difference_image 1.0.0

• Canonical URL: https://images.lsst.io/schemas/difference_image-1.0.0

• Raw JSON schema

Composition

        classDiagram
  class DifferenceImageSerializationModel_ArrayReferenceModel_["DifferenceImageSerializationModel~ArrayReferenceModel~"] {
    +str schema_version
    +int min_read_version
    +dict~str, MetadataValue~ metadata
    +list~Any~ indirect
    +str band
  }
  class ButlerInfo["ButlerInfo"] {
  }
  class SerializedDatasetRef["SerializedDatasetRef"] {
    +UUID id
    +str | None run
    +str | None component
  }
  class SerializedDatasetType["SerializedDatasetType"] {
    +str name
    +str | None storageClass
    +list~str~ | None dimensions
    +str | None parentStorageClass
    +bool isCalibration
  }
  class SerializedDataCoordinate["SerializedDataCoordinate"] {
    +dict~str, int | str~ dataId
  }
  class SerializedDimensionRecord["SerializedDimensionRecord"] {
    +str definition
  }
  class Timespan["Timespan"] {
    +tuple~int, int~ nsec
  }
  class DatasetProvenance["DatasetProvenance"] {
    +UUID | None quantum_id
    +dict~UUID, dict~str, str | int | float | bool | UUID~~ extras
  }
  class ImageSerializationModel_ArrayReferenceModel_["ImageSerializationModel~ArrayReferenceModel~"] {
    +str schema_version
    +int min_read_version
    +dict~str, MetadataValue~ metadata
    +list~Any~ indirect
    +list~int~ yx0
  }
  class ArrayReferenceQuantityModel["ArrayReferenceQuantityModel"] {
  }
  class ArrayReferenceModel["ArrayReferenceModel"] {
  }
  class InlineArrayModel["InlineArrayModel"] {
  }
  class InlineArrayQuantityModel["InlineArrayQuantityModel"] {
  }
  class SkyProjectionSerializationModel_ArrayReferenceModel_["SkyProjectionSerializationModel~ArrayReferenceModel~"] {
    +str schema_version
    +int min_read_version
    +dict~str, MetadataValue~ metadata
    +list~Any~ indirect
  }
  class TransformSerializationModel_ArrayReferenceModel_["TransformSerializationModel~ArrayReferenceModel~"] {
    +str schema_version
    +int min_read_version
    +dict~str, MetadataValue~ metadata
    +list~Any~ indirect
  }
  class DetectorFrame["DetectorFrame"] {
    +str instrument
    +int | None visit
    +int detector
    +Box bbox
    +Literal~DETECTOR~ frame_type
  }
  class TractFrame["TractFrame"] {
    +str skymap
    +int tract
    +Box bbox
    +Literal~TRACT~ frame_type
  }
  class FocalPlaneFrame["FocalPlaneFrame"] {
    +str instrument
    +int | None visit
    +Unit unit
    +Literal~FOCAL_PLANE~ frame_type
  }
  class FieldAngleFrame["FieldAngleFrame"] {
    +str instrument
    +int | None visit
    +Literal~FIELD_ANGLE~ frame_type
  }
  class GeneralFrame["GeneralFrame"] {
    +Unit unit
    +Literal~GENERAL~ frame_type
  }
  class CellGridBounds["CellGridBounds"] {
    +Box bbox
    +frozenset~CellIJ~ missing
  }
  class CellGrid["CellGrid"] {
    +Box bbox
    +YX~int~ cell_shape
  }
  class RegionSerializationModel["RegionSerializationModel"] {
    +Literal~Polygon, MultiPolygon~ type
    +list~list~tuple~float, float~ | list~tuple~float, float~~~~ coordinates
  }
  class IntersectionBoundsSerializationModel["IntersectionBoundsSerializationModel"] {
  }
  class MappingSerializationModel["MappingSerializationModel"] {
    +str ast
  }
  class MaskSerializationModel_ArrayReferenceModel_["MaskSerializationModel~ArrayReferenceModel~"] {
    +str schema_version
    +int min_read_version
    +dict~str, MetadataValue~ metadata
    +list~Any~ indirect
    +list~int~ yx0
    +list~MaskPlane | None~ planes
    +IntegerType dtype
  }
  class PiffSerializationModel["PiffSerializationModel"] {
    +str schema_version
    +int min_read_version
    +dict~str, MetadataValue~ metadata
    +list~Any~ indirect
    +int stamp_size
  }
  class PiffObjectModel["PiffObjectModel"] {
    +dict~str, PiffDict~ structs
  }
  class PiffTableModel["PiffTableModel"] {
    +PiffDict metadata
  }
  class TableModel["TableModel"] {
  }
  class GalSimPixelScaleModel["GalSimPixelScaleModel"] {
    +float scale
    +Literal~pixel_scale~ wcs_type
  }
  class MinimalStar["MinimalStar"] {
    +XY~float~ image_pos
    +bool is_flagged
    +bool is_reserve
  }
  class PSFExSerializationModel["PSFExSerializationModel"] {
    +str schema_version
    +int min_read_version
    +dict~str, MetadataValue~ metadata
    +list~Any~ indirect
    +float average_x
    +float average_y
    +float pixel_step
    +list~int~ group
    +list~int~ degree
    +list~float~ basis
    +list~float~ coeff
    +InlineArray context
  }
  class GaussianPSFSerializationModel["GaussianPSFSerializationModel"] {
    +str schema_version
    +int min_read_version
    +dict~str, MetadataValue~ metadata
    +list~Any~ indirect
    +float sigma
    +int stamp_size
  }
  class ObservationInfo["ObservationInfo"] {
    +str | None translator_name
    +str | None telescope
    +str | None instrument
    +EarthLocation | None location
    +int | None exposure_id
    +int | None visit_id
    +str | None physical_filter
    +Time | None datetime_begin
    +Time | None datetime_end
    +Quantity | None exposure_time
    +Quantity | None exposure_time_requested
    +Quantity | None dark_time
    +float | None boresight_airmass
    +Angle | None boresight_rotation_angle
    +str | None boresight_rotation_coord
    +int | None detector_num
    +str | None detector_name
    +str | None detector_unique_name
    +str | None detector_serial
    +str | None detector_group
    +int | None detector_exposure_id
    +Quantity | None focus_z
    +str | None object
    +Quantity | None temperature
    +Quantity | None pressure
    +float | None relative_humidity
    +SkyCoord | None tracking_radec
    +AltAz | None altaz_begin
    +AltAz | None altaz_end
    +str | None science_program
    +str | None observation_type
    +str | None observation_id
    +str | None observation_reason
    +str | None exposure_group
    +int | None observing_day
    +TimeDelta | None observing_day_offset
    +int | None observation_counter
    +bool | None has_simulated_content
    +int | None group_counter_start
    +int | None group_counter_end
    +bool | None can_see_sky
  }
  class ChebyshevFieldSerializationModel["ChebyshevFieldSerializationModel"] {
    +str schema_version
    +int min_read_version
    +dict~str, MetadataValue~ metadata
    +list~Any~ indirect
    +InlineArray coefficients
    +Unit | None unit
    +Literal~CHEBYSHEV~ field_type
  }
  class ProductFieldSerializationModel["ProductFieldSerializationModel"] {
    +str schema_version
    +int min_read_version
    +dict~str, MetadataValue~ metadata
    +list~Any~ indirect
    +Literal~PRODUCT~ field_type
  }
  class SplineFieldSerializationModel["SplineFieldSerializationModel"] {
    +str schema_version
    +int min_read_version
    +dict~str, MetadataValue~ metadata
    +list~Any~ indirect
    +InlineArray y
    +InlineArray x
    +Unit | None unit
    +Literal~SPLINE~ field_type
  }
  class SumFieldSerializationModel["SumFieldSerializationModel"] {
    +str schema_version
    +int min_read_version
    +dict~str, MetadataValue~ metadata
    +list~Any~ indirect
    +Literal~SUM~ field_type
  }
  class ObservationSummaryStats["ObservationSummaryStats"] {
    +str schema_version
    +int min_read_version
    +dict~str, MetadataValue~ metadata
    +list~Any~ indirect
    +float psfSigma
    +float psfArea
    +float psfIxx
    +float psfIyy
    +float psfIxy
    +float ra
    +float dec
    +float pixelScale
    +float zenithDistance
    +float expTime
    +float zeroPoint
    +float skyBg
    +float skyNoise
    +float meanVar
    +tuple~float, float, float, float~ raCorners
    +tuple~float, float, float, float~ decCorners
    +float psfAdaptiveThresholdValue
    +float psfAdaptiveIncludeThresholdMultiplier
