Apparatus and method for positionally stabilizing an image

• US 5,635,725 A
• Filed: 10/16/1996
• Issued: 06/03/1997
• Est. Priority Date: 02/15/1994
• Status: Expired due to Term

• Current Assignee: J. Carl Cooper
• Original Assignee: J. Carl Cooper
• Inventors: Cooper, J. Carl
• Primary Examiner(s): LE, QUE TAN
• Application Number:
  US08/730,768
• Time in Patent Office: 230 Days
• Field of Search: 250/559.29, 250/559.3, 250/564, 250/559.45, 359/554-557, 396/111, 396/120
• US Class Current: 250/559.29
• CPC Class Codes: G02B 27/646 compensating for small deviations, e.g. due to vibration or shake movement of one or more optical elements for control of motion blur in cameras, projectors or printers G03B2205/0007; image stabilisation in cameras peculiar to the presence or use of an electronic image sensor H04N23/68
• CPC Class Codes: G03B 21/40 Eliminating or reducing effect of flicker
• CPC Class Codes: G03B 2205/0007 Movement of one or more optical elements for control of motion blur
• CPC Class Codes: G03B 2205/0069 using electromagnetic actuators, e.g. voice coils
• CPC Class Codes: G03B 5/00 Adjustment of optical system relative to image or object surface other than for focusing
• CPC Class Codes: H04N 23/68 for stable pick-up of the scene, e.g. compensating for camera body vibrations
• CPC Class Codes: H04N 23/681 Motion detection
• CPC Class Codes: H04N 23/6811 based on the image signal
• CPC Class Codes: H04N 23/686 with a variable apex prism
• CPC Class Codes: H04N 23/687 by shifting the lens or sensor position
• CPC Class Codes: H04N 5/74 Projection arrangements for image reproduction, e.g. using eidophor

Abstract

The present disclosure teaches a method and apparatus for use in stabilizing images. The invention operates to sense the position of the image to be stabilized, compare the position of the image to a reference to determine a displacement value responsive thereto and change a correction element located in the conveyance path of the image in response to the displacement value to cause a compensating displacement of the image.

Claims

1. Apparatus for positionally stabilizing an image conveyed via a first conveyance path from an image source location and focused onto a first surface at a first location said apparatus including:

a) sensing circuitry located at a second location and responsive to said image at said second location to sense the position of said image, said sensing circuitry providing an electronic signal conveying errors in the position of said image due to gate weave in at least one dimension,

b) and an electromechanical mechanism responsive to said electronic signal to provide a variable mechanical force, said force operable to alter said first conveyance path of said image at a third location in order to improve the positional stability of said image at said first location.

3. Apparatus as claimed in claim 1 or 2 wherein said sensing of a) takes place at a second location and said altering of b) alters the conveyance of said image at a third location.

4. Apparatus as claimed in claim 1 or 2 wherein said apparatus alters the conveyance of said image at a third location in said first conveyance path in a fashion which does not interfere with the projection of the image on said first surface in order that said image may be stabilized during such projection.

5. Apparatus as claimed in claim 1 or 2 wherein said sensing in a) senses the spatial position of said image at a first time followed by altering the spatial position of said image in b) at a second time.

6. Apparatus as claimed in claim 1 or 2 wherein said image at said first location is intended for viewing by a viewer;

said sensing in a) senses the spatial position of said image as conveyed in wavelengths invisible to said viewer and said altering in b) corrects the spatial position of said image as conveyed at wavelengths visible to said viewer.

7. Apparatus as claimed in claim 1 or 2 wherein said sensing in a) operates to senses the spatial position including at least rotation of said image at said second location and said altering of b) alters the spatial position including at least rotation of said image.

8. Apparatus as claimed in claim 1 or 2 wherein said image is intended for viewing by a viewer and said sensing in a) senses the spatial position of said image at a first time before said image is viewed and said altering of b) corrects the spatial position of said image at a second time after said sensing and before viewing of the image.

9. Apparatus as claimed in claim 1 or 2 wherein said projection of said image at said first location includes time sequential projection of frames of said image on said first surface, each frame being readied for projection in a first time period during which there is no visible projection followed by a second time period in which the preceding readied frame is visibly projected, with said sensing of a) operative to sense the spatial position of said image after said image becomes stable during the latter portion of said first time period, and said altering of b) correcting the spatial position of said image thereafter.

11. Apparatus as claimed in claim 1, 2 or 10 wherein said apparatus operates to change the spatial position of said image on said first surface by tilting a transmissive flat element located in said conveyance path by varying the electric signal applied to at least two electromechanical devices located in proximity to one or more edge of said flat element said flat element thereby performing said altering.

2. Apparatus for spatially positioning an image consisting of electromagnetic radiation within a range of wavelengths which radiation is conveyed along a first conveyance path and projected on a first surface at a first location said image being further conveyed by at least one other radiation at a wavelength outside of said range which other radiation is conveyed along a second conveyance path which may include part or all of said first conveyance path, said apparatus including:

a) a sensing device responsive to said other radiation for sensing gate weave related to said image and to output a signal in response thereto and;

b) a correcting device operating in response to said signal to alter said first conveyance path in order to improve the positional accuracy of said image at said first location.

10. Apparatus for projecting an image along a conveyance path to a first surface, which apparatus operates to sequentially project frames of said image with the projection of each said frame including a plurality of time periods;

including a sensing element responsive to said projected frame during a first time period during which there is no visible projection of said image, said sensing element operating to sense the spatial position of said projected frame;

and a correcting element responsive to said sensing element and operative to alter the spatial position of said projected frame before a second time period which includes visibly projecting said image.

12. The method for spatially positioning an electromagnetic radiation image including the step of sensing said image at a first wavelength to detect the position thereof and in response thereto the step of altering the path of electromagnetic radiation which conveys said image at a second wavelength in order to improve the positional accuracy of said image.

13. The method as claimed in claim 12 wherein said step of altering is performed by moving a transmissive wedge shaped element located in the radiation beam which conveys said image.

14. The method as claimed in claim 12 wherein said step of altering is performed by moving a mirror element located to reflect the radiation beam which conveys said image.

15. The method of claim 12 wherein said image is conveyed for viewing in visible light and said first wavelength consists of a near ultraviolet or shorter wavelength.

16. The method of claim 12 wherein said image is conveyed for viewing in visible light and said first wavelength consists of a near infrared or longer wavelength.