Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

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Detecting Building Changes between Airborne Laser Scanning and Photogrammetric Data
Zhang, Zhenchao ; Vosselman, George ; Gerke, Markus ; Persello, Claudio ; Tuia, Devis ; Yang, Michael Ying - \ 2019
Remote Sensing 11 (2019)20. - ISSN 2072-4292 - 17 p.
Detecting topographic changes in an urban environment and keeping city-level point clouds up-to-date are important tasks for urban planning and monitoring. In practice, remote sensing data are often available only in different modalities for two epochs. Change detection between airborne laser scanning data and photogrammetric data is challenging due to the multi-modality of the input data and dense matching errors. This paper proposes a method to detect building changes between multimodal acquisitions. The multimodal inputs are converted and fed into a light-weighted pseudo-Siamese convolutional neural network (PSI-CNN) for change detection. Different network configurations and fusion strategies are compared. Our experiments on a large urban data set demonstrate the effectiveness of the proposed method. Our change map achieves a recall rate of 86.17%, a precision rate of 68.16%, and an F1-score of 76.13%. The comparison between Siamese architecture and feed-forward architecture brings many interesting findings and suggestions to the design of networks for multimodal data processing.
Change detection between digital surface models from airborne laser scanning and dense matching using convolutional neural networks
Zhang, Z. ; Vosselman, G. ; Gerke, M. ; Persello, C. ; Tuia, D. ; Yang, M.Y. - \ 2019
In: ISPRS Geospatial Week 2019, 10–14 June 2019, Enschede, The Netherlands. - ISPRS (ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences ) - p. 453 - 460.
Airborne Laser Scanning - Change Detection - Convolutional Neural Network (CNN) - Dense Image Matching - Digital Surface Model (DSM)

Airborne photogrammetry and airborne laser scanning are two commonly used technologies used for topographical data acquisition at the city level. Change detection between airborne laser scanning data and photogrammetric data is challenging since the two point clouds show different characteristics. After comparing the two types of point clouds, this paper proposes a feed-forward Convolutional Neural Network (CNN) to detect building changes between them. The motivation from an application point of view is that the multimodal point clouds might be available for different epochs. Our method contains three steps: First, the point clouds and orthoimages are converted to raster images. Second, square patches are cropped from raster images and then fed into CNN for change detection. Finally, the original change map is post-processed with a simple connected component analysis. Experimental results show that the patch-based recall rate reaches 0.8146 and the precision rate reaches 0.7632. Object-based evaluation shows that 74 out of 86 building changes are correctly detected.

Interferometric phase difference segmentation using Fourier parameterised deformable models
Varekamp, C. ; Hoekman, D.H. - \ 1999
In: ASCI'99 : proceedings of the Fifth Annual Conference of the Advanced School for Computing and Imaging, Heijen, The Netherlands, 15-17 June 1999 / M. Boasson, J.A. Kaandorp, J.F.M. Tonino and M.G. Vosselman (eds). - [S.l.] : [s.n.], 1999 - p. 315 - 320.
Meiotic segregation of five different reciprocal translocations in the onion fly, Hylemya antiqua (Meigen)
Vosselman, L. - \ 1981
Chromosoma 81 (1981). - ISSN 0009-5915 - p. 727 - 738.
Translocations and sex ratio distortion in the onion fly, Hylemya antiqua (Meigen), and their relevance to genetic control
Vosselman, L. - \ 1980
Landbouwhogeschool Wageningen. Promotor(en): J. Sybenga. - Wageningen : Vosselman - 117
agromyzidae - anthomyiidae - calliphoridae - chromosoomtranslocatie - drosophilidae - genetische gewasbescherming - genetica - glossinidae - insecten - muscidae - geslacht (sex) - geslachtsbepaling - steriele insecten techniek - sterilisatie - tachinidae - tephritidae - stofverplaatsing - schizophora - agromyzidae - anthomyiidae - calliphoridae - chromosome translocation - drosophilidae - genetic control - genetics - glossinidae - insects - muscidae - sex - sex determination - sterile insect release - sterilization - tachinidae - tephritidae - translocation - schizophora
Experiments on sex determination of the onion fly, Hylemya antiqua (Meigen), are reported in the first two chapters. The main purpose was to establish if the sex ratio distortion observed in certain crosses, was based on a mechanism which could be used for genetic purposes. Two types of males, XY 1 and XXY 2 , were found and the aberrant sex ratios appeared only to occur in progenies of XXY 2 (and some XXY 2 Y 2 ) males. A numerical variation for Y 2 was frequently observed in embryos, larval ganglion cells and especially in testes, which is caused by numerical non-disjunction in somatic cells. The sex ratio distortion is attributed to such a numerical variation of Y 2 between primordial germ cells. Some progenies with a highly distorted sex ratio in male direction descended probably from XXY 2 Y 2 males. Since an effective selection of XXY 2 Y 2 males is not possible, this type of sex ratio distortion is not suited for application in a genetic control method. Other subjects treated in chapters 1 and 2 are gynandromorphism, a polymorphism with respect to the length of the X-chromosome and X-polysomy. In the progeny of one cross a chromosome morphologically identical to Y 2 but lacking its holandric inheritance was found. From its inheritance in various crosses it could be concluded that it was nothing more than a (mutated) non-functional Y 2 chromosome.

