Image Processing Toolbox User's Guide
qtsetblk

Set block values in quadtree decomposition

Syntax

• ```J = qtsetblk(I,S,dim,vals)
```

Description

`J = qtsetblk(I,S,dim,vals)` replaces each `dim`-by-`dim` block in the quadtree decomposition of `I` with the corresponding `dim`-by-`dim` block in `vals`. `S` is the sparse matrix returned by `qtdecomp`; it contains the quadtree structure. `vals` is a `dim`-by-`dim`-by-`k` array, where `k` is the number of `dim`-by-`dim` blocks in the quadtree decomposition.

Class Support

`I` can be of class `logical`, `uint8`, `uint16`, `int16`, `single`, or `double`. `S` is of class `sparse`.

Remarks

The ordering of the blocks in `vals` must match the columnwise order of the blocks in `I`. For example, if `vals` is 4-by-4-by-2, `vals(:,:,1)` contains the values used to replace the first 4-by-4 block in `I`, and `vals(:,:,2)` contains the values for the second 4-by-4 block.

Example

• ```I = [1    1    1    1    2    3    6    6
1    1    2    1    4    5    6    8
1    1    1    1   10   15    7    7
1    1    1    1   20   25    7    7
20   22   20   22    1    2    3    4
20   22   22   20    5    6    7    8
20   22   20   20    9   10   11   12
22   22   20   20   13   14   15   16];

S = qtdecomp(I,5);

newvals = cat(3,zeros(4),ones(4));
J = qtsetblk(I,S,4,newvals)
```

`qtdecomp`, `qtgetblk`