Helmut Jarausch schrieb:
On 04/08/2016 03:26:53 PM, hw wrote:
Hi,
what would be the best approach to extract data
from a screencast?
The task is to acquire some data from the display of
a GUI program used interactively by a user. There are
a couple 'fields' (as in "designated areas of the display")
in which the relevant data is being displayed while the
program is being used. The acquired data needs to be
entered into a mysql database, preferably as soon as
possible. (The program needs windoze, and the sources
are unavailable :( )
The idea is to make a screen recording and postprocess
the recording with some sort of OCR software. This might
require using ffmpeg (or the like) to create a single
image from each frame of the recording; then treat each
image with an OCR software to get the interesting data
which can then be entered into the database.
Data to extract is mostly numbers. The relevant fields
can be expected to be either filled or empty. The FPS rate
of the recording can be kept reasonably low, like 1 FPS,
or perhaps even less, depending on how frequent the relevant
fields change.
Using tesseract comes to mind, but after reading that
"Tesseract's output will be very poor quality if the input
images are not preprocessed to suit it: Images (especially
screenshots) must be scaled up such that the text x-height
is at least 20 pixels,[12] any rotation or skew must be
corrected or no text will be recognized, low-frequency
changes in brightness must be high-pass filtered, or
Tesseract's binarization stage will destroy much of the
page, and dark borders must be manually removed, or they
will be misinterpreted as characters."[1]
I'm even more doubtful that this would produce usable
results with sufficient reliability.
So what might be the best way to get text/numbers out of
what a program displays?
[1]: https://en.wikipedia.org/wiki/Tesseract_(software)
I can't help with Gentoo.
Try to find an old (free) version of FineReader which runs under wine.
If you do it only occasionally, transfer the image to an Android phone where
there a good and cheap OCR apps, even FineReader.
It would be too much video to process. Besides, phones are
ok for making phone calls and entirely incompatible with
computers, which makes them useless for anything else but
making phone calls.
