Fig. 2.

The LocalZProjector component. a Comparing the output of the maximum intensity projection (MIP) output with the LocalZProjector output on the Drosophila pupal notum expressing E-cadherin-GFP. The MIP incorporates signal from other layers (cuticle, fat body) in the projection that compromises its subsequent analysis. The use of a local projection that only includes the signal around a reference surface yields better quality projections. b Example of a single Z-plane from the same dataset showing E-cad::GFP (green) and UAS-nlsRFP (red, nuclear signal). This section crosses the cell layer in a region of high-curvature. Only a band of two cell diameters can be seen in focus in this slice. The red and green stripe at the bottom left corresponds to the auto-fluorescence of the cuticle layer. The white line is used to generate the sagital section in c. c Illustration of the LocalZProjector method. A 2D filter applied on each Z-plane is configured to generate a strong response at the layer of interest. Here the filter is a standard-deviation filter of window size 21 ×21. For each (X, Y) position, the Z-plane at which this filter has the strongest response is used to build a reference surface (white segmented line) around which intensity will be collected, possibly with an offset and a Z-range. All scale bars are 10 μm