121 results about "Radiometric correction" patented technology

The invention relates to a system and method for carrying out automatic detection on small burning spots of forest or grassland fires by using the infrared (IRS) data of an environmental minisatellite HJ. The method comprises the following steps: radiometric correction, brightness temperature calculation, reflectivity calculation, cloud and water recognition, potential burning spot determination,absolute burning spot determination, background characteristic analysis, relative burning spot determination, burning spot confidence, and detecting burning spot output. According to the scheme provided by the invention, based on the characteristics of the environmental minisatellite HJ, the automatic detection on forest or grassland fires can be realized only by using the infrared (IRS) data, thereby enhancing the disaster prevention and reduction capacities of domestically-produced satellites in China, and promoting the industrialized application process of domestically-produced satellites.

The invention provides a forest aboveground biomass inversion method fused with spectrum and texture features and a forest aboveground biomass inversion system fused with the spectrum and texture features. The method comprises the following steps of calculating an aboveground biomass of a research region sample plot so as to obtain a sample plot biomass observation value; performing geometric correction and radiometric correction on high-resolution remote-sensing image panchromatic data and multispectral data; respectively performing statistical regression on the sample plot biomass observation value and a corresponding spectrum feature vegetation index, and selecting a spectrum feature inversion model; extracting various texture feature variables under different windows, respectively performing statistical regression on the sample plot biomass observation value and the corresponding texture feature variables, and selecting a texture feature inversion model; determining a weight through a sensitivity analysis of a spectrum key factor and a texture key factor, constructing a spectrum texture feature combination inversion model of the biomass, and realizing the forest aboveground biomass inversion. The method and the system provided by the invention have the advantages that the spectrum features and the texture features are fused, and the advantages of the spectrum features and the texture features for biomass inversion are fully exerted, so that the quantitative inversion precision of a forest aboveground biomass is effectively improved.

The invention relates to a polarization SAR (Synthetic Aperture Radar) terrain radiation correction and geometric correction method based on imaging surface representation. According to the method, the radiation value of the imaging surface of an SAR image is taken as the representation of a backscattering coefficient. The method comprises the following steps of 1, obtaining the SAR image and a radiation calibration file external DEM (Dynamic Effect Model) in a region; 2, performing radiation calibration according to a radiation calibration file of the original polarization SAR image; 3, calculating the unit area of the external DEM; 4, generating an SAR image line and column number lookup table according to a distance Doppler SAR positioning model and calculating the projection area of an equiphase surface; 5, generating an SAR simulation image by combining the projection area of the equiphase surface with the line and column number lookup table; 6, matching a real SAR image with the simulation SAR image, building a polynomial correction equation, and refining the line and column number lookup table; 7, carrying out terrain radiation correction on the polarization SAR image according to the backscattering coefficient expression based on the imaging surface of the SAR image; 8, carrying out geometric correction according to the refined line and column number lookup table. According to the scheme provided by the invention, the radiation distortion of the polarization SAR image, caused by terrain can be corrected, and the high-precision geometric positioning and correction of the polarization SAR image are realized.

The invention discloses a lake water body blue-green algae abundance estimation method based on remote sensing. The method comprises the following steps: carrying out high-spectrum remote sensing measurement on a lake water body by utilizing the concentration ratio of phycocyanin and chlorophyll to represent the blue-green algae abundance, selecting the ratio of remote sensing reflective rates of the two specific wave lengths and a function thereof as characteristics of blue-green algae, establishing an estimation model of the lake water body blue-green algae abundance, and estimating the lake water body blue-green algae abundance based on remote sensing. The method provided by the invention adopts a surface feature spectrograph or an onboard high-spectrum imager to carry out high-spectrum remote sensing on the lake water body, and the remote sensing reflective rate required for estimation can be obtained through performing radiation correction and atmospheric correction on aviation satellite high-spectrum data. The method provided by the invention has the advantages that the accuracy is high, the model is simple, the remote sensing reflective rates of the two wave lengths are selected, not only can the estimation on the water body blue-green algae abundance measured by the surface feature spectrograph be realized, but also the estimation on the blue-green algae abundance by virtue of aviation high-spectrum remote-sensing images is realized.

