Texas Instruments Corporation

Raytheon Ti Systems, Inc.

Gary L Sextro

Robert J Gove

Stephen Wesley Marshall

Jeffrey Brian Sampsell

Donald B Doherty

Kazuhiro Ohara

Richard C Meyer

Scott D Heimbuch

William J Sexton

Carl W Davis

Joseph G Egan

Akira Takeda

A method and apparatus for selectively scaling portions of image data based on the intensity levels of historical image data. The selective scaling, or level expansion, provides improved images by increasing or decreasing the intensity of a portion of image pixels. Black level expansion reduces the intensity of dark pixels and is appropriate when a relatively large number of the image pixels have a high intensity level. White level expansion increases the intensity of bright pixels and is appropriate when a relatively large number of image pixels have a low intensity level. Level expansion is implemented by using histogram comparators to compare the intensity of each pixel with a threshold, typically on a frame-by-frame basis. When an adequate number of pixels in each frame meet the threshold criteria, the level expansion is increased. Field accumulator is used to determine whether and by how much the image data is scaled. Field accumulator increments each time a frame meets the expansion criteria, as determined by the histogram comparators , and decrements each time a frame does not meet the expansion criteria. The value accumulated by the field accumulator is used by level expander to scale at least a portion of the input data.

Histogram-based intensity expansion

A 3D display having a closed loop feedback system dynamically adjusting the scanning pattern of laser beams on-line to maintain pointing errors of all scanned images to a specified tolerance. A predetermined alignment pattern, preferably a matrix of dots with known coordinates, is periodically injected into the image data path, preferably during non-display periods. A grid is disposed on each of two mirrors which enter into two separate light paths and are scanned. The mirrors reflect the laser beams from the grid to an optical sensor for each beam, each sensor connected to an A/D converter and producing an output proportional to the intensity of the reflected light. The sensor output is an analog function of the light intensity impinging thereon. The digitized values are stored in a grid buffer which accumulates an entire intensity pattern of grid points. The the intensity data is collected for offset and gain beams separately and the x and y centroid is computed for the gain and offset grid and used to compute adjustment values for the offset, gain and power intensity of the normal data values sent to the optics. A reference intensity sets the nominal value to which the loop corrects. The adjustment values are applied to the display data before being sent to the optics and are applied to the predetermined alignment pattern, allowing the loop to close to a specified accuracy, depending upon loop bandwidth and time constant. A linearity lookup value is applied to the display data to compensate for any fixed nonlinearity in the data path due to optics or fabrication errors.

On-line laser alignment system for three dimensional display

A method and structure for a display system having multiple spatial light modulators (SLMs) (16), each of which contributes an image of one color that is perceived by the viewer as a combined image. The SLMs (16) have more rows and columns of pixel elements (42) than rows or columns of pixel data to be displayed. A window of 'active' pixel elements (42) can be shifted up and down or right and left by selecting which pixel elements (42) are to receive data. The addressing circuit (31, 31a, 35, 35a) of each SLM 16 can be controlled so as to accomplish this shifting.

Alignment for display having multiple spatial light modulators

A sequential color system is provided in which a processor (22) is coupled to a memory (24) and a receiver (27). Images are generated by shining light from a light source (28) through a color wheel (30) and onto DMD array (26). Light from the DMD array (26) is shone on screen (32). By adjusting the speed and make-up of color wheel (30) color separation is greatly reduced or eliminated. Also there are techniques for sequential imaging which may be applied to other technologies, such as CRT technologies.

Method and apparatus for sequential color imaging

Growing community of inventors

McKinney, TX, United States of America

Gary L Sextro