Abstract: Clouds in a satellite image are replaced with a prediction of what was occluded by those clouds. The cloudy portion of the image is interpolated from a series of satellite images taken over time, some of which are cloud-free in the target image's cloudy portion. In some configurations, clouds are removed taking into account each pixel's availability—a measure of certainty that a pixel is cloud-free. Furthermore, these images may have been taken under different amounts of illumination, making it difficult to determine whether a difference between two images is due to a change in illumination or a change to the location. The effect of illumination on each image is removed before interpolating the cloudy portion of the image. In some configurations, removing the effect of illumination also takes into account pixel availability.

Abstract: Systems and methods for authoring workflows for processing data from a large-scale dataset include defining a metadata schema for the large-scale dataset, and receiving user input defining a workflow as a plurality of operations to be performed on the data. Each of the operations includes input metadata formatted according to the metadata schema. The input metadata describes input data to be processed by the operation and identifying a location for the input data in the data storage system, programmed instructions for performing an atomic operation on the input data to generate output data; and output metadata formatted according to the metadata schema. The output metadata describes the output data and identifying a location for the output data in the data storage system.

Abstract: A computing system measures terrain coverage by: obtaining sample image data representing a multispectral image of a geographic region at a sample resolution; generating, based on the sample image data, an index array of pixels for a subject terrain in which each pixel has an index value that represents a predefined relationship between a first wavelength reflectance and a second wavelength reflectance; providing the index array to a trained calibration model to generate an estimated value based on the index array, the estimated value representing an estimated amount of terrain coverage within the geographic region for the subject terrain; and outputting the estimated value for the subject terrain. The trained calibration model may be trained based on training data representing one or more reference images of one or more training geographic regions containing the subject terrain at a higher resolution than the sample resolution.

Abstract: Techniques for optically detecting a subject chemical species within an atmospheric environment are disclosed. Image data is obtained representing multispectral imagery of a geographic region captured through the atmospheric environment. The image data includes an array of band-specific intensity values for each of a plurality of spectral bands, including a sample spectral band having increased sensitivity to the subject chemical species as compared to a plurality of reference spectral bands. A background reflectance map is generated that includes an array of inter-band intensity values in which each inter-band intensity value represents a filtered combination of band-specific intensity values of albedo-normalized arrays for a grouped subset of the plurality of reference spectral bands. The albedo-normalized array of band-specific intensity values for the sample spectral band is compared to the background reflectance map to obtain an index array of intensity variance values for the subject chemical species.

Abstract: A method for source attribution comprises receiving measurements of a chemical species at a spatially distributed sensor array for a given set of spatially positioned emission sources in a physical environment using a dispersion model. Based on the received measurements, a concentration field is mapped from the emission sources to the sensor array using a forward operator. For each emission source, a likelihood data set is evaluated at least by fitting an emission rate of the chemical species using a regression model based on the mapped concentration field and real-world, runtime measurements from the sensor array. A posterior data set is evaluated based at least on the evaluated likelihood data set and historical data for the physical environment. For each sensor of the sensor array, estimated emission rates and contribution rankings for emission sources are determined and output based on the evaluation of the posterior data set.

Abstract: A method for pollutant sensor placement for pollutants from point sources is described. Data about environmental characteristics for a geographic region are received from a plurality of environmental sensors. The geographic region includes pollutant sources that emit a pollutant. The received data from one or more of the plurality of environmental sensors are transformed into common data having a common spatial and temporal discretization across the geographic region. Predicted emission plumes are generated for the pollutant sources within the geographic region that identify pollutant detection regions for the pollutant when the pollutant is emitted by the pollutant sources using the common data. Sensor locations for a plurality of pollutant sensors are greedily selected across the common spatial and temporal discretization according to a number of predicted emission plumes that are detectable by the plurality of pollutant sensors.

Abstract: A method for pollutant sensor placement is described. Data about environmental characteristics across a geographic region is received from a plurality of environmental sensors. The geographic region includes one or more pollutant sources that emit a pollutant. The received data is transformed from one or more of the plurality of environmental sensors into common data having a common grid across the geographic region. The geographic region is divided into a plurality of sub-regions based on the common data. Locations within the geographic region are determined for placement of pollutant sensors based on estimated dispersion of the pollutant through the plurality of sub-regions.

Abstract: An example system for detecting mud pump stroke information comprises a distributed acoustic sensing (DAS) data collection system coupled to a downhole drilling system, a stroke detector coupled to a mud pump of the downhole drilling system configured to detect strokes in the mud pump and to generate mud pump stroke information based on the detected strokes, and a fiber disturber coupled to the stroke detector and to optical fiber of the DAS data collection system configured to disturb the optical fiber based on mud pump stroke information generated by the stroke detector. The system further comprises a computing system comprising a processor, memory, and a pulse detection module operable to transmit optical signals into the optical fiber of the DAS data collection system, receive DAS data signals in response to the transmitted optical signals, and detect mud pump stroke information in the received DAS data signals.

Abstract: A method of monitoring a substance in a well can include disposing at least one optical electromagnetic sensor and at least one electromagnetic transmitter in the well, and inducing strain in the sensor, the strain being indicative of an electromagnetic parameter of the substance in an annulus between a casing and a wellbore of the well. A system for monitoring a substance in a well can include at least one electromagnetic transmitter, and at least one optical electromagnetic sensor with an optical waveguide extending along a wellbore to a remote location, the sensor being positioned external to a casing in the wellbore.

