Figure 3. Confocal slit detection enables direct fusion of opposing views.

(a) Transverse planes of 3D data stacks halfway between the anterior and posterior pole of an embryo expressing His2Av-mCherry (see red circle in (b)) are shown for widefield and eCSD detection. Top two rows show individual stacks acquired by the two opposing cameras in widefield and eCSD mode. Bottom row compares simultaneous widefield and eCSD images. Camera 1 and Camera 2 are oriented to the left and to the right, respectively. (b) Similar to the illumination light, also the emitted light is subject to scattering. The effect of scattering increases the deeper the image plane lies inside the embryo (dashed blue lines illustrate the light-sheet plane). The red circle indicates the transverse plane depicted in (a). (c) Comparison of intensity profile for widefield and eCSD 3D data stacks. Widefield detection collects a significant amount of photons from the far side of the embryo (around 50%), which yields a structureless blurred image (top row in (a)). Direct addition of the data thus results in a reduction of the signal-to-noise ratio (bottom row left panel in (a)). In contrast, eCSD blocks the majority of emitted photons from the far side, which enables a direct fusion (addition) of the two opposing camera stacks. All scale bars are 50 μm and all images are averages of 4 planes around the centre of the embryo.