Method and apparatus of lens alignment for capsule
First Claim
1. A method of aligning a lens module with respect to an image sensor device for a capsule camera, wherein the image sensor device comprises multiple pixel arrays and the lens module comprises multiple lens sets to form multiple images corresponding to multiple fields of view associated with the multiple lens sets, and each lens set forms one image for one corresponding pixel array associated with one field of view, the method comprising:
- presenting one or more test images in the multiple fields of view associated with the multiple lens sets;
capturing multiple images in the multiple fields of view using the multiple pixel arrays;
deriving metric measurement comprising back focus distances (BFDs) corresponding to substantially parallel optical paths associated with the multiple pixel arrays based on the multiple images captured by the multiple pixel arrays, wherein each back focus distance (BFD) is related to a distance from one image plane of one pixel array to a last lens surface of one corresponding lens set; and
adjusting lens alignment between the lens module and the image sensor device based on the metric measurement of the BFDs for the multiple lens sets; and
wherein the lens module consists of four lens sets arranged laterally to provide a combined fields-of-view of 360 degrees and the image sensor device consists of four pixel arrays, four BFDs designated as Z1, Z2, Z3 and Z4 associated with four neighboring lens sets are determined, and wherein each of pixel array and one corresponding lens set is used for capturing images in one quadrant; and
wherein rotational alignments about x-axis and y-axis are adjusted to minimize (Z2−
Z4)/2d and (Z1−
Z3)/2d respectively, and wherein d is a lateral distance between two corresponding pixel arrays on two opposite sides and the x-axis and the y-axis are in a plane parallel to the image sensor device.
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Abstract
A method and apparatus of aligning a lens module with respect to an image sensor device for a capsule camera are disclosed. The image sensor device comprises multiple pixel arrays and the lens module comprises multiple lens sets to form multiple images corresponding to multiple fields of view associated with the multiple lens sets, and each lens set forms one image for one corresponding pixel array associated with one field of view. A method according to the present invention present invention, one or more test images are presented in the multiple fields of view associated with the lens module. Multiple images in the multiple fields of view are captured using the multiple pixel arrays. Metric measurement is derived based on the multiple images captured by the multiple pixel arrays. Lens alignment between the lens module and the image sensor device is then adjusted based on the metric measurement.
11 Citations
16 Claims
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1. A method of aligning a lens module with respect to an image sensor device for a capsule camera, wherein the image sensor device comprises multiple pixel arrays and the lens module comprises multiple lens sets to form multiple images corresponding to multiple fields of view associated with the multiple lens sets, and each lens set forms one image for one corresponding pixel array associated with one field of view, the method comprising:
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presenting one or more test images in the multiple fields of view associated with the multiple lens sets; capturing multiple images in the multiple fields of view using the multiple pixel arrays; deriving metric measurement comprising back focus distances (BFDs) corresponding to substantially parallel optical paths associated with the multiple pixel arrays based on the multiple images captured by the multiple pixel arrays, wherein each back focus distance (BFD) is related to a distance from one image plane of one pixel array to a last lens surface of one corresponding lens set; and adjusting lens alignment between the lens module and the image sensor device based on the metric measurement of the BFDs for the multiple lens sets; and wherein the lens module consists of four lens sets arranged laterally to provide a combined fields-of-view of 360 degrees and the image sensor device consists of four pixel arrays, four BFDs designated as Z1, Z2, Z3 and Z4 associated with four neighboring lens sets are determined, and wherein each of pixel array and one corresponding lens set is used for capturing images in one quadrant; and wherein rotational alignments about x-axis and y-axis are adjusted to minimize (Z2−
Z4)/2d and (Z1−
Z3)/2d respectively, and wherein d is a lateral distance between two corresponding pixel arrays on two opposite sides and the x-axis and the y-axis are in a plane parallel to the image sensor device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of aligning a lens module with respect to an image sensor device for a capsule camera, wherein the image sensor device comprises multiple pixel arrays and the lens module comprises multiple lens sets to form multiple images corresponding to multiple fields of view associated with the multiple lens sets, and each lens set forms one image for one corresponding pixel array associated with one field of view, the method comprising:
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presenting one or more test images in the multiple fields of view associated with the multiple lens sets; capturing multiple images in the multiple fields of view using the multiple pixel arrays; deriving metric measurement comprising back focus distances (BFDs) corresponding to substantially parallel optical paths associated with the multiple pixel arrays based on the multiple images captured by the multiple pixel arrays, wherein each back focus distance (BFD) is related to a distance from one image plane of one pixel array to a last lens surface of one corresponding lens set; and adjusting lens alignment between the lens module and the image sensor device based on the metric measurement of the BFDs for the multiple lens sets; and wherein the lens module consists of four lens sets arranged laterally to provide a combined fields-of-view of 360 degrees and the image sensor device consists of four pixel arrays, four BFDs designated as Z1, Z2, Z3 and Z4 associated with four neighboring lens sets are determined, and wherein each of pixel array and one corresponding lens set is used for capturing images in one quadrant; and wherein the lens alignment is adjusted to minimize alignment error for all quadrants of the lens module, wherein the alignment error is determined according to |Z1−
Z2+Z3-Z4|/4.
