Patent Description:
The solid-state Lidar system may be mounted to a vehicle to detect objects in the environment surrounding the vehicle and to detect distance of those objects for environmental mapping. The output of the solid-state Lidar system may be used, for example, to autonomously or semi-autonomously control operation of the vehicle, e.g., propulsion, braking, steering, etc. Specifically, the system may be a component of or in communication with an advanced driver-assistance system (ADAS) of the vehicle.

In instances where the vehicle uses both short-range and long-range fields of view to generate the 3D map of the surrounding environment, difficulties may exist in distinguishing long-range reflections and short-range reflections such that they do not influence the distance measurement of the other.

With reference to the Figures, wherein like numerals indicate like parts throughout the several views, a system <NUM> is generally shown. Specifically, the system <NUM> is a light detection and ranging (Lidar) system. With reference to <FIG>, the system <NUM> includes two fields of view FV1, FV2 and emits light into the fields of view FV1, FV2. The system <NUM> detects the emitted light that is reflected by objects in the fields of view FV1, FV2, e.g., pedestrians, street signs, vehicle <NUM>, etc. As described below, the system <NUM> separately collects the reflected light from the two fields of view FV1, FV2.

The system <NUM> is shown in <FIG> as being mounted to a vehicle <NUM>. In such an example, the system <NUM> is operated to detect objects in the environment surrounding the vehicle <NUM> and to detect distance of those objects for environmental mapping. The output of the system <NUM> may be used, for example, to autonomously or semi-autonomously control operation of the vehicle <NUM>, e.g., propulsion, braking, steering, etc. Specifically, the system <NUM> may be a component of or in communication with an advanced driver-assistance system (ADAS) of the vehicle <NUM>. The system <NUM> may be mounted to the vehicle <NUM> in any suitable position (as one example, the system <NUM> is shown on the front of the vehicle <NUM> and directed forward). The vehicle <NUM> may have more than one system <NUM> and/or the vehicle <NUM> may include other object detection system <NUM>, including other Lidar systems. The vehicle <NUM> is shown in <FIG> as including a single system <NUM> aimed in a forward direction merely as an example. The vehicle <NUM> shown in the Figures is a passenger automobile. As other examples, the vehicle <NUM> may be of any suitable manned or un-manned type including a plane, satellite, drone, watercraft, etc..

The system <NUM> may be a solid-state Lidar system. In such an example, the system <NUM> is stationary relative to the vehicle <NUM>. For example, the system <NUM> may include a casing <NUM> that is fixed relative to the vehicle <NUM> and a silicon substrate of the system <NUM> is fixed to the casing <NUM>. The system <NUM> may be a staring, non-moving system. As another example, the system <NUM> may include elements to adjust the aim of the system <NUM>, e.g., the direction of the emitted light may be controlled by, for example, optics, mirrors, etc..

As a solid-state Lidar system, the system <NUM> may be a Flash Lidar system. In such an example, the system <NUM> emits pulses of light into the fields of view FV1, FV2. More specifically, the system <NUM> may be a 3D Flash Lidar system <NUM> that generates a 3D environmental map of the surrounding environment, as shown in part in <FIG>. An example of a compilation of the data into a 3D environmental map is shown in the fields of view FV1, FV2 in <FIG>.

Four examples of the system <NUM> are shown in <FIG>, respectively. Common numerals are used to identify common features among the examples. With reference to <FIG>, the system <NUM> includes a system controller <NUM> and two pairs of light sources <NUM>, <NUM> and photodetectors <NUM>, <NUM>. Specifically, one pair includes a first light source <NUM> and a first photodetector <NUM>, and the other pair includes a second light source <NUM> and a second photodetector <NUM>. As described further below, the first light source <NUM> emits light into the first field of view of the first photodetector <NUM>, i.e., the first field of view FV1, and the second light source <NUM> emits light into the field of view of the second photodetector <NUM>, i.e., the second field of view FV2. With reference to <FIG> and <FIG>, the system <NUM> may also include a third pair having a third light source <NUM> and a third photodetector <NUM>, in which case the third light source <NUM> emits light into the field of view of the third photodetector <NUM>, i.e., the third field of view FV3. The system <NUM> may include two or more pairs of light sources and photodetectors.

