usage_examples.txt

JPEG2000的C++实现代码

    -- For a full understanding of the `Ksteps' and `Kcoeffs' parameter
       attribute syntax, refer to the usage statement printed by
       "kdu_compress -usage".
    -- Note that the `Catk' attribute identifies the kernel to be used
       via its instance index (2 in this case).  The kernel is then
       given by the `Kextension', `Kreversible', `Ksteps' and `Kcoeffs'
       attributes with this instance index (:I2).

Ad) kdu_compress -i image.ppm -o image.jpx  Catk=2
                 Kextension:I2=CON Kreversible:I2=yes
                 Ksteps:I2={1,0,0,0},{1,0,1,1}
                 Kcoeffs:I2=-1.0,0.5
    -- Another example of Part-2 arbitrary transform kernel (ATK) features,
       this time specifying the well-known Haar (2x2) transform kernel, for
       lossless processing; the reversible Haar DWT is also known as the
       "S-transform" in the literature.

Ae) kdu_compress -i image.bmp -o image.j2c Catk=2
        Kextension:I2=SYM Kreversible:I2=yes
        Ksteps:I2={4,-1,4,8},{4,-2,4,8}
        Kcoeffs:I2=0.0625,-0.5625,-0.5625,0.0625,-0.0625,0.3125,0.3125,-0.0625
    -- Another example of Part-2 arbitrary transform kernel (ATK) features,
       this time specifying a reversible 13x7 kernel (13-tap symmetric low-pass
       analysis filter, 7-tap symmetric high-pass analysis filter) with two
       lifting steps.

Af) kdu_compress -i image.ppm -o image.jpx  -jp2_space sRGB  Mcomponents=3
                 Sprecision=8,8,8  Ssigned=no,yes,yes  Mmatrix_size:I7=9
                 Mmatrix_coeffs:I7=1,0,1.402,1,-0.344136,-0.714136,1,1.772,0
                 Mvector_size:I1=3  Mvector_coeffs:I1=128,128,128
                 Mstage_inputs:I16={0,2}  Mstage_outputs:I16={0,2}
                 Mstage_collections:I16={3,3}  Mstage_xforms:I16={MAT,7,1,0,0}
                 Mnum_stages=1 Mstages=16
    -- Compresses an RGB colour image using the conventional RGB to YCbCr
       transform to approximately decorrelate the colour channels, implemented
       here as a Part-2 multi-component transform.  The colour transform is
       actually identical to the Part-1 ICT (Irreversible Colour Transform),
       but this example is provided mainly to demonstrate the use of the
       multi-component transform.
    -- To decode the above parameter attributes, note that:
       a) There is only one multi-component transform stage, whose instance
          index is 16 (this is the I16 suffix found on the descriptive
          attributes for this stage).  The value 16 is entirely arbitrary.  I
          picked it to make things interesting.  There can, in general, be
          any number of transform stages.
       b) The single transform stage consists of only one transform block,
          defined by the `Mstage_xforms:I16' attribute -- there can be
          any number of transform blocks, in general.
       c) This block takes 3 input components and produces 3 output
          components, as indicated by the `Mstage_collections:I16' attribute.
       d) The stage inputs and stage outputs are not permuted in this example;
          they are enumerated as 0-2 in each case, as given by the
          `Mstage_inputs:I16' and `Mstage_outputs:I16' attributes.
       e) The transform block itself is implemented using an irreversible
          matrix decorrelation operator.  More specifically, the transform
          block belongs to the class of matrix decorrelation operators
          (1'st field of `Mstage_xforms:I16' record is "MAT"), with
          matrix coefficients taken from the `Mmatrix_size' and
          `Mmatrix_coeffs' attributes with instance index 7 (2'nd field of
          `Mstage_xforms:I16' is 7), using irreversible processing
          (4'th field of `Mstage_xforms:I16' is 0 -- irreversible).  Block
          outputs are added to the offset vector whose instance index is 1
          (3'rd field of `Mstage_xforms:I16' is 1), as given by the
          `Mvector_size:I1' and `Mvector_coeffs:I1' attributes.
       f) The mapping from YCbCr to RGB is performed using the 3x3 matrix,
          whose coefficients appear in raster order within the
          `Mmatrix_coeffs:I1' attribute.
       g) Since a multi-component transform is being used, the precision
          and signed/unsigned properties of the final decompressed (or
          original compressed) image components are given by `Mprecision'
          and `Msigned' (8-bit unsigned image samples in this case), while
          their number is given by `Mcomponents'.
       h) The `Sprecision' and `Ssigned' attributes record the precision
          and signed/unsigned characteristics of what we call the codestream
          components -- i.e., the components which are obtained by block
          decoding and spatial inverse wavelet transformation.  In this
          case, these are the Y, Cb and Cr components.  The RGB to YCbCr
          transform has the property that these are also 8-bit quantities
          (no range expansion), with Cb and Cr holding signed quantities
          and Y (luminance) unsigned.

Ag) kdu_compress -i image.bmp -o image.jpx  -jp2_space sRGB  Mcomponents=4
                 Sprecision=8,8,8  Ssigned=no,yes,yes  Mmatrix_size:I7=9
                 Mmatrix_coeffs:I7=1,0,1.402,1,-0.344136,-0.714136,1,1.772,0
                 Mvector_size:I1=3  Mvector_coeffs:I1=128,128,128
                 Mvector_size:I2=1  Mvector_coeffs:I2=128
                 Mstage_inputs:I16={0,2},{0,0}  Mstage_outputs:I16={0,3}
                 Mstage_collections:I16={3,3},{1,1}
                 Mstage_xforms:I16={MAT,7,1,0,0},{MAT,0,2,0,0}
                 Mnum_stages=1 Mstages=16
    -- Same as example Af), except that the multi-component transform defines
       an extra output component, which is created by a second transform
       block in the single multi-component transform stage.
          This extra transform block is described by the second record in
       each of `Mstage_collections' and `Mstage_xforms'; it takes only 1 input
       and 1 output and uses a null-transform (2'nd field in the second record
       of `Mstage_xforms:I16' is 0).  This means that the extra transform
       block simply passes its input through to its output, adding the
       offset described by `Mvector_size:I2' and `Mvector_coeffs:I2' (3'rd
       field of the second recrod in `Mstage_xforms:I16' is 2).
          The bottom line is that the 4'th output component is simply a
       replica of the 1'st raw codestream component -- the Y (luminance)
       component.  In order, the output components are R, G, B and Y.
    -- This example shows how multi-component transforms can have more
       output components than the number of codestream components -- i.e.
       the components which are actually encoded.  In fact, they can also
       have fewer components.  When confronted with this situation, the
       "kdu_compress" example associates the input image file's N components
       (N=3 here) with the first N output image components, and then figures
       out how to work back through the multi-component transform network,
       inverting or partially inverting an appropriate subset of the
       transform blocks so as to obtain the codestream components which
       must be encoded.  If there is a way of doing this, Kakadu should
       be able to find it.

Ah) kdu_compress -i image.ppm -o image.jpx  -jp2_space sRGB
                 Mcomponents=3  Creversible=yes
                 Sprecision=8,8,8  Ssigned=no,yes,yes  Mmatrix_size:I7=12
                 Mmatrix_coeffs:I7=1,0,1,0,1,1,0,0,4,-1,-1,1
                 Mvector_size:I1=3  Mvector_coeffs:I1=128,128,128
                 Mstage_inputs:I25={1,1},{2,2},{0,0}
                 Mstage_outputs:I25={2,2},{0,0},{1,1}
                 Mstage_collections:I25={3,3}  Mstage_xforms:I25={MAT,7,1,1,0}
                 Mnum_stages=1  Mstages=25
    -- Same as example Af), except that processing is performed reversibly
       and the Part-1 RCT (reversible colour transform) is implemented as a
       multi-component transform to demonstrate reversible matrix
       decorrelation transforms.
    -- To understand the reversible decorrelation transform block, observe
       firstly that the coefficients from `Mmatrix_coeffs:I7' belong to
       the following 3x4 array:
                        | 1   0   1   0 |
                    M = | 1   1   0   0 |
                        | 4  -1  -1   1 |
       Let I0, I1 and I2 denote the inputs to this transform block.  The
       reversible transform operator transforms these inputs into outputs
       via the following steps (one step per column in the matrix, M):
          i)   I2 <- I2 - round[(1*I0 +  1*I1) / 4]  = I2 - round((I0+I1)/4)
          ii)  I1 <- I1 - round[(0*I0 + -1*I2) / 1]  = I1 + I2
          iii) I0 <- I0 - round[(0*I0 + -1*I2) / 1]  = I0 + I2
          iV)  I2 <- I2 - round[(0*I0 +  0*I1) / 1]  = I2
       Noting that `Mstage_inputs:I25' associates the block inputs with
       the raw codestream components I0 -> C1=Db, I1 -> C2=Dr, I2 -> C0=Y,
       and `Mstage_outputs:I25' associates the block outputs with stage
       output components I0 -> M2=B, I1 -> M0=R, I2 -> M1=G, the above
       steps can be written as
          i)   G <- Y - round((Db + Dr)/4)
          ii)  R <- Dr + G
          iii) B <- Db + G
          iV)  G <- G
       which is exactly the Part-1 RCT transform mapping YDbDr to RGB -- of
       course, the fourth step does nothing here, but reversible
       multi-component decorrelation transforms require this final step.
    -- For a complete description of reversible multi-component decorrelation
       transforms, consult Part-2 of the JPEG2000 standard, or the interface
       description for Kakadu function `kdu_tile::get_mct_rxform_info'.

Ai) kdu_compress -i catscan.rawl*35@524288 -o catscan.jpx -jpx_layers *
                 -jpx_space sLUM Creversible=yes Sdims={512,512} Clayers=16
                 Mcomponents=35  Msigned=no  Mprecision=12
                 Sprecision=12,12,12,12,12,13  Ssigned=no,no,no,no,no,yes
                 Mvector_size:I4=35 Mvector_coeffs:I4=2048
                 Mstage_inputs:I25={0,34}  Mstage_outputs:I25={0,34}
                 Mstage_collections:I25={35,35}
                 Mstage_xforms:I25={DWT,1,4,3,0}
                 Mnum_stages=1  Mstages=25
    -- Compresses a medical volume consisting of 35 slices, each 512x512,
       represented in raw little-endian format with 12-bits per sample,
       packed into 2 bytes per sample.  This example follows example (x)
       above, but adds a multi-component transform, which is implemented
       using a 3 level DWT, based on the 5/3 reversible kernel (the kernel-id
       is 1, which is found in the second field of the `Mstage_xforms' record.
    -- To decode the above parameter attributes, note that:
       a) There is only one multi-component transform stage, whose instance
          index is 25 (this is the I25 suffix found on the descriptive
          attributes for this stage).  The value 25 is entirely arbitrary.  I
          picked it to make things interesting.  There can, in general, be
          any number of transform stages.
       b) The single transform stage consists of only one transform block,
          defined by the `Mstage_xforms:I25' attribute -- there can be
          any number of transform blocks, in general.
       c) This block takes 35 input components and produces 35 output
          components, as indicated by the `Mstage_collections:I25' attribute.
       d) The stage inputs and stage outputs are not permuted in this example;
          they are enumerated as 0-34 in each case, as given by the
          `Mstage_inputs:I25' and `Mstage_outputs:I25' attributes.
       e) The transform block itself is implemented using a DWT, whose kernel
          ID is 1 (this is the Part-1 5/3 reversible DWT kernel).  Block
          outputs are added to the offset vector whose instance index is 4
          (as given by `Mvector_size:I4' and `Mvector_coeffs:I4') and the
          DWT has 3 levels.  The final field in the `Mstage_xforms' record
          is set to 0, meaning that the canvas origin for the multi-component
          DWT is to be taken as 0.
       f) Since a multi-component transform is being used, the precision
          and signed/unsigned properties of the final decompressed (or
          original compressed) image components are given by `Mprecision'
          and `Msigned', while their number is given by `Mcomponents'.
       g) The `Sprecision' and `Ssigned' attributes record the precision
          and signed/unsigned characteristics of what we call the codestream
          components -- i.e., the components which are obtained by block
          decoding and spatial inverse wavelet transformation.  In this
          case, the first 5 are low-pass subband components, at the bottom