Other

USA As Represented by Secretary of the Navy

Harvard College

Geo-centers, Inc.

Centeye Incorporated

Geoffrey Louis Barrows

Craig William Neely

Todd Zickler

Banhalli R Ratna

Sanjeev Jagannatha Koppal

Ioannis Gkioulekas

Gregory Brill

Anno Hermanns

An apparatus for determining the location and state of an object in an environment is disclosed. Three or more light-emitting beacons are located in the environment, and each beacon transmits a light pattern that contains information needed to identify the beacon. An optical receiver is attached to the object whose location needs to be determined. The optical receiver comprising one or more cameras images the beacons, and identifies the apparent direction from which the beacon is coming based on the pixel or pixels illuminated by the beacon. The optical receiver also decodes the light pattern transmitted by each beacon to identify it. Finally, based on knowledge of the locations of the beacons in the environment and based on the apparent directions from which the beacons appear to be coming, the optical receiver determines its location, and thus the location of the object.

Localization method and apparatus

A camera configured for a predetermined environment can be made low profile in the following manner. The camera includes an image sensor that has a light sensitive portion that can sense light from the predetermined environment. A substantially opaque mask is disposed above the light sensitive portion of the image sensor and has at least one opening through which the image sensor senses light. The low profile structure of the camera can be realized with substantially transparent material disposed between the substantially opaque mask and the image sensor that has index of refraction that is greater than an index of refraction of the predetermined environment. Accordingly, light through the opening refracts as it passes through the substantially transparent material to the image sensor.

Low profile camera and vision sensor

Briefly, embodiments of an optical micro-sensor are described.

Optical micro-sensor

A monolithic camera configured for a predetermined environment can be made in the following manner. The camera is formed from an integrated circuit that has a light sensitive portion that can sense light from the predetermined environment. Two or more opaque masks are disposed within the oxide layer above the light sensitive pixel array of the image sensor. These opaque masks may be formed from the 'metal' layers typically used for signal routing in image sensor integrated circuits. The opaque masks contain arrays of holes arranged so that for each pixel there is a clear path for light to reach the pixel from a corresponding part of the visual field. Each pixel is associated with a different set of holes that allows a different region of the predetermined environment to be observed.

A vision sensor capable of generating an array of photoreceptor signals based on a visual field is provided. The vision sensor comprises an array of field circuits. Each field circuit comprises an array of pixel circuits capable of generating an array of potentials based on a visual field and a sample signal, and a control circuit capable of generating the sample signal based on the array of potentials. Each field circuit is also capable of generating an array of photoreceptor signals based on the array of potentials.

Vision sensor

An optical flow sensor for generating optical flow measurements based on a visual field is provided. The optical flow sensor comprises a binarized signal generator capable of generating binarized feature signals based on the visual field, a metafeature signal generator capable of generating metafeature signals based on the binarized feature signals, an apparatus for generating velocity reports based on the metafeature signals, and an apparatus for generating an optical flow measurement based on the velocity reports.

Optical flow sensor

An optical flow sensor is presented that directly measures the translational component of the optical flow experienced by the sensor while it is on a moving platform. The translational optical flow is measured by using a gyro to measure the platform's angular rates and then incorporating these angular rates in the optical flow computations in a manner that bypasses lags in the optical flow sensor measurement. In one embodiment, individual 'velocity report' optical flow measurements have their rotational component removed before these velocity reports are utilized in the remainder of the optical flow algorithm. In another embodiment, a movable window and shifting techniques are used to form a windowed image that has no rotational optical flow components. In another embodiment, an optical flow sensor is mounted on a gimbal and held to point in one direction even as the platform on which the optical flow sensor is mounted moves.

Translational optical flow sensor

A visual sensor for generating an array of binarized feature signals based on a visual field is provided. The visual sensor comprises an array of photoreceptor circuits capable of generating photoreceptor signals based on the visual field, an array of feature detectors capable of generating feature signals based on the photoreceptor signals, and a reconfigurable binary generator array capable of generating binarized feature signals based on the feature signals.

Feature detecting vision sensor

An improved optic flow sensor is provided which affords enhanced bandwidth without the use of a lens. A plurality of photoreceptor circuits, arranged in a linear array, sense light received from a visual field and produce a plurality of photoreceptor signals in accordance with the light sensed. A negative iris, disposed between the visual field and the photoreceptor circuits, blocks a portion of the light from the visual field so that the light blocked by the negative iris is not received by the photoreceptor circuits. The photoreceptor signals are used in determining optic flow in the visual field. The invention is useful for implementation using micro electromechanical system (MEMS) techniques.

Optic flow sensor with negative iris photoreceptor array

An optic flow sensor is provided which employs a plurality of photoreceptors and which produces a final optic flow signal that is a robust measurement of the optic flow as seen by the photoreceptors. Each array of a plurality of feature detector arrays receives, as input, photoreceptor signals from the receptors and generates a plurality of feature signals based thereon. Each optic flow measuring circuit or algorithm of a plurality of optic flow measuring circuits or algorithms receives, as input, one of the plurality of feature signals. The optic flow measuring circuits or algorithms each generate an optic flow measurement signal so that a plurality of optic flow measurement signals are generated. A fusion circuit or algorithm, which can, e.g., employ a leaky integrator circuit or algorithm, receives, as input, the optic flow measurement signals and generates the final optic flow signal based thereon.

Optic flow sensor with fused elementary motion detector outputs

This invention is a one-dimensional optic flow sensor that operates in a small region of the two-dimensional visual field. The heart of the sensor is an linear array of photoreceptors that generates a one-dimensional image representation of the visual field region of interest. The linear photoreceptor array has an orientation in the two-dimensional image space. Information in the two-dimensional image space parallel to the photoreceptor array's orientation is preserved while information in other directions is discarded. The result is that a one-dimensional optic flow algorithm using the photoreceptor array output produces a measurement of the optic flow vector onto the sensor orientation vector. In a preferred embodiment, the photoreceptor array circuitry is implemented on a focal plane chip on which an image is focused by a lens. The focal plane chip is placed slightly off the lens's focal point to blur the image. Each elongated photoreceptor has a long rectangular shaped active area, whose long dimension is perpendicular to the photoreceptor array's orientation. An iris next to the lens controls the &ldquo;shape&rdquo; of the blurring by having a transmission function derived from a low-pass spatial filter. The combination of the lens being out of focus and the shading from the iris blur the image in a controlled fashion that implements a low pass spatial filter. This reduces high spatial frequency components in the image that could cause problems due to spatial aliasing from the photoreceptor array.

Photoreceptor array for linear optical flow measurement

An active matrix circuit for compact, high resolution reflective liquid ctal displays includes a low quiescent current, low output impedance MOS transistor amplifier produced in a CMOS process. A voltage controlled input switch effects the voltage refresh of the active matrix cell by passing a data voltage to the input of the transistor amplifier when a control voltage pulse is present on the input switch control line. All active matrix cells in a given row use the same input switch control line, and all active matrix cells in a given column access the same data input line. Refresh of the active matrix cell voltage terminates when the input switch is opened, storing the data voltage on the input node capacitance of the amplifier. The active matrix circuit is particularly addressed to liquid crystal devices having fast, analog response liquid crystals with large molecular polarizations such as in the Electroclinic Liquid Crystals (ELC). Including such an amplifier in each active matrix cell facilitates delivery of the large charge required to switch such liquid crystals without incurring a concomitant drop in pixel voltage, as encountered with other active matrix cell circuits.

Cell circuit for active matrix liquid crystal displays using high

This invention is a one-dimensional elementary motion detector that measu the linear optical flow in a small subsection of the visual field. This sensor measures motion by tracking the movement of a feature across the visual field and measuring the time required to move from one location to the next. First a one-dimensional image is sampled from the visual field using a linear photoreceptor array. Feature detectors, such as edge detectors, are created with simple circuitry that performs simple computations on photoreceptor outputs. The detection of the feature's location is performed using a winner-take-all (WTA) mechanism on feature detector outputs. Motion detection is the performed by monitoring the location of the high WTA output in time to detect transitions corresponding to motion. The correspondence problem is solved by ignoring transitions to and from the end lines of the WTA output bus. Speed measurement is performed by measuring the time between WTA output transitions. This invention operates in a one-dimensional subspace of the two-dimensional visual field. The conversion of a two-dimensional image section to a one-dimensional image is performed by a specially shaped photoreceptor array which preserves image information in one direction but filters out image information in the perpendicular direction. Thus this sensor measures the projection of the 2-D optical flow vector onto the vector representing the sensor's orientation. By placing several of these sensors in different orientations and using vector arithmetic, the 2-D optical flow vector can be determined.

Growing community of inventors

Washington, DC, United States of America

Geoffrey Louis Barrows