1) Surface photometric function model type 2) Atmospheric photometric function model type 3) Type of normalization to be performedThe types of surface photometric function model types currently available in photomet are:

HapkeHen : Hapke-Henyey-Greenstein photometric model. Derive model albedo using complete Hapke model with Henyey-Greenstein single-particle phase function whose coefficients are Hg1 and Hg2, plus single scattering albedo Wh, opposition surge parameters Hh and B0, and macroscopic roughness Theta. Lambert : Simple photometric model which predicts that light incident on a surface is scattered uniformly in all directions; the total amount of reflected light depends on the incidence angle of the illumination. This function does not depend upon the outgoing light direction. LommelSeeliger : This model takes into account the radiance that results from single scattering (scattering of collimated incident light) and does not take into account the radiance that results from multiple scattering (scattering of diffuse light which has made its way indirectly to the same position by being scattered one or more times). This model depends on the incidence and emission angles. LunarLambert : This model combines a weighted sum of the LommelSeeliger and Lambert models. Given a suitable value for the LunarLambert function weight, L, this model fits the true reflectance behavior of many planetary surfaces equally well as the Hapke model. This model also depends on the incidence and emission angles. Minnaert : This model expands upon the Lambert function by introducing constant, K, that is used to describe the roughness of a surface. When the K constant is set to 1.0, then the Minnaert model is equivalent to the Lambert model. LunarLambertMcEwen : This model was developed specifically for use with the Moon. This model was designed to be used in conjunction with the MoonAlbedo normalization model.The types of atmospheric photometric function model types currently available in photomet are:

Anisotropic1 : Uses Chandrasekhar's solution for anisotropic scattering described by a one term Legendre polynomial. This model uses first order scattering approximation. Anisotropic2 : Uses Chandrasekhar's solution for anisotropic scattering described by a one term Legendre polynomial. This model uses second order scattering approximation. It is slower but more accurate than Anisotropic1. HapkeAtm1 : Provides an approximation for strongly anisotropic scattering that is similar to Hapke's model for a planetary surface. The Chandrasekhar solution for isotropic scattering is used for the multiple scattering terms, and a correction is made to the singly scattered light for anisotropic particle phase function. A one term Henyey Greenstein function is used. This model uses a first order scattering approximation. HapkeAtm2 : Provides an approximation for strongly anisotropic scattering that is similar to Hapke's model for a planetary surface. The Chandrasekhar solution for isotropic scattering is used for the multiple scattering terms, and a correction is made to the singly scattered light for anisotropic particle phase function. A one term Henyey Greenstein function is used. This model uses a second order scattering approximation. It is slower but more accurate than HapkeAtm1. Isotropic1 : Uses Chandrasekhar's solution for isotropic scattering. This model uses first order scattering approximation. Isotropic2 : Uses Chandrasekhar's solution for isotropic scattering. This model uses second order scattering approximation. It is slower but more accurate than Isotropic1.The types of normalization models currently available in photomet are:

