Patent ID: 12228947

Embodiments of the present disclosure and their advantages are best understood by referring to the detailed description that follows. It is noted that sizes of various components and distances between these components are not drawn to scale in the figures. It should be appreciated that like reference numerals are used to identify like elements illustrated in one or more of the figures.

DETAILED DESCRIPTION

Mobile platforms (e.g., UAVs, ROVs, USVs, and UGVs) participate in a number of different types of missions. In some missions, a UAV may be required to engage in aggressive navigation maneuvers at high speeds, low altitudes, and in low-light conditions. While some UAVs may use a gimbal to stabilize a payload camera for capturing high-definition video, fixed-body cameras are generally used for navigation purposes. However, conventional fixed-body cameras have limitations in relation to tracking aggressive UAV motion. Since body-fixed cameras are rigidly mounted, the image of the world can move quickly across the camera sensor. This introduces motion blur because of the significant optical flow during a sampling period. These problems are exacerbated during low-light conditions when pixel integration periods have to be increased to accumulate sufficient light. Thus, under aggressive maneuvers this becomes equivalent to only having a low-resolution image available. With only a low-resolution image available, stereo detection range is limited, meanwhile the size, weight, and power price of high-resolution stereo cameras are still incurred. Furthermore, details that are needed to spot obstacles at large distances, which are required to avoid collisions when moving fast, are lost.

The present disclosure provides systems, devices, and methods to facilitate operation of a mobile platform to solve the aforementioned problems. In one embodiment, two high-definition variable navigation imaging systems are mounted on separate gimbals of a mobile platform and used for adaptive foveal vision where points fixated on by the variable navigation imaging systems can be tracked with great acuity during aggressive maneuvers of the mobile platform. The variable navigation imaging systems may be controlled in a fixation-sacadding pattern where fixation points are tracked by the variable navigation imaging systems and used to navigate the mobile platform without collisions in both static and dynamic environments. In some embodiments, fixed-imaging systems, which may be implemented with low-resolution sensors to preserve power for the mobile platform, may be fixed to the mobile platform and may provide peripheral vision to supplement the foveal vision provided by the variable navigation imaging systems. Images provided by the fixed-imaging systems may be sampled at motion-dependent frame rates to reduce power consumption. Thus, there may be at least some vision in all direction while there is high visual acuity in the most interesting directions. Further embodiments and their advantages are discussed below.

Referring toFIG.1, illustrated is a block diagram of a survey system100including a mobile platform110and a base station130, in accordance with one or more embodiments of the disclosure. In various embodiments, mobile platform110may be configured to fly over a scene or survey area, to fly through a structure, or to approach a target and image or sense the scene, structure, or target, or portions thereof, using gimbal system123to aim payload imaging system141at the scene, structure, or target, or portions thereof, for example. Resulting imagery and/or other sensor data may be processed (e.g., by controller112) and displayed to a user through use of user interface132(e.g., one or more displays such as a multi-function display (MFD), a portable electronic device such as a tablet, laptop, or smart phone, or other appropriate interface) and/or stored in memory for later viewing and/or analysis. In some embodiments, system100may be configured to use such imagery and/or sensor data to control operation of mobile platform110and/or payload imaging system141, such as controlling gimbal system123to aim payload imaging system141towards a particular direction, or controlling propulsion system124to move mobile platform110to a desired position in a scene or structure or relative to a target.

In the embodiment shown inFIG.1, survey system100includes mobile platform110, base station130, variable navigation imaging systems140aand140b, and payload imaging system141. Mobile platform110may be implemented as a mobile platform configured to move or fly and position and/or aim imaging system141(e.g., relative to a selected, designated, or detected target). As shown inFIG.1, mobile platform110may include one or more of a controller112, an orientation sensor114, a gyroscope/accelerometer116, a global navigation satellite system (GNSS)118, a communication system120, gimbal systems122aand122b, a gimbal system123, a propulsion system124, and other modules126. Operation of mobile platform110may be substantially autonomous and/or partially or completely controlled by base station130, which may include one or more of a user interface132, a communication system134, and other modules136. In other embodiments, mobile platform110may include one or more of the elements of base station130, such as with various types of manned aircraft, terrestrial vehicles, and/or surface or subsurface watercraft. Payload Imaging system141may be physically coupled to mobile platform110via gimbal system123and may be configured to capture sensor data (e.g., visible spectrum images, infrared images, narrow aperture radar data, and/or other sensor data) of a target position, area, and/or object(s) as selected and/or framed by operation of mobile platform110and/or base station130.

Variable navigation imaging systems140aand140bmay be respectively coupled to mobile platform110via gimbal systems122aand122b. Variable navigation imaging systems140aand140bmay be directed by gimbal systems122aand122bto capture sensor data (e.g., visible spectrum images, infrared images, narrow aperture radar data, and/or other sensor data) of fixation points within an environment to facilitate operation of the mobile platform110in accordance with embodiments of the present disclosure. In some embodiments, variable navigation imaging systems140a/140bmay include a stereo vision system configured to provide image data that may be used to calculate or estimate a position of mobile platform110, for example, or to calculate or estimate a relative position of a navigational hazard in proximity to mobile platform110. In various embodiments, controller112may be configured to use such proximity and/or position information to help safely pilot mobile platform110as discussed herein.

In some embodiments, one or more of the elements of system100may be implemented in a combined housing or structure that can be coupled to or within mobile platform110and/or held or carried by a user of system100.

