Cross correlation image sensor alignment system

Claim 2

An image sensor alignment system, comprising: a reference sensor producing a reference image from viewing a target; an alignable sensor producing an alignable image from viewing the target; alignment correlation means for determining a multidimensional correlation between the reference image and the alignable image by performing a rotation-translation correlation simultaneously and determining a highest correlation as the alignable image is rotated with respect to the reference image; and sensor alignment means for moving the alignable sensor into alignment responsive to the correlation and producing aligned sensors.

Claim 3

A system as recited in claim 1, further comprising: correction means for determining segmented cross correlations between images produced by the aligned sensors; and interpolation means for interpolating one of the images after sensor alignment responsive to the segmented cross correlations.

Claim 4

A system as recited in claim 2, wherein said correction means performs a translation cross correlation for each segment.

Claim 5

A system as recited in claim 1, wherein the correlation comprises a correlation selected from among cross correlation, differential correlation and Fourier transform correlation.

Claim 6

An image sensor alignment system, comprising: a reference sensor producing a reference image from viewing a target; an alignable sensor producing an alignable image from viewing the target; alignment correlation means for determining a multidimensional correlation between the reference image and the alignable image by determining a highest correlation as the alignable image is rotated with respect to the reference image; sensor alignment means for moving the alignable sensor into alignment responsive to the correlation and producing aligned sensors; and a white noise target with subpixel features imaged by said reference and alignable sensors.

Claim 7

An image sensor alignment system, comprising: a reference sensor producing a reference image from viewing a target; an alignable sensor producing an alignable image from viewing the target; alignment correlation means for determining a multidimensional correlation between the reference image and the alignable image by determining a highest correlation as the alignable image is rotated with respect to the reference image; sensor alignment means for moving the alignable sensor into alignment responsive to the correlation and producing aligned sensors; and a white noise target with subpixel features imaged by said reference and alignable sensors.

Claim 8

A system as recited in claim 5, wherein said target has reflective or transmissive areas at random locations, and when one of said sensors produces an in focus image a two dimensional autocorrelation function of the image has a rotational-translational peak.

Claim 11

An apparatus as recited in claim 7, wherein said white noise areas have a spectral response for each area over a range of wave lengths detected by the sensors that is related to the spectral response of each other area by a scalar.

Claim 12

An apparatus as recited in claim 7, wherein each area has a predetermined probability of having a reflectance or transmission between maximum and minimum reflectance or transmittance values obtained on said substrate.

Claim 13

An apparatus as recited in claim 7, wherein when an in focus image of the target is produced by one of the sensors, a two dimensional autocorrelation function of the image has a prominent peak.

Claim 14

A target as recited in claim 7, wherein said areas comprise subpixel size features.

Claim 15

A system as recited in claim 7, wherein said correlation comprises a correlation selected from among cross correlation, differential correlation and Fourier transform correlation.

Claim 16

An image sensor alignment system, comprising: a reference sensor producing a reference image divided into blocks; an alignable sensor producing an alignable image divided into blocks; an image sensor alignment target for cross correlation alignment of said reference and alignable sensors, said target comprising: a substrate; and white noise reflective or transmissive areas of subpixel size formed on said substrate, a spectral response of each area over a range of wave lengths detected by the reference and alignable sensors is related to the spectral response of each other area by a scalar where each area has a predetermined probability of having a reflectance or transmission between a maximum reflectance or transmission obtainable with said substrate and the areas are located at random locations and when images of the target are produced by said reference and alignable sensors a periodic autocorrelation of the images when in perfect alignment has a prominent peak; alignment correlation means for simultaneously, determining a rotational-translational correlation between the reference image and the alignable image by determining a highest image correlation as the alignable image is rotated with respect to the reference image; sensor alignment means for moving the alignment sensor into alignment responsive to the highest image correlation and producing aligned sensors; correction correlation means for determining correction correlations between the corresponding blocks of the image data produced by the aligned sensors by determining a highest block correlation as one of the blocks produced by the alignable sensor is shifted with respect to the corresponding one of the blocks of the reference sensor; coefficient means for determining correction values for the corresponding blocks responsive to the correction [cross]correlations; and a coefficient bin interpolation filter correcting misregistration errors using the correction values.

Claim 17

An image sensor alignment system, comprising: a reference sensor producing a reference image divided into blocks; an alignable sensor producing an alignable image divided into blocks; an image sensor alignment target for cross correlation alignment of said reference and alignable sensors, said target comprising: a substrate; and white noise reflective or transmissive areas of subpixel size formed on said substrate, a spectral response of each area over a range of wave lengths detected by the reference and alignable sensors is related to the spectral response of each other area by a scalar where each area has a predetermined probability of having a reflectance or transmission between a maximum reflectance or transmission obtainable with said substrate and the areas are located at random locations and when images of the target are produced by said reference and alignable sensors a periodic autocorrelation of the images when in perfect alignment has a prominent peak; alignment correlation means for simultaneously, determining a rotational-translational correlation between the reference image and the alignable image by determining a highest image correlation as the alignable image is rotated with respect to the reference image; sensor alignment means for moving the alignment sensor into alignment responsive to the highest image correlation and producing aligned sensors; correction correlation means for determining correction correlations between the corresponding blocks of the image data produced by the aligned sensors by determining a highest block correlation as one of the blocks produced by the alignable sensor is shifted with respect to the corresponding one of the blocks of the reference sensor; coefficient means for determining correction values for the corresponding blocks responsive to the correction [cross]correlations; and a coefficient bin interpolation filter correcting misregistration errors using the correction values.

Claim 18

A system as recited in claim 13, wherein said alignment correlation means and said correction correlation means perform a correlation selected from among cross correlation, differential correlation and Fourier transform correlation.