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StefanJAuer / RaySAR

RaySAR is a 3D synthetic aperture radar (SAR) simulator which enables to generate SAR image layers related to detailed 3D object models. Moreover, it enables one to localize the 3D positions and surface intersection points related to reflected radar signals. In particular, RaySAR helps to understand the nature of signal multiple reflections at man-made objects (e.g. building structures) or artificial shapes. Scene models with different levels of detail can be processed - from digital surface models (DSMs) to high-end 3D structures - which can be defined in relative or absolute world coordinates. RaySAR can be run on Windows / Linux and is based on an adapted version of the open-source ray tracer POV-Ray.
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How to adjust the visualization of 2D images from Pov-Ray to RaySAR simulation to be consistent? #14

Open hks211 opened 6 months ago

hks211 commented 6 months ago

Dear Professor, When simulating a virtual tower with RaySAR, in the “Maps in 2D” module, I found that the visualization of the images I simulated is inconsistent with what is displayed in Pov-Ray. I imitated the detailed_building model Pov-Ray code you provided and made some modifications. Here are some steps of my simulation process. image (1) No Ground added and rotate <0,0,0> Due to Pov-Ray following the left-handed coordinate system, I adjusted the translation and rotation parameters. According to “look at <0,0, -60.458>”, I modified “translate <0,0, 60.458>” and “rotate <0,0,0>”. image image image image image image (2) No Ground added and rotate <90,0,0> I adjusted the translation and rotation parameters. According to “look at <0,0, -60.458>”, I modified “translate <0,0, 60.458>” and “rotate <90,0,0>”. image image image image The simulated results above are inconsistent with the orientation displayed in Pov-Ray. I’m not sure if this is related to the understanding of this. image I don't know how to set the parameters to solve this problem , could you please give me some advice? Looking forward to your reply.

StefanJAuer commented 6 months ago

Could you specify what you mean with “inconsistent”, please?

For better orientation, it is useful to add high roughness to all surfaces for the initial modeling/simulation and switch to realistic specular reflection when conducting the final simulation.

Von: hks211 @.> Gesendet: Samstag, 16. März 2024 13:46 An: StefanJAuer/RaySAR @.> Cc: Subscribed @.***> Betreff: [StefanJAuer/RaySAR] How to adjust the visualization of 2D images from Pov-Ray to RaySAR simulation to be consistent? (Issue #14)

Dear Professor, When simulating a virtual tower with RaySAR, in the “Maps in 2D” module, I found that the visualization of the images I simulated is inconsistent with what is displayed in Pov-Ray. I imitated the detailed_building model Pov-Ray code you provided and made some modifications. Here are some steps of my simulation process. (1) No Ground added and rotate <0,0,0> Due to Pov-Ray following the left-handed coordinate system, I adjusted the translation and rotation parameters. According to “look at <0,0, -60.458>”, I modified “translate <0,0, 60.458>” and “rotate <0,0,0>”. image.png (view on web)https://github.com/StefanJAuer/RaySAR/assets/144893250/f5ad6b4b-fdae-41a3-b34e-90c74276c2ab image.png (view on web)https://github.com/StefanJAuer/RaySAR/assets/144893250/479a327c-1d91-44ea-8f3d-3c7f5ccbda46 image.png (view on web)https://github.com/StefanJAuer/RaySAR/assets/144893250/967d9d4c-1d7f-40c8-bc56-446e4f1b6110 image.png (view on web)https://github.com/StefanJAuer/RaySAR/assets/144893250/06e47987-281f-41c4-a940-5c53c0fec46f image.png (view on web)https://github.com/StefanJAuer/RaySAR/assets/144893250/93aa0dec-60a2-41cd-91af-9c1e30ce2b57 image.png (view on web)https://github.com/StefanJAuer/RaySAR/assets/144893250/261d56d6-7238-4f56-9223-8be8328833f2 (2) No Ground added and rotate <90,0,0> I adjusted the translation and rotation parameters. According to “look at <0,0, -60.458>”, I modified “translate <0,0, 60.458>” and “rotate <90,0,0>”. image.png (view on web)https://github.com/StefanJAuer/RaySAR/assets/144893250/4c82ba25-9a9b-4dbc-862b-130c2c5ff944 image.png (view on web)https://github.com/StefanJAuer/RaySAR/assets/144893250/9ca78160-c1fb-444d-9cdc-45768675fd37 image.png (view on web)https://github.com/StefanJAuer/RaySAR/assets/144893250/21820144-6e15-4422-afb0-98fd03930095 image.png (view on web)https://github.com/StefanJAuer/RaySAR/assets/144893250/c76b1098-ba8e-4bf0-a427-1782a521aa4b The simulated results above are inconsistent with the orientation displayed in Pov-Ray. I’m not sure if this is related to the understanding of this. image.png (view on web)https://github.com/StefanJAuer/RaySAR/assets/144893250/64139263-2ba6-4cf5-9ce2-9cd4845a93d8 I don't know how to set the parameters to solve this problem , could you please give me some advice? Looking forward to your reply.

