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type: channel
description: Messages from Usenet group comp.lang.idl-pvwave, compiled by Paulo Penteado
items: extract circle from data with idl
items: Re: extract circle from data with idl

extract circle from data with idl
type: item
description: How can extract an circle or an ellipse from my data with IDL? With a contour plot my data form a circle, I need to know the center of this circle. From the geometry I know that if I know 3 points I can extract a circle, are there routine or function something else in IDL that using, reading my data, can give me the center?
creator: termybel
date: 2017-10-11T12:23:31-00:00

Re: extract circle from data with idl
type: item
description: On 10/11/2017 02:23 PM, termybel@gmail.com wrote: > How can extract an circle or an ellipse from my data with IDL? > With a contour plot my data form a circle, I need to know the center > of this circle. From the geometry I know that if I know 3 points I > can extract a circle, are there routine or function something else in > IDL that using, reading my data, can give me the center? ;; without using the properties of the circle or ellipse: ; DATA being the data to be contoured data=2-(([-1:1:.1]^2)#replicate(1.,21))-(replicate(1.,21)#([ -1:1:.1]^2)) ; LEVEL the appropriate level to contour level=1. contour, data, path_info=li, path_xy=lines, /path_data_coord, $ levels=[level], /path_double if n_elements(li) ne 1 then message, 'not exactly 1 contour' cont_obj =obj_new('IDLanROI',lines) void= cont_obj.ComputeGeometry(centroid=center) print, center[0:1] ;; otherwise use math to calculate the center
creator: Markus Schmassmann
date: 2017-10-11T12:41:43-00:00

Re: extract circle from data with idl
type: item
description: On Wednesday, 11 October 2017 14:23:33 UTC+2, term...@gmail.com wrote: > How can extract an circle or an ellipse from my data with IDL? > With a contour plot my data form a circle, I need to know the center of this circle. From the geometry I know that if I know 3 points I can extract a circle, are there routine or function something else in IDL that using, reading my data, can give me the center? Hi, you might also want to have a look at this article: http://www.idlcoyote.com/ip_tips/fit_ellipse.html Cheers, Helder
creator: Helder
date: 2017-10-11T12:47:50-00:00

Re: extract circle from data with idl
type: item
description: Thanks to answer but I have a probelm. You puth this: if n_elements(li) ne 1 then message, 'not exactly 1 contour' and my program say: not exactly 1 contour How I can solve it? If I ask in idl " help,/str,li" and the answer is: Structure CONTOUR_DBL_PATH_STRUCTURE, 6 tags, length=24, data length=20: TYPE BYTE 1 HIGH_LOW BYTE 1 LEVEL INT 0 N LONG 7 OFFSET LONG 0 VALUE DOUBLE 9.0000000 and for " help,/str,lines" LINES DOUBLE = Array[2, 5447] My contour isn't a perfect circle. Maybe is this the problem? This is my program where the image is a flat field panel minus dark: file_ff1='ff_100s_3.fits' ;immagine immagine_ff1=readfits (file_ff1, header1) ; leggo l'immagine del flat field panel file_dark='ff_100s_dark_3.fits' ;immagine immagine_dark=readfits (file_dark, header1) ; leggo l'immagine della dark n=100. ; secondi di esposizione dell'immagine ffp=(immagine_ff1-immagine_dark)/n ; contour per selezionare soglie di equivalore speriamo=fltarr(2048,2048) ; creo una matrice 2048x2048 dimensioni=size(speriamo,/dimensions) cubo=where(ffp lt 9.5 or ffp gt 10) wrong_matrix=array_indices(dimensioni, cubo,/dimensions) indxw=reform(wrong_matrix(0,*)) indyw=reform(wrong_matrix(1,*)) ;ffp(indxw,indyw)=0. ;c = CONTOUR(ffp, dimensions=[512,512], Title='prova cubo') ; DATA being the data to be contoured level=9 contour, smooth(ffp(250:1700, 250:1700),3), path_info=li,closed=1 , path_xy=lines, /path_data_coord, levels=[level], /path_double ; lix=lines(0,*) ; liy=lines(1,*) ; liyd=deriv(lix,liy) ;ind=where(abs(liyd) le 0.0001) if n_elements(li) ne 1 then message, 'not exactly 1 contour' cont_obj =obj_new('IDLanROI',lines) void= cont_obj.ComputeGeometry(centroid=center) ;fit_ellipse( print, center[0:1] end
creator: termybel
date: 2017-10-12T12:10:30-00:00