    +int nShapeletsStar
    +float shapeletsOnlyIqScore
    +float shapeletsIqScore
    +tuple~float, ...~ shapeletsCoeffs
    +float centroidDiffShapeletsVsSlotMedian
    +float shapeletsStarEMedian
    +float shapeletsStarUnNormalizedEMedian
    +float refCatSourceDensity
    +float astromOffsetMean
    +float astromOffsetStd
    +int nPsfStar
    +float psfStarDeltaE1Median
    +float psfStarDeltaE2Median
    +float psfStarDeltaE1Scatter
    +float psfStarDeltaE2Scatter
    +float psfStarDeltaSizeMedian
    +float psfStarDeltaSizeScatter
    +float psfStarScaledDeltaSizeScatter
    +float psfTraceRadiusDelta
    +float psfApFluxDelta
    +float psfApCorrSigmaScaledDelta
    +float maxDistToNearestPsf
    +float starEMedian
    +float starUnNormalizedEMedian
    +float starComa1Median
    +float starComa2Median
    +float starTrefoil1Median
    +float starTrefoil2Median
    +float starKurtosisMedian
    +float starE41Median
    +float starE42Median
    +float effTime
    +float effTimePsfSigmaScale
    +float effTimeSkyBgScale
    +float effTimeZeroPointScale
    +float magLim
    +float psfTE1e1
    +float psfTE1e2
    +float psfTE1ex
    +float psfTE2e1
    +float psfTE2e2
    +float psfTE2ex
    +float psfTE3e1
    +float psfTE3e2
    +float psfTE3ex
    +float psfTE4e1
    +float psfTE4e2
    +float psfTE4ex
  }
  class DetectorSerializationModel["DetectorSerializationModel"] {
    +str schema_version
    +int min_read_version
    +dict~str, MetadataValue~ metadata
    +list~Any~ indirect
    +int | None visit
  }
  class DetectorAttributes["DetectorAttributes"] {
    +str name
    +int id
    +DetectorType type
    +str serial
    +Box bbox
    +float pixel_size
    +str physical_type
  }
  class Orientation["Orientation"] {
    +float focal_plane_x
    +float focal_plane_y
    +float focal_plane_z
    +float pixel_reference_x
    +float pixel_reference_y
    +Quantity yaw
    +Quantity pitch
    +Quantity roll
  }
  class Amplifier["Amplifier"] {
    +str name
    +Box bbox
    +ReadoutCorner readout_corner
  }
  class AmplifierRawGeometry["AmplifierRawGeometry"] {
    +Box bbox
    +Box data_bbox
    +bool flip_x
    +bool flip_y
    +int x_offset
    +int y_offset
    +Box serial_overscan_bbox
    +Box parallel_overscan_bbox
    +Box prescan_bbox
    +ReadoutCorner readout_corner
  }
  class AmplifierCalibrations["AmplifierCalibrations"] {
    +float gain
    +float read_noise
    +float saturation
    +float suspect_level
    +InlineArray linearity_coefficients
    +str linearity_type
  }
  class CameraFrameSetSerializationModel["CameraFrameSetSerializationModel"] {
    +str schema_version
    +int min_read_version
    +dict~str, MetadataValue~ metadata
    +list~Any~ indirect
    +str instrument
    +str ast
  }
  class ApertureCorrectionMapSerializationModel["ApertureCorrectionMapSerializationModel"] {
    +str schema_version
    +int min_read_version
    +dict~str, MetadataValue~ metadata
    +list~Any~ indirect
  }
  class BackgroundMapSerializationModel["BackgroundMapSerializationModel"] {
    +str schema_version
    +int min_read_version
    +dict~str, MetadataValue~ metadata
    +list~Any~ indirect
    +dict~str, str~ descriptions
    +str | None subtracted
  }
  class ImageBasisConvolutionKernelSerializationModel["ImageBasisConvolutionKernelSerializationModel"] {
    +str schema_version
    +int min_read_version
    +dict~str, MetadataValue~ metadata
    +list~Any~ indirect
    +int center_y
    +int center_x
    +Literal~IMAGE_BASIS~ kernel_type
  }
  class DifferenceImageTemplateInfo["DifferenceImageTemplateInfo"] {
    +str skymap
    +int tract
    +int patch
    +UUID dataset_id
    +str dataset_run
    +Polygon bounds
    +float psf_shape_xx
    +float psf_shape_yy
    +float psf_shape_xy
    +bool psf_shape_flag
  }
  DifferenceImageSerializationModel_ArrayReferenceModel_ --> ButlerInfo : butler_info?
  DifferenceImageSerializationModel_ArrayReferenceModel_ --> ImageSerializationModel_ArrayReferenceModel_ : image
  DifferenceImageSerializationModel_ArrayReferenceModel_ --> MaskSerializationModel_ArrayReferenceModel_ : mask
  DifferenceImageSerializationModel_ArrayReferenceModel_ --> ImageSerializationModel_ArrayReferenceModel_ : variance
  DifferenceImageSerializationModel_ArrayReferenceModel_ --> SkyProjectionSerializationModel_ArrayReferenceModel_ : sky_projection
  DifferenceImageSerializationModel_ArrayReferenceModel_ --> PiffSerializationModel : psf (+other)
  DifferenceImageSerializationModel_ArrayReferenceModel_ --> PSFExSerializationModel : psf (+other)
  DifferenceImageSerializationModel_ArrayReferenceModel_ --> GaussianPSFSerializationModel : psf (+other)
  DifferenceImageSerializationModel_ArrayReferenceModel_ --> ObservationInfo : obs_info
  DifferenceImageSerializationModel_ArrayReferenceModel_ --> ChebyshevFieldSerializationModel : photometric_scaling?
  DifferenceImageSerializationModel_ArrayReferenceModel_ --> ProductFieldSerializationModel : photometric_scaling?
  DifferenceImageSerializationModel_ArrayReferenceModel_ --> SplineFieldSerializationModel : photometric_scaling?
  DifferenceImageSerializationModel_ArrayReferenceModel_ --> SumFieldSerializationModel : photometric_scaling?
  DifferenceImageSerializationModel_ArrayReferenceModel_ --> ObservationSummaryStats : summary_stats
  DifferenceImageSerializationModel_ArrayReferenceModel_ --> DetectorSerializationModel : detector
  DifferenceImageSerializationModel_ArrayReferenceModel_ --> ApertureCorrectionMapSerializationModel : aperture_corrections
  DifferenceImageSerializationModel_ArrayReferenceModel_ --> CellGridBounds : bounds? (+other)
  DifferenceImageSerializationModel_ArrayReferenceModel_ --> RegionSerializationModel : bounds? (+other)
  DifferenceImageSerializationModel_ArrayReferenceModel_ --> IntersectionBoundsSerializationModel : bounds? (+other)
  DifferenceImageSerializationModel_ArrayReferenceModel_ --> BackgroundMapSerializationModel : backgrounds
  DifferenceImageSerializationModel_ArrayReferenceModel_ --> ImageBasisConvolutionKernelSerializationModel : kernel?
  DifferenceImageSerializationModel_ArrayReferenceModel_ --> DifferenceImageTemplateInfo : templates?
  ButlerInfo --> SerializedDatasetRef : dataset
  ButlerInfo --> DatasetProvenance : provenance
  SerializedDatasetRef --> SerializedDatasetType : datasetType?
  SerializedDatasetRef --> SerializedDataCoordinate : dataId?
  SerializedDataCoordinate --> SerializedDimensionRecord : records?
  SerializedDimensionRecord --> Timespan : record+ (+other)
  DatasetProvenance --> SerializedDatasetRef : inputs*
  ImageSerializationModel_ArrayReferenceModel_ --> ButlerInfo : butler_info?
  ImageSerializationModel_ArrayReferenceModel_ --> ArrayReferenceQuantityModel : data
  ImageSerializationModel_ArrayReferenceModel_ --> ArrayReferenceModel : data
  ImageSerializationModel_ArrayReferenceModel_ --> InlineArrayModel : data
  ImageSerializationModel_ArrayReferenceModel_ --> InlineArrayQuantityModel : data
  ImageSerializationModel_ArrayReferenceModel_ --> SkyProjectionSerializationModel_ArrayReferenceModel_ : sky_projection?
  SkyProjectionSerializationModel_ArrayReferenceModel_ --> ButlerInfo : butler_info?
  SkyProjectionSerializationModel_ArrayReferenceModel_ --> TransformSerializationModel_ArrayReferenceModel_ : pixel_to_sky
  SkyProjectionSerializationModel_ArrayReferenceModel_ --> TransformSerializationModel_ArrayReferenceModel_ : fits_approximation?
  TransformSerializationModel_ArrayReferenceModel_ --> ButlerInfo : butler_info?
