Optical Array Imaging System with Improved Focusing Function

Osamu IKEDA

Optical Array Imaging System with Improved Focusing Function

Osamu IKEDA

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In a previous article, an optical array imaging system has been presented. In this system, first, a set of array data is collected by repeatedly illuminating the object with laser light from each array element, detecting the reflected light as interferogram, and extracting the reflected wave field based on the spatial heterodyne detection. Then, an eigenvalue analysis is applied to the data to derive the wave field that would backpropagate and focus at a single point on the object; in this case, the iterative algorithm is used which indicates that the object point may have the largest reflectivity. It was shown experimentally that the single-point-focusing was attained for objects having several such parts with almost the same reflectivities. A preliminary study by computer simulation, however, indicates that the probability with which the wave focuses at multiple object points would not be small enough, resulting in a degraded image with ghost image components. In this paper, the array data within subaperture regions are selectively used to attain the single-point-focusing and obtain a good image for any object. First, it is shown analytically that the change in the dimension or center position of the aperture is effective to change the eigenvector so that it attains the single-point-focusing. Then, a procedure to find the optimum subapertures and a measure evaluating the degree of single-point-focusing for the eigenvector are presented. The method is examined in detail using experimentally obtained array data, and the results show that the method is effective in obtaining good images for any objects without sacrificing image resolution. When we compare the imaging system to an automatic focusing camera, it may be said that the additional processings enhance the capability of automatic focusing to a great degree.

Publication: IEICE TRANSACTIONS on Fundamentals Vol.E76-A No.12 pp.2108-2113

Publication Date: 1993/12/25

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Type of Manuscript: PAPER

Category: Parallel/Multidimensional Signal Processing

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Osamu IKEDA, "Optical Array Imaging System with Improved Focusing Function" in IEICE TRANSACTIONS on Fundamentals, vol. E76-A, no. 12, pp. 2108-2113, December 1993, doi: .
Abstract: In a previous article, an optical array imaging system has been presented. In this system, first, a set of array data is collected by repeatedly illuminating the object with laser light from each array element, detecting the reflected light as interferogram, and extracting the reflected wave field based on the spatial heterodyne detection. Then, an eigenvalue analysis is applied to the data to derive the wave field that would backpropagate and focus at a single point on the object; in this case, the iterative algorithm is used which indicates that the object point may have the largest reflectivity. It was shown experimentally that the single-point-focusing was attained for objects having several such parts with almost the same reflectivities. A preliminary study by computer simulation, however, indicates that the probability with which the wave focuses at multiple object points would not be small enough, resulting in a degraded image with ghost image components. In this paper, the array data within subaperture regions are selectively used to attain the single-point-focusing and obtain a good image for any object. First, it is shown analytically that the change in the dimension or center position of the aperture is effective to change the eigenvector so that it attains the single-point-focusing. Then, a procedure to find the optimum subapertures and a measure evaluating the degree of single-point-focusing for the eigenvector are presented. The method is examined in detail using experimentally obtained array data, and the results show that the method is effective in obtaining good images for any objects without sacrificing image resolution. When we compare the imaging system to an automatic focusing camera, it may be said that the additional processings enhance the capability of automatic focusing to a great degree.
URL: https://global.ieice.org/en_transactions/fundamentals/10.1587/e76-a_12_2108/_p

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@ARTICLE{e76-a_12_2108,
author={Osamu IKEDA, },
journal={IEICE TRANSACTIONS on Fundamentals},
title={Optical Array Imaging System with Improved Focusing Function},
year={1993},
volume={E76-A},
number={12},
pages={2108-2113},
abstract={In a previous article, an optical array imaging system has been presented. In this system, first, a set of array data is collected by repeatedly illuminating the object with laser light from each array element, detecting the reflected light as interferogram, and extracting the reflected wave field based on the spatial heterodyne detection. Then, an eigenvalue analysis is applied to the data to derive the wave field that would backpropagate and focus at a single point on the object; in this case, the iterative algorithm is used which indicates that the object point may have the largest reflectivity. It was shown experimentally that the single-point-focusing was attained for objects having several such parts with almost the same reflectivities. A preliminary study by computer simulation, however, indicates that the probability with which the wave focuses at multiple object points would not be small enough, resulting in a degraded image with ghost image components. In this paper, the array data within subaperture regions are selectively used to attain the single-point-focusing and obtain a good image for any object. First, it is shown analytically that the change in the dimension or center position of the aperture is effective to change the eigenvector so that it attains the single-point-focusing. Then, a procedure to find the optimum subapertures and a measure evaluating the degree of single-point-focusing for the eigenvector are presented. The method is examined in detail using experimentally obtained array data, and the results show that the method is effective in obtaining good images for any objects without sacrificing image resolution. When we compare the imaging system to an automatic focusing camera, it may be said that the additional processings enhance the capability of automatic focusing to a great degree.},
keywords={},
doi={},
ISSN={},
month={December},}

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TY - JOUR
TI - Optical Array Imaging System with Improved Focusing Function
T2 - IEICE TRANSACTIONS on Fundamentals
SP - 2108
EP - 2113
AU - Osamu IKEDA
PY - 1993
DO -
JO - IEICE TRANSACTIONS on Fundamentals
SN -
VL - E76-A
IS - 12
JA - IEICE TRANSACTIONS on Fundamentals
Y1 - December 1993
AB - In a previous article, an optical array imaging system has been presented. In this system, first, a set of array data is collected by repeatedly illuminating the object with laser light from each array element, detecting the reflected light as interferogram, and extracting the reflected wave field based on the spatial heterodyne detection. Then, an eigenvalue analysis is applied to the data to derive the wave field that would backpropagate and focus at a single point on the object; in this case, the iterative algorithm is used which indicates that the object point may have the largest reflectivity. It was shown experimentally that the single-point-focusing was attained for objects having several such parts with almost the same reflectivities. A preliminary study by computer simulation, however, indicates that the probability with which the wave focuses at multiple object points would not be small enough, resulting in a degraded image with ghost image components. In this paper, the array data within subaperture regions are selectively used to attain the single-point-focusing and obtain a good image for any object. First, it is shown analytically that the change in the dimension or center position of the aperture is effective to change the eigenvector so that it attains the single-point-focusing. Then, a procedure to find the optimum subapertures and a measure evaluating the degree of single-point-focusing for the eigenvector are presented. The method is examined in detail using experimentally obtained array data, and the results show that the method is effective in obtaining good images for any objects without sacrificing image resolution. When we compare the imaging system to an automatic focusing camera, it may be said that the additional processings enhance the capability of automatic focusing to a great degree.
ER -