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10. A method of aligning a lens module with respect to an image sensor device for a capsule camera, wherein the image sensor device comprises multiple pixel arrays and the lens module comprises multiple lens sets to form multiple images corresponding to multiple fields of view associated with the multiple lens sets, and each lens set forms one image for one corresponding pixel array associated with one field of view, the method comprising:
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presenting one or more test images in the multiple fields of view associated with the multiple lens sets; capturing multiple images in the multiple fields of view using the multiple pixel arrays; deriving metric measurement comprising back focus distances (BFDs) corresponding to substantially parallel optical paths associated with the multiple pixel arrays based on the multiple images captured by the multiple pixel arrays, wherein each back focus distance (BFD) is related to a distance from one image plane of one pixel array to a last lens surface of one corresponding lens set; and adjusting lens alignment between the lens module and the image sensor device based on the metric measurement, wherein said adjusting the lens alignment comprising adjusting translational offset (Tx, Ty) between an optical center of the multiple lens set and a center of the pixel arrays to minimize the translational offset; and wherein the translational offset is determined by using a white cylindrical target as a test image to find a center of each quadrant of the lens module with four lens sets and the center of each quadrant of the lens module is determined from a center of contours of an image of the white cylindrical target. - View Dependent Claims (11, 12, 13, 14, 15)
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16. An apparatus for aligning a lens module with respect to an image sensor device for a capsule camera, wherein the image sensor device comprises multiple pixel arrays and the lens module comprises multiple lens sets to form multiple images corresponding to multiple fields of view associated with the multiple lens sets, and each lens set forms one image for one corresponding pixel array associated with one field of view, the apparatus comprising one or more electronic circuits, controllers or processors arranged to:
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present one or more test images in the multiple fields of view associated with the multiple lens sets; capture multiple images in the multiple fields of view using the multiple pixel arrays; derive metric measurement comprising back focus distances (BFDs) corresponding to substantially parallel optical paths associated with the multiple pixel arrays based on the multiple images captured by the multiple pixel arrays, wherein each back focus distance (BFD) is related to a distance from one image plane of one pixel array to a last lens surface of one corresponding lens set; and adjust lens alignment between the lens module and the image sensor device based on the metric measurement of the BFDs for the multiple lens sets; and wherein the lens module consists of four lens sets arranged laterally to provide a combined fields-of-view of 360 degrees and the image sensor device consists of four pixel arrays, four BFDs designated as Z1, Z2, Z3 and Z4 associated with four neighboring lens sets are determined, and wherein each of pixel array and one corresponding lens set is used for capturing images in one quadrant; and wherein rotational alignments about x-axis and y-axis are adjusted to minimize (Z2−
Z4)/2d and (Z1−
Z3)/2d respectively, and wherein d is a lateral distance between two corresponding pixel arrays on two opposite sides and the x-axis and the y-axis are in a plane parallel to the image sensor device.
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Specification