Re: extract circle from data with idl
type: item
description: On 10/12/2017 02:10 PM, termybel@gmail.com wrote: > Thanks to answer but I have a probelm. > > You puth this: if n_elements(li) ne 1 then message, 'not exactly 1 contour' > > and my program say: not exactly 1 contour > > How I can solve it? > > If I ask in idl " help,/str,li" and the answer is: > > Structure CONTOUR_DBL_PATH_STRUCTURE, 6 tags, length=24, data length=20: > TYPE BYTE 1 > HIGH_LOW BYTE 1 > LEVEL INT 0 > N LONG 7 > OFFSET LONG 0 > VALUE DOUBLE 9.0000000 > > and for " help,/str,lines" > LINES DOUBLE = Array[2, 5447] > > My contour isn't a perfect circle. Maybe is this the problem? > > This is my program where the image is a flat field panel minus dark: > > file_ff1='ff_100s_3.fits' ;immagine > immagine_ff1=readfits (file_ff1, header1) ; leggo l'immagine del flat field panel > file_dark='ff_100s_dark_3.fits' ;immagine > immagine_dark=readfits (file_dark, header1) ; leggo l'immagine della dark > > n=100. ; secondi di esposizione dell'immagine > ffp=(immagine_ff1-immagine_dark)/n > > ; contour per selezionare soglie di equivalore > > speriamo=fltarr(2048,2048) ; creo una matrice 2048x2048 > dimensioni=size(speriamo,/dimensions) > cubo=where(ffp lt 9.5 or ffp gt 10) > > > > wrong_matrix=array_indices(dimensioni, cubo,/dimensions) > indxw=reform(wrong_matrix(0,*)) > indyw=reform(wrong_matrix(1,*)) > ;ffp(indxw,indyw)=0. > ;c = CONTOUR(ffp, dimensions=[512,512], Title='prova cubo') > > ; DATA being the data to be contoured > level=9 > contour, smooth(ffp(250:1700, 250:1700),3), path_info=li,closed=1 , path_xy=lines, /path_data_coord, levels=[level], /path_double > ; lix=lines(0,*) > ; liy=lines(1,*) > ; liyd=deriv(lix,liy) > ;ind=where(abs(liyd) le 0.0001) > > if n_elements(li) ne 1 then message, 'not exactly 1 contour' > > > cont_obj =obj_new('IDLanROI',lines) > void= cont_obj.ComputeGeometry(centroid=center) > ;fit_ellipse( > print, center[0:1] > > end contour, smooth(ffp(250:1700, 250:1700),3), path_info=li,closed=1 , $ path_xy=lines, /path_data_coord, leve…
creator: Markus Schmassmann
date: 2017-10-12T14:27:15-00:00

Re: extract circle from data with idl
type: item
description: Il giorno giovedì 12 ottobre 2017 16:27:18 UTC+2, Markus Schmassmann ha scritto: > On 10/12/2017 02:10 PM, termybel@gmail.com wrote: >> Thanks to answer but I have a probelm. >> >> You puth this: if n_elements(li) ne 1 then message, 'not exactly 1 contour' >> >> and my program say: not exactly 1 contour >> >> How I can solve it? >> >> If I ask in idl " help,/str,li" and the answer is: >> >> Structure CONTOUR_DBL_PATH_STRUCTURE, 6 tags, length=24, data length=20: >> TYPE BYTE 1 >> HIGH_LOW BYTE 1 >> LEVEL INT 0 >> N LONG 7 >> OFFSET LONG 0 >> VALUE DOUBLE 9.0000000 >> >> and for " help,/str,lines" >> LINES DOUBLE = Array[2, 5447] >> >> My contour isn't a perfect circle. Maybe is this the problem? >> >> This is my program where the image is a flat field panel minus dark: >> >> file_ff1='ff_100s_3.fits' ;immagine >> immagine_ff1=readfits (file_ff1, header1) ; leggo l'immagine del flat field panel >> file_dark='ff_100s_dark_3.fits' ;immagine >> immagine_dark=readfits (file_dark, header1) ; leggo l'immagine della dark >> >> n=100. ; secondi di esposizione dell'immagine >> ffp=(immagine_ff1-immagine_dark)/n >> >> ; contour per selezionare soglie di equivalore >> >> speriamo=fltarr(2048,2048) ; creo una matrice 2048x2048 >> dimensioni=size(speriamo,/dimensions) >> cubo=where(ffp lt 9.5 or ffp gt 10) >> >> >> >> wrong_matrix=array_indices(dimensioni, cubo,/dimensions) >> indxw=reform(wrong_matrix(0,*)) >> indyw=reform(wrong_matrix(1,*)) >> ;ffp(indxw,indyw)=0. >> ;c = CONTOUR(ffp, dimensions=[512,512], Title='prova cubo') >> >> ; DATA being the data to be contoured >> level=9 >> contour, smooth(ffp(250:1700, 250:1700),3), path_info=li,closed=1 , path_xy=lines, /path_data_coord, levels=[level], /path_double >> ; lix=lines(0,*) >> ; liy=lines(1,*) >> ; liyd=deriv(lix,liy) >> ;ind=where(abs(liyd) le 0.0001) >> >> if n_elements(li) ne 1 then message, 'not exactly 1 contour' >> >> >> cont_obj =obj_new('IDLanROI',lines) >> void= cont_obj.ComputeGeometry(centroid=center) >> ;fit_e…
creator: termybel
date: 2017-10-15T15:43:58-00:00

