Specifies 1 to 4 input filenames: (IMAGE,GEO,GRID,CMAP) IMAGE is the input VICAR image upon which brightness correction is performed. IMAGE is required and must always be the first in this list. The remaining inputs (GEO, GRID, and CMAP) are optional and may appear anywhere in the INP list after IMAGE. IMAGE may be an image from a "supported" or "unsupported" mission. The degree of support varies with the mission and determines the amount of information that can be automatically retrieved or which must be supplied by the user. See the MISSION parameter. IMAGE may be in BYTE, HALF, FULL, or REAL data formats. There are no size restrictions. GEO is a geometric correction parameter file as created by programs RESLOC and RESLOCVO. GEO is in IBIS graphics format and is identified solely by its record size (512 bytes). GRID specifies a file of photometric function parameters in the format generated by PHOTFIT. The program recognizes it by the word "PHOTFIT" in the label, and a record size of 120 samples. NOTE: Since PHOTFIT is obsolete, this option is currently disabled. CMAP specifies a classification map as produced by program FASTCLAS. CMAP is used to limit the brightness correction to pixels of a specified class (See CLASS parameter). The program recognizes the file by the words "CLASSIFICATION MAP" in the label. CMAP must be of BYTE format and of the same size as the input image.
OUT=B where B is the output (brightness corrected) image. B will be in the same data format as the input image. If no output file is specified, then brightness correction is performed (See parameter NOCORREC.)
SIZE=(sl,ss,nl,ns) is the standard VICAR size field and specifies the image area of the input image to be operated on. SIZE specifies the starting line, starting sample, number of lines, and number of samples of the image area, so that the area will begin at (sl,ss) of the input image, and the output image will have dimensions nl x ns.
CLASS is only used when a classification map has been included among the input data (see INP parameter). It specifies a DN value that will be used to select a set of pixels from the input image, and only those pixels will be processed by PHOTFUNC. E.g., if CLASS=8 is specified, then a pixel in the input image will only be corrected if the corresponding pixel in the classification map has a DN value of 8. If the value specified by CLASS is negative, then the absolute value of CLASS is taken to denote a class that is NOT to be processed; all classes will be processed except for that one and the DN=0 (unclassifiable) class.
SOLAR=(R1,R2) where R1 and R2 are floating point numbers specifying the subsolar latitude and longitude in degrees.
SPACE=(R3,R3,R5) where R3, R4, and R5 are floating point numbers specifying the subspacecraft latitude and longitude in degrees and the distance to the center of the target in kilometers respectively.
SLAT=R4 where R4 is a floating point number specifying the subspacecraft latitude in degrees.
SLON=R5 where R5 is a floating point number specifying the subspacecraft longitude in degrees.
RMAG=R6 where R6 is a floating point number specifying the distance from subspacecraft to planet center in kilometers.
RADII=(RA,RB,RC) The three radii of the target, in kilometers, where RA = long equatorial radius RB = short equatorial radius RC = polar radius The default are values retrieved from SPICE. If SPICE is not available, the data stored in subroutine PBDATA are used.
TARGET=string Specifies the name of the target body. The target body name is one of four identifiers needed to retrieve the projection and lighting geometry from the SPICE server. If no SPICE data is available, the target name is used to retrieve the target radii via a call to PBDATA.
OMMATRIX=(R1,R2,..,R10) where Rn is a floating point number specifying the nine elements of the OM matrix used to define the relationship between planet coordinate system and camera coordiante system. The values are in row major order. The OM matrix is normally retrieved automatically by accessing the SPICE server (when available).
RSVECTOR=(R1,R2,R3) where Rn is a floating point number and R1, R2, R3 are the three values of the RS vector expressed in the planet coordinate system. The vector can be alternatively specified in polar coordinates via parameter SPACE (or SLAT, SLON and RMAG). The RS vector is normally retrieved automatically by accessing the SPICE server (when available).
OBJECT specifies that the input frame is geometrically correct; that is, all camera systems distortions have been removed. This is the default.
