) // if treshold in pic1 condition met
pic2.p[y][x].dd=0x00FF0000; //0x00RRGGBB then recolor pixel in pic2
pic1.pixel_format(_pf_rgba); // convert the derivation signed grayscale to RGBA (as biased grayscale)
// just render actual set treshold
pic2.bmp->Canvas->Brush->Style=bsClear;
pic2.bmp->Canvas->Font->Color=clYellow;
pic2.bmp->Canvas->TextOutA(5,5,AnsiString().sprintf("Treshold: %i",tr0));
pic2.bmp->Canvas->Brush->Style=bsSolid;
这段代码使用Borland的VCL封装的GDI位图/画布(对您来说不重要,只是渲染实际阈值设置),以及我自己的picture
类,因此需要一些成员变量的描述:
xs,ys
分辨率color p [ys] [xs]
直接像素访问(32位像素格式,每通道8位)pf
图像的实际选定像素格式,请参见下面的enum
enc_color/dec_color
将颜色通道打包解包到单独的数组中,以便轻松处理多个像素格式...因此,我不需要为每个像素格式分别编写每个函数clear(DWORD c)
用颜色c
填充图像color
只是DWORD dd
和BYTE db [4]
以及int i
的union
,用于简单的通道访问和有符号值处理。
以下是其中的一些代码块:
union color
{
DWORD dd; WORD dw[2]; byte db[4];
int i; short int ii[2];
color(){}; color(color& a){ *this=a; }; ~color(){}; color* operator = (const color *a) { dd=a->dd; return this; }; /*color* operator = (const color &a) { ...copy... return this; };*/
};
enum _pixel_format_enum
{
_pf_none=0, // undefined
_pf_rgba, // 32 bit RGBA
_pf_s, // 32 bit signed int
_pf_u, // 32 bit unsigned int
_pf_ss, // 2x16 bit signed int
_pf_uu, // 2x16 bit unsigned int
_pixel_format_enum_end
};
//---------------------------------------------------------------------------
void dec_color(int *p,color &c,int _pf)
{
p[0]=0;
p[1]=0;
p[2]=0;
p[3]=0;
if (_pf==_pf_rgba) // 32 bit RGBA
{
p[0]=c.db[0];
p[1]=c.db[1];
p[2]=c.db[2];
p[3]=c.db[3];
}
else if (_pf==_pf_s ) // 32 bit signed int
{
p[0]=c.i;
}
else if (_pf==_pf_u ) // 32 bit unsigned int
{
p[0]=c.dd;
}
else if (_pf==_pf_ss ) // 2x16 bit signed int
{
p[0]=c.ii[0];
p[1]=c.ii[1];
}
else if (_pf==_pf_uu ) // 2x16 bit unsigned int
{
p[0]=c.dw[0];
p[1]=c.dw[1];
}
}
//---------------------------------------------------------------------------
void dec_color(double *p,color &c,int _pf)
{
p[0]=0.0;
p[1]=0.0;
p[2]=0.0;
p[3]=0.0;
if (_pf==_pf_rgba) // 32 bit RGBA
{
p[0]=c.db[0];
p[1]=c.db[1];
p[2]=c.db[2];
p[3]=c.db[3];
}
else if (_pf==_pf_s ) // 32 bit signed int
{
p[0]=c.i;
}
else if (_pf==_pf_u ) // 32 bit unsigned int
{
p[0]=c.dd;
}
else if (_pf==_pf_ss ) // 2x16 bit signed int
{
p[0]=c.ii[0];
p[1]=c.ii[1];
}
else if (_pf==_pf_uu ) // 2x16 bit unsigned int
{
p[0]=c.dw[0];
p[1]=c.dw[1];
}
}
//---------------------------------------------------------------------------
void enc_color(int *p,color &c,int _pf)
{
c.dd=0;
if (_pf==_pf_rgba) // 32 bit RGBA
{
c.db[0]=p[0];
c.db[1]=p[1];
c.db[2]=p[2];
c.db[3]=p[3];
}
else if (_pf==_pf_s ) // 32 bit signed int
{
c.i=p[0];
}
else if (_pf==_pf_u ) // 32 bit unsigned int
{
c.dd=p[0];
}
else if (_pf==_pf_ss ) // 2x16 bit signed int
{
c.ii[0]=p[0];
c.ii[1]=p[1];
}
else if (_pf==_pf_uu ) // 2x16 bit unsigned int
{
c.dw[0]=p[0];
c.dw[1]=p[1];
}
}
//---------------------------------------------------------------------------
