Imaging method and system with optimized extended depth of focus

#This invention relates to an imaging system and method for imaging with extended depth of focus.

#Extension of the depth of focus of imaging is a common goal of various imaging systems. Techniques for extending the depth of focus of imaging systems have been developed, and are described for example in the following publications:

#U.S. Pat. No. 6,536,898 and U.S. Pat. No. 7,025,454 disclose extended depth of field optics for human eye. This technique utilizes modification of contact lenses, intraocular implants, and/or the surface of the eye itself. This is accomplished by applying selected phase variations to these optical elements (e.g., by varying surface thickness of the cornea of the eye). The phase variations EDF-code the wavefront and cause the optical transfer function to remain essentially constant within a range of distances from the in-focus position. This provides a coded image on the retina. The human brain decodes this coded image, resulting in an in-focus image over an increased depth of field.

#In order to understand the invention and to see how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:

#FIGS. 1A and 1B illustrate dispersion effects in an imaging lens with EDOF;

#FIG. 2A shows schematically an imaging lens arrangement of the present invention;

#Reference is made to FIGS. 1A and 1B illustrating dispersion occurring in an imaging lens unit utilizing EDOF phase coding.

#FIG. 1A shows the simulation results for a Through Focus Modulation Transfer Function (TFMTF) for 100 cyc/mm spatial frequency. Four graphs are shown, G1-G4, corresponding to four different wavelengths in the range 0.5-0.6 μm. This simulation was carried out with Zemax, using “Arizona Eye model”. As shown, there is a relative shift for each wavelength: the plot for wavelength 0.6 μm is shifted 0.18 mm away from the corresponding graph for wavelength of 0.5 μm.

#Assuming all wavelengths are weighted the same (are of the same intensity), the resulted plot is illustrated in FIG. 1B.