Claims
- 1. A projection method for correcting keystone distortion within an optical image that is projected onto a projection surface through a projection lens having a projection axis that is oriented in a direction that is off-axis from the surface normal of the projection surface, said projector method comprising the steps of:
(a) receiving input image data representing the optical image; (b) determining the absolute horizontal direction of the projection axis, the absolute vertical direction of the projection axis, a vertical zero reference and a horizontal zero reference; (c) calculating the vertical difference angle by subtracting the vertical zero reference from the absolute vertical direction of the projection axis and the horizontal difference angle by subtracting the horizontal zero reference from the absolute horizontal direction of the projection axis; (d) determining the keystone distortion based on the vertical difference angle and the horizontal difference angle; and (e) applying geometric correction to the image data proportional and inverse to said keystone distortion such that the projected image is free from keystone distortion.
- 2. The projection method of claim 1, wherein (e) also includes applying additional correction to the image data to correct for the effects of optical characteristics selected from the group consisting of field of view, lens distortion, lens offset, and luminance variations.
- 3. The projection method of claim 1, wherein the determination of the vertical zero reference in (b) consists of determining the constant vector of acceleration due to gravity.
- 4. The projection method of claim 1, wherein the horizontal zero reference is provided by the user.
- 5. The projection method of claim 1, wherein determination of the vertical zero reference in (b) is accomplished by positioning the projection lens in a substantially horizontal perpendicular direction and instantaneously measuring the horizontal direction and recording it as the horizontal zero reference.
- 6. The projection method of claim 1, wherein (b) further comprises receiving a data signal that contains at least one of the vertical zero reference and the horizontal zero reference.
- 7. The projection method of claim 6, wherein the data signal is provided by a directional device that is adapted to be positioned against the projection surface, for measuring the horizontal zero reference, and for providing said data signal.
- 8. A projector assembly for correcting keystone distortion within an optical image that is projected onto a projection surface based on image data, said projector assembly comprising:
(a) a projection lens having a projection axis that is oriented in a direction that is off-axis from the surface normal of the projection surface; (b) an inclination sensor coupled to the projection lens in a fixed manner for measuring the absolute vertical direction of the projection axis and a vertical zero reference and a directional sensor coupled to the projection lens and to the inclination sensor in a fixed manner for measuring the absolute horizontal direction of the projection axis; (c) an input device for receiving a horizontal zero reference; (d) a processor coupled to said directional sensor, said inclination sensor, and aid input device, said processor being adapted to determine the vertical difference angle by calculating the difference between the absolute vertical direction of the projection axis and the vertical zero reference and the horizontal difference angle by calculating the difference between the absolute horizontal direction of the projection axis and the horizontal zero reference and for calculating the keystone distortion based on the vertical difference angle and the horizontal difference angle; (e) an image correction engine applying geometric and brightness correction to the image data proportional and inverse to said keystone distortion such that the projected image is free from keystone distortion.
- 9. The projector assembly of claim 8, wherein said image correction engine is adapted to apply additional correction to the image data in order to correct for the effects of optical characteristics selected from the group consisting of field of view, lens distortion, lens offset, and luminance variations.
- 10. The projector assembly of claim 8, wherein the vertical zero reference is the constant vector of acceleration due to gravity.
- 11. The projector assembly of claim 8, further comprising an input device for receiving the horizontal zero reference from the user.
- 12. The projector assembly of claim 11, further comprising a communications device for receiving at least one of the vertical zero reference and the horizontal zero reference from an external data processing device.
- 13. The projector assembly of claim 12, wherein said external data processing device is one of the group consisting of: a computer, a handheld personal digital assistant, an infrared remote control unit, said external data processing device providing said at least one of said vertical zero reference and said horizontal zero reference to said communication device.
- 14. The projector assembly of claim 12, further comprising a directional device adapted to be positioned against the projection surface, said directional device having a direction sensor for measuring the horizontal zero reference and signaling means for providing said communication device with the horizontal zero reference.
Parent Case Info
[0001] This application claims the benefit under 35 U.S.C. 119(e) of U.S. Provisional Application No. 60/388,001, filed Jun. 12, 2002.
Provisional Applications (1)
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Number |
Date |
Country |
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60388001 |
Jun 2002 |
US |