1 institute of information technologies at bulgarian academy of science (iit-bas)

IMAGE PROCESSING SUGGESTIONS TO IMPROVETHE ASTRONOMICAL MULTIEXPOSURE WIDE FIELD

PLATES METHOD

1Institute of Information Technologies at Bulgarian Academy of Science (IIT-BAS) 2Astronomical Observatory, Belgrade

8th Serbian-Bulgarian Astronomical Conference

May 08-12, 2012, Leskovac, Serbia

a presentation by Dimo T. Dimov1

(dtdim@iinf.bas.bg )in collaboration with Milan Dimitrijevic2

(mdimitrijevic@aob.bg.ac.rs )

Acknowledgements

This work was supported by following grant of the Institute of Information Technologies (IIT) at Bulgarian Academy of Sciences (BAS): Grant # DO-02-275/2008 of the National Science Fund at Bulgarian Ministry of Education & Science.

Contents

1. Introduction2. Proposed Method Description

- Preliminary notes- The method’s idea- Formal description of the method- Extended interpretations- The algorithm proposed

3. Experiments and Discussion4. Conclusion

References

1. Aniol, R., H.W. Duerbeck, W.C. Seitter, M.K. Tsvetkov, An automatic search for flare stars in southern stellar aggregates of different ages, In L.V. Mirzoyan, B.R. Pettersen and M.K. Tsvetkov (Eds.), Flare Stars in Star Clusters, Associations and Solar Vicinity, IAU Symp. 137, Kluwer Acad. Publish., Dordrecht-Boston-London, 1990, pp. 85-94.

2. Winterberg, J., M. Nolte, W.C. Seitter, H.W. Duerbeck, M.K. Tsvetkov, K.P. Tsvetkova, “Flares and Flashes”, In J. Greiner, H.W. Duerbeck and R.E. Gershberg (Eds.), Proc. IAU Coll. 151, Springer Verlag, Berlin, 1995, p. 119.

3. Dimov, D., K. Tsvetkova, M. Tsvetkov, A. Kolev, O. Kounchev, Hough Transform Approach to Flare Stars Identification in Multi-Exposure Plates Images, Serdica J. of Computing (in a special issue on Astroinformatics) (to appear 2012)

4. Tsvetkov, M. K, K. Y. Stavrev, K. P. Tsvetkova, E. H. Semkov, A. S. Mutafov, and M. E. Michailov, The Wide-Field Plate Database: Present Status and Future Development, Baltic Astronomy, vol. 6, 271-274, 1997.

5. Dimov, D., A. Dimov, Data Driven Approach to Binarization of Astronomical Images, In: Proceedings of CompSysTech’10, June 17-18, 2010, Sofia, Bulgaria, Mini-Symposium on Astroinformatics, in 2010 - ACM International Conf. Proceeding Series, Vol. 471, ACM PRESS, NY, USA, ISBN 978-1-4503-0243-2, pp. 478-484.

6. Bertin, E., and S. Arnouts, SExtractor: Software for source extraction, Astronomy & Astrophysics Supplement Series, 117, (1996), 393-404.

An original image of “stellar chains” scanned from an archive photo plate in the

Pleiades area

The original wide field plate was produced using

the Multi Exposure Wide Field Plates Method

well known from astronomy practice of last century

1. Introduction1. Introduction

A small part of the original “stellar chains” image, zoomed.

It is well visible many chains overlap each other. And the question is: Are there any better choices for the chains Are there any better choices for the chains

params (chains’ direction and distances among components) params (chains’ direction and distances among components)

1. Introduction …1. Introduction …

1. Introduction …1. Introduction …

Are there any other choices for the chains params (chains’ direction Are there any other choices for the chains params (chains’ direction and distances among components) so that:and distances among components) so that:

- The number of overlapping chains to be minimum when The number of overlapping chains to be minimum when considering at least the well visible stars (chains) in the image ?considering at least the well visible stars (chains) in the image ?

Perhaps, it is a little late to put such a question having in mind the Perhaps, it is a little late to put such a question having in mind the Multi Exposure Wide Field Plates Method is considered obsolete for the current astronomy practice.

On the other hand, it seems very possible the astronomers’ interests On the other hand, it seems very possible the astronomers’ interests in the in the Multi Exposure Wide Field Plates Method to be renovated to be renovated due to the CCD/LCD Astronomy coming to replace the usage of due to the CCD/LCD Astronomy coming to replace the usage of classical photography. classical photography.

Any case having of positive answer to above question could help the Any case having of positive answer to above question could help the image processing quality evaluation of archival wide field image processing quality evaluation of archival wide field palates with stellar chains.palates with stellar chains.

2. Proposed Method Description

Preliminary notes:Preliminary notes:

- A preview of an original (negative) wide field plate of Pleiades area;- A preview of an original (negative) wide field plate of Pleiades area;

- Binarized (work positive) image (BPI); the rhomboidal artifact in the centre is - Binarized (work positive) image (BPI); the rhomboidal artifact in the centre is cleaned interactively;cleaned interactively;

2. Proposed Method Description …

Preliminary notes:Preliminary notes:

- Two general types of chains can be defined: a linear and a non linear one.- Two general types of chains can be defined: a linear and a non linear one.

- The linear chains are considered here, and the results are generalized for the non - The linear chains are considered here, and the results are generalized for the non linear chains.linear chains.

0,,2 6,55,44,33,22,1 ddddddd- It is usually fulfilled for the distances between consecutive components of each - It is usually fulfilled for the distances between consecutive components of each

chain:chain:

- - For the number For the number nn of components we will consider of components we will consider nn=6.=6.

