Texas Instruments Corporation

Chigroo Labs Private Limited

Bharath Patil

Subhash Chandra Venkata Sadhu

Ravishankar S Ayyagari

Jaiganesh Balakrishnan

Shantanu Prasad Prabhudesai

Anjana Sharma

Jagannathan Venkataraman

Radhika Patil

Karthik Rajagopal

Supreet Joshi

Venkata Subhash Chandra Sadhu

Arjun Jagadish Dutt

Madhav Tejaswi Boddhapu

Nithin Jose

Nilesh S Misal

Shubham Agrawal

Brijoy Amrutbhai Patel

Makarand Ramesh Kulkarni

A three dimensional time of flight (TOF) camera includes a transmitter and a receiver. The transmitter is configured to generate an electrical transmit signal at a plurality of frequencies over an integration time period and generate a transmit optical waveform corresponding with the electrical transmit signal. The receiver is configured to receive a reflected optical waveform that is the transmit optical waveform reflected off of an object, integrate the reflected optical waveform over the integration time period, and determine a distance to the target object based on a TOF of the optical waveform. The integration time period includes exposure time periods. A length of each of the exposure time periods corresponds to one of the frequencies. The TOF is determined based on a correlation of the electrical transmit signal and the return optical waveform utilizing a correlation function with respect to the integration time period.

Phase anti-aliasing using spread-spectrum techniques in an optical distance measurement system

A distance measurement system includes a light transmitter to generate a modulated light signal, a light sensor to generate measurement signals from reflected light among four quad phase angles with respect to a phase of the generated light signal, and a controller. The controller selects a first set of quad phase angles, and generates first measurement signals at the quad phase angles of the first set. Based on the first measurement signals, the controller computes a first phase angle between the generated light signal and the reflected light signal, generates a second set of quad phase angles based on the first phase angle, and generates second measurement signals at the quad phase angles of the second set. Further, based on the second measurement signals, the controller computes a second phase angle between the generated light signal and the reflected light signal and calculates a distance using the second phase angle.

Phase noise shaping in a distance measurement system

A time of flight (ToF) system includes a light source, a photosensor, a signal generator and a processor. The signal generator outputs a reference signal corresponding to a modulation function for modulated light and a modified transmitted light signal corresponding to a phase shift of the reference signal. The light source outputs the modified transmitted light signal and pixels in the photosensor receives its reflections off the scene. The reference signal is applied to the pixels and the processor determines a depth map for the scene based on values recorded by the pixels. In some examples, the phase shift is implemented using a phase locked loop controller. One or more component phases of the phase shift and an exposure time for each component phase are determined and output by the phase locked loop controller.

Multi frequency long range distance detection for amplitude modulated continuous wave time of flight cameras

Systems and methods are provided for imaging a surface via time of flight measurement. An illumination system includes an illumination driver and an illumination source and is configured to project modulated electromagnetic radiation to a point on a surface of interest. A sensor system includes a sensor driver and is configured to receive and demodulate electromagnetic radiation reflected from the surface of interest. A temperature sensor is configured to provide a measured temperature representing a temperature at one of the illumination driver and the sensor driver and located at a position remote from the one of the illumination driver and the sensor driver. A compensation component is configured to calculate a phase offset between the illumination system and the sensor system from at least the measured temperature and a model representing transient heat flow within the system.

Phase compensation in a time of flight system

Cradle for infants

The disclosure provides a circuit to mitigate ripple. The circuit includes a controller that generates a PWM (pulse width modulated) clock signal. A DC/DC converter receives the PWM clock signal, and generates an output signal. A light source is coupled to the DC/DC converter, and receives the output signal. The light source transmits light pulses during an integration time. A time integral of the output signal during the integration time is constant during a plurality of quad time periods.

Method and apparatus to mitigate ripple in a time of flight (TOF) system

Systems and methods for providing depth imaging using a CCD image sensor. In a method for visual imaging and depth imaging, steps include providing a CCD image sensor device arranged to receive light from an optical lens and having an array of pixels and corresponding pixel charge storage elements; providing a light source for transmitting light pulses responsive to a pulse control signal; providing timing signals to configure the CCD image sensor to collect and store charge from the pixel storage elements; and performing a depth calculation using a background charge, a reflected charge, and a depth charge collected in three frame periods for each pixel in the CCD image sensor. A system including a CCD image sensor for use with the embodiments is disclosed. Additional embodiments are disclosed.

System and methods for depth imaging using conventional CCD image sensors

In a single wire communications interface embodiment, a single wire is coupled between a master device and at least one slave device, the master device configured for transmitting data words as serial data to and for receiving data words as serial data from the at least one slave device, and the at least one slave device configured for transmitting data words as serial data to and receiving data words as serial data from the master device; wherein prior to transmission of any data word on the single wire by one of the master device and the slave device, a sync pulse is first transmitted on the single wire. Integrated circuit embodiments for implementing the single wire communications interface, and method embodiments incorporating the single wire communications interface are disclosed. Additional embodiments are disclosed.

Single wire communications interface and protocol

A system and method for determining a distance to a surface of interest, such as in a Time of Flight (ToF) system, includes projecting modulated electromagnetic radiation of at least two frequencies to a point on the surface of interest, receiving the electromagnetic radiation reflected from the point on the surface of interest and demodulating the received electromagnetic radiation. Whereupon, a weighted phase difference between the frequencies may be calculated, in accordance with the present systems and methods, and one bin for each of the reflected frequencies for an actual distance to the point on the surface of interest is calculated using the weighted phase difference. A final phase of the bin for the actual distance is calculated as a weighted average of the phases of the bins based on the reflected signal strengths, and the actual distance to the point on the surface of interest is then output.

Efficient implementation of distance de-aliasing for ranging systems using phase domain computation

In an embodiment, method of controlling an illumination device by an output signal of a DC-DC converter is disclosed. The output signal is controlled by a PWM signal. The method includes receiving a feedback signal corresponding to variation in the output signal with respect to a pre-determined output signal, and determining a target duty cycle of the PWM signal based on the feedback signal. The PWM signal of the target duty cycle is capable of enabling the DC-DC converter to generate the pre-determined output signal. The method includes providing the PWM signal of an effective duty cycle equal to the target duty cycle over N switching pulses of the PWM signal to the DC-DC converter. The method provides the PWM signal by providing M switching pulses of a first PWM signal of a first duty cycle, and N&#x2212;M switching pulses of a second PWM signal of a second duty cycle.

Control of illumination devices using DC-DC converters

Laser speckle reduction using a passive diffuser. A diffuser for reducing laser speckle is disclosed comprising a diffuser having a colloid configured for placement in a light path of a coherent light source. The colloid exhibits Brownian motion. The diffuser can be formed of transparent plates containing the colloid. In a system for illumination, a coherent source of light outputting a light beam along a light path is provided; and a diffuser for reducing laser speckle effects is placed in the light path, the diffuser comprising a colloid disposed in a container that is transparent to the light beam output by the coherent source. A method includes illuminating a photosensitive sensor, comprising transmitting a coherent light from a light source through a diffuser comprising a colloid and directing the light from the diffuser onto the photosensitive sensor. Additional embodiments are disclosed.

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Bengaluru, India

Bharath Patil