Extended depth of field optical systems
First Claim
1. A method for generating an optical image, comprising:
- forming an optical image with at least one optical element while modifying wavefront phase such that there are no zeros in subsequent detected spatial frequencies of the optical image over an extended depth of focus that is larger than a depth of focus occurring without modifying wavefront phase.
2 Assignments
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Accused Products
Abstract
A system for increasing the depth of field and decreasing the wavelength sensitivity and the effects of misfocus-producing aberrations of the lens of an incoherent optical system incorporates a special purpose optical mask into the incoherent system. The optical mask has been designed to cause the optical transfer function to remain essentially constant within some range from the in-focus position. Signal processing of the resulting intermediate image undoes the optical transfer modifying effects of the mask, resulting in an in-focus image over an increased depth of field. Generally the mask is placed at a principal plane or the image of a principal plane of the optical system. Preferably, the mask modifies only phase and not amplitude of light. The mask may be used to increase the useful range of passive ranging systems.
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Citations
11 Claims
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1. A method for generating an optical image, comprising:
forming an optical image with at least one optical element while modifying wavefront phase such that there are no zeros in subsequent detected spatial frequencies of the optical image over an extended depth of focus that is larger than a depth of focus occurring without modifying wavefront phase. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A system for forming an image, comprising:
at least one lens and an optical mask that cooperate to form an optical image, the optical mask modifying wavefront phase such that there are no zeros in subsequent detected spatial frequencies of the optical image over an extended depth of focus larger than a depth of focus formed without the optical mask. - View Dependent Claims (8)
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9. A system for forming an image, comprising:
a lens and a phase mask that cooperate to form an optical image characterized by an optical transfer function that has no zeros within detected spatial frequencies of a detector over a larger depth of focus than without the phase mask. - View Dependent Claims (10)
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11. A system having insensitivity to misfocus, comprising:
at least one lens and an optical mask that cooperate to form an optical image, the optical mask modifying wavefront phase such that there are no zeros in subsequent detected spatial frequencies of the optical image over a range of misfocus beyond +/−
pi/10.
Specification