Speckle reduction method

• US 7,706,048 B2
• Filed: 12/11/2008
• Issued: 04/27/2010
• Est. Priority Date: 11/01/2003
• Status: Active Grant

• Current Assignee: Ignite USA (Ignite)
• Original Assignee: Olympus Corporation, Silicon Quest Kabushiki-Kaisha
• Inventors: Ichikawa, Hirotoshi, Ishii, Fusao, Horikawa, Yoshiaki
• Primary Examiner(s): Choi; William C
• Application Number:
  US12/316,402
• Publication Number:
  US 20090115917A1
• Time in Patent Office: 502 Days
• Field of Search: 359/201.2, 359/212.1, 359/223.1, 359/224.1, 359/290, 359/298, 359/318, 348/758, 348/770, 348/771
• US Class Current: 359/290
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G09G 2320/0266 Reduction of sub-frame artefacts
• CPC Class Codes: G09G 3/2044 using dithering
• CPC Class Codes: G09G 3/346 based on modulation of the reflection angle, e.g. micromirrors micromirrors devices per se G02B26/0833

Abstract

A projection apparatus comprising a light source for projecting an illumination light through an illumination optical system to a spatial light modulator (SLM) for modulating the illumination light for generating and transmitting an image projection light to an image projection surface through a projection optical system to display an image. The projection apparatus further includes an image process unit for receiving and analyzing an input image data; and the image process unit applies a conversion process to a signal related to the input image data to generate different control patterns for a plurality of adjacent pixel elements included in the SLM for a predetermined period during at least one frame period to reproduce a gradation of the pixel whereby each of the plurality of adjacent pixel elements has a gradation of approximately a same level.

Claims

1. A projection apparatus comprising a light source for projecting an illumination light through an illumination optical system to a spatial light modulator (SLM) for modulating the illumination light for generating and transmitting an image projection light to an image projection surface through a projection optical system to display an image, the projection apparatus further comprising:

an image process unit for receiving and analyzing an input image data; and

the image process unit applies a conversion process to a signal related to the input image data to generate different control patterns for a plurality of adjacent pixel elements included in the SLM for a predetermined period during at least one frame period to reproduce a gradation of the pixel whereby each of the plurality of adjacent pixel elements has a gradation of approximately a same level.

2. The projection apparatus according to claim 1, wherein:

the image process units applies the conversion process to generate the control patterns for the plurality of pixel elements by applying a common control pattern for every one or more pixels elements included in the plural pixel elements.

3. The projection apparatus according to claim 1, wherein:

the image process units applies the conversion process to generate a different control pattern for each of the plural pixel elements for every one frame period or every plural frame periods.

4. The projection apparatus according to claim 1, further comprising:

an actuator unit for driving a screen constituting a projection surface for projecting an image thereto for displaying the image thereon.

5. The projection apparatus according to claim 1, further comprising:

an imaging position change unit for changing an image position projected by a modulation light from the SLM on a projection surface.

6. The projection apparatus according to claim 1, further comprising:

a control unit to control the SLM to project the modulation light on a projection surface in selected subframe periods within a frame selected on the basis of analysis results of an input signal including a geometric progression and accumulated progression in the selected periods.

7. The projection apparatus according to claim 1, further comprising:

a control unit to control the SLM to project the modulation light on a projection surface in selected subframe periods within a frame selected on the basis of an input signal in the selected subframes and an accumulation of the input signal in the selected subframe periods.

8. The projection apparatus according to claim 1, wherein:

The image process units applies the conversion process to generate an adjustable control pattern adjustable according to a difference of starting time of modulating a pixel element within one frame.

9. The projection apparatus according to claim 1, wherein:

the image process unit further performs a pseudo pixel conversion process for applying a conversion process to a signal related to the input image by temporally differentiating an algorithm of the conversion process for generating and displaying a gradation of a one pixel equivalent to the input image of a plurality of pixel elements included as part of the SLM.

10. A projection apparatus comprises a laser light source for emitting an illumination light through an illumination optical system for projecting to a spatial light modulation (SLM) for generating and transmitting a modulated light through a projection optical system to project the modulated light from the SLM onto a projection surface, the projection apparatus further comprising:

an image process unit for analyzing an input image; and

the image process unit further performs a pseudo pixel conversion process for applying a conversion process to a signal related to the input image by temporally differentiating an algorithm of the conversion process for generating and displaying a gradation of a one pixel equivalent to the input image of a plurality of pixel elements included as part of the SLM.

11. The projection apparatus according to claim 10, wherein:

the image process unit detects an image region with a small change of images in a plurality of consecutive frames for applying the pseudo pixel conversion process to the image data of the image region detected with the small change of images.

12. The projection apparatus according to claim 10, further comprising:

an actuator unit for driving a screen constituting a projection surface for projecting an image thereto for displaying the image thereon.

13. The projection apparatus according to claim 10, further comprising:

an imaging position change unit for changing an image position projected by a modulation light from the SLM on a projection surface, and

a control unit for controlling the SLM and the image position change unit.

14. The projection apparatus according to claim 13, wherein:

the image process unit applies a conversion process to a signal related to the input image data to generate different control patterns for a plurality of adjacent pixel elements included in the SLM for a predetermined period during at least one frame period to reproduce a gradation of the pixel whereby each of the plurality of adjacent pixel elements has a gradation of approximately a same level.