如何在R 2.15中读取.jpeg

Question

这看起来非常微不足道,但我无法用jpeg或任何类型的图像读入R 2.15.在R 2.10中,我可以使用rimage库或ReadImage库 - 例如read.jpeg - 但在R 2.15及更高版本中似乎无法做到这一点.有什么想法吗？

library('ReadImages') 
Error in library("ReadImages") : there is no package called ‘ReadImages’ > 
install.packages('ReadImages') Installing package(s) into ‘C:/Program Files/R/R-2.15.1/library’ (as ‘lib’ is unspecified) 

Warning in install.packages : package ‘ReadImages’ is not available (for R version 2.15.1) 

Answer 1

正如评论中指出的那样,试试jpeg包.

install.packages("jpeg")  ## if necessary

library(jpeg)
## get help
library(help = jpeg)
## get more help
?readJPEG

例如,来自帮助:

# read a sample file (R logo)
img <- readJPEG(system.file("img", "Rlogo.jpg", package="jpeg"))

另一种选择是rgdal,它可以从大量的格式中读取.绘图和操作的处理方式不同.

install.packages("rgdal") ## if necessary
library(rgdal)
img <- readGDAL(file.path(R.home(), "doc", "html", "logo.jpg"))

在CRAN上还有readbitmap包,总是值得基本搜索包列表以寻找你想要的东西.

Answer 2

也:

## if not already installed
install.packages("jpeg")  

library(jpeg)

?readJPEG()

img <- readJPEG("/Users/name/locationInFileDirectory/image.jpg", native = TRUE)

#this will display your image to test you read it correctly
if(exists("rasterImage")){
      plot(1:2, type='n')
      rasterImage(img,1,1,2,2)
}