FREE ELECTRONIC LIBRARY - Online materials, documents

Pages:   || 2 |

«DGPF Tagungsband 16 / 2007 – Dreiländertagung SGPBF, DGPF und OVG Automatic Dodging of Aerial Images MARTIN DRAUSCHKE 1, ANSGAR BRUNN 2, KAI ...»

-- [ Page 1 ] --

DGPF Tagungsband 16 / 2007 – Dreiländertagung SGPBF, DGPF und OVG

Automatic Dodging of Aerial Images


Abstract: We present an automated approach for the dodging of images, with which we edit

digital images as it is usually done with analogue images in dark-rooms.

Millions of aerial images of all battle fields were taken during the Second World War. They

were intensively used, e.g. for the observation of military movements, the documentation of success and failure of military operations and further planning. Today, the information of these images supports the removal of explosives of the Second World War and the identification of dangerous waste in the soil. In North Rhine-Westphalia, approximately 300.000 aerial images are scanned to handle the huge amount of available data efficiently. The scanning is done with a gray value depth of 12 bits and a pixel size of 21 μm to gain both, a high radiometric and a high geometric resolution of the images. Due to the photographic process used in the 1930s and 1940s and several reproductions, the digitized images are exposed locally very differently. Therefore, the images shall be improved by automated dodging.

Global approaches mostly returned unsatisfying results. Therefore, we present a new approach, which is based on local histogram equalization. Other methods as spreading the histogram or linear transformations of the histogram manipulate the images either too much or not enough. For the implementation of our approach, we focus not only on the quality of the resulting images, but also on robustness and performance of the algorithm. Thus, the technique can also be used for other applications concerning image improvements.

1 Introduction

1.1 Allied images for the disposal of explosives of the Second World War Millions of aerial images of all battle fields were taken during the Second World War (WWII).

Especially Great Britain already started taking photographs of parts of Germany even before the beginning of the Second World War. During the war the organization of the aerial reconnaissance was constantly improved (Babington Smith, 2004). The number of images increased rapidly (LUA NRW, 2006).

The aerial images were intensively used, e.g. for the observation of military movements, the documentation of success and failure of military operations or the planning of further strategies.

The films were developed in the field immediately after landing. A courier delivered them to the Department of Photogrammetry, Institute of Geodesy and Geoinformation, University of Bonn, Nussallee 15, 53115 Bonn, martin.drauschke@uni-bonn.de, wf@ipb.uni-bonn.de Kampfmittelbeseitigungsdienst Westfalen-Lippe, Bezirksregierung Arnsberg, In der Krone 31, 58099 Hagen, ansgar.brunn@bezreg-arnsberg.nrw.de Kampfmittelbeseitigungsdienst Rheinland, Bezirksregierung Düsseldorf, Färberstraße 136, 40223 Düsseldorf, kai.kulschewski@bezreg-duesseldorf.nrw.de DGPF Tagungsband 16 / 2007 – Dreiländertagung SGPBF, DGPF und OVG headquarters, often only a few hours after the landing of the reconnaissance plane (Stanley, 1981).

Today, these images support the removal of explosives of the Second World War or the identification of dangerous waste in the soil. North Rhine-Westphalia (NRW) has two bomb disposal services which identify, detect, remove and destroy not yet exploded bombs and other munitions. The first step of the removal of bombs is image interpretation. The services archive almost 300,000 allied images. The photo interpreter and geodesists identify in these images bombed areas, signatures of unexploded bombs and of military infrastructure and reference this data. Detection and removal units complete the job in the field.

1.2 Digitization of the archive of analog allied images Up to now analogue photo copies have been used for the image interpretation. The image interpretation task is done separately for each site. For each multi-temporal image interpretation from 10 up to several hundreds of images have to be analyzed. Therefore the explosive disposal units put a high effort in managing the analogue archives at the moment. This effort will increase when additional images will be available from recently opened archives (Carls & Müller, 2007).

In the future only digital images will be used. All sites will be interpreted from digital images.

Therefore all images have to be digitized with high accuracy resulting from high demands of interpretation quality for the bomb disposal task, i.e. a high radiometric contrast to identify small holes in the bare soil which result from the penetration of the unexploded bombs, and a high geometric accuracy to get precise coordinates of possible places of unexploded bombs.

In addition to the demands resulting from the task of bomb disposal, additional demands result from economical aspects: no human interaction should be needed for the scanning of each image nor for the improvement of the scanned images. These efforts point out that a high degree of automation of the process is needed. The large amount of images makes a priori investigations sensible and economical interesting.

