# Documentation

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# bestblk

Determine optimal block size for block processing

## Syntax

```siz = bestblk([m n],k) [mb,nb] = bestblk([m n],k) ```

## Description

`siz = bestblk([m n],k)` returns, for an `m`-by-`n` image, the optimal block size for block processing. The optimal block size is the size required along the outer partial blocks. `k` is a scalar specifying the maximum row and column dimensions for the block. If you omit this argument, the default is 100. The return value `siz` is a 1-by-2 vector containing the row and column dimensions for the block.

`[mb,nb] = bestblk([m n],k)` returns the row and column dimensions for the block in `mb` and `nb`, respectively.

## Examples

collapse all

`siz = bestblk([640 800],72)`
```siz = 64 50 ```

## Algorithms

`bestblk` returns the optimal block size given `m`, `n`, and `k`. The algorithm for determining `siz` is

• If `m` is less than or equal to `k`, return `m`.

• If `m` is greater than `k`, consider all values between `min(m/10,k/2)` and `k`. Return the value that minimizes the padding required.

The same algorithm is then repeated for `n`.