Simulated EDF Imaging
Simulation of extended depth of field imaging is routinely performed prior to the fabrication of actual systems. These simulations agree very well with measurments made with the actual systems. One of the earliest simulations involved imaging planar spoke targets at various geometrical focus settings, or object ranges. From these simulations it was clear that extended depth of field systems could dramatically alter the characteristics of traditional imaging systems.
The above images are simulations of traditional imaging of a spoke target at various degrees of misfocus. The extreme misfocus value is equivalent to:
- nearly five wavelengths of misfocus error measured at the aperture edge.
- an aberration coefficient W20 equal to 5 lambda.
- nearly 30 times the Hopkins criteria for misfocus.
A square rather than circular aperture is used in this simulation. The center region of the in-focus image is blurred due to display-related aliasing.
By moving your mouse over the above set of images, you can view the simulated focus-invariant images of the spoke target at various values of misfocus, which shows vary little change in image quality with misfocus. In fact each image, even that at an extreme value of misfocus, is comparable to the in-focus image of the traditional imaging system.
These simulation results first appeared in Applied Optics, April 95, Vol. 34, No. 11, pg 1859-1866, "Extended Depth of Field Through Wave-Front Coding".