# hist.im

##### Histogram of Pixel Values in an Image

Computes and displays a histogram of the pixel values in a pixel image.
The `hist`

method for class `"im"`

.

##### Usage

```
# S3 method for im
hist(x, …, probability=FALSE, xname)
```

##### Arguments

- x
A pixel image (object of class

`"im"`

).- …
Arguments passed to

`hist.default`

or`barplot`

.- probability
Logical. If

`TRUE`

, the histogram will be normalised to give probabilities or probability densities.- xname
Optional. Character string to be used as the name of the dataset

`x`

.

##### Details

This function computes and (by default) displays a histogram
of the pixel values in the image `x`

.

An object of class `"im"`

describes a pixel image. See `im.object`

)
for details of this class.

The function `hist.im`

is a method for the generic
function `hist`

for the class `"im"`

.

Any arguments in `...`

are passed to `hist.default`

(for numeric valued images) or `barplot`

(for factor or
logical images).
For example, such arguments control the axes, and may be used to
suppress the plotting.

##### Value

For numeric-valued images, an object of class `"histogram"`

as returned
by `hist.default`

. This object can be
plotted.

For factor-valued or logical images, an object of class
`"barplotdata"`

, which can be plotted.
This is a list with components
called `counts`

(contingency table of counts of the numbers of
pixels taking each possible value), `probs`

(corresponding relative
frequencies) and `mids`

(graphical \(x\)-coordinates of the
midpoints of the bars in the barplot).

##### See Also

`spatialcdf`

for the cumulative distribution function
of an image.

For other statistical graphics such as Q-Q plots,
use `X[]`

to extract the pixel values of image `X`

,
and apply the usual statistical graphics commands.

For information about pixel images see
`im.object`

,
`summary.im`

.

##### Examples

```
# NOT RUN {
X <- as.im(function(x,y) {x^2}, unit.square())
hist(X)
hist(cut(X,3))
# }
```

*Documentation reproduced from package spatstat, version 1.61-0, License: GPL (>= 2)*