Package nom.tam.fits

Class ImageHDU

All Implemented Interfaces:
FitsElement
Direct Known Subclasses:
NullDataHDU

public class ImageHDU extends BasicHDU<ImageData>
Header/data unit for images. Image HDUs are suitable for storing monolithic regular numerical arrays in 1 to 255 dimensions, such as a double[], float[][], or short[][][]. ((FITS supports up to 999 dimensions, but Java support maxes at at 255 -- however it's unlikely you'll find this to be a serious limitation.)
See Also:
  • Constructor Details

    • ImageHDU

      public ImageHDU(Header h, ImageData d)
      Deprecated.
      (for internal use) Its visibility should be reduced to package level in the future.
      Build an image HDU using the supplied data.
      Parameters:
      h - the header for the image.
      d - the data used in the image.
  • Method Details

    • getCanonicalXtension

      protected final String getCanonicalXtension()
      Description copied from class: BasicHDU
      Returns the canonical (expected) value for the XTENSION keywords for this type of HDU. Concrete HDU implementations should override this method as appropriate. As of FITS version 4, only the following XTENSION values are recognised: 'IMAGE', 'TABLE', and 'BINTABLE'.
      Overrides:
      getCanonicalXtension in class BasicHDU<ImageData>
      Returns:
      The value to use for the XTENSION keyword.
    • encapsulate

      @Deprecated public static ImageData encapsulate(Object o) throws IllegalArgumentException, FitsException
      Deprecated.
      (for internal use) Use ImageData.from(Object) instead. Will reduce visibility in the future
      Parameters:
      o - object to encapsulate
      Returns:
      Encapsulate an object as an ImageHDU.
      Throws:
      FitsException - does not actually throw this exception
      IllegalArgumentException - if the data is not a regular primitive numerical array suitable for an image.
    • isData

      @Deprecated public static boolean isData(Object o)
      Deprecated.
      (for internal use) Will reduce visibility in the future
      Parameters:
      o - The Object being tested.
      Returns:
      is this object can be described as a FITS image.
    • isHeader

      @Deprecated public static boolean isHeader(Header hdr)
      Deprecated.
      (for internal use) Will reduce visibility in the future
      Check that this HDU has a valid header for this type.
      Parameters:
      hdr - header to check
      Returns:
      true if this HDU has a valid header.
    • manufactureData

      @Deprecated public static ImageData manufactureData(Header hdr) throws FitsException
      Deprecated.
      (for internal use) Will reduce visibility in the future
      Prepares a data object into which the actual data can be read from an input subsequently or at a later time.
      Parameters:
      hdr - The FITS header that describes the data
      Returns:
      A data object that support reading content from a stream.
      Throws:
      FitsException - if the data could not be prepared to prescriotion.
    • manufactureHeader

      @Deprecated public static Header manufactureHeader(Data d) throws FitsException
      Deprecated.
      (for internal use) Will reduce visibility in the future
      Prepares a data object into which the actual data can be read from an input subsequently or at a later time.
      Parameters:
      d - The FITS data content of this HDU
      Returns:
      A data object that support reading content from a stream.
      Throws:
      FitsException - if the data could not be prepared to prescriotion.
    • getTiler

      public StandardImageTiler getTiler()
      Returns the class that can be used to divide this image into tiles that may be processed separately (and in parallel).
      Returns:
      image tiler for this image instance.
      See Also:
    • info

      public void info(PrintStream stream)
      Description copied from class: BasicHDU
      Print out some information about this HDU.
      Specified by:
      info in class BasicHDU<ImageData>
      Parameters:
      stream - the printstream to write the info on
    • getBUnit

      public String getBUnit()
      Returns the name of the physical unit in which images are represented.
      Overrides:
      getBUnit in class BasicHDU<ImageData>
      Returns:
      the standard name of the physical unit in which the image is expressed, e.g. "Jy beam^{-1}".
    • getBlankValue

      public long getBlankValue() throws FitsException
      Returns the integer value that signifies blank (missing or null) data in an integer image.
      Overrides:
      getBlankValue in class BasicHDU<ImageData>
      Returns:
      the integer value used for identifying blank / missing data in integer images.
      Throws:
      FitsException - if the header does not specify a blanking value or if it is not appropriate for the type of imge (that is not an integer type image)
    • getBScale

      public double getBScale()
      Returns the floating-point increment between adjacent integer values in the image. Strictly speaking, only integer-type images should define a quantization scaling, but there is no harm in having this value in floating-point images also -- which may be interpreted as a hint for quantization, perhaps.
      Overrides:
      getBScale in class BasicHDU<ImageData>
      Returns:
      the floating-point quantum that corresponds to the increment of 1 in the integer data representation.
      See Also:
    • getBZero

      public double getBZero()
      Returns the floating-point value that corresponds to an 0 integer value in the image. Strictly speaking, only integer-type images should define a quantization offset, but there is no harm in having this value in floating-point images also -- which may be interpreted as a hint for quantization, perhaps.
      Overrides:
      getBZero in class BasicHDU<ImageData>
      Returns:
      the floating point value that correspond to the integer 0 in the image data.
      See Also: