Abstract: A method for registering pixels provided in a pixel event stream comprising: acquiring image frames from a frame-based camera, each image frame being generated using an exposure period; generating a first point matrix from one or more of the image frames, the first point matrix being associated with an acquisition period of the image frames; acquiring a pixel event stream generated during the acquisition period; generating a second point matrix from pixel events of the pixel event stream, occurring during the acquisition period of the first point matrix; computing a correlation scoring function applied to at least a part of the points of the first and second point matrices, and estimating respective positions of points of the second point matrix in the first point matrix, due to depths of the points of the first point matrix related to the second point matrix, by maximizing the correlation scoring function.

Abstract: A method produces a compressed sequence of events stored in a memory, originating from an event-based camera, the sequence comprising a first run-length code representing timestamps of the sequence of events; and subsequent compressed codes including one of: (i) a second run-length code representing first coordinates of the sequence of events, at least one dictionary code representing second coordinates of the sequence of events, and data representing polarities of the sequence of events; (ii) a second run-length code representing first coordinates of the sequence of events, a number of bit-packed fields, each representing a second coordinate and polarity pair of the sequence of events; or (iii) a number of bit-packed fields, each representing a first and second coordinate and polarity triplet of the sequence of events.

Abstract: An event-based vision sensor comprises an array of pixel circuits, each configured to produce a respective photocurrent, wherein the array of pixel circuits is divided into one or more clusters of multiple pixel circuits; and a cluster control circuit configured, for each cluster, to generate (i) a summation of the photocurrents produced by the pixel circuits of the cluster and (ii) cluster events based on changes in the summation of the photocurrents.

Abstract: An event-based vision sensor, comprises an array of event-based pixels, each pixel configured to record events based on variations of a sensed photocurrent and enable, at the occurrence of an event, a request line common to pixels aligned along an axis of the array; a request arbiter configured to respond asynchronously to the enabled request lines by enqueuing corresponding line readout requests in a request queue; an event readout circuit connected to the request arbiter and configured to readout in parallel the events of a line of pixels corresponding to a current line readout request served by the arbiter; a queue length counter connected to the request lines to produce the request queue length; a queue monitor connected to the queue length counter, configured to generate an event burstiness indicator; and means configured to carry out a burstiness compensation action based on the event burstiness indicator.

Abstract: An apparatus comprising an interface and a processor. The interface may be configured to receive an asynchronous event stream from an event-based sensor. The event stream may comprise a series of pixel locations with a timestamp each generated in response to an autonomous detection by any of a plurality of pixels of the event-based sensor exceeding a threshold. The processor may be configured to detect a characteristic pattern of a flicker event in the event stream and generate an output signal containing a tick result in response to the characteristic pattern of the flicker event. A predicted recurring interval of the flicker event may be determined based on the characteristic pattern. The tick result may comprise future timestamps of the flicker event determined based on the predicted recurring interval for the timestamp of the autonomous detection of a particular one of the pixel locations.

Abstract: A pixel circuit is provided for use in an event sensor. In one implementation, the pixel circuit includes a photosensitive element configured to generate a current signal in response to brightness of light impinging on the photosensitive element, a first N-type transistor, a second N-type transistor, a first P-type transistor including a gate connected to a first bias voltage, a second P-type transistor including a gate connected to a second bias voltage, the second bias voltage being an adjustable DC bias voltage that is adjusted according to at least one of a sensed temperature or a fabrication process variation of the pixel circuit, and a voltage output that varies in response to the brightness of light impinging on the photosensitive element. An adjustment of the second bias voltage causes a DC level of the voltage output to shift up or down without changing the overall gain of the pixel circuit.

Abstract: A method is generally provided for adjusting a pattern projection rate in an active perception system, comprising the steps of observing a scene with an event-based sensor array; projecting a current light pattern of a sequence of light patterns on the scene for a given interval of time; retrieving events generated by the event-based sensor array in response to the projection of the current light pattern; monitoring a property of the event retrieval progress; and dynamically controlling the projection of the light pattern based on the property.

Abstract: A light source for structured light, comprising a plurality of light source elements arranged in an array, wherein the light source elements are configured to be driven in the following two modes: —a calibration mode, wherein only a part of light source elements are adapted to be driven; and —a normal mode, wherein the rest of the light source elements are adapted to be driven.

Abstract: A merged frame-based and event-based image sensor pixel is provided, comprising a reverse-biased photodiode; a frame-based signal readout circuit connected to a cathode of the photodiode; and an event-based signal readout circuit connected to an anode of the photodiode. Light received in the photodiode causes the production of electrons and holes. The recombination current of the holes is continuously measured for producing the event-based signal.

Abstract: An image enhancement method, comprising: obtaining a reference image frame from of a scene, by a frame-based sensor, wherein the reference image contains artifacts and has an exposure duration; obtaining a stream of events, by an event-based sensor which is synchronized with the frame-based sensor, at least during the exposure duration, wherein the events encode brightness changes of the scene corresponding to the reference image; and deriving a corrected image frame without the artifacts from the reference image frame using the stream of events.

