Radiometric and geometric characteristics of pleiades images

Pleiades images are distributed with 50cm ground sampling distance (GSD) even if the physical resolution for nadir images is just 70cm. By theory this should influence the effective GSD determined by means of point spread function at image edges. Nevertheless by edge enhancement the effective GSD can be improved, but this should cause enlarged image noise. Again image noise can be reduced by image restoration. Finally even optimized image restoration cannot improve the image information from 70cm to 50cm without loss of details, requiring a comparison of Pleiades image details with other very high resolution space images. The image noise has been determined by analysis of the whole images for any sub-area with 5 pixels times 5 pixels. Based on the standard deviation of grey values in the small sub-areas the image noise has been determined by frequency analysis. This leads to realistic results, checked by test targets. On the other hand the visual determination of image noise based on apparently homogenous sub-areas results in too high values because the human eye is not able to identify small grey value differences - it is limited to just approximately 40 grey value steps over the available gray value range, so small difference in grey values cannot be seen, enlarging results of a manual noise determination. A tri-stereo combination of Pleiades 1A in a mountainous, but partially urban, area has been analyzed and compared with images of the same area from WorldView-1, QuickBird and IKONOS. The image restoration of the Pleiades images is very good, so the effective image resolution resulted in a factor 1.0, meaning that the effective resolution corresponds to the nominal resolution of 50cm. This does not correspond to the physical resolution of 70cm, but by edge enhancement the steepness of the grey value profile across the edge can be enlarged, reducing the width of the point spread function. Without additional filtering edge enhancement enlarges the image noise, but the average image noise of approximately 1.0 grey values related to 8bit images is very small, not indicating the edge enhancement and the down sampling of the GSD from 70cm to 50cm. So the direct comparison with the other images has to give the answer if the image quality of Pleiades images is on similar level as corresponding to the nominal resolution. As expected with the image geometry there is no problem. This is the case for all used space images in the test area, where the point identification limits the accuracy of the scene orientation.

Yazar Jacobsen K.
Topan H.
Cam A.
Özendi M.
Oruc M.
Yayın Türü Conference Object
Tek Biçim Adres https://hdl.handle.net/20.500.12628/7298
Tek Biçim Adres 10.5194/isprsarchives-XL-1-173-2014
Konu Başlıkları Adjustment
Georeferencing
Radiometric
Restitution
Space
Koleksiyonlar Araştırma Çıktıları | WoS | Scopus | TR-Dizin | PubMed | SOBİAD
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Dergi Adı International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives
Dergi Cilt Bilgisi 40
Dergi Sayısı 1
Sayfalar 173 - 177
Yayın Yılı 2014
Eser Adı
[dc.title]
Radiometric and geometric characteristics of pleiades images
Yayıncı
[dc.publisher]
International Society for Photogrammetry and Remote Sensing
Yayın Türü
[dc.type]
conferenceObject
Açıklama
[dc.description]
ISPRS Technical Commission I Symposium 2014 -- 17 November 2014 through 20 November 2014 -- -- 111190
Özet
[dc.description.abstract]
Pleiades images are distributed with 50cm ground sampling distance (GSD) even if the physical resolution for nadir images is just 70cm. By theory this should influence the effective GSD determined by means of point spread function at image edges. Nevertheless by edge enhancement the effective GSD can be improved, but this should cause enlarged image noise. Again image noise can be reduced by image restoration. Finally even optimized image restoration cannot improve the image information from 70cm to 50cm without loss of details, requiring a comparison of Pleiades image details with other very high resolution space images. The image noise has been determined by analysis of the whole images for any sub-area with 5 pixels times 5 pixels. Based on the standard deviation of grey values in the small sub-areas the image noise has been determined by frequency analysis. This leads to realistic results, checked by test targets. On the other hand the visual determination of image noise based on apparently homogenous sub-areas results in too high values because the human eye is not able to identify small grey value differences - it is limited to just approximately 40 grey value steps over the available gray value range, so small difference in grey values cannot be seen, enlarging results of a manual noise determination. A tri-stereo combination of Pleiades 1A in a mountainous, but partially urban, area has been analyzed and compared with images of the same area from WorldView-1, QuickBird and IKONOS. The image restoration of the Pleiades images is very good, so the effective image resolution resulted in a factor 1.0, meaning that the effective resolution corresponds to the nominal resolution of 50cm. This does not correspond to the physical resolution of 70cm, but by edge enhancement the steepness of the grey value profile across the edge can be enlarged, reducing the width of the point spread function. Without additional filtering edge enhancement enlarges the image noise, but the average image noise of approximately 1.0 grey values related to 8bit images is very small, not indicating the edge enhancement and the down sampling of the GSD from 70cm to 50cm. So the direct comparison with the other images has to give the answer if the image quality of Pleiades images is on similar level as corresponding to the nominal resolution. As expected with the image geometry there is no problem. This is the case for all used space images in the test area, where the point identification limits the accuracy of the scene orientation.
Kayıt Giriş Tarihi
[dc.date.accessioned]
2019-12-23
Açık Erişim Tarihi
[dc.date.available]
2019-12-23
Yayın Yılı
[dc.date.issued]
2014
Tek Biçim Adres
[dc.identifier.uri]
https://dx.doi.org/10.5194/isprsarchives-XL-1-173-2014
Tek Biçim Adres
[dc.identifier.uri]
https://hdl.handle.net/20.500.12628/7298
Yayın Dili
[dc.language.iso]
eng
Konu Başlıkları
[dc.subject]
Adjustment
Konu Başlıkları
[dc.subject]
Georeferencing
Konu Başlıkları
[dc.subject]
Radiometric
Konu Başlıkları
[dc.subject]
Restitution
Konu Başlıkları
[dc.subject]
Space
Yazar
[dc.contributor.author]
Jacobsen K.
Yazar
[dc.contributor.author]
Topan H.
Yazar
[dc.contributor.author]
Cam A.
Yazar
[dc.contributor.author]
Özendi M.
Yazar
[dc.contributor.author]
Oruc M.
Haklar
[dc.rights]
info:eu-repo/semantics/openAccess
ISSN
[dc.identifier.issn]
1682-1750
Yazar Departmanı
[dc.contributor.department]
Zonguldak Bülent Ecevit Üniversitesi
İlk Sayfa Sayısı
[dc.identifier.startpage]
173
Son Sayfa Sayısı
[dc.identifier.endpage]
177
Dergi Adı
[dc.relation.journal]
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives
Dergi Sayısı
[dc.identifier.issue]
1
Dergi Cilt Bilgisi
[dc.identifier.volume]
40
Görüntülenme Sayısı ( Şehir )
Görüntülenme Sayısı ( Ülke )
Görüntülenme Sayısı ( Zaman Dağılımı )
Görüntülenme
17
09.12.2022 tarihinden bu yana
İndirme
1
09.12.2022 tarihinden bu yana
Son Erişim Tarihi
09 Şubat 2024 07:45
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Tıklayınız
images resolution Pleiades enhancement values effective restoration determined results approximately details sub-areas determination pixels nominal analysis comparison enlarged function spread sampling should physical cannot corresponds identification meaning correspond steepness resulted factor limits IKONOS QuickBird WorldView-1
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