Abstract: Disclosed in some examples are real-time video classifier systems, methods, devices, and machine readable mediums that determine whether or not to submit a current video frame to a classifier based upon a similarity score that measures a similarity between the current video frame and previous video frames found by the classifier to contain the feature of interest. For example, a similarity score may be calculated for a current video frame and a previous video frame found by the classifier to contain a feature of interest. The current video frame may be submitted to the classifier only if the similarity score is below a threshold similarity score. That is, only video frames that are sufficiently different from previous images that were found as containing the feature of interest are presented to the classifier.

Abstract: An example method includes providing source light to an optical fiber deployed in a downhole environment, receiving backscattered light from the optical fiber, and producing one or more optical interferometry signals from the backscattered light. The method also includes converting each of the one or more optical interferometry signals to an electrical signal and digitizing each electrical signal to obtain one or more digitized electrical signals. The method also includes deriving acoustic activity values as a function of time and position from the one or more digitized electrical signal. The method also includes applying at least some of the acoustic activity values to a flow prediction model to obtain a predicted fluid flow as a function of time, wherein the flow prediction model includes a proppant compensation value or factor. The method also includes storing or displaying the predicted fluid flow.

Abstract: A system includes an optical fiber and an interrogator to provide source light to the optical fiber. The system also includes a receiver coupled to the optical fiber. The receiver includes at least one fiber optic coupler that receives backscattered light and that produces one or more optical interferometry signals from the backscattered light. The receiver also includes photo-detectors that produce an electrical signal for each of the one or more optical interferometry signals. The system also includes at least one digitizer that digitizes each electrical signal. The system also includes at least one processing unit that processes each digitized electrical signal to obtain a distributed sensing signal and related energy spectrum information.

Abstract: Disclosed in some examples are real-time video classifier systems, methods, devices, and machine readable mediums that determine whether or not to submit a current video frame to a classifier based upon a similarity score that measures a similarity between the current video frame and previous video frames found by the classifier to contain the feature of interest. For example, a similarity score may be calculated for a current video frame and a previous video frame found by the classifier to contain a feature of interest. The current video frame may be submitted to the classifier only if the similarity score is below a threshold similarity score. That is, only video frames that are sufficiently different from previous images that were found as containing the feature of interest are presented to the classifier.

Abstract: A method and device for monitoring oil field operations with a fiber optic distributed acoustic sensor (DAS) that uses a continuous-wave fiber optic distributed acoustic sensor with a very small spatial sampling while being able to sense acoustic events that have a large bandwidth by employing a demodulation/decoding method utilizing multiple spread-spectrum codes.

Abstract: An example system for detecting mud pump stroke information comprises a distributed acoustic sensing (DAS) data collection system coupled to a downhole drilling system, a stroke detector coupled to a mud pump of the downhole drilling system configured to detect strokes in the mud pump and to generate mud pump stroke information based on the detected strokes, and a fiber disturber coupled to the stroke detector and to optical fiber of the DAS data collection system configured to disturb the optical fiber based on mud pump stroke information generated by the stroke detector. The system further comprises a computing system comprising a processor, memory, and a pulse detection module operable to transmit optical signals into the optical fiber of the DAS data collection system, receive DAS data signals in response to the transmitted optical signals, and detect mud pump stroke information in the received DAS data signals.

Abstract: A system includes an optical fiber and an interrogator to provide source light to the optical fiber. The system also includes a receiver coupled to the optical fiber. The receiver includes at least one fiber optic coupler that receives backscattered light and that produces optical interferometry signals from the backscattered light. The receiver also includes photo-detectors that produce an electrical signal for each of said optical interferometry signals. The system also includes at least one digitizer that digitizes the electrical signals. The system also includes at least one processing unit that calculates I/Q data from the digitized electrical signals, corrects the I/Q data based on ellipse fitting, determines phase values based on the corrected I/Q data, and determines distributed sensing parameter values based on the phase values.

Abstract: A method may include transmitting a narrowband signal into a formation using a transmitter located in a wellbore. The narrowband signal is modified by passage of through the formation and the formation reflects at least a portion of the narrowband signal back to the wellbore resulting in a modified narrowband signal having a first frequency. The method also includes sensing the modified narrowband signal with an optical waveguide positioned in the wellbore, transmitting a source signal along a length of the optical waveguide, and obtaining a backscattered return signal from the optical waveguide. The backscattered return signal is sampled at a second frequency that is less than the Nyquist rate of the modified narrowband signal. The method further includes processing the backscattered return signal to obtain an amplitude of the modified narrowband signal.

Abstract: Methods and systems are presented in this disclosure for fluid flow metering with point sensing. A transducer (acoustic sensor) located at a point externally along a pipe (e.g., deployed in a wellbore) can transform a mechanical energy of a fluid flow in the pipe into an acoustic signal, which is then acquired and digitized to obtain a digital signal. The acquired digital signal related to the fluid flow can be processed by applying various advance signal processing techniques in order to remove sharp and/or broadband resonances due to a turbulent fluid flow to determine energy associated with the fluid flow. A rate of the fluid flow can be then estimated by mapping the determined energy to a fluid flow rate.

Abstract: A method may include transmitting a narrowband signal into a formation using a transmitter located in a wellbore. The narrowband signal is modified by passage of through the formation and the formation reflects at least a portion of the narrowband signal back to the wellbore resulting in a modified narrowband signal having a first frequency. The method also includes sensing the modified narrowband signal with an optical waveguide positioned in the wellbore, transmitting a source signal along a length of the optical waveguide, and obtaining a backscattered return signal from the optical waveguide. The backscattered return signal is sampled at a second frequency that is less than the Nyquist rate of the modified narrowband signal. The method further includes processing the backscattered return signal to obtain an amplitude of the modified narrowband signal.

Abstract: A method and device for monitoring oil field operations with a fiber optic distributed acoustic sensor (DAS) that uses a continuous wave laser light source and modulates the continuous wave output of the laser light source with pseudo-random binary sequence codes.