| Band reader [message #37471] |
Sun, 28 December 2003 19:22  |
julio
Messages: 31
Registered: December 2003
|
Member |
|
|
Hello, I'm a new user of ENVI/IDL and I'm writing a routine to
calibrate the channels 1 and 2 of AVHRR images. Acording to KLM User's
Guide, the slope and intercept coeficients values depend on the CN.
I'm using the ENVI_GET_IMAGE to read the channels, but it reads the
matrix, and not unit values. How can I do to read only the CN and then
apply the right values of intercept and slope?
Thanks a lot!
|
|
|
|
| Re: Band reader [message #37561 is a reply to message #37471] |
Tue, 30 December 2003 05:13  |
julio
Messages: 31
Registered: December 2003
|
Member |
|
|
Thanks Fotis, I'll try it!
Julio
Fotis <fotis@physics.uoc.gr> wrote in message news:<bsr9pk$njg$1@nic.grnet.gr>...
> Julio wrote:
>> Hello, I'm a new user of ENVI/IDL and I'm writing a routine to
>> calibrate the channels 1 and 2 of AVHRR images. Acording to KLM User's
>> Guide, the slope and intercept coeficients values depend on the CN.
>> I'm using the ENVI_GET_IMAGE to read the channels, but it reads the
>> matrix, and not unit values. How can I do to read only the CN and then
>> apply the right values of intercept and slope?
>> Thanks a lot!
> Assume that calibr. factors change for CN values larger or less
> than 499.
> Assume b1 is the matrix of the first band (0.63 micron)
> temp1=fltarr(ns,nl)
> temp2=fltarr(ns,nl)
> calibr_b1=fltarr(ns,nl)
>
> temp1=float(b1)* SLOPE1 + INTERC1
> temp2=float(b1)* SLOPE2 + INTERC2
>
> calibr_b1=temp1 * (b1 le 499) + temp2 * (b1 gt 499)
|
|
|
|
| Re: Band reader [message #37562 is a reply to message #37471] |
Mon, 29 December 2003 23:34 |
Fotis
Messages: 2
Registered: December 2003
|
Junior Member |
|
|
Julio wrote:
> Hello, I'm a new user of ENVI/IDL and I'm writing a routine to
> calibrate the channels 1 and 2 of AVHRR images. Acording to KLM User's
> Guide, the slope and intercept coeficients values depend on the CN.
> I'm using the ENVI_GET_IMAGE to read the channels, but it reads the
> matrix, and not unit values. How can I do to read only the CN and then
> apply the right values of intercept and slope?
> Thanks a lot!
Assume that calibr. factors change for CN values larger or less
than 499.
Assume b1 is the matrix of the first band (0.63 micron)
temp1=fltarr(ns,nl)
temp2=fltarr(ns,nl)
calibr_b1=fltarr(ns,nl)
temp1=float(b1)* SLOPE1 + INTERC1
temp2=float(b1)* SLOPE2 + INTERC2
calibr_b1=temp1 * (b1 le 499) + temp2 * (b1 gt 499)
|
|
|
|
comp.lang.idl-pvwave archive
Members
Search
Help
Login
Home