Controller112may be implemented as any appropriate logic circuit and/or device (e.g., processing device, microcontroller, processor, application specific integrated circuit (ASIC), field programmable gate array (FPGA), memory storage device, memory reader, or other device or combinations of devices) that may be adapted to execute, store, and/or receive appropriate instructions, such as software instructions implementing a control loop for controlling various operations of mobile platform110and/or other elements of system100, such as the gimbal systems122a,122b, and123, variable navigation imaging systems140aand140b, payload imaging system141, fixed imaging systems128, or the propulsion system124, for example. Such software instructions may also implement methods for processing infrared images and/or other sensor signals, determining sensor information, providing user feedback (e.g., through user interface132), querying devices for operational parameters, selecting operational parameters for devices, or performing any of the various operations described herein.

In addition, a non-transitory medium may be provided for storing machine readable instructions for loading into and execution by controller112. In these and other embodiments, controller112may be implemented with other components where appropriate, such as volatile memory, non-volatile memory, one or more interfaces, and/or various analog and/or digital components for interfacing with devices of system100. For example, controller112may be adapted to store sensor signals, sensor information, parameters for coordinate frame transformations, calibration parameters, sets of calibration points, and/or other operational parameters, over time, for example, and provide such stored data to a user using user interface132. In some embodiments, controller112may be integrated with one or more other elements of mobile platform110such as gimbal systems122a,122b, and123, variable navigation imaging systems140aand140b, payload imaging system141, and fixed imaging system(s)128, for example.

In some embodiments, controller112may be configured to substantially continuously monitor and/or store the status of and/or sensor data provided by one or more elements of mobile platform110, gimbal systems122a,122b,123, variable navigation imaging systems140a,140b, payload imaging system141, fixed imaging system(s)128, and/or base station130, such as the position and/or orientation of mobile platform110, gimbal systems122a,122b,123, variable navigation imaging systems140a,140b, payload imaging system141, and/or base station130, for example.

Orientation sensor114may be implemented as one or more of a compass, float, accelerometer, and/or other device capable of measuring an orientation of mobile platform110(e.g., magnitude and direction of roll, pitch, and/or yaw, relative to one or more reference orientations such as gravity and/or Magnetic North), gimbal system122a,122b,123, fixed imaging system(s)128, and/or other elements of system100, and providing such measurements as sensor signals and/or data that may be communicated to various devices of system100. Gyroscope/accelerometer116may be implemented as one or more electronic sextants, semiconductor devices, integrated chips, accelerometer sensors, accelerometer sensor systems, or other devices capable of measuring angular velocities/accelerations and/or linear accelerations (e.g., direction and magnitude) of mobile platform110and/or other elements of system100and providing such measurements as sensor signals and/or data that may be communicated to other devices of system100(e.g., user interface132, controller112). GNSS118may be implemented according to any global navigation satellite system, including a GPS, GLONASS, and/or Galileo based receiver and/or other device capable of determining absolute and/or relative position of mobile platform110(e.g., or an element of mobile platform110) based on wireless signals received from space-born and/or terrestrial sources (e.g., eLoran, and/or other at least partially terrestrial systems), for example, and capable of providing such measurements as sensor signals and/or data (e.g., coordinates) that may be communicated to various devices of system100and other nodes participating in a mesh network. In some embodiments, GNSS118may include an altimeter, for example, or may be used to provide an absolute altitude.

Communication system120may be implemented as any wired and/or wireless communication system configured to transmit and receive analog and/or digital signals between elements of system100and other nodes participating in a mesh network. For example, communication system120may be configured to receive flight control signals and/or data from base station130and provide them to controller112and/or propulsion system124. In other embodiments, communication system120may be configured to receive images and/or other sensor information (e.g., visible spectrum and/or infrared still images or video images) from variable navigation imaging systems140aand140b, fixed imaging system(s)128, and/or payload imaging system141and relay the sensor data to controller112and/or base station130. In some embodiments, communication system120may be configured to support spread spectrum transmissions, for example, and/or multiple simultaneous communications channels between elements of system100. Wireless communication links may include one or more analog and/or digital radio communication links, such as WiFi and others, as described herein, and may be direct communication links established between elements of system100, for example, or may be relayed through one or more wireless relay stations configured to receive and retransmit wireless communications. Communication links established by communication system120may be configured to transmit data between elements of system100substantially continuously throughout operation of system100, where such data includes various types of sensor data, control parameters, and/or other data, as described herein.

Gimbal systems122aand122bmay be implemented as an actuated gimbal mount, for example, that may be controlled by controller112to stabilize variable navigation imaging systems140aand140brelative to a fixed position and/or target or to aim variable navigation imaging systems140aand140baccording to a desired direction and/or relative orientation or position. For example, controller112may receive a control signal from one or more components of system100to cause gimbal system122aor gimbal system122bto adjust a position of variable navigation imaging systems140aand140bas described in the disclosure. As such, gimbal systems122aand122bmay be configured to provide a relative orientation of variable navigation imaging system140aor140b(e.g., relative to an orientation of mobile platform110) to controller112and/or communication system120(e.g., gimbal systems122aand122bmay include their own orientation sensor114). In various embodiments, gimbal systems122aand122bmay be configured to provide power, support wired communications, and/or otherwise facilitate operation of articulated variable navigation imaging systems140aand140b. In further embodiments, gimbal systems122aand122bmay be configured to couple to a laser pointer, range finder, and/or other device, for example, to support, stabilize, power, and/or aim multiple devices (e.g., variable navigation imaging systems140a/140band one or more other devices) substantially simultaneously.