Abstract: A method for capturing motion of an object, the method comprising: installing at least one marker on the object; bringing the object having the at least one marker installed thereon in an acquisition volume; arranging at least two event-based light sensors such that respective fields of view of the at least two event-based light sensors cover the acquisition volume, wherein each event-based light sensor has an array of pixels; receiving events asynchronously from the pixels of the at least two event-based light sensors depending on variations of incident light from the at least one marker sensed by the pixels; and processing the events to position the at least one marker within the acquisition volume and capture motion of the object.

Abstract: A method is provided for operating an event-based image sensor comprising a plurality of pixel circuits arranged to form a pixel array, each pixel being arranged at a location defined by an address defined by pixel coordinates in the array, wherein each pixel circuit is configured to generate an event, such that each time a light intensity change is detected, an event is characterized by a polarity reflecting a direction of the change. The method comprises performing a line readout of groups of adjacent pixels of a line of pixels, wherein the line readout comprises generating, for each group, at least one packet expressing occurrences of events of a same polarity in said group, each packet being characterized by a polarity and a group address.

Abstract: The present invention relates to a method of tracking objects in a scene observed by an event-based sensor that produces events asynchronously from a matrix of sensing elements, wherein, from each sensing element of the matrix, respective events are produced as a function of variations of light incident on the sensing element, the method comprising: detecting, by a first process, an object in the scene from asynchronous events produced by the event-based sensor; and determining, by a second process, a track associated to the detected object from asynchronous events produced by the event-based sensor; wherein the first process has a time resolution lower than the second process.

Abstract: A method is provided for operating an event-based image sensor comprising a plurality of pixel circuits arranged to form a pixel array, each pixel being arranged at a location defined by an address defined by pixel coordinates in the array, wherein each pixel circuit is configured to generate an event, such that each time a light intensity change is detected, an event is characterized by a polarity reflecting a direction of the change. The method comprises performing a line readout of groups of adjacent pixels of a line of pixels, wherein the line readout comprises generating, for each group, at least one packet expressing occurrences of events of a same polarity in said group, each packet being characterized by a polarity and a group address.

Abstract: A pixel circuit is provided for use in an event sensor. In one implementation, the pixel circuit includes a photosensitive element configured to generate a current signal in response to brightness of light impinging on the photosensitive element, a first N-type transistor, a second N-type transistor, a first P-type transistor including a gate connected to a first bias voltage, a second P-type transistor including a gate connected to a second bias voltage, the second bias voltage being an adjustable DC bias voltage that is adjusted according to at least one of a sensed temperature or a fabrication process variation of the pixel circuit, and a voltage output that varies in response to the brightness of light impinging on the photosensitive element. An adjustment of the second bias voltage causes a DC level of the voltage output to shift up or down without changing the overall gain of the pixel circuit.

Abstract: The present disclosure generally relates to systems and methods for three-dimensional image sensing. More specifically, and without limitation, this disclosure relates to systems and methods for detecting three-dimensional images, and using asynchronous image sensors for detecting the same.

Abstract: An event-based sensor has an array of pixels facing a scene. The information to be processed includes events originating from the pixels depending on variations of incident light from the scene. A method includes storing a data structure for a set of pixels of the array, the data structure including, for each pixel of the set, event data associated with a most recent event originating from the pixel. Upon receiving a current event from a first pixel of the array, the method includes retrieving any event data included in the data structure for a group of pixels including the first pixel and a plurality of second pixels adjacent to the first pixel in the array. The current event is labelled based on at least one connectivity criterion between the current event and the most recent event originating from a pixel of the group.

Abstract: The present disclosure generally relates to systems and methods for imaging and sensing vibrations of an object. In one implementation, a system is provided for detecting vibrations that comprises a sensor with a plurality of pixels, each pixel including at least one photosensitive element. The sensor is configured to output signals related to illumination on each pixel. The system also includes at least one processor configured to receive the output signals from the sensor and detect, based on the output signals, one or more polarities. The at least one processor is also configured to determine timestamps associated with the output signals, analyze the timestamps and the polarities to detect vibrations of an object in the field of view of the sensor, and determine one or more frequencies of the detected vibrations.

Abstract: A pixel circuit is provided for use in an image sensor. The pixel circuit includes a photosensitive element configured to generate a current signal in response to brightness of light impinging on the photosensitive element, and a converter configured to receive the current signal from the photosensitive element and generate a voltage signal based on the received current signal. The pixel circuit also includes a capacitor electrically coupled to the converter in series and configured to receive the voltage signal from the converter, and an amplifier electrically coupled, at an input, to the capacitor in series and configured to generate, at an output, an amplified signal based on an output signal from the capacitor, wherein there is no feedback between the output and the input of the amplifier. Further, the pixel circuit includes a reset device configured to reset the amplifier in response to a trigger signal being generated.

Abstract: The method processes a series of events received asynchronously from an array of pixels of an event-based light sensor. Each event of the series comprises an address of a pixel of the array from which the event is received, and an attribute value depending on incident light sensed by that pixel. The method comprises: storing a data structure in a first memory, the data structure including event data for at least some of the pixels of the array, the event data for a pixel being related to at least one event most recently received from said pixel; during a timeslot, building, in a second memory having a faster access than the first memory, a map for the pixels of the array as the events of the series are received, the map including an information element for each pixel of the array, the information element having one of a plurality of values including a nil value indicating an absence of event during the timeslot; and updating the data structure after the timeslot using the map.