Automatic image-quality adjustment system

• US 6,727,489 B2
• Filed: 10/17/2001
• Issued: 04/27/2004
• Est. Priority Date: 04/19/2001
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Yano, Seiichirou
• Primary Examiner(s): Glick, Edward J.
• Assistant Examiner(s): THOMAS, COURTNEY D
• Application Number:
  US09/978,044
• Publication Number:
  US 20020153472A1
• Time in Patent Office: 923 Days
• Field of Search: 250/208.1, 250/221, 250/214.AL, 348/744, 348/750, 348/751, 348/191, 348/650, 348/657, 348/602, 348/603, 348/745, 348/746, 348/747, 345/87, 345/207, 345/63, 345/77, 345/204
• US Class Current: 250/221
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2320/066 for control of contrast
• CPC Class Codes: G09G 2320/0666 for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/36 using liquid crystals
• CPC Class Codes: H04N 9/73 Colour balance circuits, e.g. white balance circuits or colour temperature control camera processing pipelines for colour balance H04N23/88

Abstract

An image-quality adjustment system for a liquid-crystal projector detects the brightness and color of ambient light, or detects the brightness and color of the surface onto which the liquid-crystal projector projects an image. The image signal is automatically adjusted according to the detected brightness and color. For example, the brightness, contrast, and color balance of the image signal may be adjusted. The intensity of the lamp in the liquid-crystal projector may also be adjusted. A clear and natural image can thus be projected without the need for manual adjustments.

Claims

1. An image-quality adjustment system for a liquid-crystal projector that projects an image onto a surface according to an input image signal, comprising:

at least one photosensor for sensing brightness and color of external light reflected from the surface and received at the liquid-crystal projector; and

a processor for adjusting the image signal according to the detected brightness and color.

2. The image-quality adjustment system of claim 1, wherein the processor adjusts brightness, contrast, and color balance of the image signal according to the detected brightness and color.

3. The image-quality adjustment system of claim 1, wherein the liquid-crystal projector has a projection lamp, further comprising a control circuit for controlling an intensity of the lamp according to at least the detected brightness.

4. The image-quality adjustment system of claim 1, further including an additional photosensor that detects the brightness and color of ambient light.

5. A method of adjusting an image projected by a liquid-crystal projector onto a surface according to an input image signal, comprising the steps of:

(a) detecting both brightness and color of external light reflected from the surface and received at the liquid-crystal projector; and

(b) adjusting the image signal according to the detected brightness and color.

6. The method of claim 5, wherein said step (b) includes adjusting the image signal in regard to brightness, contrast, and color balance.

7. The method of claim 5, wherein the liquid-crystal projector has a projection lamp, further comprising the step of controlling an intensity of the lamp according to at least the detected brightness.

8. The method of claim 5, wherein said step (a) also detects the brightness and color of ambient light.