EXIFr : Natively read EXIF tags from R
This package natively reads EXIF tags from digital images. It does not rely on any external libraries or binary executables.
To keep things as simple as possible for the beginning, only the following tags are currently available :
- ExposureTime
- ApertureValue
- FocalLength
- ISOSpeedRatings
- PixelYDimension
- PixelXDimension
- DateTime
- Make
- Model
All values are returned as provided in the image file, so for example ExposureTime is "1/3200" and not 0.0003125
N.B. A utility function is provided to convert from the rational format rational_to_numeric("1/3200")
To install :
library(devtools)
devtools::install_github("cmartin/EXIFr")To try the code with one of the example images :
library(EXIFr)
# To list all tags :
image_path = system.file("extdata", "preview.jpg", package = "EXIFr")
read_exif_tags(image_path)Make : Canon
Model : Canon EOS DIGITAL REBEL XS
DateTime : 2013:07:09 10:23:47
ExposureTime : 1/3200
ISOSpeedRatings : 800
ApertureValue : 43/8
FocalLength : 18/1
PixelXDimension : 100
PixelYDimension : 67
# To view the value of a specific tag
read_exif_tags(image_path)[["ApertureValue"]][1] "43/8"
# or
rational_to_numeric(read_exif_tags(image_path)[["ApertureValue"]])[1] 5.375
If you need help with the EXIF format
The following resources were particularly useful :
- http://www.exiv2.org/Exif2-2.PDF
- http://code.flickr.net/2012/06/01/parsing-exif-client-side-using-javascript-2/
- http://www.media.mit.edu/pia/Research/deepview/exif.html
Problems :
Please report any bugs to the GitHub issue tracker and write any questions to charles.martin1@uqtr.ca
Citation
If this code is useful to you, please cite as :
Charles A. Martin (2015). EXIFr: Natively read EXIF tags from R. R package version 0.0.0.9004. https://github.com/cmartin/EXIFr. DOI:10.5281/zenodo.34691