Extended depth of field optical systems

A method for decreasing optical sensitivity to misfocus-related aberrations in an optical system characterized at least by an ambiguity function and a point spread function (PSF), which ambiguity function is a function of a normalized spatial frequency parameter u and a vertical variable v related to a misfocus parameter ψ, and which PSF is at least a function of the misfocus parameter ψ, the method comprising the steps of:

• imaging light from an object to form an optical image, which light is characterized by at least phase;
• detecting the optical image to generate a stored image;
• and
• post processing the stored image, in accordance with the PSF, to render an in-focus electronic image over a range of object distances between the object and the imaging system,
• wherein imaging includes altering at least phase of the light such that a main lobe of the ambiguity function is broader in v for a given value of u over an optical bandpass of the optical system, and the PSF has a functionally different form for a given value of ψ, in comparison to a main lobe of an ambiguity function, a PSF and the optical bandpass, respectively, characterizing the optical system without altering the phase for those given values of u and ψ, over the range of object distances.

A method for increasing a depth of field of an optical system characterized at least by an ambiguity function and a point spread function (PSF), which ambiguity function is a function of a normalized spatial frequency parameter u and a vertical variable v related to a misfocus parameter ψ, and which PSF is at least a function of the misfocus parameter ψ, the method comprising:

• imaging light from an object to form an image, the light being characterized by phase and amplitude;
• forming a digital representation of the image;
• and
• electronically processing the digital representation,
• wherein imaging includes altering at least the phase while maintaining the amplitude such that a main lobe of the ambiguity function is broader in v for a given value of u over an optical bandpass of the imaging system, and the PSF has a functionally different form in comparison to a main lobe of an ambiguity function, a PSF and the optical bandpass, respectively, characterizing the optical system without altering the phase for those given values of u and ψ, over a range of object distances between the object and the optical system, and
• wherein electronically processing includes modifying the digital representation in accordance with the PSF to render an in-focus electronic image over the range of object distances.