R - Inline-Base64 PNG-Bild lesen und Text analysieren

Question

Ich versuche ein Inline-Bild (PNG) zu analysieren, in Base64 codiert. Ich habe die Base64-Zeichenfolge erhalten, um das zu vereinfachen, was ich mache (Eingabe).

Das Problem ist r kann nicht mit NUL-Zeichen umgehen, und daher kann ich nicht das PNG im richtigen Format (d. H. Einschließlich NULs) schreiben.

Wenn ich versuche, das Bild zu analysieren, es einfach Fehler.

Gibt es eine Möglichkeit, ein PNG einschließlich NULs zu schreiben?

Ich benutze Windows 10, r 64bit V3.3.2.

Danke!

# install.packages('tesseract') 
# install.packages('base64enc') 

# Load required libraries 
library(tesseract) 
library(base64enc) 

# Define base64 string 
input <- "iVBORw0KGgoAAAANSUhEUgAAAHwAAAAiCAYAAACdmr05AAAGKElEQVR42u1ab4RdRxR/VlRVlaqoqipVVU3/vj9Z1X3v3petd+99SSvKqqiqKBX5sCJC9UNkV4WIqooKVVURFSKqIqpUVFXVo2o/rFplRayoFVbEWms9Xs+ZOXN33n0zd+69b24/7M4wNrl35vfmz5lzzu83t1JxxRVXXHFlN5SaF85idSuxWza8Fd7A6lbCbbgrO6VMTkaP1LzgNLjyHtQtqH2od6ut6Br8nTEaid95HvpfrHnRbeq7CXUBns0jdpYx+L7/YNWPTtS94FfouwF1gH+rXvgz/D1ZqcxNqPphH2hzJa1C/6/HWZ/XmtELMJdLuCbb84v+rLWij/ftm3ng/8KwglNrdyeh07+0wH369xJt/IDqwisHDj2ZEvP71A43ehHqPanvyv6p7nOpk/DC16HdLanPHb7RzIDw/7/p+la94Eepn67eLbrZdS88Is1vgxtk9I+EvVhrBk+UjWEFB19CozVqfAGsZ+/227mJmh8dxsWGuq7acHh+XCwoLPxR+RTyUx/+Qu9v4QlWjaHRjjzpRF9FCx563+o8lXyWGANa+lYZno/GNiDjn5Xnh0ZMazPAE1YmhjUc7obDQd0Pv0z9MS9sJJ+h+8CTiFV3gqnNAhuIHxxLvt8/Pf0YvFvlAw3mC7IKtPjVkhgLerpB1Ys+Us7P9x+G98ts/K3wg7IwrOEIl6lz16by0tTBR9NOH7nco3yg4ZXR2B99Rlb5XZHfp0kOwNVdt73ZVT8I6UQtpbvZ4H1d2LGBYROnIlwpuNs9ZSWE9VbYJau7MZoospi/iSe92AkM2uMYjOF0X2CG2grPGJLNPSLRRQO0jWETp0IZ8YDH33IKDPIdEZ+HT3dwjJ5/W3hTeI5hDEmFxk3JIBqsuS1jEiNtbWDYxIkXDOr9hh+8WRKv/0kVw+HZ9/x5dJhl6ge6T2PsAff8FVY0QlOoicNFK3oPx4/UEjcfk5p6O3pjzBPOmAaGrQye5pIYh20MmzjiBJ6J0/pW+ANSJIvu/ENBs5JZuggnuNGwwZc1dKoP786bks4EDZTrEma3YySDg4yehuciwIVtY9jEkQFnJM6L9Y+q3zk05gk5vs3tg3ZSZJF4P4o96+ABzqEbQmpIvPykyOBVCR/x0sv0/ncmwMCYEQMNDZ+J+YC1v1tg/ExXyGPYydBiA8MmTqIA7waXGtMo4nR5XSO6HVK3WKhQxZLG1MFnJONahiz02RSd4I5+0+Ymqs3w5QxGt4m6gNtwfWxsyicEFy6TUMHiaLgi3KmOsnF5kGMbaR1stEltM6hT54skh+R9+hnZwjynh9FZ2xg2cbJMelZsjEp8GV7Y6Kxoi9alU9Zk/owewDwK8DzxhNV6ukF73iukyJxzX8d+WfRp1OpVgocNDJs4WbnuaRWtkuMxCh/UZhWShU7GBd3Muomx/Ft766GC+UTmBZP69IiyNjO0HWIcNjFs4uQ9IWuGy4ve5PT04zkW9CZJqu0Mbe/n3TCFceUSmGLmoJCEdQaJjMM2hk2cTEXKqNdGKYAQT4K/s16DJsOFSRZFI8ru/hUb53deFLd2OWP/Eep3M3Ue/LaRJZ9lYNjEYcmZKXtFAk9Z8jWdFl9E5ED3TDddqAq9bUpCVEkXUrHhG74UD9QKPy0wPhYKqu1OLcUwrusuf2xgWMOhk7PKOXB0SuUuEVxw4aQS1/C7r6a5+myyKzcmHX2TZNmtkWtTzgjY1asqoSSt/irRy9sqD4RKHv6ujtpJotSKijpKxrimuw+wgWENZ0hlgzjHv3BB9Sq4KH9YoFK7UOSIEzWeKBirKobiyYsFEtSB8f9+cE66S9cKJ9D+c1kswgwVGQLpABtis3XXt0KG1Ge0wPNJm0ajI9xPSL5djO+nUxNVGxgWcdClw+Z+I32EINdlvHJTLvb2lV3mqku6uNJHd7nD9S9TuKBx9BR9t8BzfaHXnxndu8e/hkljCtiOnZ51xW/0THTVHoZNHAIjN42L1zN9llRGQbeN8Ry9h059S0vumNcBOsLpSzrdEyEhu0CBJyxoivHhlzj5Z2gDwyZOZfd8tYo3cqgDFKYvO6WILz13+jxZrpIzc3fFFVdcccUVV1xxxZXSyn/pbDU6koWAhAAAAABJRU5ErkJggg==" 
# Decode the input 
x <- base64decode(input) 
# Convert to raw before writing to disc (multiple=T removes Nul's, without it, it produces an error) 
x <- rawToChar(x,multiple=T) 
# Collapse into a string 
x <- paste0(x,collapse="") 

# Write the file out 
fileConn<-file("c:/temp/output.txt") 
writeLines(x, fileConn) 
close(fileConn) 

# parse image information 
ocr("c:/temp/output.txt") 
# error printed to console: 
> Error in FUN(X[[i]], ...) : Failed to read image 

Answer 1

Dies funktioniert für mich:

# Load required libraries 
library(tesseract) 
library(base64enc) 
input <- "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" 
x <- base64decode(input) 
fileConn<-file(tf <- tempfile(fileext = ".png"), "wb") 
writeBin(x, fileConn) 
close(fileConn) 
ocr(tf) 
# [1] "$265,000\n\n"