The DWT2D function outputs a message that indicates whether the function succeeded,, an output table of transformed (decomposed) sequences, and a meta table of wavelet-related information.
Column Name | Data Type | Description |
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messages | VARCHAR | Message that indicates whether the function was successful. |
Column Name | Data Type | Description |
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partition_column | Inherited from input table column with same name | Sequence identifier of the sequence to which the data belongs. Rows with the same partition column values belong to the same sequence. The output table has a partition_column for every partition_column in the input table. If the input table has multiple partition columns, the first one is the distribute key in both the input and output tables. If the input table has only one partition_column, the output table has as its distribute key a function-generated column named dwt_idrandom_name. Every cell of dwt_idrandom_name has the value 1. |
waveletid | INTEGER | Index of each wavelet coefficient (starting from 1 for each sequence). |
waveletcomponent | VARCHAR | Component to which the coefficient belongs. Possible values are A n , H n , V n , D n , H n-1 , ..., H 1 , V 1 , D 1 , where n is the wavelet transform level. |
input_column | DOUBLE PRECISION | Coefficient of the corresponding input column after the wavelet transform. The output table has an input_column for every input_column in the input table. |
columns | type | description |
---|---|---|
partition_column | Inherited from input table column with same name | Sequence identifier of the sequence to which the data belongs. Rows with the same partition column values belong to the same sequence. The output table has a partition_column for every partition_column in the input table. If the input table has multiple partition columns, the first one is the distribute key in both the input and output tables. If the input table has only one partition_column, the output table has as its distribute key a function-generated column named dwt_idrandom_name. Every cell of dwt_idrandom_name has the value 1. |
meta | VARCHAR | Meta information name from the following table. |
content | VARCHAR | Meta information that corresponds to the meta name (see the following table). |
The following table summarizes the information that the meta table contains for each sequence.
meta | content |
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blocklength | Pairs that represent the length of each block of coefficients. The format is (row_number, column_number). For example: (5, 5), (5, 5), (5, 6) |
length | Pair that represents the length of the original sequence in each dimension.The format is (row_number, column_number). For example: (5, 8) |
range | Minimum and maximum indexes of the original sequence. The format is (min_y_index, min_x_index), (max_y_index, max_x_index). For example: (1, 1), (5, 8) |
lowpassfilter | Low-pass filter coefficients used in the decomposition of the wavelet. |
highpassfilter | High-pass filter coefficients used in the decomposition of the wavelet. |
ilowpassfilter | Low-pass filter coefficients used in the reconstruction of the wavelet. |
ihighpassfilter | High-pass filter coefficients used in the reconstruction of the wavelet. |
level | Level of wavelet transform performed. |
extensionmode | Extension mode used in the wavelet transform. |