Omnivision Technologies, Inc.

Omnivisision Technology, Inc.

Andreas Suess

Zheng Yang

Shoushun Chen

Boyd Fowler

Tomas Geurts

Victor Lenchenkov

Eiichi Funatsu

Kevin W Johnson

Menghan Guo

Bo Mu

Qi Niu

Kaijun Feng

Wenlei Yang

Devang Patel

Kevin Johnson

A time-of-flight sensor includes an integrated circuit chip in which a voltage regulator and a load are disposed. The load includes a grouping of pixel circuits and modulation driver that is supplied power from the voltage regulator. The grouping of pixel circuits included in a pixel array disposed in the integrated circuit trip. Each one of the pixel circuits includes a photodiode configured to photogenerate charge in response to reflected modulated light, a floating diffusion configured to store a portion of charge photogenerated in the photodiode, and transfer transistor to transfer the portion of charge from the photodiode to the floating diffusion in response to a phase modulation signal generated by the modulation driver. A feedback circuit is coupled between the load and the voltage regulator and is coupled to receive a feedback signal from the feedback circuit in response to the load.

Voltage regulation for increased robustness in indirect time-of-flight sensors

A time-of-flight pixel circuit includes a photodiode configured to generate charge in response to modulated light reflected from an object. First and second transfer transistors are coupled to the photodiode. The first transfer transistor transfers a first portion of charge from the photodiode in response to a first modulation signal and the second transfer transistor transfers a second portion of charge from the photodiode in response to a second modulation signal. The second modulation signal is an inverted first modulation signal. A first floating diffusion is coupled to the first transfer transistor to receive the first portion of charge in response to a first modulation signal. Each one of a first plurality of sample and hold transistors is coupled between a respective one of a first plurality of memory nodes and the first transfer transistor.

Readout architectures for motion blur reduction in indirect time-of-flight sensors

Fixed pattern noise (FPN) reduction techniques in image sensors operated with pulse illumination are disclosed herein. In one embodiment, a method includes, during a first sub-exposure period of a frame, (a) operating a first tap of a pixel to capture a first signal corresponding to first charge at a first floating diffusion, the first charge corresponding to first light incident on a photosensor, and (b) operating a second tap of the pixel to capture a first parasitic signal corresponding to FPN at a second floating diffusion. The method further includes, during a second sub-exposure period of the frame, (a) operating the second tap to capture a second signal corresponding to second charge at the second floating diffusion, the second charge corresponding to second light incident on the photosensor, and (b) operating the first tap to capture a second parasitic signal corresponding to FPN at the first floating diffusion.

Fixed pattern noise reduction in image sensors operated with pulsed illumination

Event vision sensors with event data compression (and associated systems, devices, and methods) are disclosed herein. In one embodiment, an event vision sensor includes a plurality of event vision pixels. Each event vision pixel of the plurality is configured to generate event data based on events indicated in incident light received from an external scene, and includes a compression circuit configured to compress the event data prior to readout of the event data from the event vision pixel. Each compression circuit can include a time aggregation circuit that is configured to track a number of the events detected by the corresponding event vision pixel over a specified timing window. The compressed event data can be read out from the event vision sensors and used to generate a pseudo-frame. The event vision sensor can optionally perform frame-level compression on the pseudo-frame.

Event vision sensors with event data compression, including event vision sensors with in-pixel event data compression, and associated systems, devices, and methods

Methods for transmitting asynchronous event data via synchronous communications interfaces (and associated imaging systems) are disclosed herein. In one embodiment, an imager comprises an array of event vision pixels, and a synchronous communications transmitter configured to transmit frames of data to a synchronous communications receiver. The pixels generate event data based on activity within an external scene. The imager communicates, at a first time and to the receiver, an anticipated amount of data that will be included in a frame transmitted to the receiver at a second time. The anticipated amount of data can be based on a prediction of an amount of event data that will be generated at a future point in time for transmission to the receiver in the frame. The imager can then transmit the frame to the receiver at the second time with an amount of data corresponding to the anticipated amount of data.

Methods for transmitting asynchronous event data via synchronous communications interfaces using anticipated event rates, and associated imaging systems

Low power event driven pixels and reset control circuits for the same are disclosed herein. In one embodiment, an event driven pixel comprises a photosensor; a photocurrent-to-voltage converter coupled to the photosensor; and a difference circuit coupled to the photocurrent-to-voltage converter. The difference circuit includes a source follower transistor and is configured to generate a signal at a gate of the source follower transistor that is based on a voltage output from the photocurrent-to-voltage converter. The difference circuit is further configured to output a difference signal in response to assertion of a row select signal. The event driven pixel can further include a reset control circuit coupled to the difference circuit and configured to initialize the difference circuit, and to reset the difference circuit when the difference signal output from the event driven pixel indicates a change in the voltage greater than a threshold amount.