2. Proposed Method Description …

The proposed method idea:The proposed method idea:

- The Disjunctive Accumulated Image (DAI): Its black areas represent all possible choices - The Disjunctive Accumulated Image (DAI): Its black areas represent all possible choices for chains of length 2 (components).for chains of length 2 (components).

- How to produce DAI:- How to produce DAI:

1) get a basic empty image with 1) get a basic empty image with size equal to input BPI;size equal to input BPI;

2) make a disjunction with the BPI 2) make a disjunction with the BPI so that a given star to coincide so that a given star to coincide with the initial centre; with the initial centre;

3) make the same but for another 3) make the same but for another star, for a third one, an so on, star, for a third one, an so on, for each of the stars in BPI.for each of the stars in BPI.

The result image is the wanted DAI.The result image is the wanted DAI.

2. Proposed Method Description …

BPI RDIBPI RDI

The proposed method idea:The proposed method idea:

- The Restricted DAI (RDI) of size = ½ min(Xsize, Ysize), is really necessary - The Restricted DAI (RDI) of size = ½ min(Xsize, Ysize), is really necessary to represent to represent all actual choices for chains of length 2 (components).all actual choices for chains of length 2 (components).

2. Proposed Method Description …

RDI(2) = RDI RDI(3)RDI(2) = RDI RDI(3)

The proposed method idea:The proposed method idea:

- Scale RDI by 3/2, and make a disjunction with the initial RDI. The result RDI(3) represents - Scale RDI by 3/2, and make a disjunction with the initial RDI. The result RDI(3) represents all actual choices for chains of length 3 (components).all actual choices for chains of length 3 (components).

2. Proposed Method Description …

The proposed method idea:The proposed method idea:

- Scale RDI(3) by 4/3, and make a disjunction with the initial RDI(3). The result RDI(4) - Scale RDI(3) by 4/3, and make a disjunction with the initial RDI(3). The result RDI(4) represents all actual choices for chains of length 4 (components).represents all actual choices for chains of length 4 (components).

RDI(3) RDI(4)RDI(3) RDI(4)

2. Proposed Method Description …The proposed method idea:The proposed method idea:

- Scale RDI(4) by 5/4, and make a disjunction with the initial RDI(4). The result RDI(5) - Scale RDI(4) by 5/4, and make a disjunction with the initial RDI(4). The result RDI(5) represents all actual choices for chains of length 5 (components).represents all actual choices for chains of length 5 (components).

RDI(4) RDI(5)RDI(4) RDI(5)

2. Proposed Method Description …

RDI(5) RDI(6)RDI(5) RDI(6)

The proposed method idea:The proposed method idea:

- Scale RDI(5) by 6/5, and make a disjunction with the initial RDI(5). The result RDI(6) - Scale RDI(5) by 6/5, and make a disjunction with the initial RDI(5). The result RDI(6) represents all actual choices for chains of length 6 (components).represents all actual choices for chains of length 6 (components).

2. The proposed method result …

Optimal chains: Optimal chains:

- Slope =163- Slope =163- Basic distance = 11/1680- Basic distance = 11/1680

- Overlapping = 5 %- Overlapping = 5 %

Chains of the archive plate: Chains of the archive plate:

- Slope =3- Slope =3- Basic distance = 6/1680- Basic distance = 6/1680

- Overlapping = 29 %- Overlapping = 29 %

Discussion & Conclusions

Discussion ?

(about the method proposed considered as):

• A post processing tool to evaluate the quality of the images of archival wide field plates with stellar chains

• A pre processing tool before the real usage of the MultiExposure (wide field) Plate Method (MEPM); it would make sense if you decide the CCD/LCD Astronomy (coming to replace the photography Astronomy) will be able and/or will have a need to rehabilitate the MEPM

Thank You !(for your interest and questions )

Extra slides

Extra 1

gBPIgBPI

(star spots are replaced with original gRDI(star spots are replaced with original gRDI

intensities)intensities)

The proposed method idea:The proposed method idea:

- The Restricted Gray DAI (gRDI) of size = ½ min(Xsize, Ysize), is really necessary - to - The Restricted Gray DAI (gRDI) of size = ½ min(Xsize, Ysize), is really necessary - to represent all actual choices for chains of length 2 (components). The darker is the represent all actual choices for chains of length 2 (components). The darker is the pixel the better is choice of using it for 2-d components place.pixel the better is choice of using it for 2-d components place.

Extra 2

gRDI(2) = gRDI RDI(2)gRDI(2) = gRDI RDI(2)

Actual choices for chains of length 2 (components):Actual choices for chains of length 2 (components):

CompareCompare: Gray version with B/W version: Gray version with B/W version

Extra 3

Actual choices for chains of length 3 (components):Actual choices for chains of length 3 (components):

CompareCompare: Gray version with B/W version: Gray version with B/W version

gRDI(3) RDI(3)gRDI(3) RDI(3)

Extra 4Actual choices for chains of length 4 (components):Actual choices for chains of length 4 (components):

CompareCompare: Gray version with B/W version: Gray version with B/W version

RDI(4) RDI(4)RDI(4) RDI(4)

Extra 5Actual choices for chains of length 5 (components):Actual choices for chains of length 5 (components):

CompareCompare: Gray version with B/W version: Gray version with B/W version

gRDI(5) RDI(5)gRDI(5) RDI(5)

Extra 6

gRDI(6) RDI(6)gRDI(6) RDI(6)

Actual choices for chains of length 6 (components):Actual choices for chains of length 6 (components):

CompareCompare: Gray version with B/W version: Gray version with B/W version