The system <NUM> may be a unit. In other words, the first light source <NUM>, first photodetector <NUM>, second light source <NUM>, second photodetector <NUM>, and the system controller <NUM> may be supported by a common substrate that is attached to the vehicle <NUM>, e.g., a casing <NUM> as schematically shown in <FIG>. In the examples shown in <FIG> and <FIG>, the third light source <NUM> and the third photodetector <NUM> are supported by the casing <NUM>. The casing <NUM> may, for example, enclose the other components of the system <NUM> and may include mechanical attachment features to attach the casing <NUM> to the vehicle <NUM> and electronic connections to connect to and communicate with electronic system <NUM> of the vehicle <NUM>, e.g., components of the ADAS. The casing <NUM>, for example, may be plastic or metal and may protect the other components of the system <NUM> from environmental precipitation, dust, etc. In the alternative to the system <NUM> being a unit, components of the system may be separated and disposed at different locations of the vehicle <NUM>. In such examples, the system <NUM> may include multiple casings with each casing containing components of the system <NUM>. As one example, one casing may including one or more of the pairs of light sources <NUM>, <NUM>, <NUM> and photodetectors <NUM>, <NUM>, <NUM> and another casing may include one or more of the pairs of light sources <NUM>, <NUM>, <NUM> and photodetectors <NUM>, <NUM>, <NUM>. As another example, in addition or in the alternative, one or more of the pairs of light sources <NUM>, <NUM>, <NUM> and photodetectors <NUM>, <NUM>, <NUM> may be split among separate casings. In such examples, the system <NUM> may include any suitable number of casings.

The controller <NUM> may be a microprocessor-based controller or field programmable gate array (FPGA) implemented via circuits, chips, and/or other electronic components. In other words, the controller <NUM> is a physical, i.e., structural, component of the system <NUM>. For example, the controller <NUM> may include a processor, memory, etc. The memory of the controller <NUM> may store instructions executable by the processor, i.e., processor-executable instructions, and/or may store data. The controller <NUM> may be in communication with a communication network of the vehicle <NUM> to send and/or receive instructions from the vehicle <NUM>, e.g., components of the ADAS.

As described further below, the controller <NUM> communicates with the light sources <NUM>, <NUM>, <NUM> and the photodetectors <NUM>, <NUM>, <NUM>. Specifically, the controller <NUM> instructs the first light source <NUM> to emit light and substantially simultaneously initiates a clock. When the light is reflected, i.e., by an object in the first field of view FV1, the first photodetector <NUM> detects the reflected light and communicates this detection to the controller <NUM>, which the controller <NUM> uses to identify object location and distance to the object (based time of flight of the detected photon using the clock initiated at the emission of light from the first light source <NUM>). The controller <NUM> uses these outputs from the first photodetector <NUM> to create the environmental map and/or communicates the outputs from the first photodetector <NUM> to the vehicle <NUM>, e.g., components of the ADAS, to create the environmental map. Specifically, the controller <NUM> continuously repeats the light emission and detection of reflected light for building and updating the environmental map. While the first light source <NUM> and first photodetector <NUM> were used as examples, the controller <NUM> similarly communicates with second light source <NUM> and second photodetector <NUM> and with the third light source <NUM> and the third photodetector <NUM>.

The light sources <NUM>, <NUM>, <NUM> emit light into the fields of view FV1, FV2, FV3, respectively, for detection by the respective photodetector when the light is reflected by an object in the respective field of view FV1, FV2, FV3. The light sources <NUM>, <NUM>, <NUM> may have similar or identical architecture and/or design. For example, the light sources <NUM>, <NUM>, <NUM> may include the same type of components arranged in the same manner, in which case the corresponding components of the light sources <NUM>, <NUM>, <NUM> may be identical or may have varying characteristics (e.g., for emission of different light wavelengths as described below).

With reference to <FIG>, the light sources <NUM>, <NUM>, <NUM> may each include a light emitter (i.e., a first light emitter <NUM>, a second light emitter <NUM>, a third light emitter <NUM>). For example, the light emitter <NUM>, <NUM>, <NUM> may be a laser. The light emitter <NUM>, <NUM>, <NUM> may be, for example, a semiconductor laser. In one example, the light emitter <NUM>, <NUM>, <NUM> is a vertical-cavity surface-emitting laser (VCSEL). As another example, the light emitter <NUM>, <NUM>, <NUM> may be a diode-pumped solid-state laser (DPSSL). As another example, the light emitter <NUM>, <NUM>, <NUM> may be an edge emitting laser diode. The light sources <NUM>, <NUM>, <NUM> may be designed to emit a pulsed flash of light, e.g., a pulsed laser light. Specifically, the light emitter <NUM>, <NUM>, <NUM>, e.g., the VCSEL, is designed to emit a pulsed laser light. The light emitted by the light emitters <NUM>, <NUM>, <NUM> may be, for example, infrared light. Alternatively, the light emitted by the light emitters <NUM>, <NUM>, <NUM> may be of any suitable wavelength, as also described further below.

