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imager (version 1.0.3)

Image Processing Library Based on 'CImg'

Description

Fast image processing for images in up to 4 dimensions (two spatial dimensions, one time/depth dimension, one colour dimension). Provides most traditional image processing tools (filtering, morphology, transformations, etc.) as well as various functions for easily analysing image data using R. The package wraps 'CImg', , a simple, modern C++ library for image processing.

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Install

install.packages('imager')

Monthly Downloads

11,372

Version

1.0.3

License

LGPL-3

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Repository

https://github.com/asgr/imager/

Homepage

https://asgr.github.io/imager/

Maintainer

Aaron Robotham

Last Published

March 25th, 2025

Functions in imager (1.0.3)

Convert various objects to image lists

as.cimg.function

Create an image by sampling a function

Convert an image in spatstat format to an image in cimg format

Autocrop image region

Methods to convert various objects to pixsets

Compute the Discrete Fourier Transform of an image

Compute the bounding box of a pixset

Split a colour image into a list of separate channels

Center stencil at a location

Convert a RasterLayer/RasterBrick to a cimg image/image list

Convert a cimg object to a raster object for plotting

Convert a raster object to a cimg object

as.data.frame.cimg

Convert a pixel image to a data.frame

as.data.frame.imlist

Convert image list to data.frame

as.data.frame.pixset

Methods to convert pixsets to various objects

Blur image with a box filter.

Return or set pixel value at coordinates

Form a graph from an image

Find the boundary of a shape in a pixel set

as.igraph.pixset

Form an adjacency graph from a pixset

Capture the current R plot device as a cimg image

Canny edge detector

Concatenation for image lists

Create a cimg object

Fill in a colour in an area given by a pixset

Various useful pixsets

Return contours of image/pixset

Coordinates from pixel index

Blur image with a box filter (square window)

Add circles to plot

Photograph of sailing boats from Kodak set

blur_anisotropic

Blur image anisotropically, in an edge-preserving way.

cimg.dimensions

Image dimensions

Various shortcuts for extracting colour channels, frames, etc

Clean up and fill in pixel sets (morphological opening and closing)

distance_transform

Compute Euclidean distance function to a specified value.

Draw circle on image

Display object using CImg library

Estimate displacement field between two images.

Return pixel values in a neighbourhood defined by a stencil

Control CImg's parallelisation

Return coordinates of subset of pixels

Convert an RGB image to grayscale

Display image using CImg library

Display image list using CImg library

Grow/shrink a pixel set

Convert cimg to spatstat im object

Split an image, apply function, recombine the results as an image

Return image hessian.

Compute image gradient.

Split a video into separate frames

Flatten alpha channel

Split an image along axis, apply function, return a list

Combine a list of images into a single image

Modify parts of an image

Apply recursive Deriche filter.

diffusion_tensors

Compute field of diffusion tensors for edge-preserving smoothing.

Replicate images

Rotate an image along the XY plane.

Split an image along a certain axis (producing a list)

imager: an R library for image processing, based on CImg

extract_patches

Extract image patches and return a list

Erode/dilate image by a structuring element.

Draw rectangle on image

Correlation/convolution of image by filter

Crop the outer margins of an image

Grayscale dimensions of image

Compute Haar multiscale wavelet transform.

Highlight pixel set on image

Draw text on an image

Draw image on another image

Check that an object is an imlist object

Check that an object is a pixset object

Evaluation in an image context

Select image regions interactively

Make/save a video using ffmpeg

Check that value is in a range

Type-stable map for use with the purrr package

Mutate a data frame by adding new or replacing existing columns.

Plot objects on image using base graphics

Generate (Gaussian) white-noise image

Create an image of custom size by filling in repeated values

Split an image along axis, map function, return a data.frame

Circle detection using Hough transform

Hough transform for lines

Array subset operator for cimg objects

Replace part of an image with another

Interpolate image values

Compute image gradient

Split an image along a certain axis (producing a list)

Select part of an image

Fill-in NA values in an image

Linear index in internal vector from pixel coordinates

Return image patch summary

Compute the periodic part of an image, using the periodic/smooth decomposition of Moisan (2011)

Remove alpha channel and store as attribute

resize_doubleXY

Resize image uniformly

Build simple interactive interfaces using imager

Blur image with the median filter. In a window of size n x n centered at pixel (x,y), compute median pixel value over the window. Optionally, ignore values that are too far from the value at current pixel.

Mirror image content along specified axis

Return information on image file

Compute image hessian.

patch_summary_cimg

Extract a numerical summary from image patches, using CImg's mini-language Experimental feature.

Pad image with n pixels along specified axis

Renormalise image

A cross-shaped stencil

Threshold grayscale image

Rotate image by an arbitrary angle, around a center point.

Colour space conversions in imager

Combining images

Coordinates as images

Generates a "dirac" image, i.e. with all values set to 0 except one.

Plot a line, Hesse normal form parameterisation

Load example image

Checks that an object is a cimg object

Load image from file or URL

Plot an image list

Shift image content.

Remove empty dimensions from an array

Compute image Laplacian

Blur image isotropically.

Select a region of homogeneous colour

split_connected

Split pixset into connected components

Load all images in a directory

Permute image axes

Load a video using ffmpeg

Return the pixel grid for an image

Pixel sets (pixsets)

A pixset for NA values

px.remove_outer

Remove all connected regions that touch image boundaries

Apply function to each element of a list, then combine the result as an image by appending along specified axis

Label connected components.

Convert a magick image to a cimg image or image list and vice versa

Young-Van Vliet recursive Gaussian filter.

Display an image using base graphics

Compute watershed transform.

Return locations in pixel set

Add colour channels to a grayscale image or pixel set

Convert to cimg object

Turn an numeric array into a cimg object

as.cimg.data.frame

Create an image from a data.frame