IMAGE specifies that the input frame is not geometrically correct; that is, camera system distortions have not been removed. The default is the picture has been geometrically corrected. If IMAGE is specified, the GEOMA parameters must be supplied either through the specifiction of a documented flight project or the user can supply an alternate input file.
DISTOR specifies that the input frame is not geometrically correct; that is, camera system distortions have not been removed. The default is the picture has been geometrically corrected.
FOCAL=R1 where R1 is a floating point number and specifies the value of the camera's focal length in millimeters. The default is 1500 mm.
FOCL=R1 where R1 is a floating point number and specifies the value of the camera's focal length in millimeters. The default is 1500 mm.
LAXIS=R1 where R1 is a floating point number and specifies the value of the line of the object space optical axis. The default is R1=500.
SAXIS=R1 where R1 is a floating point number and specifies the value of the sample of the object space optical axis. The default is 500.
PSCALE=R2 where R2 is a floating point number and specifies the scale in the object space focal plane in pixels per millimetrer. The default is 84.821428.
FARENC specifies that the far encounter mode is to be used to determine the OM matrix. Be sure to specify SSCPT NORA, and the RS vector(or its equivalent).
SSCPT=(R1,R2) where R1 and R2 are floating point numbers which specify the object space line and sample respectively or the subspacecraft point in the input image. The defaults are R1=R2=0.
OSSCP=(R1,R2) where R1 and R2 are floating point numbers which specify the object space line and sample respectively or the subspacecraft point in the input image. The defaults are R1=R2=0.
ISSCP=(R1,R2) where R1 and R2 are floating point numbers which specify the image space line and sample respectively at the subspacecraft point in the input image. The default are R1=R2=0.
NORA=R1 where R1 is a floating point number specifying the angle of north in degrees. It is measured in the image plane at the subspacecraft point clockwise from up. The default is 0.
TIEPOINT=(R1,R2,R3,R4,...,RN) where Rn are floating point numbers and are lines, samples, latitudes and longitudes of the tiepoints. The numbers following TIEPOINT are in groups of four; each group specifying the line, sample, latitude, and west longitude in that order of each tiepoint. At least three points are needed to determine the OM matrix. No more than 25 points can be used and if more than 25 points are input only the first 25 will be used. If the TIEPOINTS mode is used be sure to specify the RS vector or its equivalent.
The following keywords are valid for this parameter: LAMBERT: specifies that the picture is in a Two-Standard Lambert Conformal Conic projection. MERCATOR: specifies that the picture is a Mercator projection. ORTHOGRA: specifies that the picture is an orthographic projeciton. STEROGR: specifies that the picture is a stereographic projection. POLE: specifies that the picture is a polar projection. If the user specifies POLE, he must also specify either ORTH or STER. CYLI: specifies that the picture is the normal cylindrical projection. RECT: specifies that the picture is in the simple cylindrical projection. LATL: specifies that the picture is in the simple cylindrical projeciton.
LINE=R1 where R1 is a floating point number specifying some arbitrary line in the picture which is some specified latitude and/or longitude. The default is R1=0.
SAMPLE =R1 where R1 is a floating point number specifying some arbitrary sample in the picture which is some specified latitude and/or longitude. The default is R1=0.
LATITUDE=R1 where R1 is a floating point number specifying an arbitrary latitude in the picture which is some specified latitude and/or longitude.
LONG=R1 where R1 is floating number specifying an arbitrary longitude in the picture which is some line and/or sample.
PAR1=R1 where R1 is a floating point number specifying the latitude of the standard parallels if the projection is Lambert conformal. PAR1 is the northern most parallel.
PAR2=R1 where R1 is a floating point number specifying the latitude of the standard parallels if the projection is Lambert conformal. PAR2 is the southern most parallel.
NORTH=R2 where R2 is a floating point number specifying the angle in degrees of north in the output picture. This angle is measured in the projection plane at the center of projection clockwise from up.