Low power event driven pixels with active difference detection circuitry, and reset control circuits for the same

An image sensor comprises: a control block generating a video interface enabled signal, a video interface for receiving the video interface enabled signal, a pixel array for providing a video stream to the video interface, an output port for receiving the video stream from the video interface and outputting the video stream to outside of the image sensor, a stream indicator pin for receiving the video interface enabled signal from the control block when the video interface is receiving the video interface enabled signal from the control block, where a terminal of the video interface receiving the video interface enabled signal is connected to the stream indicator pin by a conductor, and they are sealed in a package of the image sensor.

Camera having video stream indicator

Methods for transmitting asynchronous event data via synchronous communications interfaces (and associated imaging systems) are disclosed herein. In one embodiment, an imager comprises an array of event vision pixels, a synchronous communications transmitter configured to transmit frames of data to a synchronous communications receiver, and a timer configured to indicate when a threshold amount of time has elapsed. The pixels can generate event data based on activity within an external scene. The imager can be configured to insert available event data into a payload of the current frame during a first time period before the frame timer indicates that the threshold amount of time has elapsed, pad the payload with dummy data during a second time period after the frame timer indicates that the threshold amount of time has elapsed, and transmit (using the synchronous communications transmitter) the current frame of data to the synchronous communications receiver.

Methods for transmitting asynchronous event data via synchronous communications interfaces, and associated imaging systems

An image sensor has diffractive microlenses over pixels with central structures and ring(s) of material having index of refraction different from that of background material. Disposed beneath the diffractive microlenses are photodiodes that permit determining ratios of illumination of peripheral photodiodes to illumination of central photodiodes of the pixels, and, in embodiments, circuitry for determining said ratio. In embodiments, the ratio is used to find illumination wavelengths; and in other embodiments the ratio is used to determine focus of an imaging lens providing illumination. A method determines color by passing light through a diffractive lens disposed above photodiodes of the diffractive pixel and determining color from illumination peripheral and central photodiodes. An autofocus method of determining focus includes passing light through a diffractive lens and determining focus from illumination of peripheral photodiodes and central photodiodes of the pixel. In embodiments, the central structures are disks and rings are round.

Color CMOS image sensor with diffractive microlenses over subpixel photodiode arrays adapted for autofocus

A pixel circuit includes a photodiode configured to photogenerate charge in response to reflected modulated light incident upon the photodiode. A first floating diffusion is configured to store a first portion of charge photogenerated in the photodiode. A first transfer transistor is configured to transfer the first portion of charge from the photodiode to the first floating diffusion in response to a first phase signal. A first storage node is configured to store the first portion of charge from the first floating diffusion. A first decoupling circuit has a first output responsive to a first input. The first input is coupled to the first floating diffusion and the first output is coupled to first storage node. A voltage swing at the first output is greater than a voltage swing at the first input.

Readout architectures for dark current reduction in indirect time-of-flight sensors

In some embodiments, an image sensor is provided. A signal processing unit of the image sensor is configured with executable instructions that cause the signal processing unit to perform actions comprising: reading a captured scene from a pixel array; reading a value from a test initiation register; in response to determining that the value indicates a test mode: processing the captured scene to detect a region of interest associated with the value; and providing the region of interest to a first interface for transmission to a host device; and in response to determining that the value does not indicate the test mode: analyzing the captured scene using a computer vision technique to selectively generate a signal based on the analysis of the captured scene; and selectively providing the signal to a second interface for transmission to the host device.

Privacy-preserving image sensor

Low power event driven pixels with passive, differential difference detection circuitry (and reset control circuits for the same) are disclosed herein. In one embodiment, an event driven pixel comprises a photosensor, a photocurrent-to-voltage converter, and a difference circuit. The difference circuit includes (a) a first circuit branch configured to sample a reference light level based on a voltage output by the photocurrent-to-voltage converter, and to output a first analog light level onto a first column line that is based on the reference light level; and (b) a second circuit branch configured to sample a light level based on the voltage, and to output a second analog light level onto a second column line that is based on the light level. A difference between the second analog light level and the first analog light level indicates whether the event driven pixel has detected an event in an external scene.

Low power event driven pixels with passive, differential difference detection circuitry, and reset control circuits for the same

A time-of-flight pixel array includes photodiodes that generate charge in response to incident reflected modulated light. First transfer transistors transfer a first portion of the charge from the photodiodes in response to a first modulation signal and second transfer transistors transfer a second portion of the charge from the photodiodes in response to a second modulation signal, which is an inverted first modulation signal. First floating diffusions are coupled to the first transfer transistors. A binning transistor is coupled between one of the first floating diffusions and another one of the first floating diffusions. A first memory node is coupled to one of the first floating diffusions through a first sample and hold transistor and a second memory node is coupled to another one of the first floating diffusions through a second sample and hold transistor.

Readout architectures for binned indirect time-of-flight sensors

A method for estimating a signal charge collected by a pixel of an image sensor includes determining an average bias that depends on the pixel's floating-diffusion dark current and pixel-sampling period. The method also includes determining a signal-charge estimate as the average bias subtracted from a difference between a weighted sum of a plurality of N multiple-sampling values each multiplied by a respective one of a plurality of N sample-weights.

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San Jose, CA, United States of America

Andreas Suess