The meiotic segregation of a Y 1 -linked translocation T61 is reported in the third chapter. The high percentage of alternate segregation observed in T61-heterozygous males (22 YXY 2) was in good accordance with the high fertility of this translocation (95%). Because of an early separation (or asynapsis) of the centromeric regions of the acrocentric X and Y 2, chain quadrivalents with X and Y 2in terminal position predominated in diakinesis/ prometaphase I stages. In these chain quadrivalents adjacent l is supposed to be unstable since neither X nor Y 2have a neighbouring centromere in trans-position. The very low frequency of adjacent 2 is attributed to a preferential coorientation of homologous centromeres. The suitability of T61 for genetic sexing (preferential killing of females) is discussed.

Double-translocation heterozygous T14/T61 males (2 62 Y6 26XY 2) were produced by intercrossing T14-homozygous females (2 62 66 26 2XX) and T61-heterozygous males (22 Y66XY 2) These double heterozygotes showed several segregation types but for predominated. The total frequency of duplication/deficiency gametes was 60-65%. Application possibilities for these heterozygotes in genetic control of the onion fly are discussed.

The meiotic segregation of five different autosomal reciprocal translocations are given in chapter 5. For translocation T14, which has very short interstitial segments, significant differences in segregation between the sexes were found. In males the ratio of alt.: adj.1:adj.2 was about 7:3:0 and in females 8:1:3. It is assumed that the very intimate meiotic pairing in males (without chiasmata) results in relatively very short "Coorientation Determining Distances" (CDD's) between the homologous centromeres. Due to these short CDD's a preferential coorientation between homologous centromeres is expected favouring alternate and adjacent l segregation. On the contrary, in females chiasmata act very probably as reference points for coorientation. Due to variable positions of the centromeres, in T14-heterozygous females less pronounced differences in CDD's between homologous and non-homologous are expected as in males. This is suggested to be the reason that in females a coorientation between non-homologous centromeres can occur resulting in a certain frequency of adjacent 2. The very low frequencies or absence of adjacent 2 in the other four translocations is attributed to their longer interstitial segments.

For translocation T14 a pure breeding stock of homozygotes could be obtained using egg-hatch percentages and cytology for the recognition of the karyotypes (chapter 6). In cage experiments under laboratory conditions the competitiveness of the translocation homozygotes was tested. Starting from an initial population consisting of equal numbers of translocation homozygotes (TT) and wild type flies (++), the karyotype frequencies were determined for three successive, non-overlapping generations. The results obtained did not suggest substantial differences in fitness between TT and ++. In field cage experiments (chapter 7) a high diapause sensitivity was found for the translocation homozygotes as well as for the laboratory strain of wild type flies (++) used. As a consequence of this high diapause sensitivity the fitness of the homozygotes could not be determined under field conditions.

In the "General Discussion" different application possibilities of translocations for genetic control of the onion fly are discussed. A summary of unpublished data concerning the egg-hatch and pupal survival of eight threechromosome double-translocation heterozygotes and three more complex translocation heterozygotes is also presented there. The aim of these experiments was to determine if perhaps a double translocation could be isolated meeting the conditions for a stable equilibrium. However, neither of these translocations met these conditions. Firstly, the frequencies of duplication/deficiency gametes were not high enough; secondly, insufficient complementation occurred and, thirdly, the recombination percentages in the differential segments were too high (resulting in undesirable karyotypes). Two of three double translocations tested, appeared to be viable as homozygotes in the adult stage.

Genetic control of Delia antiqua. Sensitivity to diapause interfering with a field-cage experiment using a homozygous chromosomal translocation
Robinson, A.S. ; Herfst, J.M. ; Vosselman, L. - \ 1980
Bulletin of Entomological Research 70 (1980)1. - ISSN 0007-4853 - p. 103 - 111.
Fitness of a translocation homozygote in cage experiments with the onion fly, Hylemya antiqua (Meigen)
Vosselman, L. - \ 1980
Theoretical and Applied Genetics 58 (1980). - ISSN 0040-5752 - p. 79 - 85.
Sex determination of theonion fly Hylemya antiqua (Meigen) II. Sex ratio distortion by unstable somatic behaviour of chromosomme Y2, and inheritance of Y2 (YM)
Vosselman, L. - \ 1979
Chromosoma 75 (1979). - ISSN 0009-5915 - p. 353 - 367.
Sex determination of the onion fly, Hylemya antiqua (Meigen) 1. Sex chromosome polymorphism, gynandromorphism and X-polysomy
Vosselman, L. - \ 1978
Chromosoma 67 (1978). - ISSN 0009-5915 - p. 210 - 218.
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