This module performs the transformation between image space and shapelet space for galaxy sets, using the center of the galaxy image as the center of decomposition. It produces the decompositions of the object that are suitable for use in further shape algorithms. Optionally, it introduces artificial sources of error in to the decomposition. It can also reconstruct the galaxy set from the decompositions, so that the quality of decomposition can be gauged.
The shapelets are calculated up to the specified maximum n in both the n1 and n2 directions. A triangular-shaped decomposition is not used. Optional subsampling of the basis functions can be performed.
Optional sources of error currently include random linear jitter in the centroids and in the scale factor (beta).
Parameters
| Name | Type | Description |
|---|---|---|
| AlsoReconstruct | keyword | If present, will reoncstruct the decompositions into images. |
| Normalize | keyword | Normalize the shapelet decompositions so that the reconstruction has unit flux. |
| UseOptimalBetas | keyword | Use precalculated "optimal" scale factors from the data stream rather than a fixed value. |
| NumCoeff | int | Maxmimum order of the shapelet decomposition. |
| Beta | double | Shapelet scale factor to use in decompositions. Not valid if UseOptimalBetas is set. |
| BetaStep | double | If present, increase the value of beta by this amount during each process() stage. |
| CenterErrorType | string | "None" or "Linear". If linear, add a random linear error to the centroid when performing decomposition. |
| CenterErrorRadius | double | If center errors, keep centroid within this radius of the true value. |
| BetaErrorType | string | "None" or "Linear". If linear, add a random linear error to the scale factor when performing decomposition. |
| BetaErrorRadius | double | If beta errors, keep the scale factor within this radius of the true value. |
| Subsample | int | If set, subsample the basis function n*n times when performing the decomposition, where n is the given parameter. |
Inputs
| Name | Type | Description |
|---|---|---|
| GalSet/Width | int | Width of each image in pixels. |
| GalSet/Height | int | Height on each image in pixels. |
| GalSet/BiasedCount | int | Number of biased images in galaxy set. |
| GalSet/BiasedImages | double* | Array of pixel values of biased images. |
| GalSet/BiasedOptimalBetas | double* | Array of optimal scale factor for each galaxy. Used only if UseOptimalBetas is set. |
| GalSet/UnbiasedCount | int | Number of biased images in galaxy set. |
| GalSet/UnbiasedImages | double* | Array of pixel values of biased images. |
| GalSet/UnbiasedOptimalBetas | double* | Array of optimal scale factor for each galaxy. Used only if UseOptimalBetas is set. |
Outputs
| Name | Type | Description |
|---|---|---|
| GalSet/BiasedFluxes | double* | Flux for each biised galaxy. |
| GalSet/BiasedShapes | double* | Array of the shapelet decomposition for each biased galaxy. |
| GalSet/UnbiasedFluxes | double* | Flux for each unbiased galaxy. |
| GalSet/UnbiasedShapes | double* | Array of the shapelet decomposition for each unbiased galaxy. |