Axial and instantaneous tangential curvature map in Corneal Topography. How to convert axial map to tangential map?

More G. Lombardo's questions See All

Can someone suggest a way to prepare slides to observe under confocal microscope for observing fluorescent tagged proteins??

I am growing the cells on coverslips and transfecting the fluorescent tagged protein directly on them. Then i want to observe these cells under confocal microscope. Currently i am just using...

01 March 2021 6,142 3 View

How or where can I get the crystallographic information file (CIF) for PCN-222 MOF?

I need the simulated XRD pattern of PCN-222 to compare with experimental data. Thanks.

19 February 2021 4,932 3 View

Websites for virtual lab in semiconductors?

Hello everyone, Because of Covid, now all classes are online. Is there good website that also are easy to use to teach student virtual experiments about PN junctions and semiconductors? Thank...

24 December 2020 6,637 2 View

From the EDAX analyses if the material which is coated is not observed in maximum percentage then how can interpret the results?

If we doped metal oxide to semiconducting material in different ratios then the property of the resultant material will be increased.But in some lower ratios when we go through the elemental...

16 December 2020 8,190 2 View

Is there any software for calculating hit bias (HB), missed precipitation (MP), and false precipitation (FP)?

I have a time series of two rainfall products. For error decomposition analysis, I have to calculate HB, MB and FB. Is there any software for calculating these variables.

27 November 2020 980 2 View

Why Schiff bases change colour upon evaporation?

I got bright yellow coloured Schiff base after 6 hour reaction time. So i kept it for slow evaporation. Solvent was methanol. But after complete evaporation my product colour changes from yellow...

17 November 2020 3,824 2 View

How to make the children cool, who feel stressful during this pandemic-lock down without having physical outlet?

The discussion may feed the parents a way to manage and guide the children in a right direction.

12 November 2020 1,302 9 View

How to design qPCR primer for mature microRNA?

09 November 2020 9,163 3 View

Which force field should be used to simulate protein-protein complex in gromacs?

Hi, I have done a protein-protein docking. Now I want to perform MD in gromacs. I am confused with forcefields. When I tried to findout, everywhere it is written for protein-ligand but I couldn't...

29 September 2020 1,410 3 View

Charcoal mediated steroid depletion assay?

Suppose, one is doing enzyme assay of an enzyme of a steroidogenic pathway. Is it necessary to deplete the steroids from the tissue/ cell homogenate before administering substrates to check enzyme...

21 September 2020 7,439 2 View

Anyone that can help with Maxquant TMT16plex which is missing?

Hi I am very new to proteomics analysis. I have got raw files from core facility running thermofisher TMT 16plex 4 hours. I cannot find on maxquant the option TMT16Plex there is only up to 11...

25 February 2021 1,675 3 View

Fractional impervious surface (FIS) map ?

Need Help Does anyone Know how to make a Fractional impervious surface (FIS) map from NDVI map, in ArcGIS environment? Thanks in advance

24 February 2021 8,455 2 View

Can you mention any source which presents an updates forest-fire hazard or vulnerability map of North-East India?

There exists a confusion of generating fire-hazard maps with MODIS data as that way, we cannot distinguish between shifting agriculture and wildfires. I am looking for a source that provides me...

22 February 2021 9,616 2 View

Historical wind data/map?

Hello All, I am looking for the historical wind data/map (mainly the year 2020-2021). I would like to look at the wind value and direction for the specifics locations within the US for the...

18 February 2021 9,543 4 View

How can we quantify martensite in Ferrous and Titanium alloys?

How can we quantify metastable phases like martensite in Ferrous and Titanium alloys, in relation to their stable counterpart For example in EBSD, XRD, Optical? Eg, Martensite and Ferrite maps.

09 February 2021 7,572 3 View

How to perform HeatMaps of RNAseq data?

Hey, Does anyone know an easy tool (website, software ) to create a heat map for RNA-seq Data. Thank you

04 February 2021 5,979 4 View

Can anyone suggest a numerical method to calculate perimeter of a contour in charge density contour maps?

Hi i have drawn the charge density contour maps using VESTA taking CHGCAR files from VASP. Now, What I Want is that I need to know the perimeter of each contour appearing in the cross section 2D...

04 February 2021 3,637 1 View

In which group does Fine loamy, Coarse Loamy, Coarse Silty and Fine Soil falls?

I am preparing HSG map for which I need to classify the above soils into HSG group. Just want to confirm their classification i.e in which category they fall?

03 February 2021 9,902 1 View

Does Location Map of Informal Settlements in South Africa exist?

I urgently need a map that shows the point locations of informal settlements in South Africa. I am currently working on a study that seeks to relate protests location to the location of informal...

02 February 2021 4,113 7 View

How to write a literature review on fuzzy cognitive map?

want to know how to write a literature review regarding fuzzy cognitive map for my thesis work .Is there any website or search engine to write a literature review otherwise give me a idea to...

29 January 2021 4,015 4 View

Jean-Marie Parel

Call Fabrice, like us he is working from home and will be happy to see you are still doing research projects!

Siddhartha Gairola

Hi G. Lombardo could you please help out with the Axial Map generation. We too have raw placido based images.

If there is some relevant publication or open-source code that could be used, it would be very helpful.

Thanks!

G. Lombardo

Ciao Siddhartha Gairola ! You can use this nice "APPLIED OPTICS - Vol. 52, No. 7,C24-C29 ( 2013) in which you will find a method to derive AXIAL MAP and a preliminary open access routine. My suggestion it is to develop a robust routine to exctract the "placido rings" from your images (so the images should be fine) and then you need to acquire the placido rings from "sphere" within known curvature (you need at least 4/5 sphere of curvature ranging from 6-9 mm). Then I find a nice publication how to derive instantaneous/tangetial map from axial map. It is "Axial and Instantaneous Power Conversion in Corneal Topography" of Stanley A. Klein. I hope I have been of help.

G. Lombardo Thank you Sir for your help :)

I have taken a look at the following resource "Open-access operating algorithms for commercial videokeratographer and improvement of corneal sampling" by Julián Espinosa, David Mas, Jorge Pérez, and Ana Belén Roig.

Am now working on understanding it. Thanks a lot :)

Hi G. Lombardo the Axial map generation algorithm works well with the calibration step.

Did you figure out a way to generate the Tangential (Curvature) Maps?

I am trying to compute the instantaneous radius at each point using curve fitting. But that doesn't seem to work very well.

Ciao Siddhartha Gairola , I follow the step described in "Axial and Instantaneous Power Conversion in Corneal Topography" of Stanley A. Klein to derive the tangential curvature. Now I'm goindo to study arc-step method to have a more realiable tangential map. I wish you a nice day.

Ciao G. Lombardo , thank you for your help. Does the "Axial and Instantaneous Power Conversion in Corneal Topography" work well?

Also, the paper related to "Arc-Step Method" is not public. Could you please point to a paper or resource that explains this method well?

Thanks. Wishing you a good day ahead.

Hi Siddhartha Gairola I have implemented the algorithm to retrieve the instantaneous tangential curvature from axial and it seems it works fine. You need to "smooth" the result in order to have a realiable map. For arc-step method I m going to study the public article that are published. I'm just studying the method.