Object Distance Deriving Device

• US 20100103259A1
• Filed: 10/20/2009
• Published: 04/29/2010
• Est. Priority Date: 10/20/2008
• Status: Abandoned Application

• Current Assignee: Funai Electric Co., Ltd. (Funai Electric Holdings Company Limited), Osaka University
• Original Assignee: Funai Electric Co., Ltd. (Funai Electric Holdings Company Limited), Osaka University
• Inventors: Toyoda, Takashi, Masaki, Yasuo, Nakao, Yoshizumi, Horisaki, Ryoichi, TANIDA, Jun
• Application Number:
  US12/582,501
• Publication Number:
  US 20100103259A1
• Time in Patent Office: Days
• US Class Current: 348/139
• CPC Class Codes: G01B 11/026 by measuring distance between sensor and object G01B11/0608 takes precedence
• CPC Class Codes: G01C 3/08 Use of electric radiation detectors
• CPC Class Codes: G02B 27/58 Optics for apodization or superresolution; Optical synthetic aperture systems
• CPC Class Codes: G02B 3/0043 Inhomogeneous or irregular arrays, e.g. varying shape, size, height
• CPC Class Codes: G02B 7/38 measured at different points on the optical axis , e.g. focussing on two or more planes and comparing image data

Abstract

An object distance deriving device comprises: a compound-eye imaging device having imaging units with optical lenses randomly arranged for the respective imaging units; and a distance calculation unit to calculate an object distance using images captured by the compound-eye imaging device. The distance calculation unit: sets temporary distances z (S1); calculates an imaging process matrix [Hz] according to a temporary distance z (S2); estimates a high-resolution image by super-resolution processing using the imaging process matrix [Hz] (S3); uses the estimated high-resolution image to calculate an evaluation value distribution E for evaluating the temporary distance z (S4); repeats steps S2 to S4 for all temporary distances z (S5); and determines, as an object distance, one temporary distance z giving a minimum evaluation value in the evaluation value distributions E. This makes it possible to accurately derive the object distance even if the baseline length of the compound-eye imaging device is limited.

Claims

1. An object distance deriving device comprising:

image means for capturing images of an object using an imaging process expressed by a matrix (hereafter referred to as “

imaging process matrix”

); and

distance calculating means for calculating a distance (hereafter referred to as “

object distance”

) of the object from the imaging means based on the images captured by the imaging means,

wherein the distance calculating means comprises;

distance setting means for setting temporary distances between the object and the imaging means;

imaging process matrix calculating means for calculating an imaging process matrix (hereafter referred to as “

imaging process matrix calculation”

) when the object is at one of the temporary distances set by the distance setting means;

high-resolution image estimating means for estimating a high-resolution image (hereafter referred to as “

high-resolution image estimation”

) by super-resolution processing using the imaging process matrix calculated by the imaging process matrix calculating means;

evaluation value calculating means for calculating evaluation values (hereafter referred to as “

evaluation value calculation”

) to evaluate the one of the temporary distances set by the distance setting means based on differences between the images captured by the imaging means and an image obtained by multiplying the imaging process matrix and the high-resolution image estimated by the high-resolution image estimating means;

repeating means for repeating the imaging process matrix calculation, the high-resolution image estimation and the evaluation value calculation for each of the other temporary distances set by the distance setting means so as to calculate evaluation values to evaluate all the temporary distances; and

distance determining means for determining, as an object distance, one of the temporary distances which gives a minimum or maximum evaluation value in all the evaluation values to evaluate all the temporary distances.

2. The object distance deriving device according to claim 1, wherein the super-resolution processing is performed by iterative back-projection using the imaging process matrix.

3. The object distance deriving device according to claim 1,

wherein the imaging means is compound-eye imaging means comprising a solid-state imaging element and multiple randomly arranged optical lenses to form integrally arranged multiple imaging units to capture images formed by the optical lenses as unit images.

4. The object distance deriving device according to claim 1,

wherein the imaging means is compound-eye imaging means comprising a solid-state imaging element and multiple optical lenses to form integrally arranged multiple imaging units to capture images formed by the optical lenses as unit images,

wherein the optical lenses are arranged to adapt to an optimum condition calculated by an optimizing method using an evaluation function to evaluate errors of calculated object distances.

5. The object distance deriving device according to claim 4,

wherein the evaluation function is expressed by the following equation:

$C=\frac{1}{N}<br><br>\underset{i=1}{\overset{N}{\sum <br><br>}}<br><br>\stackrel{\_}{\mathrm{ei}}$

where N is total number of object distances set for calculation, i is distance number, and ei-bar is average error of object distance when calculating the object distance of a two-dimensional object placed at i-th distance.

6. The object distance deriving device according to claim 2,

wherein the imaging means is compound-eye imaging means comprising a solid-state imaging element and multiple randomly arranged optical lenses to form integrally arranged multiple imaging units to capture images formed by the optical lenses as unit images.

7. The object distance deriving device according to claim 2,

wherein the imaging means is compound-eye imaging means comprising a solid-state imaging element and multiple optical lenses to form integrally arranged multiple imaging units to capture images formed by the optical lenses as unit images,

wherein the optical lenses are arranged to adapt to an optimum condition calculated by an optimizing method using an evaluation function to evaluate errors of calculated object distances.