I want to read an Jpeg image in R. Transform it into greyscale and finally to get the Negative of the image.
I used to read the image with biOps and then make the other two transformations with EBImage.
Currently I am working with windows 8 and I cannot make this simple actions anymore, due to version issues I think.
I would like to install the correct packages or to find some other way to do this three simple steps.
Thank u!
Why are you trying to read the file in with biOps? (which is no longer available on CRAN)
#Read the file in with `EBImage`
library("EBImage")
your_image = readImage(system.file("directory", "your_image.jpg", package="EBImage"))
#perform your other transformations
Related
Is there a way to extract images from pdf using R and save them into a folder?
there are a lot of similar questions regarding other programming languages and there is apparently a way to do this in python, was wondering if the same work can be replicated in r https://www.thepythoncode.com/article/extract-pdf-images-in-python
there is pdftools package in r but does not sound like it can help much with images, only reads text and there is an option for ocr, I just want to extract the images and store them into a folder.
I can try to use reticulate package to use this python method in r but I won't be able to loop / map it as I would like. That's why I was asking if anyone knows a way in R.
thank you.
You can try something like this :
library(pdftools)
path_To_PDF <- "C:/my_pdf.pdf"
pdf_convert(path_To_PDF)
I have a bunch of audio files, which I extracted from mp4 video files using the av package. Now I want to merge all the audio files into one long output mp3.
My question: Is there a way to merge audio files in R using the av package?
I.e. when having a vector of file paths/names such as
files <- c("file1.mp3", "file2.mp3", "file3.mp3")
I am looking for a function or concise workaround within R that could handle this, maybe similar to:
av_function_that_should_exist_already(files, output = "big_fat_file.mp3")
Note 1: I do not want to paste an ffmpeg command to the terminal. If I wanted to use the terminal or some script, I could have done that. What I would like to do, is to solve this completely within R, preferably using av. (I want to avoid implementing yet another library, and overthrowing my complete code, making it into a library mixtape, when everything else already works just fine).
Note 2: I have already checked this post: How to concatenate multiple .wav files from a list in R?, I am specifically asking about av in this question, preferably not about other packages.
So, I just want to know if this is possible or not (and if maybe I'm just not seeing it). I haven't found anything in the documentation, which is mostly about converting audio and video files, not about concatenating audio or video files such as mp3 or aac.
I was thinking that this should be possible using something like:
av_audio_convert(files, output = "big_fat_file.mp3")
However, this just leads to "file1.mp3" being written to "big_fat_file.mp3" in this example, so from a vector of file names, only the first element will be processed by av_audio_convert.
Thanks for your help and ideas in advance,
Cat
I have a 174603 rows and 178 column dataframe, which I'm importing to Excel using openxlsx::saveWorkbook, (Using this package to obtain the aforementioned format of cells, with colors, header styles and so on). But the process is extremely slow, (depending on the amount of memory used by the machine it can take from 7 to 17 minutes!!) and I need a way to reduce this significantly (Doesn't need to be seconds, but anything bellow 5 min would be OK)
I've already searched other questions but they all seem to focus either in exporting to R (I have no problem with this) or writing non-formatted files to R (using write.csv and other options of the like)
Apparently I can't use xlsx package because of the settings on my computer (industrial computer, Check comments on This question)
Any suggestions regarding packages or other functionalities inside this package to make this run faster would be highly appreciated.
This question has some time ,but I had the same problem as you and came up with a solution worth mentioning.
There is package called writexl that has implemented a way to export a data frame to Excel using the C library libxlsxwriter. You can export to excel using the next code:
library(writexl)
writexl::write_xlsx(df, "Excel.xlsx",format_headers = TRUE)
The parameter format_headers only apply centered and bold titles, but I had edited the C code of the its source in github writexl library made by ropensci.
You can download it or clone it. Inside src folder you can edit write_xlsx.c file.
For example in the part that he is inserting the header format
//how to format headers (bold + center)
lxw_format * title = workbook_add_format(workbook);
format_set_bold(title);
format_set_align(title, LXW_ALIGN_CENTER);
you can add this lines to add background color to the header
format_set_pattern (title, LXW_PATTERN_SOLID);
format_set_bg_color(title, 0x8DC4E4);
There are lots of formating you can do searching in the libxlsxwriter library
When you have finished editing that file and given you have the source code in a folder called writexl, you can build and install the edited package by
shell("R CMD build writexl")
install.packages("writexl_1.2.tar.gz", repos = NULL)
Exporting again using the first chunk of code will generate the Excel with formats and faster than any other library I know about.
Hope this helps.
Have you tried ;
write.table(GroupsAlldata, file = 'Groupsalldata.txt')
in order to obtain it in txt format.
Then on Excel, you can simply transfer you can 'text to column' to put your data into a table
good luck
I read my hyperspectral (.raw) file and combine three bands to "gai_out_r" Then I output as following:
writeRaster(gai_out_r,filepath,format="GTiff")
finally I got gai_out_r.tif
But, why Win10 can't display this small tif as the pic that I output the same way from envi--save image as--tif
Two tiffs are displayed by Win10 as following:
Default windows image viewing applications doesn't support Hyperspectral Images-since you are just reading and combining 3 bands from your .raw file, the resulting image will be a hyperspectral image.You need to have separate dedicated softwares to view hypercubes or can view it using spectral-python also.
In sPy, using envi.save_image , will save it as a ENVI type file only. To save it as an rgb image file(readable in windows OS) we need to use other methods.
You are using writeRaster to write to a GTiff (GeoTiff) format file. To write to a standard tif file you can use the tiff method. With writeRaster you could also write to a PNG instead
writeRaster(gai_out_r, "gai.png")
Cause of the issue:
I had a similar issue and recognised that the exported .tif files had a different bit depth than .tif images I could open. The images could not be displayed using common applications, although they were not broken and I could open them in R or QGIS. Hence, the values were coded in a way Windows would not expect.
When you type ?writeRaster() you will find that there are various options when it comes to saving a .tif (or other format) using the raster::writeRaster() function. Click on the links therein to get to the dataType {raster} help site and you'll find there are various integer types to choose from.
Solution (write a Windows-readable GeoTIFF):
I set the following options to make the resulting .tif file readable (note the datatype option):
writeRaster(raster, filename = "/path/to/your/output.tif",
format = "GTiff", datatype = "INT1U")
Note:
I realised your post is from 2 and a half years ago... Anyways, may this answer help others who encounter this problem.
I'm trying to read some mainframe data encoded as EBCDIC into R, and am at a loss. I'd like to avoid using an external program to convert the files, since I'm operating in a corporate environment.
You can find the example files here, with both ASCII and EBCDIC versions. Note that there are no linebreaks in the EBCDIC versions of the file -- instead, I'd be specifying the width of each line manually. R has the IBM500 encoding available in my environment, which should be the correct one for these files.
However, when I run the following commands, R seems to fail entirely.
layout <- read.fwf("EBCDIC_LAYOUT", widths = c(80), fileEncoding='ibm500')
data <- read.fwf("EBCDIC_ZIPCODE", widths = c(32), fileEncoding='ibm500')
Where might I go from here?
Related -- some of the files I expect to use will be fairly large (1 GB or so). Preferably, I'd like a solution that scales reasonably well. (I tried packages like LaF, but they don't have the option to select encoding.)
Thank you very much!