SCALE=R3 where R3 is a floating point number specifying the number of kilometers per pixel at the center of projection for stereographic and orthographic projections, at the standard parallels for Lambert Conformal and at the equator for simple cylindrical, normal cylindrical and Mercator projections.
MINNAERT=R1, where R1 is a floating point number specifying the Minnaert function k value. The photometric function is: F = A * COS(i)**k * COS(e)**k-1 The photometric correction factor, f, used for the Minnaert function is: f = F/F0 = COS(i)**k * COS(e)**k-1 where: F is the brightness F0 is normalized brightness, F0=F(i=0,e=0) k is the geometrical constant i is the incidence angle e is the emission angle Minnaert is the default function, with a default k of 0.5
VEVERKA=(A,B,C,D) specifies that the Squyres-Veverka phase angle function
in conjunction the Lommel-Seeliger law is to be used, and also specifies
its four constants.
The equation for this photometric function is:
F = ( A + B*g + C*exp(-D*g) ) * COS(i) / (COS(i)+COS(e))
where: g is the phase angle in degrees
i is the incidence angle
e is the emission angle
Therefore the correction factor f performed by photfunc is given by:
f=F/F0 where F0=F(i=0,e=0,g=0)
f = (A + B*g + C*exp(-D*g)) * 2/(A+C) * COS(i)/(COS(i)+COS(e))
HAPKE=(from 4 to 6 parameters)
This is the Hapke function. There are three versions of this function
depending upon the number of parameters specified, as follows:
4-parameters W,B,H,C This is the 1978 Hapke function.
W = single scattering albedo
B = first term legendre polynomial phase function.
H = porosity
C = second term legendre polynomial phase function.
CI=cos(i)
CE=cos(e)
TP=tan(g)
R = (W/4) * (CI/(CI+CE)) * ((1+Q(TP))*PF(TP)+H(CI)*H(CE)-1)
where:
H(X)=(1+2*X)/(1+2*X*SQRT(1-W)) (multiple scattering term)
Q(TP)=EXP(-W**2/2)*(1-TP*(3-EXP(-H/TP))*(1-EXP*(-H/TP)/2H) for TP>0
=0 for TP<=0
PF(CP)=1+B*CP+C*(3*CP**2-1)/2 (phase function of a single particle)
5-parameters W,H,CK,C,B This is the 1984 Hapke function.
W = single scattering albedo
H = Backscatter parameter related to soil porosity.
CK (TBAR) = Average macroscopic slope angle in degrees.
C (OPMAG) = S(0) term in the opposition magnitude coefficient.
B = Henyey-Greenstein single particle phase function.
R = (W/4) * (C01/(C01+C11)) * SF *
( (1+QF(S0,W,H,P,HG)) * PF(CP) + H(C01)*H(C11) -1)
where:
C01 = (CI + sinI*tanTB*X1/X2)/BETA
C11 = (CE + sinE*tanTB*X3/X2)/BETA
BETA = sqrt(1+pi*(tanTB)**2)
QF(S0,W,H,P,HG) = S0*H/(W*(H-tan|P/2|)*PF(1)
X1,X2,X3,SF are complicated functions of I, E, and TB, and the remaining
functions and symbols are as defined above.
PF(CP) = (1-HG**2)/(1+HG**2+2*HG*CP)**1.5,
6-parameters W,H,CK,C,B,XLG2 This is the 1984 Hapke function.
W = single scattering albedo
H = Backscatter parameter related to soil porosity.
CK (TBAR) = Average macroscopic slope angle in degrees.
C (OPMAG) = S(0) term in the opposition magnitude coefficient.
B = Term#1 in Legendre polynomial particle phase function.
XLG2 = Term#2 in Legendre polynomial particle phase function.
Note: these functions are also normalized as f=F/F0
where F0=F(i=0,e=0,g=0)
MOSHER = (A,B,C,D,E,F) specifies that the MOSHER function is to be used
to process the input image.