In some embodiments, gimbal systems122a/122bmay be adapted to rotate variable navigation imaging systems140a/140b+−90 degrees, or up to 360 degrees, in a vertical plane relative to an orientation and/or position of mobile platform110. In further embodiments, gimbal system122a/122bmay rotate variable navigation imaging system140a/140bto be parallel to a longitudinal axis or a lateral axis of mobile platform110as mobile platform110yaws, which may provide 360 degree ranging and/or imaging in a horizontal plane relative to mobile platform110. In various embodiments, controller112may be configured to monitor an orientation of gimbal systems122a/122band/or variable navigation imaging systems140a/140brelative to mobile platform110, for example, or an absolute or relative orientation of an element of variable navigation imaging system140(e.g., imaging module142). Such orientation data may be transmitted to other elements of system100for monitoring, storage, or further processing, as described herein.

Gimbal system123may be implemented as an actuated gimbal mount, for example, that may be controlled by controller112to stabilize and direct payload imaging system141relative to a target or to aim imaging system141according to a desired direction and/or relative orientation or position. For example, controller112may receive a control signal from one or more components of system100to cause gimbal system123to adjust a position of payload imaging system141as described in the disclosure. As such, gimbal system123may be configured to provide a relative orientation of payload imaging system141(e.g., relative to an orientation of mobile platform110) to controller112and/or communication system120(e.g., gimbal system123may include its own orientation sensor114). In other embodiments, gimbal system123may be implemented as a gravity driven mount (e.g., non-actuated). In various embodiments, gimbal system123may be configured to provide power, support wired communications, and/or otherwise facilitate operation of articulated sensor/payload imaging system141. In further embodiments, gimbal system123may be configured to couple to a laser pointer, range finder, and/or other device, for example, to support, stabilize, power, and/or aim multiple devices (e.g., payload imaging system141and one or more other devices) substantially simultaneously.

In some embodiments, gimbal system123may be adapted to rotate payload imaging system141+−90 degrees, or up to 360 degrees, in a vertical plane relative to an orientation and/or position of mobile platform110. In further embodiments, gimbal system123may rotate payload imaging system141to be parallel to a longitudinal axis or a lateral axis of mobile platform110as mobile platform110yaws, which may provide 360 degree ranging and/or imaging in a horizontal plane relative to mobile platform110. In various embodiments, controller112may be configured to monitor an orientation of gimbal system123and/or payload imaging system141relative to mobile platform110, for example, or an absolute or relative orientation of an element of payload imaging system141(e.g., a sensor of payload imaging system141). Such orientation data may be transmitted to other elements of system100for monitoring, storage, or further processing, as described herein.

Propulsion system124may be implemented as one or more propellers, turbines, or other thrust-based propulsion systems, and/or other types of propulsion systems that can be used to provide motive force and/or lift to mobile platform110and/or to steer mobile platform110. In some embodiments, propulsion system124may include multiple propellers (e.g., a tri, quad, hex, oct, or other type “copter”) that can be controlled (e.g., by controller112) to provide lift and motion for mobile platform110and to provide an orientation for mobile platform110. In other embodiments, propulsion system124may be configured primarily to provide thrust while other structures of mobile platform110provide lift, such as in a fixed wing embodiment (e.g., where wings provide the lift) and/or an aerostat embodiment (e.g., balloons, airships, hybrid aerostats). In various embodiments, propulsion system124may be implemented with a portable power supply, such as a battery and/or a combustion engine/generator and fuel supply.

Fixed imaging system(s)128may be implemented as an imaging device fixed to the body of mobile platform110such that a position and orientation is fixed relative to the body of the mobile platform, according in various embodiments. Fixed imaging system(2) may include one or more imaging modules, which may be implemented as a cooled and/or uncooled array of detector elements, such as visible spectrum and/or infrared sensitive detector elements, including quantum well infrared photodetector elements, bolometer or microbolometer based detector elements, type II superlattice based detector elements, and/or other infrared spectrum detector elements that can be arranged in a focal plane array. In various embodiments, an imaging module of a fixed imaging system128may include one or more logic devices that can be configured to process imagery captured by detector elements of the imaging module before providing the imagery to controller112. Fixed imaging system(s)128may be arranged on the mobile platform110and configured to perform any of the operations or methods described herein, at least in part, or in combination with controller112and/or user interface132. An example fixed imaging system(s)128configuration includes using 6 fixed imaging systems, each covering a 90-degree sector to give complete 360-degree coverage. Using on-chip down-sampling of the images provided by fixed imaging system(s)128to approximately the order of 128×128 pixels and recording at 1200 Hz, the fixed imaging system(s)128can track rotations of 1000-1500 degrees per second with an optical flow of less than one pixel per frame. The same one-pixel optical flow per frame criteria would be fulfilled when flying mobile platform110at speeds in excess of 10 m/s at 1 m distance from the surface (e.g., wall, ground, roof, etc.). When not sampling at high rates, these low-resolution fixed imaging system(s)128should consume little power and thus minimally impact an average power consumption for mobile platform110. Thus, a motion-dependent frame rate adjustment may be used to operate efficiently where the frame rate can be kept high enough to maintain the one pixel optical-flow per the frame tracking criteria.