The invention discloses a dynamic compensation method for attitude angle errors of an optical remote sensing satellite based on ground navigation. The dynamic compensation method includes the following steps: (1) performing effectiveness processing on ephemeris data and attitude data downloaded from the satellite, namely eliminating outliers points in the data and re-determining the values of the points; (2) determining an extracting range of control points on a first level image which is an image corrected by radiation, determining an extracting range of control points on a reference image according to the extracting range on the first level image and data after processing in the step (1), intercepting the extracting ranges on the first level image and the reference image respectively, and generating one sub-image of the first level image which is an image subjected to radiometric correction and one sub-image of the reference image which is an orthoimage; (3) performing automatic pairing of the control points by adopting intercepted the sub-images of the first level image and the reference image, and eliminating mispairing points; (4) selecting at least 3 pairs of homonymy control points with different sequence orders and smallest Euclidean distances apart from a scenario center from the sub-images of the first level image and the reference image, and calculating attitude angle errors; and (5) performing compensation on an attitude angle of the optical remote sensing satellite by adopting determined attitude angle errors.

The present invention relates to a method for estimating PM2.5 and PM10 by use of satellite multispectral image data, and the method comprises geometric correction of satellite images, radiometric correction of the satellite images, preprocessing dark pixel selection of remote sensing data, angle information calculation, estimation of aerosol optical thickness, and estimation of the PM2.5 and the PM10. Compared with crowd sourcing data, the relationship between the aerosol optical thickness of each dark pixel and near ground air observation indexes is established, and the PM2.5 and the PM10 are estimated. The method can achieve large-scale, stable and fine PM2.5 and PM10 estimation, and meets the requirements of application of satellite remote sensing technology in wide range environmental monitoring especially in air quality evaluation.

The present inventors have developed a ground station that, when installed in a field, can collect upwelling and downwelling radiation, and GPS location coordinates, Data from remotely sensed imagery (RSI) can he used to monitor crop health. Use of the ground station can obviate the need for personnel to he deployed into the field during drone overflights for management of agriculture.

The invention discloses a method for detecting the urban region change based on multi-temporal SAR (synthetic aperture radar) images. The method comprises the following steps: firstly, collecting two multi-temporal SAR images of the same region at different periods, and correcting the SAR images by geometric correction and radiometric correction; and secondarily, processing the two corrected multi-temporal SAR images of the same region at different periods to obtain the change detection result. The detection method is simple, practical, and easy to realize, and is proposed special for the application of urban remote sensing images. The method has the unique advantage on image representation when being used for detecting the time-space change of urban regions with complex structural characteristics.

The invention discloses a snapshot type high spectral remote sensing system with a drone and a consistency radiation correction method, and belongs to the technical field of drone low-altitude remote sensing technology. The system comprises the drone, a consistency radiation correction subsystem, a self-stabilized holder and a high spectral image acquisition device, wherein the self-stabilized holder and the high spectral image acquisition device carried by the drone. The high spectral image acquisition device comprises a snapshot type full-width imaging high spectral camera carried by the self-stabilized holder. The consistency radiation correction subsystem comprises a radiation correction target, an illuminance meter and a GPS, wherein the illuminance meter and the GPS are carried by the drone. The system is fast in imaging speed, high in quality and capable of achieving consistency correction of high spectral images in changeable weather.

The present disclosure provides for a correction filter that may be configured to comprise a predetermined arrangement of thin film layers. This arrangement of thin film layers may be such that it effectively enables a correction filter to generate a predetermined spectral response, wherein said predetermined spectral response is substantially the same as a determined instrument response correction associated with an instrument. The invention of the present disclosure therefore provides for effectively compensating for transmission inefficiencies associated with an instrument without the need for separate reference measurements to determine and correct for instrument response.

A system and method for generating radiometrically corrected surface images is provided. This includes providing one or more surface images of a first resolution of a surface area in the form of digital images which has a surface image sensor measurement of an intensity value of radiation in a given wavelength band reflected from the surface for each pixel of the images. A reference image of a second resolution of a corresponding surface area is provided to the surface of the surface image. The reference image has a surface reflectance for each pixel of the reference image for an equivalent wavelength band to the given wavelength band of the surface image. A functional relationship is modelled which relates the surface image sensor measurement for pixels of a surface image to the surface reflectance for pixels of the reference image to provide an estimated surface reflectance for each pixel of the surface images.

The invention provides a satellite image relative radiation correction method and device. The method comprises the steps: obtaining a to-be-corrected satellite image which comprises a plurality of image regions, and enabling one pixel in each image region to correspond to one satellite probe element; establishing a histogram lookup table, determining a relative radiation calibration coefficient, and performing relative radiation correction on the satellite image according to the relative radiation calibration coefficient; performing line loss processing on the satellite image after relative radiation correction; carrying out local stripe processing on the satellite image after line loss processing, and supplementing the lost image; de-overlapping and de-chromatic aberration are carried outon the satellite image after local strip processing, so that the overall radiation of the satellite image is consistent. In this way, effective relative radiation correction can be carried out on satellite images, and the stripe or strip radiation difference phenomenon of the satellite images and the chromatic aberration between the satellite images are eliminated.