The first 4 values that follow the keyword have the same function as
the constants for VEVERKA, the last 2 correspond to the values of the
Minnaert "k" and a phase angle coefficient. The MOSHER function is a
combination of the Veverka and Minnaert functions:
PAC=A+B*g+C*exp(-D*g)
F = PAC * (cos(i)**(E+F*g)) * (cos(e)**(E+F*g-1))
where
g is the phase angle in degrees
i is the incidence angle
e is the emission angle
The correction applied by photfunc is:
f=F/F0, F0=F(i=0,e=0,g=0)
PAC=A+B*g+C*exp(-D*g)*2/(A+C)
f = PAC * (cos(i)**(E+F*g)) * (cos(e)**(E+F*g-1))
COOK=K where K is a floating point number specifying the COOK parameter. The
Cook function is a modification to the 1978 Hapke function so W, B, H, and C
should also be specified, using parameter HAPKE. The modification to the
Hapke function is in redefining incidence and emission angles to their
new values:
cos(i) <-- sqrt(1-K*K*(1-cos(i)*cos(i)))
cos(e) <-- sqrt(1-K*K*(1-cos(e)*cos(e)))
If HAPKE is not specified, or is specified with 5 values, then this parameter
is ignored.
Specifies the BURATTI-VEVERKA function.
The function is of the form:
ci
Q= A*-------*f(a) + (1-A)*ci
ci+ce
p(a)*pi*((2/3)*(1-A)+A*F)-(2/3)*(1-A)*(sin(a)+(pi-a)*cos(a))
f(a)=------------------------------------------------------------
(A*pi/2)*(1-sin(a/2)*tan(a/2)*ln(cot(a/4)))
p(a)=B+C*a+D*exp(-E*a)
The coefficients A,B,C,D,E,F are input parameters 1-6.
and where
a=phase angle
i=incidence angle
e=emission angle
ci=cos(i)
ce=cos(e)
The correction applied by photfunc is:
f=Q/q, q=Q(a=0,i=0,e=0)
q=(B+D-1)*(2/3)*(1-A) + A*(B+D)*F +(1-A)
The coefficients look like: (.5,.6,-.003,.14,.14,1.0)
The following articles discuss the function and parameters.
See Icarus 59 392-405 Buratti
See Icarus 46 137-155 Veverka
Specifies the Irvine function. There are three parameters corresponding
to the constants k,a,b in the equation:
B*Fsun k (1-exp(-ci/a)
F=------- * (ci*ce) * ------------
pi*ce (1-exp(-ce/b)
where
i=incidence angle
e=emission angle
ci=cos(i)
ce=cos(e)
The correction applied by photfunc is:
f=F/F0, F0=F(i=0,e=0)
Also the constants k,a,b are typically 0.9, 0.118, and 0.0039 respectively.
For these values and at i=0 and e=0 the term (1-exp(-1/a))/(1-exp(-1/b))=1
so it is omitted from the normalization F0.
The implemented function in Photfunc is therefore:
k
(ci*ce) (1-exp(-ci/a)
f=F/F0= ------- * ------------
ce (1-exp(-ce/b)
Example: irvine=(.9,.118,.0039)
Keyword identifying the mission from which the image as acquired. Valid missions are: CASSI: Cassini ISS GLL: Galileo VGR-1 and VGR-2: Voyager 1 and 2 VIKOR: Viking Orbiter (1976) MAR10: Mariner Venus Mercury mission (a.k.a. MVM73). MAR-9: Mariner 9 (Mars) WFPC1 and WFPC2: Wide Field Planetary Camera (Space Telescope) before and after camera upgrade. SIPS: Silicon Imaging Photometers System, Table Mountain Observatory 24" telescope in the 512 lines by 512 sample mode at the Cassigrain focus. QUEST: the SIPS used with a Questar 700 mm lens in the 512 lines by 512 sample mode. For each of these missions, the camera focal length, the line and sample coordinates of the optical axis intercept point, and the picture scale in pixels/mm for each specific camera are automatically loaded from built-in tables. See the CAMERA parameter for a view of this table. In addition, for all the JPL missions (Cassini, Galileo, Voyager, Viking Orbiter, Mariners 9 and 10), a model of the geometric camera distortions is also retrieved. For missions using a CCD camera system (Cassini, Galileo), a radial distortion model of the optics is used. For vidicon camera systems (Voyager, Viking Orbiter, Mariners 9 and 10), the distortions are modeled by the reseau pattern on the face plate of the camera. Nominal displacements for this reseau pattern are used for each specific camera. For more accurate results, locate the reseau directly from the image using RESLOC or RESLOCVO. For the other missions, the image is assumed to be free from distortions. Finally, for Cassini, Galileo, and Voyager, SPICE data containing the projection and lighting geometry for the image is automatically retrieved via the MIPS SPICE server. The 'NOSPICE keyword suppresses this feature.