Other modules126may include other and/or additional sensors, actuators, communications modules/nodes, and/or user interface devices, for example, and may be used to provide additional environmental information related to operation of mobile platform110, for example. In some embodiments, other modules126may include a humidity sensor, a wind and/or water temperature sensor, a barometer, an altimeter, a radar system, a proximity sensor, a visible spectrum camera or infrared camera (with an additional mount), an irradiance detector, and/or other environmental sensors providing measurements and/or other sensor signals that can be displayed to a user and/or used by other devices of system100(e.g., controller112) to provide operational control of mobile platform110and/or system100.

In some embodiments, other modules126may include one or more actuated and/or articulated devices (e.g., multi-spectrum active illuminators, visible and/or IR cameras, radars, sonars, and/or other actuated devices) coupled to mobile platform110, where each actuated device includes one or more actuators adapted to adjust an orientation of the device, relative to mobile platform110, in response to one or more control signals (e.g., provided by controller112). In particular, other modules126may include a stereo vision system configured to provide image data that may be used to calculate or estimate a position of mobile platform110, for example, or to calculate or estimate a relative position of a navigational hazard in proximity to mobile platform110. In various embodiments, controller112may be configured to use such proximity and/or position information to help safely pilot mobile platform110and/or monitor communication link quality with the base station130.

User interface132of base station130may be implemented as one or more of a display, a touch screen, a keyboard, a mouse, a joystick, a knob, a steering wheel, a yoke, and/or any other device capable of accepting user input and/or providing feedback to a user. In various embodiments, user interface132may be adapted to provide user input (e.g., as a type of signal and/or sensor information transmitted by communication system134of base station130) to other devices of system100, such as controller112. User interface132may also be implemented with one or more logic devices (e.g., similar to controller112) that may be adapted to store and/or execute instructions, such as software instructions, implementing any of the various processes and/or methods described herein. For example, user interface132may be adapted to form communication links, transmit and/or receive communications (e.g., infrared images and/or other sensor signals, control signals, sensor information, user input, and/or other information), for example, or to perform various other processes and/or methods described herein.

In some embodiments, user interface132may be adapted to accept user input including a user-defined target heading, waypoint, route, and/or orientation for an element of system100, for example, and to generate control signals to cause mobile platform110to move according to the target heading, route, and/or orientation, or to aim payload imaging system141or variable navigation imaging systems140aand140baccordingly. In other embodiments, user interface132may be adapted to accept user input modifying a control loop parameter of controller112, for example. In further embodiments, user interface132may be adapted to accept user input including a user-defined target attitude, orientation, and/or position for an actuated or articulated device (e.g., payload imaging system141) associated with mobile platform110, for example, and to generate control signals for adjusting an orientation and/or position of the actuated device according to the target altitude, orientation, and/or position. Such control signals may be transmitted to controller112(e.g., using communication system134and120), which may then control mobile platform110accordingly.

Communication system134may be implemented as any wired and/or wireless communication system configured to transmit and receive analog and/or digital signals between elements of system100and/or nodes participating in a mesh network. For example, communication system134may be configured to transmit flight control signals or commands from user interface132to communication systems120or144. In other embodiments, communication system134may be configured to receive sensor data (e.g., visible spectrum and/or infrared still images or video images, or other sensor data) from imaging system140. In some embodiments, communication system134may be configured to support spread spectrum transmissions, for example, and/or multiple simultaneous communications channels between elements of system100. In various embodiments, communication system134may be configured to monitor the status of a communication link established between base station130, imaging system140, mobile platform110, and/or the nodes participating in the mesh network (e.g., including packet loss of transmitted and received data between elements of system100or the nodes of the mesh network, such as with digital communication links). Such status information may be provided to user interface132, for example, or transmitted to other elements of system100for monitoring, storage, or further processing, as described herein.

Other modules136of base station130may include other and/or additional sensors, actuators, communications modules/nodes, and/or user interface devices used to provide additional environmental information associated with base station130, for example. In some embodiments, other modules136may include a humidity sensor, a wind and/or water temperature sensor, a barometer, a radar system, a visible spectrum camera, an infrared camera, a GNSS, and/or other environmental sensors providing measurements and/or other sensor signals that can be displayed to a user and/or used by other devices of system100(e.g., controller112) to provide operational control of mobile platform110and/or system100or to process sensor data to compensate for environmental conditions, such as an water content in the atmosphere approximately at the same altitude and/or within the same area as mobile platform110and/or base station130, for example. In some embodiments, other modules136may include one or more actuated and/or articulated devices (e.g., multi-spectrum active illuminators, visible and/or IR cameras, radars, sonars, and/or other actuated devices), where each actuated device includes one or more actuators adapted to adjust an orientation of the device in response to one or more control signals (e.g., provided by user interface132).

In embodiments where variable navigation imaging system140a(and similarly variable navigation imaging system140b) is implemented as an imaging device, variable navigation imaging system140amay include an imaging module142, which may be implemented as a cooled and/or uncooled array of detector elements, such as visible spectrum and/or infrared sensitive detector elements, including quantum well infrared photodetector elements, bolometer or microbolometer based detector elements, type II superlattice based detector elements, and/or other infrared spectrum detector elements that can be arranged in a focal plane array. In various embodiments, imaging module142may include one or more logic devices that can be configured to process imagery captured by detector elements of imaging module142before providing the imagery to memory146or communication system144. More generally, imaging module142may be configured to perform any of the operations or methods described herein, at least in part, or in combination with controller112and/or user interface132. In some embodiments, the imaging module142may be a component of the controller112.