— Reply to this email directly, view it on GitHubhttps://github.com/StefanJAuer/RaySAR/issues/14, or unsubscribehttps://github.com/notifications/unsubscribe-auth/AD4U5T772AJZFR3MOT3PSCDYYQ5IBAVCNFSM6AAAAABEZJL5VGVHI2DSMVQWIX3LMV43ASLTON2WKOZSGE4DSOJVGE4TINI. You are receiving this because you are subscribed to this thread.Message ID: @.**@.>>

hks211 commented 6 months ago

Due to Pov-Ray follows a left-handed coordinate system, why are the simulated SAR images generated by Pov-Ray different from the reflection intensity images generated by RaySAR? image Here are some of my understandings, mapping from Pov-Ray to RaySAR is to look down on the y-axis, the x-axis is mapped to Azimuth, and the z-axis is mapped to Slant Range Pixels. So we see a different image in RaySAR than the image we see in Pov-Ray, is that right?

StefanJAuer commented 6 months ago

POV-Ray renders optical images in the width & height plane (optical images), RaySAR uses the generated point cloud of SAR phase centers to generate images in the width & depth plane (reflectivity maps). Hence, there is a difference by definition.

Regards Stefan Auer

Von: hks211 @.> Gesendet: Montag, 18. März 2024 13:09 An: StefanJAuer/RaySAR @.> Cc: Auer, Stefan @.>; Comment @.> Betreff: Re: [StefanJAuer/RaySAR] How to adjust the visualization of 2D images from Pov-Ray to RaySAR simulation to be consistent? (Issue #14)

Due to Pov-Ray follows a left-handed coordinate system, why are the simulated SAR images generated by Pov-Ray different from the reflection intensity images generated by RaySAR? image.png (view on web)https://github.com/StefanJAuer/RaySAR/assets/144893250/02378e04-52dc-4c5a-9063-6fbb6863780a Here are some of my understandings, mapping from Pov-Ray to RaySAR is to look down on the y-axis, the x-axis is mapped to Azimuth, and the z-axis is mapped to Slant Range Pixels. So we see a different image in RaySAR than the image we see in Pov-Ray, is that right?

— Reply to this email directly, view it on GitHubhttps://github.com/StefanJAuer/RaySAR/issues/14#issuecomment-2003743261, or unsubscribehttps://github.com/notifications/unsubscribe-auth/AD4U5T5PP5CMOFAWC2KMIF3YY3KONAVCNFSM6AAAAABEZJL5VGVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDAMBTG42DGMRWGE. You are receiving this because you commented.Message ID: @.***>

hks211 commented 6 months ago

Thank you for your guidance, which made me better understand the principles of simulation, and then I correctly generated the correct results.