Lung field segmentation is a prerequisite step for the development of a computer-aided diagnosis system for interstitial lung diseases observed in chest HRCT images. Conventional methods of lung field segmentation rely on a large gray value contrast between lung fields and surrounding tissues. These methods fail on lung HRCT images with dense and diffused pathology. An efficient prepro- cessing could improve the accuracy of segmentation of pathological lung field in HRCT images. In this paper, a convolution neural network is used for localization of lung fields in HRCT images. The proposed method provides an optimal bounding box enclosing the lung fields irrespective of the presence of diffuse pathology. The performance of the proposed algorithm is validated on 330 lung HRCT images obtained from MedGift database on ZF and VGG networks. The model achieves a mean average precision of 0.94 with ZF net and a slightly better performance giving a mean average precision of 0.95 in case of VGG net.
In this paper, we investigate the effect of the error criteria used during a training phase of the artificial neural network (ANN) on the accuracy of the classifier for classification of lung tissues affected with Interstitial Lung Diseases (ILD). Mean square error (MSE) and the cross-entropy (CE) criteria are chosen being most popular choice in state-of-the-art implementations. The classification experiment performed on the six interstitial lung disease (ILD) patterns viz. Consolidation, Emphysema, Ground Glass Opacity, Micronodules, Fibrosis and Healthy from MedGIFT database. The texture features from an arbitrary region of interest (AROI) are extracted using Gabor filter. Two different neural networks are trained with the scaled conjugate gradient back propagation algorithm with MSE and CE error criteria function respectively for weight updation. Performance is evaluated in terms of average accuracy of these classifiers using 4 fold cross-validation. Each network is trained for five times for each fold with randomly initialized weight vectors and accuracies are computed. Significant improvement in classification accuracy is observed when ANN is trained by using CE (67.27%) as error function compared to MSE (63.60%). Moreover, standard deviation of the classification accuracy for the network trained with CE (6.69) error criteria is found less as compared to network trained with MSE (10.32) criteria.
In this paper, retrieval accuracy of different types of pulmonary nodules is studied. The trainee radiologists could enrich their knowledge using the visual information of the retrieved nodules. In the proposed retrieval system, the pulmonary nodules are segmented using a semi-automated technique. Several 3D features are explored to improve the performance of the proposed retrieval system. A set of relevant shape and texture features is determined for efficient representation of the nodules in the feature space. The proposed CBIR system is validated on a data set of 542 nodules of Lung Image Database Consortium and Image Database Resource Initiative (LIDC/IDRI). The nodules with composite rank of malignancy “1”, “2” are considered as benign and “4”, “5” are considered as malignant. Considering top five retrieved images, the precision of the proposed retrieval system are 84.76%, 80.75%, and 80.34% for well-circumscribed, juxta-pleural, and juxtavascular nodules, respectively.
Presently, unplanned changes of land use have become a major problem. Most land use changes occur without a clear
and logical planning with little attention to their environmental impacts. In last four-decade, urban growth in Delhi has
occurred rapidly in some unwanted direction and destroyed valuable agriculture lands in its surround. Rapid changes in
land use / cover occurring over large areas; remote sensing technology is an essential and useful tool in monitoring of
this area. Monitoring of land use/cover change are increasingly reliant on information derived from remotely sensed data.
Such information provides the data link to other techniques to understand the human processes behind these changes.
Specially, in agricultural area in suburb (or countryside) of a metropolitan city like Delhi. In this paper different change
detection approaches (such as Post classification comparison and spectral change detection techniques) were evaluated
with available images of National Capital Territory of Delhi during 1973 to 2001. These techniques were analyzed
independently, using the concept of well-known procedures to define the best approach/methodology for addressing the
change detection issues in this study.
Aerosol presence reduces sunshine hours and the amount of radiation received.
The extent of reduction in radiation during this extreme event (January-March 1999) was
relatively lower, as the extent of the diffused radiation increases. During this time, the
reduction ranged from 5-12%. The differential response of the crops (wheat, rice and
sugarcane) under changed proportion of direct and diffused radiation due to haze was
seen through using crop simulation models (WTGROWS for wheat, DSSAT for rice and
sugarcane). The growing conditions were optimal. Regions chosen for simulation were
north-west India for wheat, coastal and southern regions for rice and north-eastern,
western and southern regions for sugarcane. Simulation results were obtained in terms of
phenology, biomass and economic yield at harvest. There was slight reduction in the yield
of these three crops due to reduction in the radiation, but coupled weather changes
(lowering of temperature, etc.) due to cloudy condition could benefit the crops through
phenology modifications and other crop process activities, which can some times give
higher yields of crops under the aerosol layer when compared to no haze layer situation.
