This image is an expansion of a 4D movie like the one
you saw in "4D Demo".
It is a 4-dimensional data set consisting of images taken at predefined
intervals and optical sections. Researchers can specify the number
of optical sections they wish to observe for a given time point and
then the microsope system changes focus to obtain each focal plane.
Such optical sectioning not only allows researchers to observe events
that might be happening at different planes of focus but also allows
them to create a data set that has the biological events they are
studying in the best focus. For example, here, the researcher used
4 focal planes with 5 time intervals for every focal plane. The images
you see here are all from a single embryo. Accordingly, each row,
from left to right, is the same embryo at a different time point.
Each column, from top to down, is the same embryo in different focal
plane. When the recording was done, the researcher can select the
focal plane that contains the most relevant data. Here, for example,
from top to bottom, the 3rd image might be the best choice.