1.3 Overview of the rest of the paper In the following we will describe the scanning process. In chapter 3 we will report on several tests of image improvement methods which use intuitive and commercially available algorithms.

Afterwards in chapter 4 we will present results and demonstrate some properties. This paper closes with a short summary and an outlook on the further work which has to be done in the scanning project.

2 Automated scanning of allied images of the WWII

2.1 Scanning overview In the 1990s Germany got access to images from the British archive of allied aerial images, which nowadays is hosted at TARA 4. Back then hundreds of boxes with cut aerial images were brought to Germany. Each of the borrowed images is a copy in an unknown series of copies of The Aerial Reconnaissance Archives (TARA) at Keele University, www.evidenceincamera.co.uk, last visit: 1.5.2007

DGPF Tagungsband 16 / 2007 – Dreiländertagung SGPBF, DGPF und OVG

the original photographs. These copies survived somehow the confusion during and after WWII.

These images were reproduced on film rolls and were archived in Germany again. Since then, they have been used to generate analogue photos for manual image interpretation of the bomb disposal units for the last 15 years. During the photographic reproduction process on paper a line-based photographic dodging was performed in a dark-room. The exposure time was calculated from the brightness of each reproduced image line.

For the scanning project the existence of the film rolls is a big benefit, because the rolls allow automatic scanning by a photogrammetric scanner. We use a unique label found on each image to identify each image on the film roll and scan the images with 21µm resolution in 12 bits.

Although the image is scanned with 12 bits, storage of the data follows in 16 bits. To avoid timeconsuming and individual scan settings for each film and each image resp., only one set of parameters is used during the scan process for efficient scanning. That is why in most cases the overall image quality of the original scans is inadequate. Figure 1 gives an impression of the quality of the majority of the scanned images.

This scanning result does obviously not allow a reliable interpretation. Thus, an algorithm for image improvement has to be found. The following demands have to be satisfied by the resulting


• They need to be interpretable by specialists in allied image interpretation.

• They should have a nice look because they should allow a quick overview on bomb penetration and waste pollution.

• They have to reveal small structures like small holes in the ground of blinders.

• The algorithm has to adapt to the failures of the available images.

• It has to keep the geometry of the image.

• It has to be as fast as the scanning of the image.

2.2 Scanning in detail and quality management of the scanned images The aim of scanning is to optimize the information content, as well as the histogram, but not the optimization of the visual impression. Additionally, all radiometric properties of the analog images which are supposed to be scanned need to be reproduced in the digital images as good as possible. The complete reprographic range of each image is to be scanned during the scanning process.

In order to optimize the image information content, all digital images must fulfill the following general conditions: There must be no irregular swaths / scan lines and stains in the digital image, and the radiometric contrasts in the dark (shadows) and in the light image areas (clouds, snow, overexposed areas), which can be seen in the original image, must also exist in the scanned image.

Furthermore, the radiometric resolution of 16 bits must effectively be utilized. In addition the histogram of a so called inner range has to fulfill certain conditions. The inner range only

DGPF Tagungsband 16 / 2007 – Dreiländertagung SGPBF, DGPF und OVG

contains objects which were captured during the original exposure. No superimposed fiducial marks nor any text are allowed to exist in the inner range.

The inner range has no constant offset to the unique label. In order to avoid complex individual detection of the inner range of each image, the inner range can be defined, so that the distance from the original image area on all four sides, does not exceed the value of 1,5cm.

For the optimization of the image information the guideline of

the scanning contains the following items:

• The histogram of the whole scanned image has to range from 6553 to 58983. Within this range the minimum of 245 grey values must possess a frequency greater than 0,01% of the number of pixels in the inner range,

• Maximally 0,01 % of all grey values in the inner range are allowed to exceed the grey value from 1 to 6553, and the grey value from 58983 to 65535.

Figure 1. Input Image

• The grey values 0 and 65536 are not permitted.

Through the introduction of these boundary conditions, a later transformation to 8 bit is guaranteed, so that all objects of a 16 bit image taken during the photo flight are present. They can then be optimized during radiometric post-processing to avoid underexposures or overexposures in the 16 bit scanned image. The histogram derived from the 8 bit image is almost complete and the grey values from the 8 bit image are not derived from extrapolations.

3 Previous Work Let I be the input image with 0 ≤ I(x,y) ≤ gmax for all pixels (x,y) of the image and H its histogram. Fig. 1 shows a scanned aerial image of an area in North Rhine-Westphalia and Fig. 2 its histogram.