In some embodiments, variable navigation imaging system140amay be implemented with a second or additional imaging modules similar to imaging module142, for example, that may include detector elements configured to detect other electromagnetic spectrums, such as visible light, ultraviolet, and/or other electromagnetic spectrums or subsets of such spectrums. In various embodiments, such additional imaging modules may be calibrated or registered to imaging module142such that images captured by each imaging module occupy a known and at least partially overlapping field of view of the other imaging modules, thereby allowing different spectrum images to be geometrically registered to each other (e.g., by scaling and/or positioning). In some embodiments, different spectrum images may be registered to each other using pattern recognition processing in addition or as an alternative to reliance on a known overlapping field of view.

Communication system144of variable navigation imaging system140amay be implemented as any wired and/or wireless communications module configured to transmit and receive analog and/or digital signals between elements of system100. For example, communication system144may be configured to transmit infrared images from imaging module142to communication systems120or134. In other embodiments, communication system144may be configured to receive control signals (e.g., control signals directing capture, focus, selective filtering, and/or other operation of variable navigation imaging system140) from controller112and/or user interface132. In some embodiments, communication system144may be configured to support spread spectrum transmissions, for example, and/or multiple simultaneous communications channels between elements of system100. In various embodiments, communication system144may be configured to monitor and communicate the status of an orientation of the variable navigation imaging system140a. Such status information may be used, for example, to adjust the orientation of the variable navigation imaging system140ato capture images of fixed positions as discussed herein.

Memory146may be implemented as one or more machine readable mediums and/or logic devices configured to store software instructions, sensor signals, control signals, operational parameters, calibration parameters, infrared images, and/or other data facilitating operation of system100, for example, and provide it to various elements of system100. Memory146may also be implemented, at least in part, as removable memory, such as a secure digital memory card for example including an interface for such memory.

Orientation sensor148of variable navigation imaging system140amay be implemented similar to orientation sensor114or gyroscope/accelerometer116, and/or any other device capable of measuring an orientation of variable navigation imaging system140a, imaging module142, and/or other elements of variable navigation imaging system140a(e.g., magnitude and direction of roll, pitch, and/or yaw, relative to one or more reference orientations such as gravity, Magnetic North, and/or an orientation of mobile platform110) and providing such measurements as sensor signals that may be communicated to various devices of system100. Gyroscope/accelerometer (e.g., angular motion sensor)150of variable navigation imaging system140amay be implemented as one or more electronic sextants, semiconductor devices, integrated chips, accelerometer sensors, accelerometer sensor systems, or other devices capable of measuring angular velocities/accelerations (e.g., angular motion) and/or linear accelerations (e.g., direction and magnitude) of variable navigation imaging system140aand/or various elements of variable navigation imaging system140aand providing such measurements as sensor signals that may be communicated to various devices of system100.

Other modules152of variable navigation imaging system140may include other and/or additional sensors, actuators, communications modules/nodes, cooled or uncooled optical filters, and/or user interface devices used to provide additional environmental information associated with variable navigation imaging system140, for example. In some embodiments, other modules152may include a humidity sensor, a wind and/or water temperature sensor, a barometer, a radar system, a visible spectrum camera, an infrared camera, a GNSS, and/or other environmental sensors providing measurements and/or other sensor signals that can be displayed to a user and/or used by imaging module142or other devices of system100(e.g., controller112) to provide operational control of mobile platform110and/or system100or to process imagery to compensate for environmental conditions.

In general, each of the elements of system100may be implemented with any appropriate logic device (e.g., processing device, microcontroller, processor, application specific integrated circuit (ASIC), field programmable gate array (FPGA), memory storage device, memory reader, or other device or combinations of devices) that may be adapted to execute, store, and/or receive appropriate instructions, such as software instructions implementing a method for providing sensor data and/or imagery, for example, or for transmitting and/or receiving communications, such as sensor signals, sensor information, and/or control signals, between one or more devices of system100. In addition, one or more non-transitory mediums may be provided for storing machine readable instructions for loading into and execution by any logic device implemented with one or more of the devices of system100. In these and other embodiments, the logic devices may be implemented with other components where appropriate, such as volatile memory, non-volatile memory, and/or one or more interfaces (e.g., inter-integrated circuit (I2C) interfaces, mobile industry processor interfaces (MIPI), joint test action group (JTAG) interfaces (e.g., IEEE 1149.1 standard test access port and boundary-scan architecture), and/or other interfaces, such as an interface for one or more antennas, or an interface for a particular type of sensor).

Sensor signals, control signals, and other signals may be communicated among elements of system100using a variety of wired and/or wireless communication techniques, including voltage signaling, Ethernet, WiFi, Bluetooth, Zigbee, Xbee, Micronet, Cursor-on-Target (CoT) or other medium and/or short range wired and/or wireless networking protocols and/or implementations, for example. In such embodiments, each element of system100may include one or more modules supporting wired, wireless, and/or a combination of wired and wireless communication techniques. In some embodiments, various elements or portions of elements of system100may be integrated with each other, for example, or may be integrated onto a single printed circuit board (PCB) to reduce system complexity, manufacturing costs, power requirements, coordinate frame errors, and/or timing errors between the various sensor measurements. Each element of system100may include one or more batteries, capacitors, or other electrical power storage devices, for example, and may include one or more solar cell modules or other electrical power generating devices. In some embodiments, one or more of the devices may be powered by a power source for mobile platform110, using one or more power leads. Such power leads may also be used to support one or more communication techniques between elements of system100.

