MATLAB Function Reference |

histogram2

Compute a two dimensional histogram

**Syntax**

[result,descriptor] = histogram2(x,y) [result,descriptor] = histogram2(x,y,descriptor)

**Description**

The `discriptor`

describes the cells of the histogram. The
`discriptor`

consists of two row vectors with three elements
`[lowerx,upperx,ncellx;lowery,uppery,ncelly]`

. The default values are
`lowerx=min(x)-deltax/2`

, `upperx=max(x)+deltax/2`

and
`ncellx=ceil(length(x)^(1/3))`

, where
`deltax=(max(x)-min(x))/(length(x)-1)`

and similar for `y`

.

Its assumed that `lowerx < upperx`

, ```
lowery <
uppery
```

, `ncelly >= 1`

,
`ncelly >= 1`

and `length(x) == length(y)`

. Futhermore its assumed that both `x`

and `y`

are row
vectors.

The `result`

is a matrix vector containing the histogram of
`x`

and `y`

.
The indices `(indexx,indexy)`

of the histogram cells are computed by ```
indexx = round( (x(i)-lowerx) / (upperx-lowerx) * ncellx
) + 1/2
```

and ```
indexy = round( (x(i)-lowery) / (uppery-lowery) * ncelly
) + 1/2
```

. If one of the indices is out of the range ```
1 <= indexx <=
ncellx
```

or ```
1 <= indexy <=
ncelly
```

, consequently `x(i) < lowerx`

,
`upperx <= x(i)`

,`y(i) < lowery`

or
`uppery <= y(i)`

, the elements `x(i)`

and
`y(i)`

are excluded from the histogram.

**See Also**

**Literature**

None

**Source code**

MATLAB Function Reference |