Dr. Safwat H. Shakir Hanna Profile

Dr. Safwat H. Shakir Hanna

Director of TEXGED at Prairie View A&M Univ

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Publications (7)

Proceedings Article | 20 October 2005 Paper

Characteristics of AVIRIS bands measurements in agricultural crops at Blythe area, California: V. studies on alfalfa spectral data

Safwat Shakir Hanna, Michael Rethwisch

Proceedings Volume 5976, 59761R (2005) https://doi.org/10.1117/12.628161

KEYWORDS: Reflectivity, Radiometry, Agriculture, Whole body imaging, Vegetation, Spectroscopy, Binary data, Absorption, Data centers, Data acquisition

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The present study is focusing on the following main objectives that are: 1) to compare the spectral and radiometric characteristics of AVIRIS data from Alfalfa crops with the spectra measured by FieldSpecR ASD radiometer; 2) to study the impact of growth regulators that applied on alfalfa in comparison of data collected from AVIRIS seen and; 3) to build a spectral library for the alfalfa crop that exposed to growth regulators that were studied. AVIRIS data from Blythe were acquired in June 1997 to study the agricultural spectra from different crops and for identification of crops in other areas with similar environmental factors and similar spectral properties. On June 26-28, 2001 spectra were collected from Alfalfa fields using the FieldSpecR ASD spectrometer at Blythe area, California (at the 114o 33.52 W Longitude and 33o 39.76 N Latitude to Longitude 114o 33.54 W and Latitude 33 39.88 N). The alfalfa crop fields were treated with different chemicals of growth regulators. These growth regulators were AuxiGro, Apogee and Messenger. These chemicals were used in different concentrations. Environmental parameters were studied such as the soil water content (WC), pH, and organic matter (OM). The results of this study showed that there is a significant correlation between the data that were collected by AVIRIS image scene in 1997 and spectral data collected by the FieldSpec spectrometer in the same places that were scanned by AVIRIS. This correlation allowed us to build a spectral library to be used in ENVI-IDL software. Furthermore, using IDL algorithms of Spectral Angle Mapper classification (SAM), Spectral Feature Fitting (SFF) and Spectral Binary Encoding (SPE) showed an excellent agreement between the traced spectra from the AVIRIS image and the spectral radiometer data collected from the alfalfa crops treated with growth regulators (i.e. the correlation is between 75 - 94% match). Three widely used vegetation indices such as NDVI, WBI, and PRI, showed that there are significant correlations between WBI and NDVI (r²= 0.44 - 0.88 for alfalfa crops treated by growth regulators. Further use of the AVIRIS images can be of a value to crops identification or crops yield for commercial use.

Proceedings Article | 24 February 2004 Paper

Characteristics of AVIRIS band measurements in agricultural crops at Blythe Area, California: IV. Studies on cotton varieties spectral data

Safwat Shakir Hanna, Michael Rethwisch

Proceedings Volume 5232, (2004) https://doi.org/10.1117/12.512387

KEYWORDS: Reflectivity, Radiometry, Agriculture, Vegetation, Whole body imaging, Spectroscopy, Absorption, Soil science, Visible radiation, Sensors

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AVIRIS data from Blythe were acquired in June 1997 to study the agricultural spectra from different crops and for identification of crops in other areas with similar environmental factors and similar spectral properties. The main objectives of this study are: 1) to compare the spectral and radiometric characteristics of AVIRIS data from verities of cotton crop with the spectra measured by FieldSpecR ASD radiometer; 2) to explore the use of AVIRIS images in identifying agricultural crops; 3) to study the impact of environmental factors on selected crops and; 4) to build a spectral library for the cotton crop varieties that were studied. A long-term goal is to extend the spectral library for different vegetation or crops in different stages of growth or different varieties. In order to support our study, on June 26, 2001 we collected spectral data using the FieldSpec spectrometer from selected fields planted with different cotton varieties at Blythe area, California (at the Longitude 114° 41.88 W and Latitude 33° 24.27N to Longitude 114° 41.86 W and Latitude 33° 24.00N). The spectral data of cotton varieties were studied. Environmental parameters were studied such as the soil water content (WC), pH, organic matter (OM), C% and nitrogen (N%). The results of this study showed that there were differences in the signatures of different cotton varieties. Also, there was a significant correlation between the data that were collected by AVIRIS image scene in 1997 and spectral data collected by the FieldSpec spectrometer. This correlation allowed us to build a spectral library to be used in ENVI-IDL software. This leads to identification of different cotton varieties and in particular the visible part of the spectra. AVIRIS data are in agreement with FieldSpec data. Using IDL algorithms of Spectral Angle Mapper classification (SAM), Spectral Feature Fitting (SFF) and Spectral Binary Encoding (SPE) showed that there is an excellent agreement between the predicted and the actual crop type (i.e. the correlation is between 85 - 90% match). Further use of the AVIRIS images can be of a value to crops identification or crops yield for commercial use. The yield data of Cotton varieties were correlated significantly with the spectral data from the AVIRIS and from the hand-held radiometer and it showed the impact of different environmental parameters on the yield of the crop.

Proceedings Article | 17 March 2003 Paper

Characteristics of AVIRIS bands measurements in agricultural crops at Blythe area, California: III. Studies on Teff grass

Safwat Shakir Hanna, Michael Rethwisch

Proceedings Volume 4879, (2003) https://doi.org/10.1117/12.462487

KEYWORDS: Reflectivity, Vegetation, Radiometry, Agriculture, Whole body imaging, Absorption, Spectroscopy, Sensors, Data acquisition, Binary data

Read Abstract +

AVIRIS data from Blythe were acquired in June 1997 to study the agricultural spectra from different crops and for identification of crops in other areas with similar environmental factors and similar spectral properties. In this respect; the main objectives of this study are: 1) to compare the spectral and radiometric characteristics of AVIRIS data from agriculture crops with the spectra measured by FieldSpec ASD radiometer; 2) to explore the use of AVIRIS images in identifying agricultural crops; 3) to study the impact of environmental factors on selected crops and; 4) to build a spectral library for the crops that were studied. A long-term goal is to extend the spectral library for different vegetation or crops in different stages of growth. In order to support our study, on July 18-19, 2000 we collected spectra using the FieldSpec spectrometer from selected fields planted with different crops at Blythe area, California (at the Longitude 114° 33.28 W and Latitude 33° 25.42 N to Longitude of 114° 44.53 W and 33° 39.77 N Latitude. The teff grass spectra were studied. Teff grass fields were treated with different types of irrigation (i.e. wet to dry conditions). Additional parameters were studied such as the soil water content (WC), pH, organic matter (OM) and nitrogen (N%). The results of this study showed that there is a significant correlation between the data that were collected by AVIRIS image scene in 1997 and spectral data collected by the FieldSpec spectrometer. This correlation allowed us to build a spectral library to be used in ENVI-IDL software. This leads to identification of different crops and in particular the visible part of the spectra. AVIRIS data are in agreement with FieldSpec data. Using IDL algorithms of Spectral Angle Mapper classification (SAM), Spectral Feature Fitting (SFF) and Spectral Binary Encoding (SPE) showed that there is an excellent agreement between the predicted and the actual crop type (i.e. the correlation is between 85 - 90% match). Further use of the AVIRIS images can be of a value to crops identification or crops yield for commercial use. The yield data of Teff grass were correlated significantly with the spectral data from the AVIRIS and from the hand-held radiometer and it showed the impact of irrigation on the yield of the crop.

Proceedings Article | 28 January 2002 Paper

Characteristics of AVIRIS bands measurements in agricultural crops at Blythe area, California: II. Studies on kenaf, Hibiscus canabinus

Safwat Shakir Hanna, Michael Rethwisch

Proceedings Volume 4542, (2002) https://doi.org/10.1117/12.454190

KEYWORDS: Reflectivity, Radiometry, Vegetation, Agriculture, Spectroscopy, Whole body imaging, Visible radiation, Binary data, Absorption, Feature extraction