Shutter centered Spacecraft Event Time of the image for which SPICE data is to be printed. SCET is only required if INP is not specified.
CAM=I1 where I1 is an integer specifying the camera serial number. The default
is to obtain I1 from the picture label. The camera serial number (together
with the mission ID) is used to retrieve the focal length, line and sample
of the optical-axis intercept point, and the picture scale from built-in
tables. The current values in these tables are:
CAMERA FOCAL LAXIS SAXIS PSCALE (pixels/mm)
CASSI NAC 1 2000.00 512 512 83.333333
CASSI WAC 2 200.736 " " "
CASSI NAC 2x2 21 2000.00 256 256 41.666665
CASSI WAC 2x2 22 200.736 " " "
CASSI NAC 4x4 41 2000.00 128 128 20.833333
CASSI WAC 4x4 42 200.736 " " "
GLL 1 1501.039 400 400 65.6167979
GLL 2x2 sum 2 1501.039 200 200 32.8083990
VGR-2 WA 4 200.770 500 500 84.821428
VGR-2 NA 5 1503.49 " " "
VGR-1 WA 6 200.465 " " "
VGR-1 NA 7 1500.19 " " "
VIKOR 1A 7 474.610 575 625 85.0
VIKOR 1B 4 474.398 " " "
VIKOR 2A 8 474.101 " " "
VIKOR 2B 6 474.448 " " "
MAR10 A 1 1495.66 400 475 74.78
MAR10 B 1 1503.69 400 475 74.78
MAR-9 1 52.267 400 475 75.0
MAR-9 2 500.636 " " "
WFPC1 1 67991. 400 400 66.66667
WFPC1 2 31168. " " "
WFPC2 1 67991. " " "
WFPC2 2 31168. " " "
SIPS 1 9753.6 256 256 51.2
QUESTAR 1 700. 256 256 512.
Note: These tables are obtained via a call to VICAR subroutine GETCAMCON. For
active missions, these values may be updated as they are more accurately
determined.
See also MISSION parameter.
NOPROJ: specifies that the picture was not taken by one of the mentioned projects.
LINC=I1 where I1 is an integer specifying the line spacings of the tiepoints at which the photometric function is computed exactly. The default is I1=10.
SINC=I1 where I1 is an integer specifying the sample spacings of the tiepoints at which the photometric function is computed exactly. The default is I1 = 10.
INC=I1 where I1 is an integer specifying the line spacings of the tiepoints at which the photometric function is computed exactly. The default is I1=10.
INCR=I1 where I1 is an integer specitying the sample spacings of the tiepoints at which the photometric function is computed exactly. The default is I1=10.
Keyword: Perform no interpolation. Instead, compute photometric function exactly for each pixel on the target.
PRINT specifies that the program print out the following information about the input picture, at the tiepoints, line, sample, latitude, longitude, incidence angle, emission angle, phase angle, computed brightness correction, from the photometric function, and object space line and sample. These angles are in degrees. Only the points that are actually on the visible side of the planet and illuminated are printed out. The default is to not print this.
ALL specifies that the data from PRINT be printed out for points beyond the terminator, i.e. points not illuminated.
NOCORREC specifies that the program not perform the photometric function correction. The default is to perform it, unless no output file is specified.