  TransformSerializationModel_ArrayReferenceModel_ --> DetectorFrame : frames* (+other)
  TransformSerializationModel_ArrayReferenceModel_ --> TractFrame : frames* (+other)
  TransformSerializationModel_ArrayReferenceModel_ --> FocalPlaneFrame : frames* (+other)
  TransformSerializationModel_ArrayReferenceModel_ --> FieldAngleFrame : frames* (+other)
  TransformSerializationModel_ArrayReferenceModel_ --> GeneralFrame : frames* (+other)
  TransformSerializationModel_ArrayReferenceModel_ --> CellGridBounds : bounds* (+other)
  TransformSerializationModel_ArrayReferenceModel_ --> RegionSerializationModel : bounds* (+other)
  TransformSerializationModel_ArrayReferenceModel_ --> IntersectionBoundsSerializationModel : bounds* (+other)
  TransformSerializationModel_ArrayReferenceModel_ --> ArrayReferenceModel : mappings*
  TransformSerializationModel_ArrayReferenceModel_ --> MappingSerializationModel : mappings*
  CellGridBounds --> CellGrid : grid
  IntersectionBoundsSerializationModel --> CellGridBounds : a (+other)
  IntersectionBoundsSerializationModel --> RegionSerializationModel : a (+other)
  IntersectionBoundsSerializationModel --> IntersectionBoundsSerializationModel : a (+other)
  IntersectionBoundsSerializationModel --> CellGridBounds : b (+other)
  IntersectionBoundsSerializationModel --> RegionSerializationModel : b (+other)
  IntersectionBoundsSerializationModel --> IntersectionBoundsSerializationModel : b (+other)
  MaskSerializationModel_ArrayReferenceModel_ --> ButlerInfo : butler_info?
  MaskSerializationModel_ArrayReferenceModel_ --> ArrayReferenceModel : data*
  MaskSerializationModel_ArrayReferenceModel_ --> InlineArrayModel : data*
  MaskSerializationModel_ArrayReferenceModel_ --> SkyProjectionSerializationModel_ArrayReferenceModel_ : sky_projection?
  PiffSerializationModel --> ButlerInfo : butler_info?
  PiffSerializationModel --> PiffObjectModel : piff
  PiffSerializationModel --> MinimalStar : stars*
  PiffSerializationModel --> CellGridBounds : bounds (+other)
  PiffSerializationModel --> RegionSerializationModel : bounds (+other)
  PiffSerializationModel --> IntersectionBoundsSerializationModel : bounds (+other)
  PiffObjectModel --> PiffTableModel : tables+
  PiffObjectModel --> GalSimPixelScaleModel : wcs+
  PiffObjectModel --> PiffObjectModel : objects+
  PiffTableModel --> TableModel : table
  PSFExSerializationModel --> ButlerInfo : butler_info?
  PSFExSerializationModel --> ArrayReferenceModel : parameters
  PSFExSerializationModel --> InlineArrayModel : parameters
  PSFExSerializationModel --> CellGridBounds : bounds (+other)
  PSFExSerializationModel --> RegionSerializationModel : bounds (+other)
  PSFExSerializationModel --> IntersectionBoundsSerializationModel : bounds (+other)
  GaussianPSFSerializationModel --> ButlerInfo : butler_info?
  GaussianPSFSerializationModel --> CellGridBounds : bounds (+other)
  GaussianPSFSerializationModel --> RegionSerializationModel : bounds (+other)
  GaussianPSFSerializationModel --> IntersectionBoundsSerializationModel : bounds (+other)
  ChebyshevFieldSerializationModel --> ButlerInfo : butler_info?
  ChebyshevFieldSerializationModel --> CellGridBounds : bounds (+other)
  ChebyshevFieldSerializationModel --> RegionSerializationModel : bounds (+other)
  ChebyshevFieldSerializationModel --> IntersectionBoundsSerializationModel : bounds (+other)
  ProductFieldSerializationModel --> ButlerInfo : butler_info?
  ProductFieldSerializationModel --> ChebyshevFieldSerializationModel : operands*
  ProductFieldSerializationModel --> ProductFieldSerializationModel : operands*
  ProductFieldSerializationModel --> SplineFieldSerializationModel : operands*
  ProductFieldSerializationModel --> SumFieldSerializationModel : operands*
  SplineFieldSerializationModel --> ButlerInfo : butler_info?