Read Abstract +

AVIRIS data from Blythe,Calfornia , were acquired in June 1997 to study the agricultural spectra from different crops and for identification of crops in other areas with similar environmental factors and similar spectral properties. In this respect; the main objectives of this study are: 1) to compare the spectral and radiometric characteristics of AVIRIS data from agriculture crops with the spectra measured by FieldSpecR ASD radiometer; 2) to explore the use of AVIRIS images in identifying agriculture crops; and; 3) to build a spectral library for the crops that were studied. A long-term goal is to extend the spectral library for different vegetation or crops in different stages of growth. In order to support our study, on July 18-19, 2000 we collected spectra using the FieldSpecR ASD spectrometer from selected fields planted with different crops at Blythe area, California (at the Longitude 114 degree(s) 33.28 W and Latitude 33 degree(s) 25.42 N to Longitude 114 degree(s) 44.35 W and 33 degree(s) 39.77 N Latitude). The results of this study showed that there is a significant correlation between the data that were collected by AVIRIS image scene in 1997 and spectral data collected by the FieldSpecR spectrometer. This correlation allowed us to build a spectral library to be used in ENVI_IDL software. This leads to identification of different crops and in particular the visible part of the spectra. Furthermore, using IDL-ENVI algorithms of Spectral Angle Mapper classification (SAM), Spectral Feature Fitting (SFF) and Spectral Binary Encoding (SPE) showed that there is an excellent agreement between the predicted and the actual crop type (i.e. The correlation is between 85-90% match). Further use of the AVIRIS images can be of a value to crops identification or crops yield for commercial use. Kenaf crop spectra were studied. The kenaf varieties (Tainung 2, Everglades 41) were significantly differentiated by both the spectral data from AVIRIS and from the hand-held radiometer.

Proceedings Article | 23 January 2001 Paper

Characterization model for crop stress using hand-held radiometer data

Safwat Shakir Hanna

Proceedings Volume 4171, (2001) https://doi.org/10.1117/12.413959

KEYWORDS: Vegetation, Reflectivity, Medium wave, Data modeling, Soil science, Near infrared, Infrared radiation, Radiometry, Mass attenuation coefficient, Whole body imaging

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Remotely sensed reflectance from stressed and non-stressed crop vegetative cover can be predicted from two combinations of spectral bands as a ratio or as normalized vegetation indices. The most common spectral bands used lie in the red and infrared region (350-800 nm) and are dominated by the absorption of chlorophyll and other accessory pigments. In addition, reflectance in the middle infrared is dominated by absorption from liquid water contained in plant’s tissues. The objectives of the present work are: 1) to develop characterization model to evaluate the reflectance data from frequently irrigated and water stressed alfalfa, Sudan grass, and other crops such cotton as using a handheld radiometer and assess the spectral correlation with the ground-truth and; 2) The model will be better model to evaluate the stressed crops. The experiment was designed to collect reflectance data from cotton crops planted at the Blythe area, California. The fields are planted with cotton crops in different stages of maturity at Longitude of -114°32.79 and -114°32.80 and Latitude 33° 39.64. With a field spectrometer, the scan over each treatment was made at 1 hr intervals between 10:00 a.m. and 2:00 p.m. Pacific Day Time (PDT). Vegetative samples were taken from the two treatments (i.e. stressed and unstressed vegetation) during the initial sampling for purposes of conducting chemical analysis. Soil samples were collected to determine the amount of available soil moisture differences in the two treatments. The suggested model in the present paper is called the Model of Water Stress (MWS) where it include in it the statistical values and parameters, indicates that the stressed crops have values higher than unstressed crops in MWS scale. This means that the model is differentiating between the stressed and unstressed vegetation. Additional work will evaluate the reflectance peaks and their relationship to other parameters that were collected and are relevant to the applications of the model. The model will be tested against the AVIRIS data that were collected at the same time of the collection of ground-truth data.

Proceedings Article | 17 December 1999 Paper

Spectral characterization of water stress impact on some agricultural crops: III. Studies on Sudan grass and other different crops using handheld radiometer

Safwat Shakir Hanna, B. Girmay-Gwahid

Proceedings Volume 3868, (1999) https://doi.org/10.1117/12.373091

KEYWORDS: Reflectivity, Radiometry, Vegetation, Soil science, Phase modulation, Whole body imaging, Agriculture, Absorption, Liquids, Spectroscopy

