spatstat.geom (version 2.1-0)

mean.im: Mean and Median of Pixel Values in an Image

Description

Calculates the mean or median of the pixel values in a pixel image.

Usage

```## S3 method for class 'im'
## mean(x, trim=0, na.rm=TRUE, ...) ## S3 method for class 'im'
## median(x, na.rm=TRUE)        [R < 3.4.0]
## median(x, na.rm=TRUE, ...)   [R >= 3.4.0]```

Arguments

x

A pixel image (object of class `"im"`).

na.rm

Logical value indicating whether `NA` values should be stripped before the computation proceeds.

trim

The fraction (0 to 0.5) of pixel values to be trimmed from each end of their range, before the mean is computed.

Ignored.

A single number.

Details

These functions calculate the mean and median 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 `mean.im` is a method for the generic function `mean` for the class `"im"`. Similarly `median.im` is a method for the generic `median`.

If the image `x` is logical-valued, the mean value of `x` is the fraction of pixels that have the value `TRUE`. The median is not defined.

If the image `x` is factor-valued, then the mean of `x` is the mean of the integer codes of the pixel values. The median is are not defined.

Other mathematical operations on images are supported by `Math.im`, `Summary.im` and `Complex.im`.

Other information about an image can be obtained using `summary.im` or `quantile.im`.

`Math.im` for other operations.

Generics and default methods: `mean`, `median`.

`quantile.im`, `anyNA.im`, `im.object`, `summary.im`.

Examples

```# NOT RUN {
X <- as.im(function(x,y) {x^2}, unit.square())
mean(X)
median(X)
mean(X, trim=0.05)
# }
```