Expression intensity profiles taken from embryos imaged in different orientations. (a) The average intensity profile measured on the image bottom (blue), side (green) or top (red) with respect to the orientation of the embryo in the microscope. Intensities for eve stripe 1 were measured within two strips 1/16th of the width of the embryo circumference located on the left and right lateral midlines, after normalizing the expression values by setting the 1st percentile of the values in the whole embryo to 0 and the 99th percentile to 1. The plot shows the average intensity along the a/p axis for these strips. The difference in height between the three graphs gives an indication of the orientation-specific error. The measured intensity differs by less than 10% when the embryo surface is perpendicular or parallel to the optical axis. (b) An indication of the variation between individual PointClouds; the 52 profiles used to obtain the top average profile in (a).