Diffused radiation is more photo-synthetically active, and this feature has still to be
included in most of the existing crop growth models, as the existing crop models do not
differentiate between direct and diffused radiation. The scope of using remote sensing for
assessing the haze layer (spatial and temporal extent) could be employed in the crop
simulation models for regional impact analysis.
Directional reflectance measurement has been found to be better and more reliable compared to the conventional statistical approach to retrieve plant biophysical parameters as it takes care of its anisotropic nature. Keeping this in view, a field experiment was conducted with the objectives set as (i) to relate canopy biophysical parameters and geometry to its bidirectional reflectance, (ii) to evaluate a canopy reflectance model to best represent the radiative transfer within the canopy for its inversion and (iii) to retrieve crop biophysical parameters through inversion of the model. Two varieties of the mustard crop (Brassica juncea L) were grown with two nitrogen treatments to generate a wide range of Leaf Area Index (LAI) and biomass. The reflectance data obtained at 5nm interval for a range of 400- 1100nm were integrated to IRS LISS -II sensor's four band values using Newton Cotes Integration technique. Biophysical parameters were estimated synchronizing with the bi-directional reflectance measurements. The radiative transfer model PROSAIL was used for its evaluation and to retrieve biophysical parameters mainly LAI and Average Leaf Angle (ALA) through its inversion. Look Up Table (LUT) of BRDF was prepared simulating through PROSAIL model varying only LAI (0.2 interval from 1.2 to 5.4 ) and ALA (5° interval from 40 to 55°) parameters and inversion was done using a merit function and numerical optimization technique given by Press et al., 1986. The derived LAI and ALA values from inversion were well matched with observed one with RMSE 0.521 and 5.57, respectively.
Wheat is an important food crop of the country. Its productivity lies in a very wide
range due to diverse bio-physical and socio-economic conditions in the growing regions.
Crop cutting and sample surveys are time consuming as well tedious, and procedure of
forecast is delayed. CAPE methodology, which uses remote sensing, ground truth and
prevailing weather, has been very successful, but empirical in nature. In a joint IARI-SAC
Research Programme, possibility of linking the dynamic wheat growth model with the
remote sensing input and other relational database layers was tried. Use of WTGROWS, a
wheat growth model developed at IARI, with the remote sensing and relational databases
is dynamic and can be updated whenever weather, acreage and fertilizer and other inputs
are received. National wheat yield forecast was done for three seasons on meteorological
sub-division scale by using WTGROWS, relational database layers and satellite image.
WTGROWS was run for historic weather dataset (last 25 years), with the relational
database inputs through their associated growth rates and compared with the productivity
trends of the met-subdivision. Calibration factor, for each met-subdivision, were obtained
to capture the other biotic and abiotic stresses and subsequently used to bring down the
yields at each sub-division to realistic scale. The satellite image was used to compute the
acreage with wheat in each sub-division. Meteorological data for each-subdivision was
obtained from IMD (weekly basis). WTGROWS was run with actual weather data obtained upto a given time, and weather normals use for subsequent period, and the forecast was
prepared. This was updated on weekly basis, and the methodology could forecast the
wheat yield well in advance with a great accuracy. This procedure shows the pathway for
Crop Growth Monitoring System (CGMS) for the country, to be used for land use planning
and agri-production estimates, which although looks difficult for diverse agro-ecologies and
wide range of bio-physical and socio-economic characters contributing to differential
productivity trends.
A study was undertaken to validate the Wheat Growth Simulator (WTGROWS) in the farmers' fields of Alipur Block of Delhi and linking satellite derived vegetation index with the simulation model to estimate the wheat yield. Date of sowing, management practices and cultivars varied widely among the study sites. Leaf area index (LAI), phenological development and agronomic management (fertilizers and irrigation) were monitored at regular intervals for the 25 field sites selected in the study area. Above ground biomass and grain yield were recorded at harvest. Using the parameters derived for these sites, WTGROWS was run for each of the individual 25 sites. Crop phenology, temporal course of LAI and grain yield of each site was compared with the actual observations. The simulated and actual LAI temporal profile matched well for sites with different dates of sowing, excepting larger deviation noticed in the later stages of the crop growth. The simulated pre-anthesis duration and total above ground biomass were also correlated well with the observed values being mostly within ±15%. There were large discrepancies in simulated and observed grain yield. A satellite image near anthesis of IRS 1D LISS-3 was acquired for the study area. The sites were identified on the image and their vegetation indices were derived. Average grey value in Infrared (IR) and Red (R) band, Ratio Vegetation Index (RVI), Soil Adjusted Vegetation Index (SAVI) and Normalized Difference Vegetation Index (NDVI) were giving significant relation with measured LAI of 5th February which corresponded to crop anthesis stage. The relation between vegetation indices and LAI was logarithmic in nature. This logarithmic relation was incorporated into the WTGROWS to force the LAI to the equation-derived value at particular growth stage and model yield was computed and compared with actual observations.
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