Re: extract circle from data with idl
type: item
description: Il giorno giovedì 12 ottobre 2017 16:27:18 UTC+2, Markus Schmassmann ha scritto: > On 10/12/2017 02:10 PM, termybel@gmail.com wrote: >> Thanks to answer but I have a probelm. >> >> You puth this: if n_elements(li) ne 1 then message, 'not exactly 1 contour' >> >> and my program say: not exactly 1 contour >> >> How I can solve it? >> >> If I ask in idl " help,/str,li" and the answer is: >> >> Structure CONTOUR_DBL_PATH_STRUCTURE, 6 tags, length=24, data length=20: >> TYPE BYTE 1 >> HIGH_LOW BYTE 1 >> LEVEL INT 0 >> N LONG 7 >> OFFSET LONG 0 >> VALUE DOUBLE 9.0000000 >> >> and for " help,/str,lines" >> LINES DOUBLE = Array[2, 5447] >> >> My contour isn't a perfect circle. Maybe is this the problem? >> >> This is my program where the image is a flat field panel minus dark: >> >> file_ff1='ff_100s_3.fits' ;immagine >> immagine_ff1=readfits (file_ff1, header1) ; leggo l'immagine del flat field panel >> file_dark='ff_100s_dark_3.fits' ;immagine >> immagine_dark=readfits (file_dark, header1) ; leggo l'immagine della dark >> >> n=100. ; secondi di esposizione dell'immagine >> ffp=(immagine_ff1-immagine_dark)/n >> >> ; contour per selezionare soglie di equivalore >> >> speriamo=fltarr(2048,2048) ; creo una matrice 2048x2048 >> dimensioni=size(speriamo,/dimensions) >> cubo=where(ffp lt 9.5 or ffp gt 10) >> >> >> >> wrong_matrix=array_indices(dimensioni, cubo,/dimensions) >> indxw=reform(wrong_matrix(0,*)) >> indyw=reform(wrong_matrix(1,*)) >> ;ffp(indxw,indyw)=0. >> ;c = CONTOUR(ffp, dimensions=[512,512], Title='prova cubo') >> >> ; DATA being the data to be contoured >> level=9 >> contour, smooth(ffp(250:1700, 250:1700),3), path_info=li,closed=1 , path_xy=lines, /path_data_coord, levels=[level], /path_double >> ; lix=lines(0,*) >> ; liy=lines(1,*) >> ; liyd=deriv(lix,liy) >> ;ind=where(abs(liyd) le 0.0001) >> >> if n_elements(li) ne 1 then message, 'not exactly 1 contour' >> >> >> cont_obj =obj_new('IDLanROI',lines) >> void= cont_obj.ComputeGeometry(centroid=center) >> ;fit_e…
creator: termybel
date: 2017-10-15T16:08:02-00:00