MAXD=I3 where I3 is an integer specifying the maximum data number the program can output. The default is 255. If the data is HALF or REAL, I3=32767.
NOSPICE disables access the the MIPS SPICE server. All geometry information must be provided via the parameter list.
TERM=R1 where R1 is a floating point number specifying the closest distance in degrees that pixels computed by interpolation may approach the terminator. Points closer than this are computed exactly. Default is R1=0.
LIMB=R2 Where R2 is a floating point number specifying the closest distance in degrees that pixels computed by interpolation may approach the limb. Points closer than this are computed exactly. Default is R2=0. the definition of the limb. See section on OPERATION. The default is R2=0.
MULT=R3 where R3 is a floating point number specifying that the output DN be multiplied by a constant, R3. This is accomplished by dividing the calculated brightness correction at a tiepoint by this constant. The default is R3=1.
Optional keyword. This is the maximum permitted intensity boost to correct for the limb and terminator darkening caused by the photometric function. If the determined correction is greater than this the DN will remain unchanged. Notice the default is 5.
SPICEMODE=LOCAL specifies that SPICE data is to be retrieved from local SPICE kernels. SPICEMODE=REMOTE specifies that SPICE data is to be retrieved via the SPICE server. If SPICEMODE is defaulted, the logical name (or environmental variable) DEFAULTSPICE is used to determine whether LOCAL or REMOTE is used. Note that if SPICE data is not found in LOCAL or REMOTE mode, the other mode is attempted.
CKNAME is a four character string specifying the C-kernel to be used: CKNAME C KERNEL -------- ------------- DAVI MIPS_DAVI.CK NAV MIPS_NAV.CK FARE MIPS_FARENC.CK NAV2 MIPS_NAV2.CK NEAR MIPS_NEAR.CK AMOS MIPS_AMOS.CK NAIF the best NAIF kernel is used If defaulted, the kernels are searched in the above order.
CKID is an alternative way to specify the prefered C-kernel (see CKNAME
parameter):
CKID CKNAME C KERNEL
---- -------- -------------
M906 DAVI MIPS_DAVI.CK
M905 NAV MIPS_NAV.CK
M904 FARE MIPS_FARENC.CK
M903 NAV2 MIPS_NAV2.CK
M902 NEAR MIPS_NEAR.CK
M901 AMOS MIPS_AMOS.CK
varies NAIF there are a large number of these files
Ex: CKID=M901 specifies the four character ID which uniquely identifies the
C-kernel MIPS_AMOS.CK.
A complete list of the C-kernel IDs is located in the ASCII file assigned the
logical name (or environmental variable) KERNELDB.
If specified, CKID overrides the CKNAME parameter.
USERID is a three character string which identifies the user who created the
camera pointing.
Ex: USERID=HBM identifies Helen Mortensen as the creator of the camera
pointing.
GROUPID is a three character string which identifies the group which created the camera pointing. Ex: GROUPID=040 identifies group 040 as the creator of the camera pointing.
INSTITUTE is a four character string identifying the facility which created the camera pointing. Ex: INSTITUTE=MIPS specifies that MIPS created the camera pointing.
PURPOSE is a four character string identifying the purpose of the observation or the purpose of processing. For example, PURPOSE=MOSA identifies the image as part of a mosaic sequence PURPOSE=COLO identifies the image as part of a color sequence
PROGRAM is the first six characters of the program creating the camera pointing. Ex: PROGRAM=FARENC specifies that FARENC created the camera pointing.
SPKID specifies the four character ID which uniquely identifies the SP kernel used to create the camera pointing. The SP-kernel IDs are located in the ASCII file assigned the logical name (or environmental variable) KERNELDB. Ex: SPKID=N015 specifies the SP kernel GLL_LONG_2.BSP
REQUNUM is a four character string identifying the IPL request number for which the camera pointing was created. Ex: REQNUM=3456 identifies (somewhat) request number R123456
Date and time the camera pointing was created in the form 'YEARMMDDHHMM'.
Ex: CDATE=199602291200 specifies that the pointing was created at noon
on February 29, 1996.