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Multi-band wavelet for using Spot panchromatic and multispectral images / Wei Shi in Photogrammetric Engineering & Remote Sensing, PERS, vol 69 n° 5 (May 2003)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 69 n° 5 (May 2003) . - pp 513 - 520 Titre : Multi-band wavelet for using Spot panchromatic and multispectral images Type de document : Article/Communication Auteurs : Wei Shi, Auteur ; C. Zhu, Auteur ; Ca. Zhu, Auteur ; X. Yang, Auteur Année de publication : 2003 Article en page(s) : pp 513 - 520 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique [Termes IGN] fusion d'images [Termes IGN] image Landsat-TM [Termes IGN] image multibande [Termes IGN] image panchromatique [Termes IGN] image SPOT [Termes IGN] ondelette [Termes IGN] transformation en ondelettes [Termes IGN] transformation intensité-teinte-saturation Résumé : (Auteur) With the development of remote sensing technology, fusion of remotely sensed images, such as SPOT panchromatic (SPOT P) with SPOT multispectral images (SPOT XS) or Landsat Thematic Mapper (TM), has become more important in order to obtain richer information in the spatial and spectral domains simultaneously. Many fusion methods have been developed based on the twoband wavelet transformation. However, due to the limitations of the transformation characteristics themselves, the twoband wavelet is not very efficient for the fusion of images whose ratio of spatial resolutions is not 2n (n = 1, 2, 3, ...), e.g., for fusing a 101 resolution panchromatic SPOT image and with 30m resolution multispectral TM images. However, a recently developed new wavelet branchmultiband wavelet can potentially be applied to solve this problem. In this paper, we develop a new approach for fusing SPOT P images with multispectral TM images based on multiband wavelet transformation. First, the theoretical basis of multiband wavelet is presented and its transformation properties are analyzed. Second, a new method for fusing a SPOT P image with multispectral images using the multiband wavelet is proposed. Specifically, the threeband wavelet is implemented to fuse 1 10m SPOT panchromatic and 30m multispectral TM images. Third, this new method is compared with previous methods such as the twoband wavelet and IHS methods for image fusion. The proposed multiband wavelet approach demonstrates an improvement in spatial and spectral characteristics for fusing SPOT P and multispectral TM images. Numéro de notice : A2003-082 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.69.5.513 En ligne : https://doi.org/10.14358/PERS.69.5.513 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=22378 [article]

Comparison of gray-level reduction and different texture spectrum encoding methods for land-use classification using a panchromatic Ikonos image / B. Xu in Photogrammetric Engineering & Remote Sensing, PERS, vol 69 n° 5 (May 2003)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 69 n° 5 (May 2003) . - pp 529 - 536 Titre : Comparison of gray-level reduction and different texture spectrum encoding methods for land-use classification using a panchromatic Ikonos image Type de document : Article/Communication Auteurs : B. Xu, Auteur ; E. Seto, Auteur ; P. Gong, Auteur ; R. Spear, Auteur Année de publication : 2003 Article en page(s) : pp 529 - 536 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique [Termes IGN] analyse spectrale [Termes IGN] analyse texturale [Termes IGN] classification contextuelle [Termes IGN] compression d'image [Termes IGN] image à résolution métrique [Termes IGN] image Ikonos [Termes IGN] image panchromatique [Termes IGN] niveau de gris (image) [Termes IGN] texture d'image [Termes IGN] uniformisation d'histogramme [Termes IGN] utilisation du sol Résumé : (Auteur) In this paper, we evaluate the potential of a frequency-based contextual classifier (FBC) for landuse classification with a panchromatic Ikonos image. To capture the spatial arrangement of image graylevel values and use such information in image classification, we applied texture spectrum (TS) directly in the FBC. The effects of several data preprocessing and reduction methods on the performance of the FBC are also evaluated. The methods include four graylevel reduction (GLR) techniques and several modifications to the TS technique. The purpose of data reduction is to improve the classification efficiency of the FBC. The GLR schemes were minmax linear compression (LC), gray level binning (BN), histogram equalization (HE), and piecewise nonlinear compression (PC). Instead of using the texture measures derived from the texture spectrum, we directly applied texture spectra of various sizes in the classification. We modified the encoding algorithm in the TS and were able to reduce the number of texture units from its original 6561 to 256, 81, and 16, leading to as much as a 410 times computation efficiency. The original image and GLR images were subsequently classified with the FBC. We compared the classification accuracies and found that the GLR methods resulted in accuracies similar to that of the original image (within 0.03 kappa value). There was little difference in classification accuracy (within 0.03 kappa value) among the three modified TS methods, which were all outperformed by the original TS method. All TS methods performed considerably better than the use of the original image and the GLR methods. Numéro de notice : A2003-083 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.69.5.529 En ligne : http://dx.doi.org/10.14358/PERS.69.5.529 Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=22379 [article]

Image calibration to like-values in mapping shallow water quality from multitemporal data / M.A.. Islam in Photogrammetric Engineering & Remote Sensing, PERS, vol 69 n° 5 (May 2003)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 69 n° 5 (May 2003) . - pp 567 - 575 Titre : Image calibration to like-values in mapping shallow water quality from multitemporal data Type de document : Article/Communication Auteurs : M.A.. Islam, Auteur ; J. Gao, Auteur ; D. Neil, Auteur ; P. Bell, Auteur Année de publication : 2003 Article en page(s) : pp 567 - 575 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique [Termes IGN] classification dirigée [Termes IGN] étalonnage radiométrique [Termes IGN] image Landsat-TM [Termes IGN] image multitemporelle [Termes IGN] modèle stochastique [Termes IGN] qualité des eaux Résumé : (Auteur) The applicability of image calibration to likevalues in mapping water quality parameters from multitemporal images is explored. Six sets of water samples were collected at satellite overpasses over Moreton Bay, Brisbane, Australia. Analysis of these samples reveals that waters in this shallow bay are mostly TSS dominated, even though they are occasionally dominated by chlorophyll as well. Three of the images were calibrated to a reference image based on invariant targets. Predictive models constructed from the reference image were applied to estimating total suspended sediment (TSS) and Secchi depth from another image at a discrepancy of around 35 percent. Application of the predictive model for TSS concentration to another image acquired at a time of different water types resulted in a discrepancy of 152 percent. Therefore, image calibration to likevalues could be used to reliably map certain water quality parameters from multitemporal TM images so long as the water type under study remains unchanged. This method is limited in that the mapped results could be rather inaccurate if the water type under study has changed considerably. Thus, the approach needs to be refined in shallow water from multitemporal satellite imagery. Numéro de notice : A2003-084 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1016/S0034-4257(01)00205-X En ligne : http://dx.doi.org/10.1016/S0034-4257(01)00205-X Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=22380 [article]