如何为两个窗口拟合 EELS 背景

如何解决如何为两个窗口拟合 EELS 背景

dm-script 提供了拟合指数背景的功能，例如：

image src := GetFrontimage()
number bEs = 340 // eV
number bEe = 390 // eV
image signal := EELSSubtractPowerLawBackground(src,bEs,bEe)

然而，对于弱信号，我们希望通过拟合两个窗口背景来提高信噪比，例如：

有谁知道如何通过脚本来适应这种背景？ 提前致谢。

解决方法

感谢 BmyGuest，但我想构建一个全自动程序。 幸运的是，我找到了一个简单的写下脚本的解决方案。 代码如下：

// reference:
// https://towardsdatascience.com/mathematics-for-machine-learning-linear-regression-least-square-regression-de09cf53757c
// key information:
// y = mx + b
// where m = sum ((xdata-xmean)*(ydata-ymean)) / sum ((xdata-xmean)**2)
//       b = ymean - m*xmean

class FittingTwoWindowBkg : object {
    FittingTwoWindowBkg(object self) {
        Result("Script object 'FittingTwoWindowBkg' ["+self.ScriptObjectGetID().hex()+"] constructed.\n");
    };
    
    ~FittingTwoWindowBkg(object self) {
        Result("Script object 'FittingTwoWindowBkg' ["+self.ScriptObjectGetID().hex()+"] destructed.\n");
    };
    
    image TwoWindowBkgFitting(object self,image src,number Eng1,number Rng1,number Eng2,number Rng2) {
        number Eorignal = src.ImageGetDimensionOrigin(2)
        number Estep = src.ImageGetDimensionScale(2)
        number sx,sy,sz
        src.Get3DSize(sx,sz)
        
        image axis = src.ImageClone()
        axis = iplane*Estep + Eorignal
        axis.SetName("Energy axis")
        
        // the power law bkg I = A E^-r can be simplified to
        // the linear formula by : log(I) = -r*log(E) + log(A)
        image data = src.ImageClone()
        data = log(data)
        data.SetName("log SI")
        
        number ch1 = trunc((Eng1-Eorignal)/Estep)
        number r1= trunc(Rng1/Estep)
        number ch2 = trunc((Eng2-Eorignal)/Estep)
        number r2= trunc(Rng2/Estep)
        number nsz = r1+r2
        
        // prepare for regression
        image xdata := RealImage("xdata",4,sx,nsz)
        xdata.Slice3(0,1,2,r1,1) = axis.Slice3(0,ch1,1)
        xdata.Slice3(0,r2,ch2,1)
        
        image ydata := RealImage("ydata",nsz)
        ydata.Slice3(0,1) = data.Slice3(0,1)
        ydata.Slice3(0,1)
        
        image xmean := RealImage("xmean",nsz)
        image ymean := RealImage("ymean",nsz)
        for (number i=0; i<nsz; i++) {
            // to repeat the mean value as a 3d stack
            // the sum value of each pixel can be rapidly done by the Project function
            xmean.Slice2(0,i,1) = Project(xdata,2) / nsz
            ymean.Slice2(0,1) = Project(ydata,2) / nsz
        };
        
        // do regression
        image m = Project((xdata-xmean)*(ydata-ymean),2) / Project((xdata-xmean)**2,2)
        image b = ymean[icol,irow,0] - m*xmean[icol,0]
        
        // to apply y=mx+b to all the planes
        image bkg := src.ImageClone()
        for (number i=0; i<sz; i++) {
            bkg.Slice2(0,1) = m*axis.Slice2(0,1)+b
        };
        
        // reconstruct to the power law bkg
        bkg = exp(bkg)
        
        return bkg
    };
    
}

{
    Object FTW = Alloc(FittingTwoWindowBkg)
    number Eng1 = 1500      // eV,1st Energy of fitting window
    number Rng1 = 200       // eV,fitting range of 1st window
    number Eng2 = 2600      // eV,2nd Energy of fitting window
    number Rng2 = 200       // eV,fitting range of 2nd window
    image src := GetFrontImage()
    image bkg := FTW.TwoWindowBkgFitting(src,Eng1,Rng1,Eng2,Rng2)
    bkg.ShowImage()
};

,

不幸的是，不存在用于此的明确命令。 但是，可以通过模仿手动操作来解决此问题：添加 ROI 以显示内容。

以下脚本执行您想要的操作，但它确实需要显示频谱，并将删除其上的其他 ROI。

context.SaveAsync(item)