The information of the input image is not recognizable for human eyes, since over 90% of all pixels have one of the 10%-highest grey values. The scanning of the image has been adjusted in such a way, that all information is preserved during the Figure 2. Histogram of input image after quantization to 8 bits.

scan process. Thus,

DGPF Tagungsband 16 / 2007 – Dreiländertagung SGPBF, DGPF und OVG

the frame of the image contains almost all the dark parts of the image. The rest of the image is too light for recognizing structures in the photographed landscape manually.

The analysis of the histogram of such an image shows that many grey values occur in the image, but most of them not more than only a few times. There is a number of small peaks in the middle of the histogram most of which result from the grey values of the image frame. The maximum in the histogram is located near the highest possible grey value gmax.

Finally, we denote the output image with O(x,y).

3.1 Inner-range dodging with local histogram spreading In a first approach, we use histogram spreading for improving the visibility in the images.

Therefore, it is necessary to select an inner-range of an image to exclude the frame around the scene in the aerial image. The inner range has to be defined interactively due to writings on the

–  –  –

Figure 3. Dodging with histogram spreading.

Part (a) shows the global approach, parts (b-d) show the results of an inner-range dodging with variable patch sizes. Therefore, we divided the image into 4 patches (b), 100 patches (c) or 400 patches (d) of equal size.

DGPF Tagungsband 16 / 2007 – Dreiländertagung SGPBF, DGPF und OVG is strenghened too much. The patch size for the best results takes the size of the histogram and the characteristics of the imaging process into account.

5 Summary and Outlook In this article we have presented a project of the explosives disposal services of NRW for scanning and enhancing allied aerial images of the WWII. The resulting, dodged images have the quality that is necessary for image interpretation aimed at finding bombed areas and blinders. The tested software has the envisaged speed.

Meanwhile 20,000 images have been processed successfully. The production line of the dodging will be installed in short time. The digitization project will go on.

Several tasks have to be realised for allied images during the next years, e.g. the automatic georeferencing of the scanned images, the automatic model building of Figure 7. Effects of patch size for dodging results.

flight stripes and the automatic First row left, only one patch has been used (global interpretation of aerial images for bomb approach); right, row-wise dodging. Second row craters and blinders. left, small patches with 300 x 300 pixels; right, bigger patches with 4000 x 4000 pixels.

Acknowledgements: We thank the surveying office of NRW which does the scanning as a part of a contract with the Ministry of the Interior of North Rhine-Westphalia, department 75 and which performed the first tests of different commercially available dodging algorithms. We also thank TARA for supporting this publication by its images.

6 Literature BABINGTON SMITH, C., 2004: Evidence in Camera: The Story of Photographic Intelligence in the Second World War. Sutton Publishing.

Pages:   || 2 |

Similar works:

«  THIRTY-FIFTH SESSION OF THE IPCC Geneva, 6-9 June 2012 IPCC-XXXV/Doc. 21 (11.V.2012) Agenda Item: 5.3 ENGLISH ONLY PROGRESS IN THE PREPARATION OF FIFTH ASSESSMENT REPORT (AR5) Working Group III Progress Report (Submitted by the Co-Chairs of the IPCC Working Group III) IPCC Secretariat c/o WMO • 7bis, Avenue de la Paix • C.P. 2300 • 1211 Geneva 2 • Switzerland telephone : +41 (0) 22 730 8208 / 54 / 84 • fax : +41 (0) 22 730 8025 / 13 • email : IPCC-Sec@wmo.int • www.ipcc.ch   ...»

«REPUBLIC OF THE PHILIPPINES SANGGUNIANG PANLUNGSOD GENERAL SANTOS CITY MINUTES OF THE 118TH REGULAR SESSION OF THE 17TH SANGGUNIANG PANLUNGSOD OF THE CITY OF GENERAL SANTOS, HELD AT THE SESSION HALL, SANGGUNIANG PANLUNGSOD BUILDING, ON MONDAY, DECEMBER 7, 2015 AT 9:15 A.M. PRESENT: Vice Mayor Shirlyn L. Bañas-Nograles Presiding Officer Councilor Elizabeth B. Bagonoc Councilor Ramon R. Melliza Councilor Franklin M. Gacal, Jr. (late) Councilor Rosalita T. Nuñez Councilor Brix T. Tan Councilor...»

«WELCOME TO LINDLEY CHURCH OF ENGLAND INFANT SCHOOL A Guide to Starting School for you and your Child Welcome from the Headteacher It is with great pleasure that we welcome you and your child to Lindley Church of England Infant School. Over the next few years we hope to get to know your child as well as you do, provide them with the best education and help nurture and develop their personal and social skills. We have a very successful and happy school that is held in high regard by the local...»

