Abstract: A method of gas detection comprises emitting radiation of different wavelengths across the absorption spectrum of a gas towards a target area; and analysing the spectrum of returned radiation from the target area to identify the gas in the target area using the time correlation of the emitted radiation and the returning radiation. The radiation is modulated using respective modulation codes for the different wavelengths and the modulation codes are modified by the insertion of a gap between each bit of the modulation code, the gap having a duration of at least n?1 bits where n is the number of different wavelengths.

Abstract: A method of identifying substances, such as atmospheric and greenhouse gases, comprises emitting modulated radiation of different wavelengths towards a target area, wherein the radiation is modulated using respective modulation codes for a predetermined number n of wavelength bands that correspond to a range across an absorption spectrum for the substance, and analyzing the spectrum of radiation from the target area to identify the gas in the target area. The spectrum is analyzed using a time correlation of the emitted modulated radiation and the detected radiation. The radiation is modulated using respective modulation codes for the different wavelengths, and the modulation codes may be modified by insertion of a gap between each bit of the modulation code, the gap having a duration of at least n-1 bits.

Abstract: A method of operating an optical device, comprising: tuning a diode laser wavelength spectrum corresponding to at least a first spectral feature associated with an absorption spectrum of a gas; modulating output radiation of the diode laser; transmitting the modulated output radiation of the diode laser through optical guide elements in a scan towards a first target area; receiving scattered diode laser radiation from the first target area and directing it to a detector; correlating the received scattered diode laser radiation with the transmitted first output radiation to create one or more correlated data sets; and forming an area scan of locations in the first target area to determine concentration of the gas between the optical device and the locations, wherein multiple correlated data sets corresponding to fixed spatial points are used for determining concentration of the gas for each of the locations.

Abstract: A method of gas detection comprises emitting radiation of different wavelengths across the absorption spectrum of a gas towards a target area; and analysing the spectrum of returned radiation from the target area to identify the gas in the target area using the time correlation of the emitted radiation and the returning radiation. The radiation is modulated using respective modulation codes for the different wavelengths and the modulation codes are modified by the insertion of a gap between each bit of the modulation code, the gap having a duration of at least n?1 bits where n is the number of different wavelengths.

Abstract: Methods and systems for detecting and measuring gas flow are disclosed in which lidar distance information, acquired during the detection of gas using a lidar sensor, is used together with local wind data to determine a rate of flow for the detected gas. The local wind data, which may comprise one or more vectors or a 3D wind model, may be determined based on prevailing wind data and the lidar distance information, and can use computational fluid dynamics (CFD) models to determine the wind velocity through 3D structures identified using the lidar sensor. The detection of gas flow using the disclosed technology may be particularly useful for the remote detection and quantification of leaks from natural gas (methane) wells and pipelines to locate, quantify and map fugitive emissions.

Abstract: A method of gas detection comprises emitting radiation of different wavelengths across the absorption spectrum of a gas towards a target area; and analysing the spectrum of returned laser light from the target area to identify the gas in the target area using the time correlation of the emitted radiation and the returning radiation. The radiation is modulated using respective orthogonal modulation codes for the different wavelengths and the modulation codes are modified by the insertion of a gap between each bit of the modulation code, the gap having a duration of at least n-1 bits where n is the number of different wavelengths.

Abstract: Embodiments of the present disclosure disclose a method and system for displaying x-ray image, an x-ray machine, and a storage medium. The method includes: obtaining a captured current image of a target region; determining at least one to-be-optimized region in the current image; and for each to-be-optimized region, obtaining a maximum grayscale value and a minimum grayscale value in the to-be-optimized region, determining a window width and a window level for the to- be-optimized region according to the maximum grayscale value and the minimum grayscale value, and displaying the current image based on the window width and the window level. The technical solutions in the embodiments of the present disclosure can improve image display resolution of a current to-be-optimized region.

Abstract: A method of operating an optical device, the method comprising tuning a first emission wavelength of a first output radiation of a laser device continuously within a first wavelength spectrum by modulating a drive current thereof with a first drive current modulation having a frequency of at least 100 KHz. The first wavelength spectrum comprises a first spectral feature associated with at least part of a gas absorption spectrum of at least one gas. The method comprises the steps of modulating the first output radiation of the laser device with a first output modulation, the first output modulation comprising a first plurality of binary pulses, scanning the first wavelength spectrum at a rate of at least 1 ?m per second, projecting the first output radiation towards a first target area, receiving scattered radiation from the first target area, and processing the scattered radiation.

Abstract: Methods and apparatus for detecting and measuring gas flow are disclosed in which lidar distance information, acquired during the detection of gas using a lidar sensor, is used together with prevailing wind data to determine local wind data for the leak location. This local wind data, which may comprise one or more vectors or a 3D wind model, is used in the determination of flow rate.