FIG.2illustrates a diagram of survey system200including mobile platforms110A and110B, each with imaging systems140and associated gimbal systems122in accordance with an embodiment of the disclosure. In the embodiment shown inFIG.2, survey system200includes base station130; mobile platform110A with gimbal systems122aand122bcoupled to variable navigation imaging systems140aand140b, gimbal system122coupled to payload imaging system141, and fixed imaging systems128; and mobile platform110B with gimbal systems122aand122bcoupled to variable navigation imaging systems140aand140b, gimbal system122coupled to payload imaging system141, and fixed imaging systems128. In some embodiments, base station130may be configured to control motion, position, and/or orientation of mobile platform110A, mobile platform110B, and/or variable navigation imaging systems140aand140bor payload imaging system141(e.g., via their respective gimbal systems). More generally, survey system200may include any number of mobile platforms110,110A, and/or110B.

FIG.3illustrates a flow diagram of a process300for operating mobile platform110in accordance with one or more embodiments of the disclosure. In some embodiments, process300ofFIG.3may be implemented as software instructions executed by one or more logic circuits associated with corresponding electronic devices, sensors, and/or structures depicted inFIGS.1-2(e.g., controller112). More generally, the operations ofFIG.3may be implemented with any combination of software instructions, mechanical elements, and/or electronic hardware (e.g., inductors, capacitors, amplifiers, actuators, or other analog and/or digital components). It should also be appreciated that any step, sub-step, sub-process, or block of process300may be performed in an order or arrangement different from the embodiments illustrated byFIG.3. For example, in some embodiments, one or more blocks may be omitted from or added to process300. Furthermore, block inputs, block outputs, various sensor signals, sensor information, calibration parameters, and/or other operational parameters may be stored to one or more memories prior to moving to a following portion of a corresponding process. Note that in describingFIG.3, reference is made toFIGS.1-2and4A-4C, however, it will be appreciated that embodiments ofFIG.3are not limited byFIGS.1-2and4A-4C.

At block302ofFIG.3, a logic circuit may control gimbal system122aof mobile platform110to selectively direct variable navigation imaging system140ato a first fixation point402in an environment400A, as shown inFIG.4. Fixation point402may be located at a distance404away from the mobile platform110and on a surface in the environment400A such as a wall, building, tree, mountain, or other static structure/object. In some embodiments, a fixation point will be selected in the direction of flight of mobile platform110, at the end of a flight corridor, which may allow the fixation point to be tracked by the logic circuit for as long as needed while mobile platform110moves along the flight corridor. For example, the direction of flight inFIG.4Amay be in the y-direction and fixation point402may be at a position in the flight corridor. In some cases where there are less than optimal visual references available in the direction of flight (e.g., clear blue skies), the logic circuit may control gimbal system122ato search for other image regions with better visual references available, for example, on the ground below in the direction of flight. By selecting a fixation point at the end of the flight corridor, the logic circuit can use the variable navigation imaging system140afor collision avoidance while flying toward the fixation point. For example, the logic circuit may be able to determine that there are no obstacles in the flight path from the mobile platform110to the fixation point402.

Various fixation techniques may reduce motion blur in a local image region around the fixation point, and the further away from the fixation point in the image plane, the stronger the motion blur effect may become. Thus, in some embodiments, the logic circuit may downscale the image received from variable navigation imaging system140ato analyze coarser resolutions further away from fixation point402. In this way, useful information can still be extracted at the coarser resolution. In some embodiments, this may be referred to as foveal vision. Foveal vision can be realized in the following ways, or by combinations thereof. First, foveal vision can be realized through digital image binning of a standard uniformly sampled image. Second, foveal vision can be realized by designing a camera chip where the pixels enlarge the further away from the center of the image. Third, foveal vision can be realized by designing a camera chip where pixel density decreases the further away from the center of the image. Fourth, foveal vision can be realized by designing a lens that has a high magnification in the center of the image and a low magnification at the edges of the image. One advantage of the first approach for foveal vision is that the rate of subsampling away from the fixation point can be digitally varied dynamically depending on movement speed and lighting conditions, which may be referred to as adaptive digital foveal vision according to some embodiments.

At block304ofFIG.3, the logic circuit may control gimbal system122bof mobile platform110to selectively direct variable navigation imaging system140bto a second fixation point, similar to block302. For example, as shown inFIG.4A, the logic circuit may control gimbal system122bto direct variable navigation imaging system140bto a fixation point406in the environment400A. The second fixation point406may be located at a distance408away from the mobile platform110where the distance408is greater than the distance404. In some cases, distance408may be a predefined magnitude greater than distance404. When mobile platform110is moving in a flight path along the y-direction as shown inFIG.4A, the first fixation point402can be used as a first reference point, and as mobile platform110approaches the first fixation point402, the second fixation point406can be used as a second reference point to further navigate the mobile platform110along the flight path.