Re: extract circle from data with idl
type: item
description: On 10/15/2017 06:08 PM, termybel@gmail.com wrote: > Il giorno giovedì 12 ottobre 2017 16:27:18 UTC+2, Markus Schmassmann ha scritto: >> On 10/12/2017 02:10 PM, termybel@gmail.com wrote: >>> Thanks to answer but I have a probelm. >>> >>> You puth this: if n_elements(li) ne 1 then message, 'not exactly 1 contour' >>> >>> and my program say: not exactly 1 contour >>> >>> How I can solve it? >>> >>> If I ask in idl " help,/str,li" and the answer is: >>> >>> Structure CONTOUR_DBL_PATH_STRUCTURE, 6 tags, length=24, data length=20: >>> TYPE BYTE 1 >>> HIGH_LOW BYTE 1 >>> LEVEL INT 0 >>> N LONG 7 >>> OFFSET LONG 0 >>> VALUE DOUBLE 9.0000000 >>> >>> and for " help,/str,lines" >>> LINES DOUBLE = Array[2, 5447] >>> >>> My contour isn't a perfect circle. Maybe is this the problem? >>> >>> This is my program where the image is a flat field panel minus dark: >>> >>> file_ff1='ff_100s_3.fits' ;immagine >>> immagine_ff1=readfits (file_ff1, header1) ; leggo l'immagine del flat field panel >>> file_dark='ff_100s_dark_3.fits' ;immagine >>> immagine_dark=readfits (file_dark, header1) ; leggo l'immagine della dark >>> >>> n=100. ; secondi di esposizione dell'immagine >>> ffp=(immagine_ff1-immagine_dark)/n >>> >>> ; contour per selezionare soglie di equivalore >>> >>> speriamo=fltarr(2048,2048) ; creo una matrice 2048x2048 >>> dimensioni=size(speriamo,/dimensions) >>> cubo=where(ffp lt 9.5 or ffp gt 10) >>> >>> >>> >>> wrong_matrix=array_indices(dimensioni, cubo,/dimensions) >>> indxw=reform(wrong_matrix(0,*)) >>> indyw=reform(wrong_matrix(1,*)) >>> ;ffp(indxw,indyw)=0. >>> ;c = CONTOUR(ffp, dimensions=[512,512], Title='prova cubo') >>> >>> ; DATA being the data to be contoured >>> level=9 >>> contour, smooth(ffp(250:1700, 250:1700),3), path_info=li,closed=1 , path_xy=lines, /path_data_coord, levels=[level], /path_double >>> ; lix=lines(0,*) >>> ; liy=lines(1,*) >>> ; liyd=deriv(lix,liy) >>> ;ind=where(abs(liyd) le 0.0001) >>> >>> if n_elements(li) ne 1 then message, 'not exactly 1 conto…
creator: Markus Schmassmann
date: 2017-10-16T09:20:56-00:00

Re: extract circle from data with idl
type: item
description: Il giorno lunedì 16 ottobre 2017 11:20:59 UTC+2, Markus Schmassmann ha scritto: > On 10/15/2017 06:08 PM, termybel@gmail.com wrote: >> Il giorno giovedì 12 ottobre 2017 16:27:18 UTC+2, Markus Schmassmann ha scritto: >>> On 10/12/2017 02:10 PM, termybel@gmail.com wrote: >>>> Thanks to answer but I have a probelm. >>>> >>>> You puth this: if n_elements(li) ne 1 then message, 'not exactly 1 contour' >>>> >>>> and my program say: not exactly 1 contour >>>> >>>> How I can solve it? >>>> >>>> If I ask in idl " help,/str,li" and the answer is: >>>> >>>> Structure CONTOUR_DBL_PATH_STRUCTURE, 6 tags, length=24, data length=20: >>>> TYPE BYTE 1 >>>> HIGH_LOW BYTE 1 >>>> LEVEL INT 0 >>>> N LONG 7 >>>> OFFSET LONG 0 >>>> VALUE DOUBLE 9.0000000 >>>> >>>> and for " help,/str,lines" >>>> LINES DOUBLE = Array[2, 5447] >>>> >>>> My contour isn't a perfect circle. Maybe is this the problem? >>>> >>>> This is my program where the image is a flat field panel minus dark: >>>> >>>> file_ff1='ff_100s_3.fits' ;immagine >>>> immagine_ff1=readfits (file_ff1, header1) ; leggo l'immagine del flat field panel >>>> file_dark='ff_100s_dark_3.fits' ;immagine >>>> immagine_dark=readfits (file_dark, header1) ; leggo l'immagine della dark >>>> >>>> n=100. ; secondi di esposizione dell'immagine >>>> ffp=(immagine_ff1-immagine_dark)/n >>>> >>>> ; contour per selezionare soglie di equivalore >>>> >>>> speriamo=fltarr(2048,2048) ; creo una matrice 2048x2048 >>>> dimensioni=size(speriamo,/dimensions) >>>> cubo=where(ffp lt 9.5 or ffp gt 10) >>>> >>>> >>>> >>>> wrong_matrix=array_indices(dimensioni, cubo,/dimensions) >>>> indxw=reform(wrong_matrix(0,*)) >>>> indyw=reform(wrong_matrix(1,*)) >>>> ;ffp(indxw,indyw)=0. >>>> ;c = CONTOUR(ffp, dimensions=[512,512], Title='prova cubo') >>>> >>>> ; DATA being the data to be contoured >>>> level=9 >>>> contour, smooth(ffp(250:1700, 250:1700),3), path_info=li,closed=1 , path_xy=lines, /path_data_coord, levels=[level], /path_double >>>> ; lix=lines(0,*) >>>> ; liy=li…
creator: termybel
date: 2017-10-16T10:23:34-00:00