Albedo : Normalization without atmosphere. Each pixel is divided by the model photometric function evaluated at the geometry of that pixel, then multiplied by the function at reference geometry with incidence and phase angles equal to Incref and emission angle 0. This has the effect of removing brightness variations due to incidence angle and showing relative albedo variations with the same contrast everywhere. If topographic shading is present, it will be amplified more in regions of low incidence angle and will not appear uniform. AlbedoAtm : Normalization with atmosphere. For each pixel, a model of atmospheric scattering is subtracted and a surface model is divided out, both evaluated at the actual geometry of the pixel. Then the resulting value is multiplied by the surface function at reference conditions is added. In normal usage, the reference condition has normal incidence (Incref=0) and no atmosphere (Tauref=0) but in some cases it may be desirable to normalize images to a different incidence angle or a finite optical depth to obtain a more uniform appearance. As with the Albedo model, if topographic shading is present, it will be amplified more at high incidence angles and will not appear uniform. Mixed : Normalization without atmosphere. Used to do albedo normalization over most of the planet, but near the terminator it will normalize topographic contrast to avoid the seams that can occur with the usual albedo normalization. The two effects will be joined seamlessly at incidence angle Incmat. Incmat must be adjusted to give the best equalization of contrast at all incidence angles. The Albedo parameter must also be adjusted so the topographically normalized regions at high incidence angle are set to an albedo compatible with the albedo-normalized data at lower incidence. MoonAlbedo : Normalization without atmosphere. This model was designed specifically for use on Lunar data. It will compute normalized albedo for the Moon, normalized to 0 degrees emission angle and 30 degrees illumination and phase angles. The LunarLambertMcEwen photometric function was designed to be used with this normalization model. NoNormalization : Normalization without atmosphere. No normalization is performed. Only photometric correction is performed. Shade : Normalization without atmosphere. The surface photometric function is evaluated at the geometry of the image in order to calculate a shaded relief image of the ellipsoid (and in the future the DEM). The radiance of the model surface is set to Albedo at incidence angle Incref and zero phase. The image data is not used. ShadeAtm : Normalization with atmosphere. The surface photometric function is used to simulate an image by relief shading, just like the Shade model, but the effects of atmospheric scattering are also included in the calculation. Topo : Normalization without atmosphere. Used to normalize topographic shading to uniform contrast regardless of incidence angle. Such a normalization would exagerate albedo variations at large incidence angles, so this model is used as part of a three step process in which (1) the image is temporarily normalized for albedo; (2) a highpass divide filter is used to remove regional albedo variations; and (3) the image is renormalized with the Topo mode to undo the first normalization and equalize topographic shading. The reference state in the first step MUST have Incref=0 because this is waht is undone in the final step. If there are no significant albedo variations, step (2) can be skipped but step (1) must not be. TopoAtm : Normalization with atmosphere. As with the Topo model, this option is used in the final step of a three step process: (1) normalize with the AlbedoAtm model, Incref=0, and Tauref=0 to temporarily remove atmosphere and normalize albedo variations; (2) use highpass divide filter to remove albedo variations; and (3) normalize with the TopoAtm model to undo the temporary normalization and equalize topographic shading.As you can see above, the only normalization models that make use of atmospheric correction are: AlbedoAtm, ShadeAtm, and TopoAtm. Atmospheric correction is not applied by any of the other normalization models. If you specify an atmospheric model in a PVL along with a normalization model that does not do atmospheric correction, then the atmospheric model will be ignored. Each of the above photometric, atmospheric, and normalization models has specific parameters that apply to them. Here is a list of the models and their related parameters (in parentheses):

HapkeHen (B0,Hg1,Hg2,Hh,Theta,Wh) Lambert LommelSeeliger LunarLambert (L) Minnaert (K) LunarLambertMcEwen Anisotropic1 (Bha,Bharef,Hnorm,Nulneg,Tau,Tauref,Wha,Wharef) Anisotropic2 (Bha,Bharef,Hnorm,Nulneg,Tau,Tauref,Wha,Wharef) HapkeAtm1 (Hga,Hgaref,Hnorm,Nulneg,Tau,Tauref,Wha,Wharef) HapkeAtm2 (Hga,Hgaref,Hnorm,Nulneg,Tau,Tauref,Wha,Wharef) Isotropic1 (Hnorm,Nulneg,Tau,Tauref,Wha,Wharef) Isotropic2 (Hnorm,Nulneg,Tau,Tauref,Wha,Wharef) Albedo (Albedo,Incmat,Incref,Thresh) AlbedoAtm (Incref) Mixed (Albedo,Incmat,Incref,Thresh) MoonAlbedo (Bsh1,D,E,F,G2,H,Wl,Xb1,Xb2,Xmul) NoNormalization Shade (Albedo,Incref) ShadeAtm (Albedo,Incref) Topo (Albedo,Incref,Thresh) TopoAtm (Albedo,Incref)Here is a description of each parameter along with a valid range of values and the default for that parameter:

Photometric parameters: ----------------------- B0: Hapke opposition surge component: 0 <= value : default is 0.0 Bh: Hapke Legendre coefficient for single particle phase function: -1 <= value <= 1 : default is 0.0 Ch: Hapke Legendre coefficient for single particle phase function: -1 <= value <= 1 : default is 0.0 Hg1: Hapke Henyey Greenstein coefficient for single particle phase function: -1 < value < 1 : default is 0.0 Hg2: Hapke Henyey Greenstein coefficient for single particle phase function: 0 <= value <= 1 : default is 0.0 Hh: Hapke opposition surge component: 0 <= value : default is 0.0 K: Minnaert function exponent: 0 <= value : default is 1.0 L: Lunar-Lambert function weight: no limit : default is 1.0 Theta: Hapke macroscopic roughness component: 0 <= value <= 90 : default is 0.0 Wh: Hapke single scattering albedo component: 0 < value <= 1 : default is 0.5 Atmospheric parameters: ----------------------- Bha : Coefficient of the single particle Legendre phase function: -1 <= value <= 1 : default is 0.85 Hga : Coefficient of single particle Henyey Greenstein phase function: -1 < value < 1 : default is 0.68 Hnorm : Atmospheric shell thickness normalized to the planet radius: 0 <= value : default is .003 Nulneg : Determines if negative values after removal of atmospheric effects will be set to NULL: YES or NO : default is NO Tau : Normal optical depth of the atmosphere: 0 <= value : default is 0.28 Tauref : Reference value of Tau to which the image will be normalized: 0 <= value : default is 0.0 Wha : Single scattering albedo of atmospheric particles: 0 < value < 1 : default is 0.95 Normalization parameters: ------------------------- Albedo : Albedo to which the image will be normalized: no limit : default is 1.0 Bsh1 : Albedo dependent phase function normalization parameter: 0 <= value : default is 0.08 D : Albedo dependent phase function normalization parameter: no limit : default is 0.14 E : Albedo dependent phase function normalization parameter: no limit : default is -0.4179 F : Albedo dependent phase function normalization parameter: no limit : default is 0.55 G2 : Albedo dependent phase function normalization parameter: no limit : default is 0.02 H : Albedo dependent phase function normalization parameter: no limit : default is 0.048 Incmat : Specifies incidence angle where albedo normalization transitions to incidence normalization: 0 <= value < 90 : default is 0.0 Incref : Reference incidence angle to which the image will be normalized: 0 <= value < 90 : default is 0.0 Thresh : Sets upper limit on amount of amplification in regions of small incidence angle: no limit : default is 30.0 Wl : Wavelength in micrometers of the image being normalized: no limit : default is 1.0 Xb1 : Albedo dependent phase function normalization parameter: no limit : default is -0.0817 Xb2 : Albedo dependent phase function normalization parameter: no limit : default is 0.0081 Xmul : Used to convert radiance to reflectance or apply a calibration fudge factor: no limit : default is 1.0Here are some example PVL files:

Example 1: Object = PhotometricModel Group = Algorithm Name = Lambert EndGroup EndObject Object = NormalizationModel Group = Algorithm Name = NoNormalization EndGroup EndObject -------------------------------- Example 2: Object = PhotometricModel Group = Algorithm Name = Minnaert K = .5 EndGroup EndObject Object = NormalizationModel Group = Algorithm Name = Albedo Incref = 0.0 Incmat = 0.0 Albedo = 1.0 Thresh = 30.0 EndGroup EndObject -------------------------------- Example 3: Object = PhotometricModel Group = Algorithm Name = HapkeHen Wh = 0.52 Hh = 0.0 B0 = 0.0 Theta = 30.0 Hg1 = .213 Hg2 = 1.0 EndGroup EndObject Object = AtmosphericModel Group = Algorithm Name = HapkeAtm2 Hnorm = .003 Tau = 0.28 Tauref = 0.0 Wha = .95 Hga = 0.68 EndGroup EndObject Object = NormalizationModel Group = Algorithm Name = AlbedoAtm Incref = 0.0 EndGroup EndObject -------------------------------- Example 4 (Used to process Clementine UVVIS filter "a" data): Object = PhotometricModel Group = Algorithm Name = LunarLambertMcEwen EndGroup EndObject Object = NormalizationModel Group = Algorithm Name = MoonAlbedo D = 0.0 E = -0.222 F = 0.5 G2 = 0.39 H = 0.062 Bsh1 = 2.31 EndGroup EndObject -------------------------------- Example 5 (Used to process Clementine UVVIS filter "b" data): Object = PhotometricModel Group = Algorithm Name = LunarLambertMcEwen EndGroup EndObject Object = NormalizationModel Group = Algorithm Name = MoonAlbedo D = 0.0 E = -0.218 F = 0.5 G2 = 0.4 H = 0.054 Bsh1 = 1.6 EndGroup EndObject -------------------------------- Example 6 (Used to process Clementine UVVIS filter "cde" data): Object = PhotometricModel Group = Algorithm Name = LunarLambertMcEwen EndGroup EndObject Object = NormalizationModel Group = Algorithm Name = MoonAlbedo D = 0.0 E = -0.226 F = 0.5 G2 = 0.36 H = 0.052 Bsh1 = 1.35 EndGroup EndObject