Auto-focus (AF) lens and process

An AF lens and process system for movement of a lens, while acquiring a color image, to obtain the best focus of the color image on the focal plane of an imager comprising:

• providing a lens having a pre-determined amount of longitudinal chromatic aberrations (LCA), the lens focusing the color image on the focal plane of an imager, the imager providing an array of data values for the primary colors of Red (R), Green (G) and Blue (B),
• providing a means for calculating an R, G and B image quality signal, and for calculating a present difference function based on the R, G and B image quality signals,
• providing a means for comparing the present calculated difference function with previously stored calculated difference functions in an array of previously stored calculated difference functions with corresponding lens position distance value pairs and
• finding a best match between the present calculated difference function and the previously stored calculated difference function, and outputting the corresponding lens position distance value to
• a Lens Movement Control System for moving the lens to obtain a best focus position.

An AF lens and process system for movement of a lens, while acquiring a color image, to obtain the best focus of the color image on the focal plane of an imager comprising:

• a lens having a pre-determined amount of longitudinal chromatic aberrations (LCA) through an aperture, the lens focusing the color image on the focal plane of an imager, the imager providing an array of intensity values for the primary colors of Red (R). Green (G) and Blue (B),
• a means responsive to the intensity values of each of the primary colors for calculating an R, G and B image quality signal,
• a comparator circuit for comparing the values of the R, G and B image quality signals and,
• a logic circuit for outputting a positive direction command to drive the lens in a first direction if the B image quality signal is greater than the R image quality signal and if the R image quality signal is greater than the G image quality signal.

An AF lens and process system for movement of a lens, while acquiring a color image, to obtain the best focus of the color image on the focal plane of an imager comprising:

• providing a lens having a pre-determined amount of longitudinal chromatic aberrations (LCA), the lens focusing the color image on the focal plane of an imager, the imager providing an array of data values for the primary colors of Red (R), Green (G) and Blue (B),
• providing a means for calculating an R, G and B image quality signal, and for calculating a present difference function based on the R, G and B image quality signals,
• providing a means for comparing the present calculated difference function with previously stored calculated difference functions in an array of previously stored calculated difference functions with corresponding lens position distance value pairs and
• finding a best match between the present calculated difference function and the previously stored calculated difference function, and outputting the corresponding lens position distance value to
• a Lens Movement Control System for moving the lens to obtain a best focus position.