As set forth above, the system <NUM> may be a staring, non-moving system. As another example, the system <NUM> may include elements to adjust the aim of the system <NUM>. For example, with continued reference to <FIG>, any of the light sources <NUM>, <NUM>, <NUM> may include beam steering device <NUM> that direct and/or diffuse the light from the light emitter <NUM>, <NUM>, <NUM> into the respective field of view FV1, FV2, FV3. In the example shown in <FIG>, the light beams are emitted from the system <NUM> as horizontal lines. In such an example, the beam steering device <NUM> may emit the light as the horizontal beam and/or may adjust the vertical location of the light beam. While the beam steering devices <NUM> are shown in <FIG>, it should be appreciated that the beam steering devices <NUM> may be eliminated from <FIG> in an example where the system <NUM> is a staring, non-moving system. In such an example, the light source <NUM>, <NUM>, <NUM>, e.g., the VCSEL, exposes the entire respective field of view FV1, FV2, FV3 at once, i.e., at the same time.

In examples including the beam steering device <NUM>, the beam steering device <NUM> may be a micromirror. For example, the beam steering device <NUM> may be a micro-electro-mechanical system <NUM> (MEMS) mirror. As an example, the beam steering device <NUM> may be a digital micromirror device (DMD) that includes an array of pixel-mirrors that are capable of being tilted to deflect light. As another example, the MEMS mirror may include a mirror on a gimbal that is tilted, e.g., by application of voltage. As another example, the beam steering device <NUM> may be a liquid-crystal solid-state device. While the first, second, and third beam steering devices are all labeled with reference numeral <NUM>, it should be appreciated that the beam steering devices <NUM> may of the same type or different types; and in examples in which the beam steering devices <NUM> are of the same type, the beam steering devices <NUM> may be identical or may have different characteristics.

With continued reference to <FIG>, the system <NUM> includes transmission optics through which light exits the system <NUM>. Specifically, the first light source <NUM> includes first transmission optics <NUM> through which light emitted by the first light emitter <NUM> exits the system <NUM> into the first field of view FV1 and second transmission optics <NUM> through which light emitted by the second light emitter <NUM> exits the system <NUM> into the second field of view FV2. The third light source <NUM> includes third transmission optics <NUM> through which light emitted by the third light emitter <NUM> exits the system <NUM> into the third field of view FV3. The transmission optics <NUM>, <NUM>, <NUM> may include any suitable number of lenses. The transmission optics <NUM>, <NUM>, <NUM> may have similar or identical architecture and/or design. For example, the transmission optics <NUM>, <NUM>, <NUM> may include the same type of components arranged in the same manner, in which case the corresponding components of the transmission optics <NUM>, <NUM>, <NUM> may be identical or may have varying characteristics (e.g., for emission of different light wavelengths as described below).

The first light source <NUM> is aimed at the first field of view FV1 and the second light source <NUM> is aimed at the second field of view FV2. Specifically, the system <NUM> emits light from the first light source <NUM> into a first field of illumination and emits light from the second light source <NUM> into a second field of illumination. In the examples shown in <FIG> and <FIG>, the third light source <NUM> is aimed at the third field of view FV3. The field of illumination is the area exposed to light emitted from the light sources <NUM>, <NUM>, <NUM>. The first field of illumination may substantially match the first field of view FV1 and the second field of illumination may substantially match the second field of view FV2 ("substantially match" is based on manufacturing capabilities and tolerances of the light sources <NUM>, <NUM>, <NUM> and the photodetectors <NUM>, <NUM>, <NUM>), as is the case shown for example in <FIG>. The first field of illumination and the second field of illumination may overlap, as described further below. In the examples shown in <FIG> and <FIG>, the second field of illumination and the third field of illumination may overlap, as described further below.

