Apparatus and method for automated visual distortion adjustments for a portable projection device

• US 8,322,863 B1
• Filed: 06/18/2010
• Issued: 12/04/2012
• Est. Priority Date: 06/18/2010
• Status: Expired due to Fees

• Current Assignee: Christine Hana Kim, Samuel Seungmin Cho
• Original Assignee: Christine Hana Kim, Samuel Seungmin Cho
• Inventors: Cho, Samuel Seungmin, Kim, Christine Hana
• Primary Examiner(s): Luu, Thanh
• Assistant Examiner(s): NAPHAS, RENEE D
• Application Number:
  US12/819,172
• Time in Patent Office: 900 Days
• Field of Search: 353/69, 353/70, 353/121, 352/140, 352105-120, 359/676, 359/677, 382/295, 382/275, 348/745
• US Class Current: 353/70
• CPC Class Codes: H04N 9/3185 Geometric adjustment, e.g. keystone or convergence optical or mechanical adjustment of convergence H04N9/317; using scanning means H04N3/22; optical or mechanical adjustments of projectors not peculiar to the presence of an electronic spatial light modulator G03B21/14
• CPC Class Codes: H04N 9/3194 including sensor feedback

Abstract

An apparatus and a method are disclosed for automated projection image adjustments for a portable projection device. In one embodiment of the invention, the apparatus periodically polls a tilt sensor inside the portable projection device and uses the tilt sensor reading as a key to a lookup table which stores pre-computed visual distortion adjustment values. Furthermore, the apparatus can also poll a distance measurement sensor to measure a distance between a projector lens and a presumed projection surface periodically. The measured distance value can also be used as an additional parameter to the key for the lookup table to retrieve appropriate visual distortion adjustment values which are pre-computed and stored in the lookup table. The fast pre-computed adjustment value retrieval without real-time computation of graphical transformations to correct the visual distortions minimizes processor load, energy consumption, and processing delays for projection image corrections.

Claims

1. An apparatus for automated visual distortion adjustments for a portable projection device, the apparatus comprising:

a three-dimensional tilt sensor embedded in the portable projection device, wherein the three-dimensional tilt sensor is designed to determine a current horizontal (x-axis) position, a current vertical (y-axis) position, a current depth (z-axis) position, and a current clockwise or counterclockwise rotational orientation of the portable projection device relative to a horizontal plane or a vertical plane;

a distance measurement sensor next to a projector lens embedded in the portable projection device, wherein the distance measurement sensor is designed to determine a current distance reading between a surface of the portable projection device and a presumed projection surface;

a lookup table (LUT) unit operatively connected to the three-dimensional tilt sensor and the distance measurement sensor, wherein the LUT unit takes the current horizontal (x-axis) position, the current vertical (y-axis) position, and the current depth (z-axis) position sensor output values from the three-dimensional tilt sensor and the current distance reading from the distance measurement sensor as a combined lookup table key to retrieve a yaw distortion correction value and a rotational orientation correction value from the LUT unit for an automated three-dimensional (x-axis, y-axis, and z-axis) correction for adjustment or prevention of both yaw and rotational orientation-related projection distortion from the portable projection device; and

a graphics processor and/or a central processing unit (CPU) in the portable projection device to produce, process, and/or control a corrected projection image based on the yaw distortion correction value and/or the rotational orientation correction value retrieved from the LUT unit.

2. The apparatus of claim 1, wherein the combined lookup table key comprising the current horizontal (x-axis) position, the current vertical (y-axis) position, and the current depth (z-axis) position sensor output values from the three-dimensional tilt sensor and the current distance reading from the distance measurement sensor also retrieves a vertical keystone adjustment value and a focal adjustment value from the LUT unit.

3. The apparatus of claim 2, wherein the graphics processor and/or the CPU are capable of producing, processing, and/or controlling the corrected projection image in three dimensions (x-axis, y-axis, and z-axis) based on the yaw distortion correction value, the rotational orientation correction value, the vertical keystone adjustment value, and/or the focal adjustment value retrieved from the LUT unit.

4. The apparatus of claim 3, further comprising a display driver configured to produce, process, and/or control the corrected projection image transmitted to the projector lens for image projection.

5. The apparatus of claim 3, further comprising a graphics signal input interface which is designed to receive an external graphics signal source or an internal graphics signal source which can be transmitted to the graphics processor or the CPU.

6. The apparatus of claim 3, wherein the corrected projection image is a tilt-leveled and/or keystone-balanced adjustment of a raw projection image, which may have appeared tilted clockwise, counterclockwise, or visually skewed if the tilt-leveled and/or keystone-balanced adjustment were not performed.

7. The apparatus of claim 1, wherein the combined lookup table key comprises at least one voltage reading as an output from the three-dimensional tilt sensor and at least one distance measurement reading as an output from the distance sensor.

8. The apparatus of claim 1, further comprising a distance measurement sensor interface operatively connected to the distance measurement sensor, wherein the distance measurement sensor interface is designed to communicate with the distance measurement sensor and a central processing unit (CPU) (i.e. a microprocessor or a microcontroller) of the portable projection device.

9. The apparatus of claim 1, wherein the three-dimensional tilt sensor and the distance measurement sensor are periodically polled by the central processing unit (CPU) of the portable projection device to obtain current sensor output values which are used as the combined lookup table key to retrieve the yaw distortion correction value, the rotational orientation correction value, the vertical keystone adjustment value, and/or the focal adjustment value stored in the LUT unit.

10. The apparatus of claim 1, wherein the portable projection device is a mobile device which integrates a miniaturized projector.

11. The apparatus of claim 1, wherein the LUT unit is implemented on a non-volatile memory unit, a programmable semiconductor chip, and/or a software module stored in a data storage medium.

12. A method for automatically adjusting a visual distortion from a portable projection device, the method comprising the steps of:

reading sensor output values from a three-dimensional tilt sensor to determine a current horizontal (x-axis) position, a current vertical (y-axis) position, a current depth (z-axis) position, and a current clockwise or counterclockwise rotational orientation for a visual distortion correction;

reading a distance sensor for a distance measurement reading between a surface of the portable projection device and a projected surface, wherein the projected surface is on a vertical plane typically represented by a projection screen or a wall;

using the sensor output values from the three-dimensional tilt sensor and the distance measurement reading from the distance sensor as a combined lookup table (LUT) key to retrieve a yaw distortion correction value and a rotational orientation correction value stored in a lookup table (LUT) unit for an automated three-dimensional (x-axis, y-axis, and z-axis) correction for adjustment or prevention of both yaw and rotational orientation-related projection distortion from the portable projection device; and

instructing a graphics processor or a central processing unit (CPU) of the portable projection device to produce, process, and/or control a corrected projection image based on the yaw distortion correction value, the rotational orientation correction value, the vertical keystone adjustment value, and/or the focal adjustment value retrieved from the LUT unit.

13. The method of claim 12, further comprising a step of using a display driver operatively connected to the graphics processor or the CPU to formulate and/or transmit the corrected projection image to the projector lens, wherein the corrected projection image is a result of adjusting a raw projection image in three dimensions (x-axis, y-axis, and z-axis) with the yaw distortion correction value, the rotational orientation correction value, the vertical keystone adjustment value, and/or the focal adjustment value retrieved from the LUT unit.

14. The method of claim 12, wherein the lookup table (LUT) key comprises at least one voltage reading as an output from the three-dimensional tilt sensor and at least one distance measurement reading as an output from the distance sensor.

15. The method of claim 13, wherein the corrected projection image is a tilt-leveled and/or keystone-balanced adjustment of the raw projection image, which may have appeared tilted clockwise, counterclockwise, or visually skewed if the tilt-leveled and/or keystone-balanced adjustment of the raw projection image were not performed.

16. An apparatus for automated visual distortion adjustments for a mobile device integrating a miniaturized projector, the apparatus comprising:

a three-dimensional tilt sensor embedded in the mobile device integrating the miniaturized projector, wherein the three-dimensional tilt sensor is designed to determine a current horizontal (x-axis) position, a current vertical (y-axis) position, a current depth axis (z-axis) position, and a current clockwise or counterclockwise rotational orientation of the mobile device relative to a horizontal plane or a vertical plane;

a distance measurement sensor next to a projector lens of the miniaturized projector embedded in the mobile device, wherein the distance measurement sensor is designed to determine a current distance reading between a surface of the mobile device and a presumed projection surface;

a lookup table (LUT) unit operatively connected to the three-dimensional tilt sensor and the distance measurement sensor, wherein the LUT unit takes the current horizontal (x-axis) position, the current vertical (y-axis) position, and the current depth axis (z-axis) position sensor output values from the three-dimensional tilt sensor and the current distance reading from the distance measurement sensor as a combined lookup table key to retrieve a yaw distortion correction value and a rotational orientation correction value from the LUT unit for an automated three-dimensional (x-axis, y-axis, and z-axis) correction for adjustment or prevention of both yaw and rotational orientation-related projection distortion from the mobile device integrating the miniaturized projector; and

a graphics processor and/or a central processing unit (CPU) in the mobile device integrating the miniaturized projector to produce, process, and/or control a corrected projection image based on the yaw distortion correction value and/or the rotational orientation correction value retrieved from the LUT unit.

17. The apparatus of claim 16, wherein the combined lookup table key comprising the current horizontal (x-axis) position, the current vertical (y-axis) position, and the current depth (z-axis) position sensor output values from the three-dimensional tilt sensor and the current distance reading from the distance measurement sensor also retrieves a vertical keystone adjustment value and a focal adjustment value from the LUT unit.

18. The apparatus of claim 16, wherein the graphics processor and/or the CPU are capable of producing, processing, and/or controlling the corrected projection image in three dimensions (x-axis, y-axis, and z-axis) based on the yaw distortion correction value, the rotational orientation correction value, the vertical keystone adjustment value, and/or the focal adjustment value retrieved from the LUT unit.

19. The apparatus of claim 18, wherein the corrected projection image is a tilt-leveled and/or keystone-balanced adjustment of a raw projection image, which may have appeared tilted clockwise, counterclockwise, or visually skewed if the tilt-leveled and/or keystone-balanced adjustment were not performed.