void enc_color(double *p,color &c,int _pf)
{
c.dd=0;
if (_pf==_pf_rgba) // 32 bit RGBA
{
c.db[0]=p[0];
c.db[1]=p[1];
c.db[2]=p[2];
c.db[3]=p[3];
}
else if (_pf==_pf_s ) // 32 bit signed int
{
c.i=p[0];
}
else if (_pf==_pf_u ) // 32 bit unsigned int
{
c.dd=p[0];
}
else if (_pf==_pf_ss ) // 2x16 bit signed int
{
c.ii[0]=p[0];
c.ii[1]=p[1];
}
else if (_pf==_pf_uu ) // 2x16 bit unsigned int
{
c.dw[0]=p[0];
c.dw[1]=p[1];
}
}
//---------------------------------------------------------------------------
void picture::smooth(int n)
{
color *q0,*q1;
int x,y,i,c0[4],c1[4],c2[4];
bool _signed;
if ((xs<2)||(ys<2)) return;
for (;n>0;n--)
{
#define loop_beg for (y=0;y<ys-1;y++){ q0=p[y]; q1=p[y+1]; for (x=0;x<xs-1;x++) { dec_color(c0,q0[x],pf); dec_color(c1,q0[x+1],pf); dec_color(c2,q1[x],pf);
#define loop_end enc_color(c0,q0[x ],pf); }}
if (pf==_pf_rgba) loop_beg for (i=0;i<4;i++) { c0[i]=(c0[i]+c0[i]+c1[i]+c2[i])>>2; clamp_u8(c0[i]); } loop_end
if (pf==_pf_s ) loop_beg { c0[0]=(c0[0]+c0[0]+c1[0]+c2[0])/ 4; clamp_s32(c0[0]); } loop_end
if (pf==_pf_u ) loop_beg { c0[0]=(c0[0]+c0[0]+c1[0]+c2[0])>>2; clamp_u32(c0[0]); } loop_end
if (pf==_pf_ss ) loop_beg for (i=0;i<2;i++) { c0[i]=(c0[i]+c0[i]+c1[i]+c2[i])/ 4; clamp_s16(c0[i]); } loop_end
if (pf==_pf_uu ) loop_beg for (i=0;i<2;i++) { c0[i]=(c0[i]+c0[i]+c1[i]+c2[i])>>2; clamp_u16(c0[i]); } loop_end
#undef loop_beg
#define loop_beg for (y=ys-1;y>0;y--){ q0=p[y]; q1=p[y-1]; for (x=xs-1;x>0;x--) { dec_color(c0,q0[x],pf); dec_color(c1,q0[x-1],pf); dec_color(c2,q1[x],pf);
if (pf==_pf_rgba) loop_beg for (i=0;i<4;i++) { c0[i]=(c0[i]+c0[i]+c1[i]+c2[i])>>2; clamp_u8(c0[i]); } loop_end
if (pf==_pf_s ) loop_beg { c0[0]=(c0[0]+c0[0]+c1[0]+c2[0])/ 4; clamp_s32(c0[0]); } loop_end
if (pf==_pf_u ) loop_beg { c0[0]=(c0[0]+c0[0]+c1[0]+c2[0])>>2; clamp_u32(c0[0]); } loop_end
if (pf==_pf_ss ) loop_beg for (i=0;i<2;i++) { c0[i]=(c0[i]+c0[i]+c1[i]+c2[i])/ 4; clamp_s16(c0[i]); } loop_end
if (pf==_pf_uu ) loop_beg for (i=0;i<2;i++) { c0[i]=(c0[i]+c0[i]+c1[i]+c2[i])>>2; clamp_u16(c0[i]); } loop_end
#undef loop_beg
#undef loop_end
}
}
//---------------------------------------------------------------------------
void picture::enhance_range()
{
int i,x,y,a0[4],min[4],max,n,c0,c1,q,c;
if (xs<1) return;
if (ys<1) return;
n=0; // dimensions to interpolate
if (pf==_pf_s ) { n=1; c0=0; c1=127*3; }
if (pf==_pf_u ) { n=1; c0=0; c1=255*3; }
if (pf==_pf_ss ) { n=2; c0=0; c1=32767; }
if (pf==_pf_uu ) { n=2; c0=0; c1=65535; }
if (pf==_pf_rgba) { n=4; c0=0; c1= 255; }
// find min,max
dec_color(a0,p[0][0],pf);
for (i=0;i<n;i++) min[i]=a0[i]; max=0;
for (y=0;y<ys;y++)
for (x=0;x<xs;x++)
{
dec_color(a0,p[y][x],pf);
for (q=0,i=0;i<n;i++)
{
c=a0[i]; if (c<0) c=-c;
if (min[i]>c) min[i]=c;
if (max<c) max=c;
}
}
// change dynamic range to max
for (y=0;y<ys;y++)
for (x=0;x<xs;x++)
{
dec_color(a0,p[y][x],pf);
