The Uab Research Foundation (the University of Alabama at Birmingham)

Axometrics, Inc.

Other

Matthew H Smith

Kurt R Denninghoff

Lloyd W Hillman

Russell A Chipman

Thomas E Minnich

Arthur Lompado

Yang Zou

Raghunandan Manchenahalli

Methods and systems are provided to measure the optical anisotropy properties of a film on glass or other substrates. This technique is suitable for production environments, and is not strongly affected by the TFT or CF active area on LCD panels, even for very high pixel density displays. A method is provided for measuring a magnitude and orientation of optical anisotropy. These methods and systems include an optical anisotropy measurement apparatus for measuring anisotropic materials in a reflection or transmission configuration. The methods and systems may measure a Mueller matrix, diattentuation orientation, or retardance of a sample at one or more rotation angles to calculate anisotropic magnitude and orientation.

Method and apparatus for measuring parameters of optical anisotropy

Method and apparatus for testing of LCD cells is disclosed. An LCD cell under test () may be mounted to translatable table () between polarization state generator () and polarization state analyzer (). For each location on cell () to be tested, a variety of known polarization states () are launched through LCD cell () and detected by polarization state analyzer (). Electrical signals representative of polarization states are acquired by computer (). Within computer (), a model () of polarization properties of LCD cell () is developed based on estimations of what physical parameters of LCD cell () are believed to be. RMS differences between simulated polarization properties and measured polarization properties are minimized by iteratively refining () modeled physical cell properties, at which point cell thickness and other physical parameters of the LCD cell may be deduced.

Method and apparatus for determining polarization-altering element parameters from full mueller matrix measurements

Method and apparatus for determining liquid crystal cell parameters from full mueller matrix measurements

Method and apparatus for testing of LCD panels is disclosed. An LCD panel under test is mounted to a translatable table between a polarization state generator and polarization state analyzer. For each location on the screen to be tested, a continuum of known polarization states are launched through the LCD screen and detected by the polarization state analyzer. Electrical signals representative of such polarization states are acquired by a computer. Within the computer, a model of polarization properties of the LCD panel is developed based on estimations of what the physical parameters of the LCD panel are believed to be. RMS differences between simulated polarization properties and measured polarization properties are minimized by iteratively refining the modeled physical cell properties, at which point cell thickness and other physical parameters of the LCD screen may be deduced.

Method and apparatus for determining liquid crystal cell parameters from full Mueller matrix measurements

A method and apparatus are provided for accurately measuring the blood oxygen saturation with a retinal vessel. The apparatus includes an optical source for illuminating the retinal vessel with optical signals. The apparatus also includes a filter, such as an aperture, disposed within the path of the optical signals returning from the eye. The filter preferentially passes single pass optical signals that have diffused through the retinal layer and/or the choroidal layer of the eye while traversing the retinal vessel only once, while blocking or otherwise redirecting the other optical signals. The apparatus also includes a detector for separately detecting at least the single pass optical signals and, in some instances, the other optical signals as well. The apparatus can also include a processing element for determining the blood oxygen saturation in the retinal vessel based upon the optical signals that have been detected.

Method and apparatus for measuring blood oxygen saturation in a retinal vessel by separately detecting single pass optical signals

Methods, apparatus and computer program products are provided for more accurately determining the percent transmittance of a vessel, such as a retinal vessel, at each of a number of different wavelengths and, in turn, for more accurately determining the blood oxygen saturation within the vessel. The blood oxygen saturation is determined based upon a plurality of images of the vessel obtained with illumination of different wavelengths. Background images are generated based upon respective images of the vessel in order to approximate the tissue bed underlying the vessel, such as the background fundus underlying the retinal vessel. Thereafter, a plurality of transmittance images are determined based upon respective pairs of the background images and the images of the vessel, such as by dividing the image of the vessel by the respective background image. Based upon a plurality of transmittance images, the blood oxygen saturation in the vessel may be determined.

Multispectral image processing method, apparatus and computer program product for determining the blood oxygen saturation in a vessel

An improved optical scanning spectroscopic method and apparatus is provided that alternately scans the posterior portion of an eye with laser signals emitted by different ones of a plurality of lasers such that a data frame can be constructed that includes interlaced portions formed from signals returning from the posterior portion of the eye in response to illumination by laser signals emitted by different ones of the plurality of lasers. As such, the same data frame includes data attributable to the reflection of laser signals from each of the plurality of lasers even though the subject's eye is not subjected to simultaneous illumination by each of the lasers, thereby protecting the subject's eye. According to one further aspect of the invention, the optical scanning spectroscopic method and apparatus can illuminate the posterior portion of the subject's eye in response to a trigger at a predetermined point in the cardiac cycle of the subject such that the resulting data frame relates to at least a predetermined portion of the cardiac cycle of the subject, thereby permitting a detailed analysis of one or more phases of the cardiac cycle of the subject.

Optical scanning spectroscopic apparatus and associated method

The method and apparatus for measuring the transmittance of blood within a retinal vessel detects the intensity of light reflected from illuminated portions of an eye, including the retinal vessel and background fundus, and adjusts the corresponding intensity signals to compensate for reflections from the retinal vessel. In particular, the transmittance measuring method and apparatus constructs an intensity profile function based upon the intensity signals. As a result, the intensity profile function approximates the intensity of light transmitted through the retinal vessel as a function of retinal vessel position. During the construction of the intensity profile function, the transmittance measuring method and apparatus can compensate for at least some of the reflections of light from the retinal vessel which occurred prior to propagation of the light through the retinal vessel, thereby increasing the accuracy with which the transmittance of blood within a retinal vessel is measured. In addition, the transmittance measuring method and apparatus can compensate for the finite point spread function of the light with which the eye is illuminated in order to further increase the resulting measurement accuracy.

Method and apparatus for accurately measuring the transmittance of blood

The method and apparatus for measuring the oxygen saturation of blood within a retinal vessel illuminates the retinal vessel with light having a combination of wavelengths selected to reduce the error in the measured blood oxygen saturation. The oxygen saturation measuring method and apparatus illuminates a retinal vessel with light having the selected combination of wavelengths. For example, the oxygen saturation measuring method and apparatus can illuminate the retinal vessel with light having a first wavelength between 460 nm and 503 nm, a second wavelength between 600 nm, and 770 nm and a third wavelength between 770 nm and 1000 nm. The oxygen saturation measuring method and apparatus then measures the transmittance of the blood within the retinal vessel in response to the illumination at each of the selected wavelengths. Based upon the respective transmittances of the blood within the retinal vessel that are measured at each of the selected wavelengths, the oxygen saturation measuring method and apparatus determines the oxygen saturation of the blood within the retinal vessel. By appropriately selecting the combination of wavelengths with which the retinal vessel is illuminated, the corresponding error in the measured blood oxygen saturation can be reduced.

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Madison, AL, United States of America

Matthew H Smith