U.S. patent application number 11/484282 was filed with the patent office on 2008-01-17 for peripheral inspection system and method.
This patent application is currently assigned to Microview Technology Ptd Ltd. Invention is credited to Sergey Smorgon, Victor Vertoprakhov, Wong Soon Wei.
Application Number | 20080013820 11/484282 |
Document ID | / |
Family ID | 38949310 |
Filed Date | 2008-01-17 |
United States Patent
Application |
20080013820 |
Kind Code |
A1 |
Vertoprakhov; Victor ; et
al. |
January 17, 2008 |
Peripheral inspection system and method
Abstract
A method of inspecting two or more sides of an object is
provided. The method includes generating one set of image data of
two or more sides of the object, such as by using spherical mirror
segments that project all sides of the object onto a single image
and generating an X by Y array of image data of the single image.
The projection of the image data is then compensated for, such as
by identifying inspection processes to locate defects of the object
in the projected image data or by converting the image data from
the projected inspection coordinates to Cartesian coordinates.
Predetermined inspection processes are then performed on the
compensated image data, such as by using the inspection processes
that are optimised for use with the projected image data or by
converting the projected image data into a Cartesian format and
using Cartesian image data inspection processes.
Inventors: |
Vertoprakhov; Victor;
(Novosibirsk, RU) ; Wei; Wong Soon; (Singapore,
SG) ; Smorgon; Sergey; (Krasniyarsk, RU) |
Correspondence
Address: |
Mr. Christopher John Rourk;Jackson Walker LLP
901 Main Street, Suite 6000
DALLAS
TX
75202
US
|
Assignee: |
Microview Technology Ptd
Ltd
|
Family ID: |
38949310 |
Appl. No.: |
11/484282 |
Filed: |
July 11, 2006 |
Current U.S.
Class: |
382/141 |
Current CPC
Class: |
G06T 3/0043 20130101;
G06T 7/0004 20130101; G01N 21/952 20130101; G06T 2207/30164
20130101; G01N 21/8806 20130101; G01N 21/8803 20130101; G06T 5/006
20130101; G06T 2207/30108 20130101 |
Class at
Publication: |
382/141 |
International
Class: |
G06K 9/00 20060101
G06K009/00 |
Claims
1. A method of inspecting two or more sides of an object
comprising: generating one set of image data of two or more sides
of the object; compensating for projection of the image data; and
performing predetermined inspection processes on the compensated
image data.
2. The method of claim 1 wherein generating one set of image data
of two or more sides of the object comprises: placing the object
under a first spherical segment mirror; and receiving image data
from the first spherical segment mirror a circumferential spherical
segment mirror that encircles the object.
3. The method of claim 1 wherein compensating for projection of the
image data comprises converting the image data from an inspection
coordinate format into a Cartesian coordinate format.
4. The method of claim 1 wherein performing predetermined
inspection processes on the compensated image data comprises using
inspection processes that are optimised for data generated in the
inspection coordinate format.
5. A system for inspecting two or more sides of an object
comprising: two or more mirrors and one or more lenses generating
an image of the two or more sides of the object; an image data
generation system generating image data of the image of the two or
more sides of the object; and a projected image data inspection
system compensating for projection of the image of the two or more
sides of the object and analysing the compensated image data to
determine whether the object contains defects.
6. The system of claim 5 wherein the two or more mirrors comprise:
a first spherical mirror segment located between the object and the
image data generation system; and one or more lenses located
between a second spherical mirror and the image data generation
system.
7. The system of claim 5 wherein the two or more mirrors comprise:
a conical mirror segment located between the object and the lens;
and a spherical mirror segment encircling the conical mirror
segment and the object.
8. The system of claim 5 wherein the projected image data
inspection system comprises a polar inspection system receiving
projected polar image data of the object and performing one or more
inspection processes on the projected polar image data.
9. The system of claim 5 wherein the projected image data
inspection system comprises a Cartesian mapping and inspection
system receiving projected polar image data of the object,
converting the projected polar image data into Cartesian coordinate
data, and performing one or more inspection processes on the
Cartesian coordinate data.
10. The system of claim 5 wherein the projected image data
inspection system comprises a peripheral location system receiving
projected polar image data of the object and identifying a
predetermined feature on the periphery of the object.
11. The system of claim 5 wherein the two or more mirrors comprise:
a first mirror segment located between the object and the image
data generation system; a second mirror segment encircling the
first mirror segment and the object; and a lens located between the
object and the image data generation system.
12. The system of claim 6 wherein the first spherical mirror
segment has a hole through which the object is inspected.
13. The system of claim 7 wherein the conical mirror segment has a
hole through which the object is inspected.
Description
FIELD OF THE INVENTION
[0001] The invention relates to optical inspection of objects to
determine whether they meet required manufacturing specifications,
and in particular to the optical inspection of the periphery of an
object using a single set of image data.
BACKGROUND OF THE INVENTION
[0002] It is known to optically inspect manufactured items for
defects that would render the item unusable. For objects have
multiple surfaces, such as bolts or other items having a 3D
continuous periphery, inspection typically requires obtaining
multiple sets of image data. For example, such objects may be
initially oriented in a predetermined position and then moved to
other pre-determined positions. This requires multiple images of
the object to be generated. Furthermore, the inspection system must
still track the object and recognise it once it has reached the new
orientation. This process requires a computationally intensive
operation that can be the limiting factor in the production and
quality control of objects.
SUMMARY OF THE INVENTION
[0003] In accordance with the present invention, a system and
method for inspecting objects are provided that overcome known
problems with systems and methods for inspecting objects.
[0004] In particular, a system and method for inspecting objects
are provided which utilize a single set of image data that captures
two or more sides of the object, such as image data of the entire
periphery of the object in projected polar coordinates.
[0005] In accordance with an exemplary embodiment of the present
invention, a method of inspecting two or more sides of an object is
provided. The method includes generating one set of image data of
two or more sides of the object, such as by using spherical mirror
segments that project all sides of the object onto a single image
and generating an X by Y array of image data of the single image.
The projection of the image data is then compensated for, such as
by identifying inspection processes to locate defects of the object
in the projected image data or by converting the image data from
the projected inspection coordinates to Cartesian coordinates.
Predetermined inspection processes are then performed on the
compensated image data, such as by using the inspection processes
that are optimised for use with the projected image data or by
converting the projected image data into a Cartesian format and
using Cartesian image data inspection processes.
[0006] The present invention provides many important technical
advantages. One important technical advantage of the present
invention is an inspection system that utilizes a single image of
an object under inspection, where spherical or conical mirrors are
used to present a circumferential image of the sides of the object,
so as to eliminate the need to obtain multiple images.
[0007] Those skilled in the art will further appreciate the
advantages and superior features of the invention together with
other important aspects thereof on reading the detailed description
that follows in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a diagram of a system for generating a single
image of the entire periphery of an object and performing an
inspection in accordance with an exemplary embodiment of the
present invention;
[0009] FIG. 2 is a diagram of a system for performing a peripheral
inspection of an object in accordance with the present
invention;
[0010] FIG. 3 is a diagram of a system for analyzing a single set
of polar projection image data of an object under inspection in
accordance with an exemplary embodiment of the present
invention
[0011] FIG. 4 is a flowchart of a method for processing peripheral
image data in accordance with an exemplary environment of the
present invention;
[0012] FIGS. 5A and 5B are sets of image data generated to
demonstrate an exemplary embodiment of the present invention;
[0013] FIG. 6 is a diagram of a system for generating a single
image of the top and the entire periphery of an object and
performing an inspection in accordance with an exemplary embodiment
of the present invention;
[0014] FIG. 7 is a diagram of a system for generating an image of
the top and entire periphery of an object and performing an
inspection in accordance with an exemplary embodiment of the
present invention;
[0015] FIG. 8 is a diagram of a system for generating an image of
the top and entire periphery of an object using a cone mirror in
accordance with an exemplary embodiment of the present
invention;
[0016] FIG. 9 is a diagram of a system for generating an image of
the top and entire periphery of an object and performing an
inspection in accordance with an exemplary embodiment of the
present invention;
[0017] FIGS. 10A and 10B are sets of image data generated to
demonstrate an exemplary embodiment for generating a single image
of the top and the entire periphery of an object and performing an
inspection;
[0018] FIG. 11 is a diagram showing surfaces utilized herein.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0019] In the description that follows, like parts are marked
throughout the specification and drawings with the same reference
numerals, respectively. The drawing figures might not be to scale,
and certain components can be shown in generalized or schematic
form and identified by commercial designations in the interest of
clarity and conciseness.
[0020] FIG. 1 is a diagram of a system 100 for generating a single
image of the entire periphery of an object and performing an
inspection in accordance with an exemplary embodiment of the
present invention. System 100 includes peripheral inspection system
102, which can be implemented in hardware, software, or a suitable
combination of hardware and software, and which can one or more
software systems operating on a general purpose processing
platform.
[0021] As used herein, a hardware system can include a combination
of discrete components, an integrated circuit, an
application-specific integrated circuit, a field programmable gate
array, or other suitable hardware. A software system can include
one or more objects, agents, threads, lines of code, subroutines,
separate software applications, two or more lines of code or other
suitable software structures operating in two or more software
applications or on two or more processors, or other suitable
software structures. In one exemplary embodiment, a software system
can include one or more lines of code or other suitable software
structures operating in a general purpose software application,
such as an operating system, and one or more lines of code or other
suitable software structures operating in a specific purpose
software application.
[0022] Peripheral inspection system 102 is coupled to camera 104.
As used herein, the term "coupled" and its cognate terms such as
"couples" or "couple," can include a physical connection (such as a
wire, optical fiber, or a telecommunications medium), a virtual
connection (such as through randomly assigned memory locations of a
data memory device or a hypertext transfer protocol (HTTP) link), a
logical connection (such as through one or more semiconductor
devices in an integrated circuit), or other suitable
connections.
[0023] Camera 104 generates image data of the periphery of an
object under inspection. Lens 106 is used to focus light from
mirror 108 onto an array of image sensors of camera 104. Mirror 108
is a spherical mirror section that receives image data from the
periphery of the object under inspection from mirror 110. Mirror
110 is also a spherical mirror section that projects the periphery
of the object under inspection onto mirror 108. Ring light 112 or
other suitable lights illuminate the object under inspection.
[0024] In operation, the curvature of mirrors 108 and 110 are
coordinated with the height of the object under inspection and the
distance between mirror 108 and the object under inspection to
allow a single image of the periphery of the object under
inspection to be provided to camera 104. For example, the radius of
curvature of mirror 110 and mirror 108 can be coordinated such that
the object under inspection, when appropriately placed, can be seen
from all sides from a single image generated at camera 104 from
mirror 108 and lens 106. The radius of curvature of mirrors 108 and
110 and suitable distances can be calculated using general optics
theory. In one exemplary embodiment of the present invention, the
radius of the curvature of mirrors 108 and 110 are 13 mm and 31.3
mm, respectively. An aspherical profile of the mirrors 108 and 110
can be applied to reduce an image aberration.
[0025] In one exemplary embodiment, the image data generated by
system 100 is polar projection data, where the distance between
points around the periphery of the top of the object under
inspection is less than the distance between points around the
periphery of the bottom of the object under inspection. Peripheral
inspection system 102 receives the image data of the object under
inspection and identifies defects or other anomalies, such as by
compensating for projection of the image of the object. In one
exemplary embodiment, compensation is accomplished by performing
conventional image data analysis (e.g. such as generation of a
histogram of pixel brightness data) based on analysis of known
defects in sets of projected image data. Likewise, identification
of predetermined shapes within the projected image data can be
performed based on a predetermined relationship between the object
under inspection and the projected image data of that object. In
one exemplary embodiment, compensation can include conversion of
the image data from polar projection image data into a different
coordinate format, or in other suitable manners.
[0026] FIG. 2 is a diagram of a system 200 for performing a
peripheral inspection of an object in accordance with the present
invention. System 200 uses a cone mirror 204 in place of a
spherical mirror 108.
[0027] As previously described, camera 104 generates image data of
an image provided by the lens through the cone mirror 204.
Spherical mirror 206 has a known spherical curvature and a radius
that allows the polar projection image of the object under
inspection that is generated by reflection of the image onto cone
mirror 204 and generation into a set of image data by camera 104 to
be inspected. The radius of curvature of mirrors 206 and angle of
the cone 204 and suitable distances can be derived from general
optics theory. An aspherical profile of the mirror 206 can be
applied to reduce image aberration.
[0028] In operation, camera 104 generates a single set of image
data for analysis by peripheral inspection system 102, such as to
eliminate the need for generating multiple images of different
sides of the object under inspection. The angle and size of cone
mirror 204 is coordinated with the dimensions of spherical mirror
206 to allow a single set of polar projection image data of the
periphery of an object under inspection to be generated.
[0029] FIG. 3 is a diagram of a system 300 for analyzing a single
set of polar projection image data of an object under inspection in
accordance with an exemplary embodiment of the present invention.
System 300 includes peripheral inspection system 102, and polar
inspection system 302, Cartesian mapping and inspection system 304,
peripheral mapping location 306, and defect notification system
308, each of which can be implemented in hardware, software, or a
suitable combination of hardware and software, and which can be one
or more software systems operating on a general purpose processing
platform.
[0030] Polar inspection system 302 receives image data that
includes a polar projection of a circumferential view of an object
under inspection. As previously described, such image data will
typically be in polar projection format, such that items towards
the center of the set of image data have a physical separation that
is less than items towards the periphery of the set of image data.
As such, polar inspection system 302 generates a set of image data
to identify defects or other items that require an operator to be
notified so that the object under inspection can be discarded or
set aside for repair. Polar inspection system 302 can be used to
identify predetermined metrics, such as a histogram or other
statistical mapping of pixel brightness data, direct location
procedures such as object mapping of known defect shapes, masking
of predetermined sections of the image of the object that are not
subject to inspection, indexing of features in the image data, or
other suitable image inspection processes.
[0031] Cartesian mapping and inspection system 304 receives the
image data in polar coordinate format and maps the polar coordinate
image data to a Cartesian coordinate system. In one exemplary
embodiment, the relationship between the location of individual
pixels and the image data generated at those locations can be
determined based on a mathematical relationship based on the
dimensions of the set of mirrors that are used to generate the
peripheral image data. In this manner, the polar projected image
data can be mapped to a Cartesian coordinate system to allow image
data inspection processes that require the use of Cartesian
coordinate data to be utilized.
[0032] Peripheral location system 306 receives image data in a
polar projection forma, Cartesian format, or other suitable
formats, and locates one or more peripheral identifiers. In one
exemplary embodiment, an object under inspection may have
predetermined markings or features are identified by peripheral
location system 306, to allow inspection of the object image data
to be indexed. Likewise, peripheral location system 306 can use
other suitable processes such as identifying external indexing
features of equipment holding the object under inspection,
generating histograms of pixel data for sections of the image data
of the object under inspection data, locating text, applying masks,
or other suitable processes. In one exemplary embodiment,
peripheral location system 306 can generate error data in the event
a peripheral orientation of the object under inspection can not be
determined.
[0033] Defect notification system 308 receives inspection data from
polar inspection system 302, Cartesian mapping and inspection
system 304, peripheral location system 306, or other suitable
systems and generates and defect notification data. In one
exemplary environment, the defect notification data can cause an
object under inspection to be extracted for further analysis, such
as for manual inspection, to determine whether the object under
inspection can be repaired, to determine whether the object must be
discarded, or for other suitable purposes. Likewise, defect
notification system 308 can generate control data to cause the
object under inspection to be discarded by suitable mechanisms,
such as where the object under inspection is a low cost part and
the cost of repair is greater than the cost of disposal. Likewise,
other suitable notification data can be generated by defect
notification system 308.
[0034] In operation, system 300 allows peripheral image data of an
object under inspection to be analyzed. Such peripheral image data
is typically in a polar projection format, and may be mapped into a
Cartesian system for inspection or can be inspected in its polar
projection format. Indexing of features of the object under
inspection may be required, and notification of an operator or
generation of other control data for processing of potentially
defective components can be performed by system 300.
[0035] FIG. 4 is a flowchart of a method 400 for processing
peripheral image data in accordance with an exemplary environment
of the present invention. Method 400 begins are 402 where image
data is received. In one exemplary environment, the image data can
be polar projection data generated by an imaging lens 106 together
with a spherical center mirror receiving peripheral image data of
an object under inspection from and encircling mirror. Likewise,
cone-shaped mirrors are other simple mirrors can be used. The
method then proceeds to 404.
[0036] At 404, it is determined whether Cartesian mapping of the
object under inspection is to be performed. In one exemplary
embodiment, the image data can be generated in a polar projection
format, such that mapping to Cartesian coordinates may be performed
in order to perform inspection processes on the image data. If it
is determined that Cartesian mapping is not to be performed, the
method proceeds to 404 where the image data is analyzed using one
or more polar projection inspection processes. In one exemplary
embodiment, histograms or other suitable data can be used to
analyze the pixels generated by the inspection image,
identification of groups of pixels having predetermined
characteristics can be performed, detection of projected text or
other features can be used, or other suitable polar projected image
data inspection methods can be applied. The method then proceeds to
412.
[0037] If it is determined that Cartesian mapping is to be
performed at 404, the method proceeds to 406, where the image data
is converted from polar projected data to Cartesian coordinate
data. In one exemplary embodiment, the mathematical relationship
between the object under inspection and mirrors that are used to
project each side of the object under inspection into a single
image can be used to map from the polar projection data to
Cartesian coordinate data. Other suitable processes can also or
alternatively be used. The method then proceeds to 408.
[0038] At 408, the mapped image data is analyzed using one or more
Cartesian inspection processes. In one exemplary embodiment, the
image data can be analyzed using histogram analysis, location of
predetermined features or letters in the image data, indexing of
the image data based on a map of features in the image data,
blocking of areas from processing that are not under inspection, or
other suitable processes.
[0039] At 412, it is determined whether a defect has been located.
If no defect has been located, the method proceeds to 416,
otherwise the method proceeds to 414 where notification data is
generated. In one exemplary embodiment, notification data can
include data that notifies an operator that a object under
inspection needs to be checked for damage. Likewise, the
notification data can include control data to a suitable device to
remove the object under inspection. Likewise, other suitable
notification data can be generated. The method then proceeds to
416.
[0040] At 416, the next inspection piece is advanced. In one
exemplary embodiment, inspection can be formed "on the fly", such
that advancement to the next inspection piece occurs in a
continuous process. Likewise, the next inspection piece can be
advanced upon completion of inspection of the current inspection
piece, such as where the inspection piece is discarded upon
generation of notification data. Likewise, other suitable processes
can be used. The method then proceeds to 416.
[0041] At 416, image data of the new object under inspection is
generated. In one exemplary embodiment, a single camera can be used
to capture a projected peripheral image having projected polar
coordinates. Likewise, other suitable processes can be used. The
method then returns to 402.
[0042] In operation, method 400 allows a single set of image data
to be analyzed that contains image data from all sides of an object
under inspection. In one exemplary embodiment, mirrors can be used
to generate a projected polar coordinate view of all sides of an
object under inspection, such that image data generated is taken at
a single spot so as to reduce the number of sets of image data that
need to be generated. Likewise, other suitable processes can be
used.
[0043] FIGS. 5A and 5B are sets of image data 500A and 500B
generated to demonstrate an exemplary embodiment of the present
invention. Image data set 500A shows a side view of a cylinder on
which the words "Microview tech" have been inscribed. Image data
set 500B shows a circumferential image of the sides of the
cylinder. The image data set 500B was taken by system shown on FIG.
1. As can be seen from FIG. 5A, only the letters "Microv" are
discernable from the flat side view presented to the image data
generating device. In contrast, FIG. 5B shows the entire phrase
"Microview tech," albeit in a projected polar coordinate system
wherein the spacing of the image at the "top" of the letters is
closer than the spacing of the image at the "bottom" of the
letters. Furthermore, it can be observed that the letters "Microv"
correspond to less than 50% of the information provided about the
periphery of the cylinder, such that it would be necessary to take
at least three side-on images of the cylinder to obtain all of the
information from the periphery of the cylinder.
[0044] Furthermore, it is noted that the letters of "Microv" from
the side-on image are themselves projected onto a cylinder, such
that the spacing of the letters on the side of the cylinder is less
than the spacing of the letters that directly face the image data
generating device. As such, even if multiple sets of side-on image
data were used, it might still be necessary to either convert that
data from the cylinder projection plane to a Cartesian coordinate
plane, or to take a larger number of sets of side-on image data
such that the areas of the image data set where the areas having
unacceptable variation due to projection onto a cylinder can be
masked. As such, the present invention allows a single set of image
data to be analyzed that provides a larger segment of the periphery
of an object under inspection than side-on viewing, which reduces
the number of sets of image data that must be generated and
analyzed and increases the inspection speed of the system.
[0045] FIG. 6 is a diagram of a system 600 for generating a single
image of the top and the entire periphery of an object and
performing an inspection in accordance with an exemplary embodiment
of the present invention. System 600 includes mirror 602 which is a
spherical section mirror that has a center orifice to allow the top
of the object under inspection to also be imaged.
[0046] FIG. 7 is a diagram of a system 700 for generating an image
of the top and entire periphery of an object and performing an
inspection in accordance with an exemplary embodiment of the
present invention. In addition to a spherical segment mirror 704,
system 700 uses a lens 702 to focus the image on the top of the
object under inspection. Lens 702 can be used to generate suitable
magnification of the image of the top of the object at the same
time.
[0047] FIG. 8 is a diagram of a system 800 for generating an image
of the top and entire periphery of an object using a cone mirror in
accordance with an exemplary embodiment of the present invention.
System 800 uses cone mirror 802 with a center orifice to allow the
top of the object under inspection to also be imaged.
[0048] FIG. 9 is a diagram of a system 900 for generating an image
of the top and entire periphery of an object and performing an
inspection in accordance with an exemplary embodiment of the
present invention. In addition to a conical segment mirror 902,
system 900 uses additional lenses 904 to focus the image on of the
top of the object under inspection. The lenses 904 can be used to
generate suitable magnification of the image of the top of the
object at the same time.
[0049] FIGS. 10A and 10B are sets of image data 1000A and 1000B
generated to demonstrate an exemplary embodiment of the present
invention. Image data set 1000B shows a circumferential image of
the sides of the cylinder and top image at the center, such as
might be obtained using system 700 or other suitable systems. In
addition to the side markings of FIGS. 5A and 5B, FIGS. 10A and 10B
include markings on the top of the object under inspection. As
shown in FIG. 10A, these markings further require an image to be
made of the top as well as of the sides of the object under
inspection. As such, obtaining a single set of image data as shown
in FIG. 10B further reduces the amount of image data that must be
generated in order to perform an inspection of the object.
[0050] FIG. 11 is a diagram showing surfaces utilized herein.
Exemplary Dimensions
[0051] Dimensions for one exemplary embodiment of the present
invention are provided in Table 1:
TABLE-US-00001 TABLE 1 Radius, Thickness, Diameter, Schott Surface
mm mm mm Glass Note 1 Infinity 1.00 60 BK7 Cover glass 2 Infinity
24.00 60 -- 3 -31.3 -20.00 60 Mirror (*) Dmax = 60; Dmin = 32 4
-13.0 84.67 18 Mirror (**) 5(stop) -- 32.52 2.5 -- Paraxial (***);
F = 25 mm 6 Image Notes: (*) Outer circumferential mirror. It has
circular aperture: Dmax = 60 mm; Dmin = 32 mm. (**) Inner spherical
mirror (***) Paraxial lens (F = 25 mm) is used. It can be replaced
by real objective lens with focal lens 25 mm and aperture value
F/#N = 8 up to F/#N = 16.
[0052] Dimensions for another exemplary embodiment of the present
invention such as that shown in FIG. 11 that includes an object
cylinder diameter range of 5 to 10 mm are provided in Table 2:
TABLE-US-00002 TABLE 2 Radius, Thickness, Diameter, Schott Surface
mm mm mm Glass Note 1 Infinity 1.00 60 BK7 Cover glass 2 Infinity
24.00 60 -- 3 -31.30 -20.00 60 Mirror (*) Dmax = 60; Dmin = 32 4
-13.00 84.67 18 Mirror (**) 5(stop) 22.80 4.20 2.5 BK7 (***) 6
-8.40 1.50 3 SF5 7 -18.06 32.00 3 8 Image Notes: (*) Outer
circumferential mirror. It has circular aperture: Dmax = 60 mm;
Dmin = 32 mm; (**) Inner spherical mirror; (***) Imaging lens (F =
25 mm) is doublet (surfaces 5, 6 & 7).
[0053] A camera such as model A102f from Basler AG company or other
suitable cameras can be used to generate the image data.
[0054] Dimensions for one exemplary embodiment of the present
invention that includes an object cylinder diameter range of 22 mm
are provided in Table 3:
TABLE-US-00003 TABLE 3 Radius, Thickness, Diameter, Schott Surface
mm mm mm Glass Note 1 Infinity 3.00 120 B270 Cover glass 2 Infinity
42.00 120 -- 3 -60.00 31.3 114.6 Mirror (*) Dmax = 114.6; Dmin = 66
4 -31.00 183.08 44 Mirror (**) 5(stop) 22.80 4.20 2.5 BK7 (***) 6
-8.40 1.50 3 Sf5 7 -18.06 32.00 3 8 Image Notes: (*) Outer
circumferential mirror. It has circular aperture: Dmax = 114.6 mm;
Dmin = 66 mm; (**) Inner spherical mirror; (***) Imaging lens (F =
25 mm) is doublet (surfaces 5, 6 & 7).
[0055] Dimensions for another embodiment of the present invention
using a cone mirror and having an object cylinder diameter of 22 mm
are provided in Table 4:
TABLE-US-00004 TABLE 4 Thick- Diam- Radius, ness, eter, Schott
Conic, Surface R, mm mm mm Glass k Note 1 Infinity 3.00 96.0 B270 0
Cover glass 2 Infinity 38.97 96.0 -- 0 3 -48.14 -22.20 94.6 Mirror
0 Dmax = 94.6; (*) Dmin = 66 4 -1E-19 98.77 30.0 Mirror -2.26 Cone
angle (***) 96.degree. 36' 5(stop) 22.80 4.20 2.5 BK7 0 (**) 6
-8.40 1.50 3.0 SF5 0 7 -18.06 30.27 3.0 -- 0 8 Image Notes: (*)
Outer circumferential mirror. It has circular aperture: Dmax =
114.6 mm; Dmin = 66 mm (**) Imaging lens (F = 25 mm) is a doublet
(surfaces 5, 6 & 7 (***) Cone surface with top angle 96.degree.
36'
[0056] The "sag" or z-coordinate of the standard surface is given
by:
[0057] Error! Objects cannot be created from editing field
codes.
where: [0058] c=1/R is the curvature (the reciprocal of the radius
R) [0059] r=radial coordinate in lens units and [0060] k=conic
constant. The conic constant is less than -1 for hyperbolas, -1 for
parabolas, between -1 and 0 for ellipses, 0 for spheres, and
greater than 0 for oblate ellipsoids. The conic constant is less
than 0 and the radius is 0<|R|<<1 for a cone surface.
[0061] Although exemplary embodiments of a system and method of the
present invention have been described in detail herein, those
skilled in the art will also recognize that various substitutions
and modifications can be made to the systems and methods without
departing from the scope and spirit of the appended claims.
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