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Vegetation monitoring has been one of the major targets of remote sensing studies. Remotely sensed reflectance concerning the impact of environmental factors upon crop vegetative cover can be predicted from two combinations of spectral bands as a ratio or as normalized vegetation indices. The most common spectral bands used lie in the red and infrared region (350 - 800 nm) and are dominated by the absorption of chlorophyll and other accessory pigments. In addition, reflectance in the middle infrared is dominated by absorption from liquid water contained in plant's tissues. The objectives of the present work are: (1) to evaluate the reflectance data from frequently irrigated and water stressed Sudan grass and other crops using a handheld radiometer and assess the spectral correlation with the ground-truth; (2) to evaluate the applications of a Hyperspectral Structure Component Index (HSCI) developed by Shakir and Girmay-Gwahid in 1998; and (3) to evaluate the application of Index of Relative Stress (IRS) proposed by Shakir and Girmay-Gwahid in 1998. The experiment was designed to collect reflectance data from Sudan grass and other crops planted at the Blythe Research Station, California in rows. The size of the plots for Sudan grass was in rows, the unstressed mature stands were 9 feet tall, and the stressed mature stands were 5 feet tall. The other fields are in nearby and planted with cotton crops in different stages of maturity. With a field spectrometer, the scan over each treatment was made at 1-hr intervals between 10:00 a.m. and 2:00 p.m. Pacific DayTime (PDT). Vegetative samples were taken from the two treatments during the initial sampling for purposes of conducting chemical analysis. Soil samples were collected to determine the amount of available soil moisture differences in the two treatments. The results of this experiment showed that in the 850 - 1150 nm wavelength ranges, the stressed Sudan grass stands showed lower reflectance than unstressed stands. However, the reflectance of stressed Sudan grass stands was higher than the unstressed stands above the 1150 nm. This is probably due to the absorption from liquid water contained in the unstressed plant tissues. The same pattern was found in the cotton crop. The analysis of data using the (HSCI) model showed that the stressed Sudan grass stands have values less than 1 and under unstressed Sudan grass stands have the value greater than 1. This means that the model is differentiating between the stressed and unstressed vegetation. Additional work will evaluate the reflectance peaks and their relationship to other parameters that were collected and are relevant to the applications of the model. Furthermore; the Index of Relative Stress (IRS) showed that the unstressed vegetation stands is higher in values than in the stressed.

Proceedings Article | 11 December 1998 Paper

Spectral characterization of water stress impact on some agricultural crops: II. Studies on alfalfa using handheld radiometer

Safwat Shakir Hanna, B. Girmay-Gwahid

Proceedings Volume 3499, (1998) https://doi.org/10.1117/12.332762

KEYWORDS: Reflectivity, Radiometry, Phase modulation, Agriculture, Vegetation, Soil science, Absorption, Infrared radiation, Liquids, Tissues

Read Abstract +

Remotely sensed reflectance from stressed and non-stressed crop vegetative cover can be predicted from two combination of spectral bands as a ratio or as normalized vegetation indices. The most common spectral bands used lie in the red and infrared region (350 - 800 nm) and are dominated by the absorption of chlorophyll and other accessory pigments. In addition, reflectance in the middle infrared is dominated by absorption from liquid water contained in plant's tissues. The objectives of the present work are: (1) to evaluate the reflectance data from frequently irrigated and water stressed alfalfa using a handheld radiometer and assess the spectral correlation with the ground-truth and; (2) to evaluate the applications of a Hyperspectral Structure Component Index (HSCI) proposed by Shakir and Girmay-Gwahid (1998). The experiment was designed to collect reflectance data from alfalfa (pure alfalfa stand and a plot where alfalfa was mixed with sedge grass) planted at the Blythe Research Station, California. The size of the plots was 30 X 50 ft². With a field spectrometer, the scan over each treatment was made at 1 hr intervals between 10:00 a.m. and 2:00 p.m. Pacific Day Time (PDT). Vegetative samples were taken from the two treatments during the initial sampling for purposes of conducting chemical analysis. Soil samples were collected to determine the amount of available soil moisture differences in the two treatments. The results of this experiment showed that in the 850 - 1150 nm wavelength range the stressed alfalfa plots showed lower reflectance than unstressed plots. However; the reflectance of stressed alfalfa was higher than the unstressed stands above the 1150 nm. This is probably due to the absorption from liquid water contained in the unstressed plant tissues. The analysis of data using the (HSCI) model showed that the stressed pure alfalfa plots have values less than 1 and under unstressed alfalfa plots have the value greater than 1. This means that the model is differentiating between the stressed and unstressed vegetation. Additional work will evaluate the reflectance peaks and their relationship to other parameters that were collected and are relevant to the applications of the model.

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