With continued reference to <FIG>, the system <NUM> includes a first receiving unit <NUM> and a second receiving unit <NUM>. In the examples shown in <FIG> and <FIG>, the system <NUM> may include a third receiving unit <NUM>. The first receiving unit <NUM> includes the first photodetector <NUM> and may include first receiving optics <NUM>. The second receiving unit <NUM> includes the second photodetector <NUM> and may include second receiving optics <NUM>. The third receiving unit <NUM> includes the third photodetector <NUM> and may include third receiving optics <NUM>.

For the purposes of this disclosure, the term "photodetector" includes a single photodetector or an array of photodetectors, e.g., an array of photodiodes. The photodetectors <NUM>, <NUM>, <NUM> may be, for example, avalanche photodiode detectors. As one example, the photodetectors <NUM>, <NUM>, <NUM> may be a single-photon avalanche diode (SPAD). As another example, the photodetectors <NUM>, <NUM>, <NUM> may be a PIN diode. The photodetectors <NUM>, <NUM>, <NUM> may have similar or identical architecture and/or design. For example, the photodetectors <NUM>, <NUM>, <NUM> may include the same type of components arranged in the same manner, in which case the corresponding components of the photodetectors <NUM>, <NUM>, <NUM> may be identical or may have varying characteristics.

The first field of view FV1 is the area in which reflected light may be sensed by the first photodetector <NUM>, the second field of view FV2 is the area in which reflected light may be sensed by the second photodetector <NUM>, and the third field of view FV3 is the area in which reflected light may be sensed by the third photodetector <NUM>. The first field of view FV1 and the second field of view FV2 may overlap. In other words, as least part of the first field of view FV1 and at least part of the second field of view FV2 occupy the same space such that an object in the overlap will reflect light toward both photodetectors <NUM>, <NUM>. For example, as shown in <FIG> and <FIG>, the first field of view FV1 and the second field of view FV2 may be centered on each other, i.e., aimed in substantially the same direction ("substantially the same" is based on manufacturing capabilities and tolerances of the light sources <NUM>, <NUM>, <NUM> and the photodetectors <NUM>, <NUM>, <NUM>). In the examples shown in <FIG> and <FIG>, the first field of view FV1 and the second field of view FV2 may be aimed in different directions while overlapping. With continued reference to <FIG> and <FIG>, the second field of view FV2 and third field of view FV3 may overlap. In <FIG> and <FIG>, the second field of view FV2 and the third field of view FV3 may be aimed in different directions while overlapping. In the example shown in <FIG> and <FIG>, the first field of view FV1, the second field of view FV2, and the third field of view FV3 are each aimed in a different direction.

The fields of view FV1, FV2, FV3 may have different widths and/or lengths. In the examples shown in <FIG> and <FIG>, the length of the first field of view FV1 is shorter than the length of the second field of view FV2. In other words, the first photodetector <NUM> has a short range and the second photodetector <NUM> has a long range. In the examples shown in <FIG> and <FIG>, the first field of view FV1 is wider than the second field of view FV2.

Light reflected in the fields of view FV1, FV2, FV3 is reflected to receiving optics <NUM>, <NUM>, <NUM>. The receiving optics <NUM>, <NUM>, <NUM> may include any suitable number of lenses, filters, etc..

The system <NUM> may distinguish between the reflected light that was emitted by the first light source <NUM> and reflected light that was emitted by the second light source <NUM> based on differences in wavelength of the light. For example, with reference to <FIG> and <FIG>, the first light source <NUM> and the second light source <NUM> may emit light having different wavelengths λ1, λ2 and the first receiving unit <NUM> and the second receiving unit <NUM> may detect light having different wavelengths λ1, λ2. In other words, the first receiving unit <NUM> may be designed to detect the wavelength λ1 of light that was emitted from the first light source <NUM> and reflected by a reflecting surface in the first field of view FV1 (and detect little or no light at wavelength λ2 emitted from the second light source <NUM>) and the second receiving unit <NUM> may be designed to detect wavelength λ2 of the light that was emitted from the second light source <NUM> and reflected by a reflecting surface in the second field of view FV2 (and detect little or no light at wavelength λ1 emitted from the first light source <NUM>).