At block306ofFIG.3, the logic circuit may navigate the mobile platform110based on image data received from variable navigation imaging system140aand variable navigation imaging system140b. By using gimbal systems122aand122bto direct variable navigation imaging systems140aand140bto fixation points, the image region around the fixation points should have no optical flow and should not suffer from motion blur under aggressive maneuvers by the mobile platform110in low-light conditions. Thus, the logic circuit can perform the aggressive maneuvers more safely as there will be no or minimal vision sensor blindness.

At block308ofFIG.3, the logic circuit may further control and navigate the mobile platform. For example, referring again toFIG.4A, the logic circuit may control gimbal system122ato direct variable navigation imaging system140ato a third fixation point410in the environment400A where the fixation point410aligns with the flight path of the mobile platform110in the y-direction and is farther away than the second fixation point406relative to the mobile platform110. Variable navigation imaging system140amay be directed to the third fixation point410as the mobile platform moves along the flight path toward the first fixation point402. For example, variable navigation imaging system140amay saccade from the first fixation point402to the third fixation point410when mobile platform110enters a certain threshold proximity to the first fixation point402. Thus, in one embodiment, mobile platform110can be navigated using variable navigation imaging systems140aand140bin a leap-frog manner where variable navigation system140afixates on a first point some short distance ahead, variable navigation imaging system140bfixates on a second point (e.g., twice as far away), and when mobile platform110approaches the first point, the variable navigation imaging system140acan saccade ahead to a third fixation point beyond the second point, and so on and so forth as mobile platform110moves along a flight path. This pattern has an advantage of almost always having two distinct fixation points which can improve navigation performance in static environments. Also, in various embodiments where the variable navigation imaging systems140aand140bare directed one at a time, there should be no periods of complete blindness (e.g., periods where neither variable navigation imaging system is able to provide useable image data to help navigate mobile platform110).

In another embodiment, the logic circuit may control gimbal system122bto saccade variable navigation imaging system140bbetween a plurality of fixation points in an environment while gimbal system122adirects variable navigation imaging system140ato a fixation point. For example, as shown in the environment400B ofFIG.4B, variable navigation imaging system140amay be directed to fixation point418at the end of a flight corridor for the mobile platform110to maintain a steady course while the second gimbal system122bis used to repeatedly saccade and fixate variable navigation imaging system140bon a plurality of fixation points (e.g., fixation points419and420). The logic circuit may receive image data from variable navigation imaging system140bto search the surroundings for new flight corridors, possible threats or obstacles, possible targets to track, or another visually determined objective. In some embodiments, the logic circuit may use the image data from variable navigation imaging system140bas it searches to determine new fixation points for changing a direction of mobile platform110. In some embodiments, the image data received from variable navigation imaging system140bmay be relayed to base station130for an operator to view available fixation points and select fixation points to provide back to the logic circuit in instructions for navigating mobile platform110.

In some embodiments, when variable navigation imaging system140bsaccades between a plurality of fixation points, if the distances of the saccades are small enough (e.g., less than a threshold rotational distance), the gimbal system's122bactuators are implemented to be sufficiently fast, and the inter-frame interval of images captured by variable navigation imaging system140bis long enough (typically under good lighting conditions), saccade blindness can be eliminated or reduced by timing the saccade with the inter-frame interval.

Referring again toFIG.4B, in some cases where variable navigation imaging system140bis searching for new flight corridors, variable navigation imaging system140acan be fixated on fixation point418that aligns with a current direction of navigation (y-direction shown inFIG.4B). Based on image data received from variable navigation imaging system140bduring its searching, the logic circuit can control gimbal system122bto direct variable navigation imaging system140bto fixation point420that aligns with a determined next direction of navigation. The logic circuit may steer mobile platform110from the current direction to the next direction. Gimbal system122bmay direct variable navigation imaging system140bto fixation point420at an inter-frame interval such that there is no vision sensor blindness when changing directions from the current direction to the next direction. Selecting the next fixation point, such as when changing directions, may be based on several factors including the motion of mobile platform110, geometry and texture of the surroundings in an environment, locations of possible moving obstacles, objects, or targets, and the task mobile platform is trying to solve. In implementations, trade-offs vary in different tasks such as passive motion tracking tasks, an exploration task, a search for a specific object, or following a specific target. In some embodiments, executing a neural network on a low-resolution 360-degree peripheral image provided by fixed imaging systems128may be used to select fixation points. In other implementations where a virtual/augmented reality headset is used to operate mobile platform110, additional cameras in the headset that watch the eye-movements of a pilot may be used to select fixation points.

Referring toFIG.4C, the logic circuit may control gimbal system122bto saccade variable navigation imaging system140abetween tracking a target424in an environment400C and a fixation point422along a flight path of the mobile platform110. At some instances, the variable navigation imaging system140aand140bmay both be fixated on the target424. For example, when flying beside moving target424and to avoid obstacles426and428, variable navigation imaging system140acan repeatedly saccade between monitoring the flight corridor by fixating on point422and stereo fixating the moving target424concurrently with variable navigation imaging system140b. When both variable navigation imaging systems140aand140bare fixated on target424, the logic circuit may generate a stereo vision output of target424based on images captured of target424and received from variable navigation imaging systems140aand140b. When moving in a static environment where there are no moving obstacles, one variable navigation imaging system may be sufficient for collision avoidance and three-dimensional mapping using structure from motion. However, in a dynamic environment such as environment400C having moving obstacles, stereo vision is convenient to resolve visual ambiguities of the changes in visual appearance caused by image sensor motion or obstacle motion. For example, target424may be a moving person, a manned-vehicle, or another mobile platform such as a UAV. In such cases, it may be helpful to fixate both variable navigation imaging systems140aand140bon the moving target424to accurately estimate the moving target's position relative to mobile platform110using stereo fixation.

If the target's424motion relative to the environment400C is sufficiently large, a conflict may arise between fixating on the target424and fixating on the environment400C and possible obstacles (e.g., obstacles426and428). This may be solved by fixation-release, where one or both variable navigation imaging systems140aand140brelease their fixation on moving target424to instead fixate on the background in environment400C for navigation purposes before being directed back to the moving target424for another short period of time before releasing and repeating. A leap-frog approach can also be used in which one of the variable navigation imaging systems is always fixated on the moving target424and they alternate between fixating on the target424and fixating on a point in the flight path to assist in navigation of mobile platform110. In some embodiments, a plurality of different fixation points can be used to track a plurality of moving targets in an environment. Depending on application, mobile platform110may slow down in motion to accommodate additional fixation points for additional moving targets.

As shown inFIGS.4A-4C, mobile platform110may have fixed imaging systems128that can be used for further operation and navigation of the mobile platform110. For example, fixed imaging systems128may be body-fixed to the mobile platform110and capable of providing images of peripheral fields of view414and416, which may be peripheral with respect to the fields of view of variable navigation imaging systems140aand140b. For example, inFIG.4C, when variable navigation imaging systems140aand140bare fixated on target424, the logic circuit may be able to navigate the mobile platform110based on images received from the fixed imaging systems128. In some embodiments, fixed imaging systems128may capture images of their fields of view414and416(e.g., peripheral fields of view) at a frame rate that correlates to an optical flow of a scene (in field of view) captured by an imaging sensor of the fixed imaging system to reduce power consumption of the mobile platform110. For example, the optical flow may be the pattern of apparent motion of objects, surfaces, and edges in a visual scene caused by the relative motion between the mobile platform110and the scene. In some cases, images captured by fixed imaging systems128may be used for additional collision avoidance (e.g., to detect and evade collision with obstacles426and428) as peripheral fields of view414and416may be able to capture obstacles426and428in scenarios where variable navigation imaging systems140aand140bdo not sense obstacles426and428, such as when variable navigation imaging systems140aand140bare fixated on target424to assess whether target424is a threat.

As an illustration, in a high-speed pursuit of moving target424, if target424is actively trying to evade mobile platform110, the logic circuit may perform fixation-release or use multiple fixation points to keep track of the environment400C to avoid any collisions. In such cases, stereo-fixation may be maintained on target424and the logic circuit can rely on peripheral vision provided by fixed imaging systems128to avoid collisions. In such cases, the logic circuit may navigate mobile platform in the wake of moving target424to further minimize the risk of collision.

In some embodiments, the logic circuit may determine an orientation of gimbal systems122aand122band/or variable navigation imaging systems140aand140bwith respect to the body of the mobile platform110by comparing the images received from fixed imaging systems128to images received from variable navigation imaging systems140aand140b. For example, the logic circuit may determine visual features from images received from the variable navigation imaging systems140aand/or140band match them to common visual features in the images received from fixed imaging systems128to make any adjustments necessary to the orientation of gimbal systems122aand122bor variable navigation imaging systems140aand140b. In some embodiments, the matching may be performed using low-resolution images from the fixed imaging systems128and downscaled versions of the images from the variable navigation imaging systems140aand140b.

It will be appreciated that in various embodiments, fixed imaging systems128may not be implemented in mobile platform110. For example, variable navigation imaging systems140aand140bcan be used to capture forward, downward, rear, and upward view. Left and right stereo views may be achieved by yawing mobile platform110.

Referring toFIGS.4A-4C, in some embodiments, the logic circuit may use payload imaging system141to capture images of a scene in the environment. The logic circuit may control gimbal system123to selectively orient payload imaging system141to capture the scene in the environment. For example, the scene may include targets or other objects of interest. In some embodiments, instructions for directing the payload imaging system141to capture certain images may be received from the base station130ofFIG.1. It will be appreciated that variable navigation imaging systems140aand140bmay be used primarily for navigation purposes and especially during aggressive maneuvers of mobile platform110while payload imaging system141may generally be used for surveying an environment and gathering sensor data related to the environment.

Where applicable, various embodiments provided by the present disclosure can be implemented using hardware, software, or combinations of hardware and software. Also, where applicable, the various hardware components and/or software components set forth herein can be combined into composite components comprising software, hardware, and/or both without departing from the spirit of the present disclosure. Where applicable, the various hardware components and/or software components set forth herein can be separated into sub-components comprising software, hardware, or both without departing from the spirit of the present disclosure. In addition, where applicable, it is contemplated that software components can be implemented as hardware components, and vice-versa.

Software in accordance with the present disclosure, such as non-transitory instructions, program code, and/or data, can be stored on one or more non-transitory machine-readable mediums. It is also contemplated that software identified herein can be implemented using one or more general purpose or specific purpose computers and/or computer systems, networked and/or otherwise. Where applicable, the ordering of various steps described herein can be changed, combined into composite steps, and/or separated into sub-steps to provide features described herein.

Embodiments described above illustrate but do not limit the invention. It should also be understood that numerous modifications and variations are possible in accordance with the principles of the present invention. Accordingly, the scope of the invention is defined only by the following claims.