for (i=0;i<n;i++) a0[i]=c0+(((a0[i]-min[i])*(c1-c0))/(max-min[i]+1));
// for (i=0;i<n;i++) if (a0[i]<c0) a0[i]=c0; // clamp if needed
// for (i=0;i<n;i++) if (a0[i]>c1) a0[i]=c1; // clamp if needed
enc_color(a0,p[y][x],pf);
}
}
//---------------------------------------------------------------------------
void picture::derivey()
{
int i,x,y,a0[4],a1[4];
if (ys<2) return;
for (y=0;y<ys-1;y++)
for (x=0;x<xs;x++)
{
dec_color(a0,p[y ][x],pf);
dec_color(a1,p[y+1][x],pf);
for (i=0;i<4;i++) a0[i]=a1[i]-a0[i];
enc_color(a0,p[y][x],pf);
}
for (x=0;x<xs;x++) p[ys-1][x]=p[ys-2][x];
}
//---------------------------------------------------------------------------
y
轴求导 像素颜色
... 例如,我对输入图像的每个像素使用了以下公式:pixel(x,y)=pixel(x,y)-pixel(x,y-1)
注意结果是有符号的,所以你可以通过一些偏差来进行归一化... 或者使用 ab
的值,或者将其处理为有符号的值... 在我的例子中,我使用了偏差,因此灰色区域的导数为零... 黑色是最负的,白色是最正的。 - SpektreBlur your image (Im) with a median filter to decrease the noise:
ImB=medfilt2(Im,[20 20]);
Find the edges using sobel mask and dilate them a little bit to connect close components, and 'clean' the overall image to get rid of small areas
edges = edge(ImB,'sobel');
se = strel('disk',1);
EnhancedEdges = imdilate(edges, se);
EdgeClean = bwareaopen(EnhancedEdges,1e3);
You then have your two zones, that you can detect separately using bwlabel
L=bwlabel(EdgeClean);
Finally, plot the two zones corresponding to L=1 and L=2
[x1 y1] = find(L==1);
[x2 y2] = find(L==2);
plot(y1,x1,'g',y2,x2,'r')
由于您的原始图像质量很好,除了噪点之外,所以步骤不多。您可能需要在参数上进行调整,因为我是从下载版本的图像开始的,这可能比原始图像质量低。当然,这只是一个最小化的代码,但我仍然希望能够帮到您。
Toghe
而不是 Dpeurich
,或者我错过了一些已删除的评论吗? - Spektrepkg load image
pkg load signal
median_filter_size = 10;
min_vertical_distance_between_layers = 35;
min_bright_level = 100/255;
img_rgb = imread("oct.png");% it's http://i.stack.imgur.com/PBnOj.png
img = im2double(img_rgb(:,:,1));
img=medfilt2(img,[median_filter_size median_filter_size]);
function idx = find_max(img,col_idx,min_vertical_distance_between_layers,min_bright_level)
c1=img(:,col_idx);
[pks idx]=findpeaks(c1,"MinPeakDistance",min_vertical_distance_between_layers,"MinPeakHeight",min_bright_level);
if ( rows(idx) < 2 )
idx=[1;1];
return
endif
% sort decreasing peak value
A=[pks idx];
A=sortrows(A,-1);
% keep the two biggest peaks
pks=A(1:2,1);
idx=A(1:2,2);
% sort by row index
A=[pks idx];
A=sortrows(A,2);
pks=A(1:2,1);
idx=A(1:2,2);
endfunction
layers=[];
idxs=1:1:columns(img);
for col_idx=idxs
layers=[layers find_max(img,col_idx,min_vertical_distance_between_layers,min_bright_level)];
endfor
hold on
imshow(img)
plot(idxs,layers(1,:),'r.')
plot(idxs,layers(2,:),'g.')
my_range=1:columns(idxs);
for i = my_range
x = idxs(i);
y1 = layers(1,i);
y2 = layers(2,i);
if y1 > rows(img_rgb) || y2 > rows(img_rgb) || x > columns(img_rgb) || y1==1 || y2==1
continue
endif
img_rgb(y1,x,:) = [255 0 0];
img_rgb(y2,x,:) = [0 255 0];
endfor
imwrite(img_rgb,"dst.png")
"dst.png"
,如下所示: