Focal plane scanner with reciprocating spatial window

• US 6,166,373 A
• Filed: 07/21/1998
• Issued: 12/26/2000
• Est. Priority Date: 07/21/1998
• Status: Expired due to Fees

• Current Assignee: Institute For Technology Development
• Original Assignee: Institute For Technology Development
• Inventors: Mao, Chengye
• Primary Examiner(s): Ham, Seungsook
• Assistant Examiner(s): PYO, KEVIN K
• Application Number:
  US09/120,092
• Time in Patent Office: 889 Days
• Field of Search: 250/226, 250/208.1, 250/234, 250/201.2, 250/201.4, 250/201.8, 356/310, 356/326, 356/328, 356/375, 356/376
• US Class Current: 250/226
• CPC Class Codes: G01C 11/025 by scanning the object
• CPC Class Codes: G01J 2003/064 Use of other elements for scan, e.g. mirror, fixed grating
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/0202 Mechanical elements; Supports for optical elements
• CPC Class Codes: G01J 3/0208 using focussing or collimating elements, e.g. lenses or mirrors; performing aberration correction
• CPC Class Codes: G01J 3/0218 using optical fibers
• CPC Class Codes: G01J 3/06 Scanning arrangements arrangements for order-selection
• CPC Class Codes: G01J 3/14 using refracting elements, e.g. prisms G01J3/18, G01J3/26 take precedence prisms per se G02B5/04
• CPC Class Codes: G01J 3/18 using diffraction elements, e.g. grating gratings per se G02B
• CPC Class Codes: G01J 3/26 using multiple reflection, e.g. Fabry-Perot interferometer, variable interference filters
• CPC Class Codes: G01J 3/2823 Imaging spectrometer

Abstract

A focal plane scanner having a front objective lens, a spatial window for selectively passing a portion of the image therethrough, and a CCD array for receiving the passed portion of the image. All embodiments have a common feature whereby the spatial window and CCD array are mounted for simultaneous relative reciprocating movement with respect to the front objective lens, and the spatial window is mounted within the focal plane of the front objective. In a first embodiment, the spatial window is a slit and the CCD array is one-dimensional, and successive rows of the image in the focal plane of the front objective lens are passed to the CCD array by an image relay lens interposed between the slit and the CCD array. In a second embodiment, the spatial window is a slit, the CCD array is two-dimensional, and a prism-grating-prism optical spectrometer is interposed between the slit and the CCD array so as to cause the scanned row to be split into a plurality of spectral separations onto the CCD array. In a third embodiment, the CCD array is two-dimensional and the spatial window is a rectangular linear variable filter ("LVF") window, so as to cause the scanned rows impinging on the LVF to be bandpass filtered into spectral components onto the CCD array through an image relay lens interposed between the LVF and the CCD array.

Claims

1. A focal plane scanner for viewing an image of a target, said scanner comprising:

(a) first optical objective lens means for focusing said image in a focal plane of said first optical objective lens means, said focal plane having formed therewithin a plurality of substantially parallel row portions of said image;

(b) spatial window means for selectively passing a subset of row portions of said plurality of row portions of said image through said focal plane and for selectively blocking all those row portions of said plurality of row portions that are not within said passed subset at a given moment from passing through said focal plane;

said spatial window means being mounted for reciprocating translational movement within said focal plane, relative to said first objective lens means, in a direction substantially perpendicular to said plurality of row portions of said image;

(c) motion means for moving said spatial window means within said focal plane, relative to said first objective lens means, in said direction substantially perpendicular to said plurality of row portions of said image; and

(d) image sampling array means for receiving said passed subset of row portions of said image and for converting said passed subset of row portions of said image into an electronic charge representation of said image, said image sampling array means being mounted in fixed relation with respect to said spatial window means.

2. The focal plane scanner as recited in claim 1, in which said passed subset of row portions contains only a single row portion of said plurality of row portions of said image and said spatial window means is a slit selectively passing only said single row portion of said plurality of row portions of said image.

3. The focal plane scanner as recited in claim 2, in which said image sampling array means is a one-dimensional charge coupled device array onto which said passed single row portion of said plurality of row portions is received.

4. The focal plane scanner as recited in claim 3, in which said scanner includes optical image relay means, interposed between said one-dimensional charge coupled device array and said slit, for relaying said passed single row portion of said image to said one-dimensional charge coupled device array.

5. The focal plane scanner as recited in claim 2, in which said image sampling array means is a two-dimensional charge coupled device array and said scanner includes spectrum separation means, interposed between said slit and said two-dimensional charge coupled device array, for spreadedly separating said passed single row portion of said image into a spectrum of said image received onto said two-dimensional charge coupled device array.

6. The focal plane scanner as recited in claim 5, in which said spectrum separation means is an optical spectrometer, said optical spectrometer comprising, in sequential order as said image passes therethrough:

(a) a collimating lens;

(b) a first prism;

(c) a diffraction grating;

(d) a second prism; and

(e) a focusing lens.

7. The focal plane scanner as recited in claim 1, in which said passed subset of row portions includes multiple row portions from said plurality of row portions of said image and said spatial window means includes a linear variable filter selectively passing only said multiple row portions from said plurality of row portions, said linear variable filter having a linear-variable bandpass along said direction substantially perpendicular to said plurality of row portions of said image.

8. The focal plane scanner as recited in claim 7, in which said image sampling array means is a two-dimensional charge coupled device array onto which said passed multiple row portions are received after having been bandpass-filtered by said linear variable filter.

9. The focal plane scanner as recited in claim 8, in which said scanner includes optical image relay means, interposed between said two-dimensional charge coupled device array and said spatial window means, for relaying said passed multiple row portions of said image to said two-dimensional charge coupled device array after said passed multiple row portions have been bandpass-filtered by said linear variable filter.

10. A focal plane scanner for viewing an image of a target, said scanner comprising:

(a) first optical objective lens means for focusing said image in a focal plane of said first optical objective lens means, said focal plane having formed therewithin a plurality of substantially parallel row portions of said image;

(b) spatial window means for selectively passing a single row portion of said plurality of row portions of said image through said focal plane and for selectively blocking all those row portions of said plurality of row portions that are not within said passed single row portion of said plurality of row portions of said image at a given moment from passing through said focal plane;

said spatial window means being a slit mounted for reciprocating movement within said focal plane, relative to said first objective lens means, in a direction substantially perpendicular to said plurality of row portions of said image;

(c) translation stage mounting means for reciprocatingly moving said spatial window means within said focal plane, relative to said first objective lens means, in said direction substantially perpendicular to said plurality of row portions of said image, said translation stage mounting means comprising;

i. a front portion having said first optical objective lens mounted in fixed relation thereto;

ii. a rear potion having said spatial window means mounted in fixed relation thereto;

iii. reciprocation mounting means mounting said front portion for reciprocating movement, relative to said rear portion, in said direction substantially perpendicular to said plurality of row portions of said image; and

iv. motor means for reciprocatingly moving said front portion relative to said rear portion;

(d) image sampling array means for receiving said passed single row portion of said image and for converting said passed single row portion of said image into an electrical signal representation of said image, said image sampling array means being mounted in fixed relation with respect to said spatial window means, said image sampling array means comprising a one-dimensional charge coupled device array onto which said passed single row portion is received;

and

(e) optical image relay means, interposed between said one-dimensional charge coupled device array and said spatial window means, for relaying said passed single row portion of said image to said one-dimensional charge coupled device array.

11. The focal plane scanner as recited in claim 10, additionally comprising:

(a) frame grabber means for receiving said electrical signal representation of said image and storing said electrical signal representation into a memory; and

(b) computer means for controlling said motor means.

12. A focal plane scanner for viewing an image of a target, said scanner comprising:

(a) first optical objective lens means for focusing said image in a focal plane of said first optical objective lens means, said focal plane having formed therewithin a plurality of substantially parallel row portions of said image;

(b) spatial window means for selectively passing a single row portion of said plurality of row portions of said image through said focal plane and for selectively blocking all those row portions of said plurality of row portions that are not within said passed single row portion of said plurality of row portions of said image at a given moment from passing through said focal plane;

said spatial window means being a slit mounted for reciprocating movement within said focal plane, relative to said first objective lens means, in a direction substantially perpendicular to said plurality of row portions of said image;

(c) translation stage mounting means for reciprocatingly moving said spatial window means within said focal plane, relative to said first objective lens means, in said direction substantially perpendicular to said plurality of row portions of said image, said translation stage mounting means comprising;

i. a front portion having said first optical objective lens mounted in fixed relation thereto;

ii. a rear potion having said spatial window means mounted in fixed relation thereto;

iii. reciprocation mounting means mounting said front portion for reciprocating movement, relative to said rear portion, in said direction substantially perpendicular to said plurality of row portions of said image; and

iv. motor means for reciprocatingly moving said front portion relative to said rear portion;

(d) spectrum separation means for spreadedly separating said passed single row portion of said image into a spectrum of said image;

said spectrum separation means being an optical spectrometer comprising, in sequential order as said image passes therethrough;

i. a collimating lens;

ii. a first prism;

iii. a diffraction grating;

iv. a second prism; and

v. a focusing lens;

and,

(e) image sampling array means for receiving said spectrum of said image and for converting said spectrum of said image into an electrical signal representation of said spectrum of said image, said image sampling array means being mounted in fixed relation with respect to said spatial window means;

said image sampling array means comprising a two-dimensional charge coupled device array onto which said spectrum of said image is received;

said spectrum separation means being interposed between said slit and said two-dimensional charge coupled device array.

13. The focal plane scanner as recited in claim 12, additionally comprising:

(a) frame grabber means for receiving said electrical signal representation of said image and storing said electrical signal representation into a memory; and

(b) computer means for controlling said motor means.

14. A focal plane scanner for viewing an image of a target, said scanner comprising:

(a) first optical objective lens means for focusing said image in a focal plane of said first optical objective lens means, said focal plane having formed therewithin a plurality of substantially parallel row portions of said image;

(b) spatial window means for selectively passing a subset of row portions of said plurality of row portions of said image through said focal plane and for selectively blocking all those row portions of said plurality of row portions that are not within said passed subset at a given moment from passing through said focal plane;

said passed subset of row portions including multiple row portions from said plurality of row portions of said image;

said spatial window means including a linear variable filter selectively passing only said multiple row portions from said plurality of row portions;

said linear variable filter having a linear-variable bandpass along a direction substantially perpendicular to said plurality of row portions of said image and said linear variable filter being mounted for reciprocating movement within said focal plane, relative to said first objective lens means, in said direction substantially perpendicular to said plurality of row portions of said image;

(c) translation stage mounting means for reciprocatingly moving said spatial window means within said focal plane, relative to said first objective lens means, in said direction substantially perpendicular to said plurality of row portions of said image, said translation stage mounting means comprising;

i. a front portion having said first optical objective lens mounted in fixed relation thereto;

ii. a rear potion having said spatial window means mounted in fixed relation thereto;

iii. reciprocation mounting means mounting said front portion for reciprocating movement, relative to said rear portion, in said direction substantially perpendicular to said plurality of row portions of said image; and

iv. motor means for reciprocatingly moving said front portion relative to said rear portion;

(d) image sampling array means for receiving said passed multiple row portions of said image and for converting said passed multiple row portions of said image into an electrical signal representation of said image, said image sampling array means being mounted in fixed relation with respect to said spatial window means, said image sampling array means comprising a two-dimensional charge coupled device array onto which said passed multiple row portions of said image are received; and

(e) optical image relay means, interposed between said two-dimensional charge coupled device array and said spatial window means, for relaying said passed multiple row portions of said image to said two-dimensional charge coupled device array.

15. The focal plane scanner as recited in claim 14, additionally comprising:

(a) frame grabber means for receiving said electrical signal representation of said image and storing said electrical signal representation into a memory; and

(b) computer means for controlling said motor means.