使用R中的基本图形绘制JPG图像

Question

I am searching for a simple way to plot a photographic JPEG image on a graphics device in R.

For example the following using the raster package appears to ignore the colour attributes in the image. I want to reproduce the photograph in its original colours:

library(raster)
library(rgdal)

myJPG <- raster("colourfulPic.jpg")
plot(myJPG)  ## Recolours JPEG;

I have discovered that the package rimage has recently been archived and appears to no longer be recommended for use (see here ), if it, indeed, ever did what I need.

Similarly the EBImage for BioConductor, which may also possibly work, is not built for 64 bit Windows, and unfortunately I need this architecture.

Please tell me I missing something very obvious in base graphics?

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Answer 1

Here goes an updated solution, that relies only on the jpeg package and handles color and greyscale images ( packages used in other solutions are outdated and won't install with a recent R version ).

The solution consists in this plot function:

plot_jpeg = function(path, add=FALSE)
{
  require('jpeg')
  jpg = readJPEG(path, native=T) # read the file
  res = dim(jpg)[2:1] # get the resolution, [x, y]
  if (!add) # initialize an empty plot area if add==FALSE
    plot(1,1,xlim=c(1,res[1]),ylim=c(1,res[2]),asp=1,type='n',xaxs='i',yaxs='i',xaxt='n',yaxt='n',xlab='',ylab='',bty='n')
  rasterImage(jpg,1,1,res[1],res[2])
}

This function can then be called with the path of the picture as argument, for example:

plot_jpeg('~/nyancat.jpg')

To add the picture to an existing plot, use the switch add=TRUE - and be wary of axis limits!

Answer 2

Using the imager package:

library(imager)

image <- load.image(image_filename)
plot(image)

This works for a number of image formats including jpeg , gif , etc...

Answer 3

如果要构建RMarkdown文档， knitr::include_graphics()是直接且简单的。

Answer 4

Instead of rimage , perhaps use the package ReadImages :

library('ReadImages')
myjpg <- read.jpeg('E:/bigfoot.jpg')
plot(myjpg)

Answer 5

raster Has a built-in function for this called plotRGB

library(raster)  
myJPG <- stack("colourfulPic.jpg")  
plotRGB(myJPG)  

Answer 6

Please note that ReadImages is now deprecated. Instead you could install the biOps package , which also contains a rich set of image manipulation methods. Use as follows:

library(jpeg)
library(biOps)

image <- readJPEG("test.jpg")

# image is of type imagedata (the red,green,blue channel images concatenated)

plot(image)

Edit: An object of type imagedata is accessed as image[Y,X,Channel] , btw