Similarly, the third receiving unit <NUM> may be designed to detect light that was emitted from the third light source <NUM> at a third wavelength λ3 and reflected by a reflecting surface in the third field of view FV3 (and detect little or no light emitted at wavelengths λ1, λ2 from the first light source <NUM> and the second light source <NUM>). As another example, the third receiving unit <NUM> may be designed to detect light that was emitted from the third light source <NUM> at the first wavelength λ1 and reflected by a reflecting surface in the third field of view FV3. In such an example, the first receiving unit <NUM> and the third receiving unit <NUM> are pointed in different directions such that the first and third fields of view FV1, FV3 do not overlap (see <FIG>).

<FIG> is a schematic showing the operation of the example shown in <FIG> and <FIG> is a schematic showing the operation of the example, shown in <FIG>. As set forth above, with reference to <FIG>, the first light source <NUM> is designed to emit light having a first wavelength λ1 (see <FIG>) and the second light source <NUM> is designed to emit light having a second wavelength λ2 (see <FIG>). First wavelength λ1 and second wavelength λ2 are different. In addition, the first receiving unit <NUM> transmits light at the first wavelength λ1, i.e., light reflected in the first field of view FV1, and filters out light at the second wavelength λ2, and the second receiving unit <NUM> transmits light at the second wavelength λ2, i.e., light reflected in the second field of view FV2, and filters out light at the first wavelength λ1. Using this filtering, the system is able to distinguish between reflections in the first and second fields of view FV1, FV2.

With reference to <FIG> and <FIG>, the first light source <NUM>, the second light source <NUM>, the third light source <NUM> may be designed to emit light at the desired wavelength. As an example, the first light emitter <NUM>, the second light emitter <NUM>, and the third light emitter <NUM> may be designed to generate and emit light at the desired wavelength. As another example in addition or in the alternative to the design of the light emitters <NUM>, <NUM>, <NUM>, the transmitting optics may include bandpass filters that filter the light emitted from the light emitters <NUM>, <NUM>, <NUM> to the desired wavelength.

With reference to <FIG> and <FIG>, the first receiving optics <NUM> may include a first bandpass filter <NUM> and the second receiving optics <NUM> may include a second bandpass filter <NUM>. With reference to <FIG>, the third receiving optics <NUM> may include a third bandpass filter <NUM>. The bandpass filters <NUM>, <NUM>, <NUM> are optical filters, i.e., physical elements that are at least part of the receiving optics <NUM>, <NUM>, <NUM>. In the examples shown in <FIG> and <FIG>, the first bandpass filter <NUM> covers the first photodetector <NUM> and the second bandpass filter <NUM> covers the second photodetector <NUM>, i.e., reflected light entering the system <NUM> travels through at least one of the bandpass filters. With reference to <FIG>, the third bandpass filter <NUM> covers the third photodetector <NUM>. The bandpass filters <NUM>, <NUM>, <NUM> may be narrow-bandpass filters.

<FIG> shows operation of the bandpass filters <NUM>, <NUM>. <FIG> shows the wavelength curves of the light emitted from the first light source <NUM> and the second light source <NUM> shown in solid lines. The dotted lines show the wavelength curve of the first bandpass filter <NUM> having a first bandwidth BW1 and the second bandpass filter having a second bandwidth BW2. The first bandpass filter <NUM> is designed to transmit light in the first bandwidth BW1 (and attenuate outside the first bandwidth BW1) and the second bandpass filter <NUM> designed to transmit light in a second bandwidth BW2 (and attenuate outside the second bandwidth BW2). The wavelength range of light emitted from the first light source <NUM> is in the first bandwidth BW1 and the wavelength range of light emitted from the second light source <NUM> is in the second bandwidth BW2. In other words, the first light source <NUM> is designed to emit light in the first bandwidth BW1 and the second light source <NUM> is designed to emit light in the second bandwidth BW2. For example, in <FIG> both the wavelength curve of light emitted from the first light source <NUM> and the wavelength curve of the first bandpass filter <NUM> have a center wavelength at λ1 and the first bandwidth BW1 is larger than the range of wavelengths emitted by the first light source <NUM>. Similarly, both the wavelength curve of light emitted from the second light source <NUM> and the wavelength curve of the second bandpass filter <NUM> have a center wavelength at λ2 and the first bandwidth BW2 is larger than the range of wavelengths emitted by the second light source <NUM>. In the example shown in <FIG>, the center wavelength of the wavelength curve emitted from the first light source <NUM> is outside the second bandwidth BW2, and the center wavelength of the wavelength curve emitted from the second light source <NUM> is outside the first bandwidth BW1.