«Tijdschrift van het N ederlands Radiogenootsehap DEEL 25 No. 1 1960 Een instrument voor het meten van zeer kleine capaciteitsvariaties door P. de W aard *) Sum m ary A description is given of an instrument for the measurement of very small capacitance variations. Form ula’s are derived for the theoretical limits on linearity, noise level and dynamic range. Practical limits on these characteristics are discussed. Stability of the instrument, expressed as an equivalent capacitance change is 1 0...»

«COUNSEL TO CHRISTIANS GEORGE MULLER FirstLove Publications P.O. Box 2190 Dublin, CA 94568 Tel. (510) 305-3994 www.firstlovepublications.org info@firstlovepublications.org FirstLove Publications is a ministry of: Christ Bible Church Visit our web site: www.christbiblechurch.org to learn more about our church and to listen to messages from our sermon archive. Christian literature on various topics may be downloaded free of charge at: www.firstlovepublications.org Comments are welcome. Email us at...»

«House of Lords: Religious Representation The membership of the House of Lords includes twenty six Church of England Bishops and Archbishops on an ex officio basis, their right to sit and vote in the House established by ancient usage and by statute. This Library Note provides background information on the role of Bishops in the second chamber, and in the context of the Government‘s proposals for reform of the House, it examines arguments made both in favour and against their continued...»

«Is Public-Private Partnership Obsolete? Assessing the Obstacles and Shortcomings of PPP Claude M´nard e To cite this version: Claude M´nard. Is Public-Private Partnership Obsolete? Assessing the Obstacles and Shorte comings of PPP. Piet de Vries et Etienne B. Yehoue. The Routledge Companion to PublicPrivate Partnerships, Routledge, pp.149-174, 2013, 978-0-415-78199-2. halshs-00653090 HAL Id: halshs-00653090 https://halshs.archives-ouvertes.fr/halshs-00653090 Submitted on 23 Jan 2012 HAL is a...»

«COLLEGIALITY OF BISHOPS AND PRIESTS1/ by Fr. Eugene Duffy2/ Serious problems are beginning to develop in the priest-bishop relationship as a result of how the child sexual abuse crisis has been handled. There is a real danger that this strained relationship might take root and become a defining feature of how priests and bishops relate to one another. If such were to happen, it would go against the tradition of the Church, which has always seen priest and bishop as the closest of co-operators...»

«Report title Agenda item Property PFI Project Progress Report Meeting Date Finance, Procurement & Property Committee 17 November 2008 Report by Document Number (29/10/2008) Head of Property FEP 1271 Public Summary This report updates on progress with the Property PFI Project since the last report in September 2008 (FEP 1241) and seeks members’ approval to reduce the project scope to fit within the assumed level of PFI credits (see part II report on today’s agenda). It also updates on the...»

«Daniel's Den Together Everyone Achieves More Annual Report 1 September 2010 – 31st August 2011 Daniel’s Den Company Limited by Guarantee Registration number 5303714 Registered Office 38 Berkhamsted Avenue, Wembley, Middlesex HA9 6DT England -1– Daniel’s Den Annual Report 1 September 2010 – 31 August 2011 Contents Page 1 Front cover 2 Contents A message from the Managing Director of Daniel’s Den What is our mission and vision? Who’s who – members of teams 5-10 What have we done?...»

«City of Sherwood, Oregon Request for Proposals For Consultant Services Sanitary Sewer System Master Plan Update General Information The City of Sherwood owns, operates, and manages a gravity sanitary sewer collection system. Trunk sewers, pumping stations, pressure mains, and treatment facilities are under the auspices of Clean Water Services (CWS). The City of Sherwood is seeking the services of a qualified consulting engineering firm to prepare a comprehensive Sanitary Sewer System Master...»

«MATRON/HOUSEKEEPER – Residential post (Westcott House – maximum 44 girls aged 11-17, and Grosvenor House – maximum 18 boys aged 11-13) Full-time, term-time only To commence September 2016 Sherborne International was founded in 1977 as the original International Study Centre. Its early mission was simply to help non-native English speaking boys from overseas to prepare to sit Sherborne School’s entry examination. However its aim now is to prepare both boys and girls from overseas to join...»

<<  HOME   |    CONTACTS
2017 www.thesis.dislib.info - Online materials, documents

Materials of this site are available for review, all rights belong to their respective owners.
If you do not agree with the fact that your material is placed on this site, please, email us, we will within 1-2 business days delete him.