  SplineFieldSerializationModel --> CellGridBounds : bounds (+other)
  SplineFieldSerializationModel --> RegionSerializationModel : bounds (+other)
  SplineFieldSerializationModel --> IntersectionBoundsSerializationModel : bounds (+other)
  SplineFieldSerializationModel --> ArrayReferenceModel : data
  SplineFieldSerializationModel --> InlineArrayModel : data
  SumFieldSerializationModel --> ButlerInfo : butler_info?
  SumFieldSerializationModel --> ChebyshevFieldSerializationModel : operands*
  SumFieldSerializationModel --> ProductFieldSerializationModel : operands*
  SumFieldSerializationModel --> SplineFieldSerializationModel : operands*
  SumFieldSerializationModel --> SumFieldSerializationModel : operands*
  ObservationSummaryStats --> ButlerInfo : butler_info?
  DetectorSerializationModel --> ButlerInfo : butler_info?
  DetectorSerializationModel --> DetectorAttributes : attributes
  DetectorSerializationModel --> Amplifier : amplifiers*
  DetectorSerializationModel --> CameraFrameSetSerializationModel : frames?
  DetectorAttributes --> Orientation : orientation
  Amplifier --> AmplifierRawGeometry : assembled_raw_geometry?
  Amplifier --> AmplifierRawGeometry : unassembled_raw_geometry?
  Amplifier --> AmplifierCalibrations : nominal_calibrations?
  CameraFrameSetSerializationModel --> ButlerInfo : butler_info?
  ApertureCorrectionMapSerializationModel --> ButlerInfo : butler_info?
  ApertureCorrectionMapSerializationModel --> ChebyshevFieldSerializationModel : fields+
  ApertureCorrectionMapSerializationModel --> ProductFieldSerializationModel : fields+
  ApertureCorrectionMapSerializationModel --> SplineFieldSerializationModel : fields+
  ApertureCorrectionMapSerializationModel --> SumFieldSerializationModel : fields+
  BackgroundMapSerializationModel --> ButlerInfo : butler_info?
  BackgroundMapSerializationModel --> ChebyshevFieldSerializationModel : fields+
  BackgroundMapSerializationModel --> ProductFieldSerializationModel : fields+
  BackgroundMapSerializationModel --> SplineFieldSerializationModel : fields+
  BackgroundMapSerializationModel --> SumFieldSerializationModel : fields+
  ImageBasisConvolutionKernelSerializationModel --> ButlerInfo : butler_info?
  ImageBasisConvolutionKernelSerializationModel --> ArrayReferenceModel : basis
  ImageBasisConvolutionKernelSerializationModel --> InlineArrayModel : basis
  ImageBasisConvolutionKernelSerializationModel --> ChebyshevFieldSerializationModel : spatial*
  ImageBasisConvolutionKernelSerializationModel --> ProductFieldSerializationModel : spatial*
  ImageBasisConvolutionKernelSerializationModel --> SplineFieldSerializationModel : spatial*
  ImageBasisConvolutionKernelSerializationModel --> SumFieldSerializationModel : spatial*
    

Fields

Field	Type	Required	Description
aperture_corrections	aperture_correction_map	no	Aperture corrections, keyed by flux algorithm.
backgrounds	background_map	no	Background models associated with this image.
band	string	yes	Short name of the bandpass filter.
bounds	BoundsSerializationModel | null	no	Pixel validity region, if different from the image bounding box.
butler_info	ButlerInfo | null	no	Information about the butler dataset backed by this file.
detector	detector	yes	Geometry and electronic information for the detector.
image	image	yes	The main data image.
indirect	array of any	no	Serialized nested objects that may be saved or read more than once.
kernel	image_basis_convolution_kernel | null	yes	The convolution kernel used to match the (warped) template to the science image.
mask	mask	yes	Bitmask that annotates the main image’s pixels.
metadata	object	no	Additional unstructured metadata.
min_read_version	integer	no	Smallest reader major that can interpret this tree.
obs_info	ObservationInfo	yes	Standardized description of visit metadata
photometric_scaling	FieldSerializationModel | null	no	Scaling that can be used to multiply a post-ISR image to yield calibrated pixel values.
psf	piff_psf | psfex_psf | gaussian_psf | any	yes	PSF model for the image.
schema_version	string	no	Data-model schema version of this tree (major.minor.patch).
sky_projection	sky_projection	yes	Projection that maps the pixel grid to the sky.
summary_stats	observation_summary_stats	yes	Summary statistics for the observation.
templates	array of DifferenceImageTemplateInfo | null	yes	Information about the template coadds that went into this difference image
variance	image	yes	Per-pixel variance estimates for the main image.