In the example shown in <FIG>, the light sources <NUM>, <NUM> and bandpass filters <NUM>, <NUM> are designed such that the difference between the center wavelength CW2 (i.e., at peak transmission) of the wavelength curve second bandwidth BW2 and the center wavelength CW1 (i.e., at peak transmission) of the second bandwidth BW1 plus the full-width half-maximum of the wavelength curve of light emitted from the first light source <NUM> is greater than the full-width half-maximum of the curve of the first bandpass filter <NUM>.

In other words, the light sources <NUM>, <NUM> and the bandpass filters <NUM>, <NUM> may be designed according the following relationship: <MAT> where.

This relationship reduces cross-talk, e.g., the first photodetector <NUM> detecting reflected light generated by the second light source <NUM> and the second photodetector <NUM> detecting reflected light generated by the first light source <NUM>. Any remaining "false signals" from cross-talk data points may be removed, for example, by using histogramming.

While the first and second light sources <NUM>, <NUM> and bandpass filters <NUM>, <NUM> are described above, the relationship between the second light source <NUM> and the third light source <NUM> may be similar or identical to that described above. As one example, with reference to <FIG>, the first and third light source <NUM>, <NUM> may be identical and first and third bandpass filters <NUM>, <NUM> may be identical.

In such examples shown in <FIG>, <FIG>, <FIG>, the relationship described above allows for light to be emitted substantially simultaneously from the first light source <NUM> and the second light source <NUM> (and the third light source <NUM> in the example in <FIG> and <FIG>). In other words, the controller <NUM> may be programmed to emit light substantially simultaneously from the first light source <NUM> and the second light source <NUM> (and the third light source <NUM> in the example in <FIG> and <FIG>). In other words, the controller <NUM> may substantially simultaneously instruct the first light source <NUM> to emit light and the second light source <NUM> to emit light and substantially simultaneously initiate a clock for both or each photodetector <NUM>, <NUM>, <NUM> (and similarly for the third light source <NUM> in the example in <FIG> and <FIG>). "Substantially simultaneously" is based on given manufacturing capabilities and tolerances of the light sources <NUM>, <NUM>, <NUM> and the photodetectors <NUM>, <NUM>, <NUM>.

<FIG> shows an example method <NUM> of operation of the system <NUM> in <FIG> and <FIG>. As shown in block <NUM>, the method includes emitting light from the first light source <NUM> and the second light source <NUM>. Specifically, the method may include substantially simultaneously emitting light from the first light source <NUM> and the second light source <NUM>. In the example of <FIG>, the method may also include substantially simultaneously emitting light from the third light source <NUM>. In other words, the controller <NUM> instructs the first light source <NUM> and the second light source <NUM> (and the third light source <NUM> in <FIG>) to emit light substantially simultaneously.

Specifically, block <NUM> may include emitting light from the first light source <NUM> at the first wavelength λ1 that is within the first bandwidth BW1, i.e., the bandwidth transmitted by the first bandpass filter <NUM>, and may include emitting light from the second light source <NUM> at the second wavelength λ2 that is within the second bandwidth BW2, i.e., the bandwidth transmitted by the second bandpass filter <NUM>. The difference between the second wavelength λ2 and the first wavelength λ1 plus the full-width half-maximum of the waveform of the light emitted from the first light source <NUM> is greater than the full-width half-maximum of the first bandpass filter <NUM>.

As also described above, block <NUM> may include emitting light from the first light source <NUM> and the second light source <NUM> as pulsed laser light. Similarly, for the example shown in <FIG>, block <NUM> may include emitting light from the third lights source as pulsed laser light.

With continued reference to <FIG>, block <NUM> includes filtering to the first bandwidth BW1, i.e., attenuating light outside the first bandwidth BW1, light that is emitted by the first light source <NUM> and reflected by a reflecting surface. Specifically, the light emitted by the first light source <NUM> and reflected at the first receiving unit <NUM> may be filtered with the first bandpass filter <NUM>, as described above. In block <NUM>, the method includes detecting light that is filtered to the first bandwidth BW1. Specifically, this filtered light is detected by the first photodetector <NUM>, as described above. Said differently, the first photodetector <NUM> may detect light in the first bandwidth BW1 transmitted by the first bandpass filter <NUM>.