Abstract: A method of operating an optical device, the method comprising tuning a first emission wavelength of a first output radiation of a laser device continuously within a first wavelength spectrum by modulating a drive current thereof with a first drive current modulation having a frequency of at least 100 kHz. The first wavelength spectrum comprises a first spectral feature associated with at least part of a gas absorption spectrum of at least one gas. The method comprises the steps of modulating the first output radiation of the laser device with a first output modulation, the first output modulation comprising a first plurality of binary pulses, scanning the first wavelength spectrum at a rate of at least 1 ?m per second, projecting the first output radiation towards a first target area, receiving scattered radiation from the first target area, and processing the scattered radiation.

Abstract: Techniques are disclosed for acquiring a captured target image of a target region. When it is determined that there is at least one to-be-optimized region of a bright region and/or a dark region in the target image, calculating, for each to-be-optimized region, a pixel average of the to-be-optimized region in the target image, and determining a to-be-optimized region received dose corresponding to the pixel average of the to-be-optimized region; adjusting an X-ray emission dose of an X-ray source according to a principle of making the to-be-optimized region received dose reach an X-ray reference received dose, and acquiring optimized images of the target region captured based on the X-ray emission dose adjusted to meet a requirement; and adding and synthesizing the optimized images, or adding and synthesizing the optimized images and the target image, to obtain an X-ray image of the target region.

Abstract: A method of operating an optical device, the method comprising tuning a first emission wavelength of a first output radiation of a laser device continuously within a first wavelength spectrum by modulating a drive current thereof with a first drive current modulation having a frequency of at least 100 KHz. The first wavelength spectrum comprises a first spectral feature associated with at least part of a gas absorption spectrum of at least one gas. The method comprises the steps of modulating the first output radiation of the laser device with a first output modulation, the first output modulation comprising a first plurality of binary pulses, scanning the first wavelength spectrum at a rate of at least 1 ?m per second, projecting the first output radiation towards a first target area, receiving scattered radiation from the first target area, and processing the scattered radiation.

Abstract: Methods and apparatus for detecting and measuring gas flow are disclosed in which lidar distance information, acquired during the detection of gas using a lidar sensor, is used together with prevailing wind data to determine local wind data for the leak location. This local wind data, which may comprise one or more vectors or a 3D wind model, is used in the determination of flow rate.

Abstract: A method of measuring the concentration of a gas in a target environment using a laser lidar system, comprises directing a laser beam towards an environment containing the gas, tuning the laser wavelength over a wavelength range including the absorption line of the gas, and measuring intensity of laser light returned from the environment containing the gas, as a result of scattering as a function of time. The intensity vs time is then converted into gas absorption vs wavelength, and the gas absorption vs wavelength is used to determine the concentration of the gas in the target environment.

Abstract: A lidar system for detection of a gas comprises an optical transceiver for transmitting and receiving optical radiation. A method of operating the system comprises performing spatially scanned sensing measurements of the gas across a system field of view, and analyzing the sensing measurements to determine the presence and location of excess of the gas in the system field of view. Based on the determined location, an adjusted system field of view is determined and spatially scanned sensing measurements of the gas are performed across the adjusted system field of view to obtain sensing measurements at higher spatial resolution.

Abstract: A lidar system for detection of a gas comprises an optical transceiver for transmitting and receiving optical radiation. A method of operating the system comprises performing spatially scanned sensing measurements of the gas across a system field of view, and analyzing the sensing measurements to determine the presence and location of excess of the gas in the system field of view. Based on the determined location, an adjusted system field of view is determined and spatially scanned sensing measurements of the gas are performed across the adjusted system field of view to obtain sensing measurements at higher spatial resolution.

Abstract: A lidar system for detection of a gas comprises an optical transceiver for transmitting and receiving optical radiation. A method of operating the system comprises performing spatially scanned sensing measurements of the gas across a system field of view, and analyzing the sensing measurements to determine the presence and location of excess of the gas in the system field of view. Based on the determined location, an adjusted system field of view is determined and spatially scanned sensing measurements of the gas are performed across the adjusted system field of view to obtain sensing measurements at higher spatial resolution.

Abstract: A method of measuring the concentration of a gas in a target environment using a laser lidar system, comprises directing a laser beam towards an environment containing the gas, tuning the laser wavelength over a wavelength range including the absorption line of the gas, and measuring intensity of laser light returned from the environment containing the gas, as a result of scattering as a function of time. The intensity vs time is then converted into gas absorption vs wavelength, and the gas absorption vs wavelength is used to determine the concentration of the gas in the target environment.

Abstract: A method of measuring the concentration of a gas in a target environment using a laser lidar system, comprises directing a laser beam towards an environment containing the gas, tuning the laser wavelength over a wavelength range including the absorption line of the gas, and measuring intensity of laser light returned from the environment containing the gas, as a result of scattering as a function of time.

Abstract: An optical assembly for a laser projection and return laser light detection device comprises a housing; a first series of components arranged in the housing to define an exit path for laser radiation entering from a laser source and then exiting from the housing; a second series of components arranged in the housing to define a return path for scattered returns of the laser radiation entering the housing and passing to a detector; a polarising beam splitter/combiner common to the exit path and the return path arranged to polarise laser light exiting from the housing and to separate scattered laser light returned to the assembly, that is orthogonally polarised to the exiting laser radiation. The polarising beam splitter/combiner forms a window to the housing.