Multichannel imaging

Some articles published in 2024 reported the use QLSI with multichannel cameras, in particular with a 2-color camera 1, and a 4-polarisation camera 2. For these implementations, 2 to 4 interferograms shall be extracted from the raw camera image.

1

Single-shot quantitative phase-fluorescence imaging using cross-grating wavefront microscopy, B. Marthy, M. Benefice, G. Baffou, Sci. Rep. (2024)

2

Capturing the Full Electromagnetic Field of Light using Polarization-Resolved Cross-Grating Wavefront Microscopy, B. Marthy, M. Benefice, G. Baffou, submitted (2024)

Multicolor imaging

If the interferogram arises from a 2-color camera, the two interferograms can be extracted using the splitColors method:

Itf0 = importItfRef(folder,MI);
Itf = Itf0.splitColors();

If the input Itf0 is a list (an array) or \(N\) Interfero objects, then the output Itf is a \(N\times2\) array of Interfero objects, where each column is one color.

Some color cameras suffer from crosstalk between neighboring dexels of different colors. To correct for this crosstalk, use the Interfero method crosstalkCorrection:

Itf0 = importItfRef(folder,MI);
Itf = Itf0.splitColors();

Then, Itf can be processed like a normal Interfero object array using the QLSIprocess method:

IM = QLSIprocess(Itf, IL);

and just like Itf, IM is a \(N\times2\) ImageQLSI object array.

Multipolar imaging

If the interferogram arises from a 4-polarisation camera, the 4 interferograms can be extracted using the method splitPolars method:

Itf0 = importItfRef(folder,MI);
Itf = Itf0.splitPolars();

If the input Itf0 is a list (an array) or \(N\) Interfero objects, then the output Itf is a \(N\times4\) array of Interfero objects, where each column is one polarisation.

Then, Itf can be processed like a normal Interfero object using the QLSIprocess method:

IM = QLSIprocess(Itf, IL);

and just like Itf, IM is a \(N\times4\) ImageQLSI objects.

Then, the polarisation maps can be extracted using the CGMpolar method:

polarImages = IMmulti.CGMpolar();

The output polarImages is a structure containing the fields theta0, phibar, dphi, and rgbImage. They can be displayed using:

figure,
subplot(2,2,1)
imagegb(polarImages.theta0)
set(gca,'Colormap',hsv)
title("\theta_0")
subplot(2,2,2)
imagegb(polarImages.phibar)
title("\bar\phi")
subplot(2,2,3)
imageph(polarImages.dphi)
title("\delta\phi")
subplot(2,2,4)
imagegb(polarImages.rgbImage)
colormap(gca,hsv)
fullscreen