With continued reference to <FIG>, block <NUM> includes filtering to the second bandwidth BW2, i.e., attenuating light outside the second bandwidth BW2, light that is emitted by the second light source <NUM> and reflected by a reflecting surface. Specifically, the light emitted by the second light source <NUM> and reflected at the second receiving unit <NUM> may be filtered with the second bandpass filter <NUM>, as described above. In block <NUM>, the method includes detecting light that is filtered to the second bandwidth BW2. Specifically, this filtered light is detected by the second photodetector <NUM>, as described above. Said differently, the second photodetector <NUM> may detect light in the second bandwidth BW2 transmitted by the second bandpass filter <NUM>.

With continued reference to <FIG>, block <NUM> includes filtering to the third bandwidth light that is emitted by the third light source <NUM> and reflected by a reflecting surface. Specifically, the light emitted by the third light source <NUM> and reflected at the third receiving unit <NUM> may be filtered with the third bandpass filter <NUM>, as described above. In block <NUM>, the method includes detecting light that is filtered to the third bandwidth. Specifically, this filtered light is detected by the third photodetector <NUM>, as described above. Said differently, the third photodetector <NUM> may detect light in the third bandwidth transmitted by the third bandpass filter <NUM>.

In block <NUM>, the method includes determining the location and distance of the object that reflected light back to the system <NUM>. Block <NUM> may include eliminating or reducing "false signals" due to cross-talk, as described above. This may be accomplished, for example, by histogramming. Block <NUM> may be performed by the controller <NUM> or by another component of the vehicle <NUM>, e.g., another component of the ADAS.

<FIG> and <FIG> show two examples of the system <NUM> that distinguishes between the reflected light in the first field of view FV1 in the second field of view FV2. Specifically, the controller <NUM> controls the timing of emission of light and collection of light to distinguish between reflected light in the first field of view FV1 and in the second field of view FV2, i.e., is temporally based.

<FIG> is a schematic showing the operation of the example shown in <FIG> and <FIG> is a schematic showing the operation of the example shown in <FIG>. With reference to <FIG> and <FIG>, the controller <NUM> is programmed to substantially simultaneously emit a pulse of light from the first light source <NUM> and the second light source <NUM>. With reference to <FIG>, the controller <NUM> is programmed to emit a pulse of light from the third light source <NUM> substantially simultaneously with the first light source <NUM> and the second light source <NUM>.

The controller <NUM> is programmed to, during a first time period, activate the first photodetector <NUM> and deactivate the second photodetector <NUM> and, during a second time period, activate the second photodetector <NUM> and deactivate the first photodetector <NUM>. Specifically, the second time period initiates after the first time period and extends beyond the first time period. With reference to <FIG>, the first field of view FV1 is shorter than the second field of view FV2, as described above, i.e., the first photodetector <NUM> is short range and the second photodetector <NUM> is long range). Accordingly, the time of flight of photons emitted from the second light source <NUM> to the second field of view FV2 will be greater than the first light source <NUM> to the first field of view FV1. Thus, when the first photodetector <NUM> is activated and the second photodetector <NUM> is deactivated during the first time period, the first photodetector <NUM> detects light reflected in the first field of view FV1, including the light emitted by the first light source <NUM> (which is returning to the system <NUM> during the first time period). When the first photodetector <NUM> is deactivated and the second photodetector <NUM> is activated during the second time period, the second photodetector <NUM> detects the light reflected in the portion <NUM> (identified in <FIG>) of the second field of view FV2 that extends beyond the first field of view FV1, i.e., the light emitted by the second light source <NUM>. The activation/deactivation of the first and second photodetectors <NUM>, <NUM> allows the second photodetector <NUM> to detect the light emitted by the second light source <NUM> (which is returning to the system <NUM> during the second time period) and not the first light source <NUM> (which has already returned to the system <NUM>). Said differently, short-range detection occurs during the first time period and long-range detection occurs during the second time period. For the purposes of this disclosure, an "activated" photodetector detects light and outputs corresponding data and a "deactivated" photodetector does not detect light or output corresponding data, e.g., is unpowered.

