Reading png as a N x 3 matrix in R

Question

I would like to read a simple black/white picture in png format into R. I need 3 information for each pixel, the x, y coordinates and color information(0 for white, 1 for black).

I need this information to run a function that checks if there are any closed white elements in the picture or not.

Any tips will be more than welcome. Thanks!

take a look at http://stackoverflow.com/questions/14769628/how-to-get-pixel-data-from-an-image-using-r — amonk, May 20 '17 at 15:09
Hi, I have seen this question. An there the proposition is to convert to ppm, but I cannot do it outside R. — Kasia, May 20 '17 at 15:53

score 2 · Accepted Answer · answered May 20 '17 at 18:01

2

This appears to be almost trivial if you have imager package installed. The color numbers here are inverted, but you should be able to change this without a problem.

library(imager)

xy <- load.image("vds9S.png")
head(as.data.frame(xy))

  x y value
1 1 1     1
2 2 1     1
3 3 1     1
4 4 1     1
5 5 1     1
6 6 1     1

answered May 20 '17 at 18:01

Roman Luštrik

69,533
24
154
197

Thank you so much! – Kasia May 20 '17 at 18:06

Reading png as a N x 3 matrix in R

1 Answers1