The invention discloses a glacier area change monitoring method based on remote sensing image fusion. The method comprises the steps of (1) carrying out geometric correction and radiometric correction on homologous LANDSAT images of two periods, carrying out IHS decomposition on images of different periods, obtaining the brightness, hue, saturation components of the images, (2) through substituting the hue components to obtain a fusion image such that a glacier change area is highlighted, and (3) using a decision tree classification method to extract a glacier area change area. According to the method, homologous remote sensing images are used to monitor a glacier change, the information of the glacier change area is enhanced, the method has the advantages of a small amount of calculation, high monitoring efficiency and easy implementation, a new measure is provided for monitoring the glacier change, and a result is visual and clear.

The invention discloses a relative radiation correction method of a remote-sensing image. The method include steps: performing high and low frequency separation on a to-be-corrected image, performingrelative radiation correction on a low frequency portion, calculating a correction coefficient through linear regression of invariant feature points in the low frequency, protecting high frequency information containing the feature change reserved in the low frequency, and finding invariant feature points in the low frequency portion of the to-be-corrected image and a low frequency portion of a reference image by employing an adaptive threshold through an IR-MAD algorithm. According to the method, wavelet transformation and a multivariate alteration detection method are adopted, the problem ofrelative radiation correction is solved from high and low frequency separation and selection of the invariant feature points, the high frequency information containing the feature change reserved inthe low frequency is protected, and a radiation correction result is in favor of multi-temporal image analysis including change detection.

This invention discloses a practical method for landslide detection in large space, which comprises the following steps: image synthesis, ice and snow detection, removal of non-potential landslide area, detection of potential landslide area, feature calculation, landslide detection model construction and precision validation; this invention avoids radiometric correction and outlier by detecting landslide from synthetic image. That guarantees practical applicability of the proposal. Firstly, detecting potential landslides can avoid the imbalanced sample distribution issue between background objects and landslides when training the landslide detection model. The landslide is further detected by building a random forest model based on the spectral features and textural features of potential landslide pixels in different neighboring time domains. It fully considers the changes of objects in different time domains, and lays a foundation for efficient landslide extraction. This model is relatively reliable and practical for automatically detecting landslide from large-scale images.

In an optical system, a color filter mosaic can determine first color pixel locations, second color pixel locations, and third color pixel locations in an array of sensor pixels. The optical system can capture overhead images, which can be subtracted to form a background-subtracted tri-color image of a reflection of sunlight from at least one ground-based curved mirror. A processor can scale color values at the first and second color pixel locations of the tri-color background-subtracted image. The processor can form a single-color background-subtracted image from the scaled color values at the first color pixel locations, the scaled color values at the second color pixel locations, and third color values at the third color pixel locations. The single-color background-subtracted image can correspond to a point spread function or a line spread function of the optical system.

The invention provides an infrared image relative radiation correction method based on on-orbit classified statistic, which comprises the following steps: a first step, classifying natural objects which are acquired from an on-orbit image of a satellite by means of a K-means algorithm according to a gray scale difference, thereby classifying the natural objects to a low-brightness range, an intermediate-brightness range and a high-brightness range, and acquiring turning points in segmented correction; a second step, performing histogram matching processing on the low-brightness range, and obtaining the radiation correction look-up table of the low-brightness range; a third step, performing a least square fitting processing on the intermediate-brightness range, and obtaining the radiation correction look-up table of the intermediate-brightness range; a fourth step, performing calculation on the high-brightness range by means of a linear model with a gradient of 1 and intercept of 0 for obtaining the radiation correction look-up table of the high-brightness range; and a fifth step, performing transition area processing on the turning points according to the radiation correction look-up tables after processing. The infrared image relative radiation correction method can effectively settle problems of insufficient on-satellite calibration data and matching deviation between calibration device setting and characteristic of an actual reconnaissance objective.

The invention belongs to the aviation remote sensing image preprocessing technology field and particularly relates to a system-level relative radiation correction method for aviation whisk broom multispectral scanner multi-stripe images. The method is advantaged in that on the basis of real-time relative radiation correction on a single-stripe scanning image machine, system-level relative radiation correction for the multi-stripe scanning images is carried out to eliminate change of non-uniformity among the multi-stripe images after time accumulation, and image stripe removal and image enhancement processing are further carried out to enhance the image visual interpretation effect.