The first time period may initiate simultaneously with emission of light from the first and second light sources <NUM>, <NUM>. The second time period initiates after the first time period and extends beyond the first time period. The first time period and the second time period overlap. In such an example, the first time period may begin with the simultaneous emission of light from the first and second light source <NUM>, <NUM>, the second time period subsequently begins, the first time period subsequently ends, and the second time period subsequently ends. This timing reduces cross-talk, e.g., the first photodetector <NUM> detecting reflected light generated by the second light source <NUM>, and the second photodetector <NUM> detecting reflected light generated by the first light source <NUM>. Any remaining "false signals" from cross-talk data points may be removed by using histogramming. The light emitted from the first and second light sources <NUM>, <NUM> may be the same or different wavelengths.

With reference to <FIG> and <FIG>, the controller <NUM> may be programmed to, during the first time period, activate the third photodetector <NUM>. In such an example, the first photodetector <NUM> and the photodetector simultaneously detect reflected light. In the example shown in <FIG>, the first photodetector <NUM> and the third photodetector <NUM> may be aimed in different directions such that the first field of view FV1 and the third field of view FV3 do not overlap. The light emitted from the first and third light sources <NUM> may be the same or different wavelengths.

<FIG> shows an example method <NUM> of operation the system <NUM> in <FIG> and <FIG>. As shown in block <NUM>, the method includes emitting light from the first light source <NUM> and the second light source <NUM>. Specifically, the method may include substantially simultaneously emitting light from the first light source <NUM> and the second light source <NUM>. In the example of <FIG>, the method may also include substantially simultaneously emitting light from the third light source <NUM>. In other words, the controller <NUM> instructs the first light source <NUM> and the second light source <NUM> (and the third light source <NUM> in <FIG>) to emit light substantially simultaneously. Specifically, block <NUM> may include emitting light from the first light source <NUM> into first field of view FV1 and simultaneously emitting light from the second light source <NUM> into the second field of view FV2 that overlaps the first field of view FV1.

In block <NUM>, a clock is started. For example, the controller <NUM> starts the clock and the first and second time periods are based on the clock. The controller <NUM> may start the clock at the simultaneous emission of light from the first and second light source <NUM>, <NUM>. The clock is used to determine the time of flight of reflected photons detected by the photodetectors <NUM>, <NUM>, <NUM> to determine distance of the object that reflected the light.

In block <NUM>, the method includes, during the first time period, activating the first photodetector <NUM> and deactivating the second photodetector <NUM>. As described above, during the first time period, the first photodetector <NUM> is detecting photons reflected in the first field of view FV1 and not photons reflected in the portion <NUM> of the second field of view FV2 that extends beyond the first field of view FV1 because the reflected photons in the portion <NUM> of the second field of view FV2 do not return within the first time period. In other words, short-range detection occurs during the first time period.

Block <NUM> may include, during the first time period, activating the third photodetector <NUM>. As described above, in such an example, the first photodetector <NUM> may detect photons reflected in the first field of view FV1 simultaneously with the detection of photons reflected in the third field of view FV3 by the third photodetector <NUM>. In such an example, e.g., <FIG>, the first and third field of views FV1, FV3 are aimed in different directions.

In block <NUM>, the method includes, during the second time period, deactivating the first photodetector <NUM> (and deactivating the third photodetector <NUM> in examples including the third photodetector <NUM>) and activating the second photodetector <NUM>. As described above, during the second time period, the second photodetector <NUM> is detecting photons reflected in the portion <NUM> of the second field of view FV2 that extends beyond the first field of view FV1 because the reflected photons from the first field of view FV1 have returned before the second time period and the reflected photons from the portion <NUM> of the second field of view FV2 that extends beyond the first field of view FV1 return during the second time period. In other words, long-range detection occurs during the second time period.

Claim 1:
A system (<NUM>) comprising:
a first photodetector (<NUM>) having a first field of view (FV1);
a second photodetector (<NUM>) having a second field of view (FV2) overlapping the first field of view;
a first light source (<NUM>) aimed at the first field of view (FV1);
a second light source (<NUM>) aimed at the second field of view (FV2); and
a first bandpass filter (<NUM>) covering the first photodetector (<NUM>) and a second bandpass filter (<NUM>) covering the second photodetector (<NUM>), the first bandpass filter (<NUM>) designed to transmit light in a first bandwidth (BW1) and the second bandpass filter (<NUM>) designed to transmit light in a second bandwidth (BW2) different than the first bandwidth (BW1) ,
wherein the first light source (<NUM>) is designed to emit light having a first wavelength (λ1) in the first bandwidth (BW1) and the second light source (<NUM>) is designed to emit light having a second wavelength (λ2) in the second bandwidth (BW2).