Convert RGB-image to one-channel gray image in R EBImage

image-processing, r

Solution

Sorry if I am wrong, but as I understand your conversion to greyscale is not being done in a proper way. In general with EBImage conversion to grayscale is done with the command `grayimage<-channel(yourimage,"gray")` and image(grayimage) gives

Image
  colormode: Grayscale 
  storage.mode: double 
  dim: X Y 
  nb.total.frames: 1 
  nb.render.frames: 1

where the colormode gives the `nb.total.frames:3`

Problem

An R-beginner question: I wanted to convert an RGB-Image to grayscale and display/plot it with image() ``` library(EBImage) orig = readImage("c:/test/b/s2.png") gray = orig colorMode(gray) = Grayscale display(gray) #works image(gray) #Error 'z' should be a matrix ``` The image converted by colorMode(gray) = Grayscale seems to be incompatible with image-function. Does Crayscale image in R EBImage has more than one channel? Then I converted it manually and was able to call image() on it ``` r = channel(orig,"r") g = channel(orig,"g") b = channel(orig,"b") gray1 = 0.21*r+0.71*g+0.07*b display(gray1) image(gray1) #works ``` However, the images both gray differed slightly concerning intensity. Is there a way to convert RGB to one channel gray in R EBImage? EDIT For answering the question, why EBImage: The package provides some image-processing functions. E.g. I could display easily the intensity graph (img2) of a scanned test-stripe (img1) using further EBImage commands: ``` blotgraph = resize(gblur(gray1,3),200,1) plot(blotgraph, type="l") ``` I was not aware how to solve such kind of tasks without EBImage

Original source