I have a Lidar data in .las file and i want to remove Noise from IT ?
is this is possible in open sources tools i.e las tool ,LibLas or any other open source ,
Because my finding are we can achieve this in point cloud library using .pcd file format But can we do same in Lib las or las tools
It's not clear, from the question, if you need to perform noise removal programmatically or through a tool. Let's try to break down your problem anyway. The point-cloud-library has a nice set of features to perform noise reduction and removal. However, as you noticed, it mainly works on pcl files. You have a couple of options to convert your las files to pcl:
You can add this set of readers to your PCL-based project. The LAS reader seems to be able to read las files.
You can use the PDAL toolchain, and do something like pdal translate original.las output.pcd.
For the noise removal part you also have a couple of options, once you have the files: you can either either use one of the many noise removal filters from PCL (see here and here, e.g. StatisticalOutlierRemoval) by calling the related classes in your code, or simply use the PDAL processing pipeline from the command line to further clean your data, as described in one of their tutorials.
Related
I have literally hundreds of slides created with python-pptx. Many of these slides have charts I would like to use in a docx file. So what I would like to do is use python-docx to import these slides/charts into a docx file. Is that possible?
No, not with the current python-pptx or python-docx APIs.
Such a thing is possible of course, since the Word application will allow you to "paste" charts from PowerPoint and in fact the charts themselves are specified in DrawingML, an XML vocabulary that is shared between PowerPoint, Word, and Excel.
But to make this work with Python, you'd have to dig quite deep into the internals of both python-pptx and python-docx (although their architectures are much the same). You would probably also need to learn more about the respective XML vocabularies than you really wanted to know. So you might want to consider alternate approaches such as using win32com support for this sort of thing, especially if you are running on Windows and this is a one-time job and does not need to be hosted on a server for ongoing use.
If you thought you did want to tackle it, a good first step might be to inspect the XML related to a PowerPoint chart (located in both the slide and the chart-parts of the PPTX package) and also inspect the corresponding XML that appears in a Word (.docx) file that includes a chart. That will give you an idea of what needs to come over from the PPTX package, what transformations it may need to undergo (namespace changes perhaps) and where it would need to be added into the DOCX package, including updating relationship files and perhaps updating certain ID values to make them unique in the target package.
I'm dealing with DXF files in Python. Reading only.
So far every file I've opened has Polyfaces defined (besides of Lines, arcs and circles...). I'm planning to do all my calculations using polyfaces only. But I'm afraid that some other 3D software saves a DXF without a polyface in it. Since I couldn't find any information that tells me they are mandatory I want to know how to be safe that my code will not fail by lack of polyfaces.
Should I trust more in Lines and Arcs instead? Are they mandatory?
I am a new one to Common Lisp (using Clozure Common Lisp under Microsoft Windows), who is familiar with c and python before. So maybe the questions are stupid here, but be patient to give me some help.
1) What's is the usual way to run a common lisp script?
Now, I wrote a bat file under windows to call ccl exe(wx86cl.exe) and evaluate (progn (load "my_script_full_path") (ccl:quit)) every time when I want to "run" my script. Is this a standard way to "run" a script for common lisp?
Any other suggestion about this?
2) What's the difference between (require 'cxml) and (asdf:operate 'asdf:load-op :cxml)?
They are seems to be the same for my script, which one should I use?
3) ignore it, not a clear question
4) When I want to load some library (such as require 'cxml), it always takes time(3s or even 5s) to load cxml every time when I "run" my script, there is also much log to standard output I show below, it seems like checking something internal. Does it means I have to spent 3-5s to load cxml every time when I want to run a simple test? It seems like a little inefficient and the output is noisy. Any suggestion?
My Script
(require 'cxml) (some-code-using-cxml)
And the output
; Loading system definition from D:/_play_/lispbox-0.7/quicklisp/dists/quicklisp/software/cxml-20101107-git/cxml.asd into #<Package "ASDF0">
;;; Checking for wide character support... yes, using code points.
; Registering #<SYSTEM "cxml-xml">
......
some my script output
---EDIT TO ADD MORE----
5) I must say that I almost forget the way of dumping image to accelerate the loading speed of lisp library. So, what is the normal process for us to develop a (maybe very simple) lisp script?
Base on the answer of what I got now, I guess maybe
a) edit your script
b) test it via a REPL environment, SLIME is a really good choice, and there should be many loop between a <==> b
c) dump the image to distribute it?( I am no sure about this)
6) Furthermore, what is the common way/form for us to release/distribute the final program?
For a lisp library, we just release our source code, and let someone else can "load/require" them.
For a lisp program, we dump a image to distribute it when we confirm that all functions go well.
Am I right?
What form do we use in a real product? Do we always dump all the thing into a image at final to speed up the loading speed?
1) Yes, the normal way to run a whole programme is to use a launcher script. However, windows has much, much better scripting support these days than just the bat interpreter. Windows Scripting Host and PowerShell ship as standard.
1a) During development, it is usual to simply type things in a the REPL (Read-Eval-Print-Loop, i.e. the lisp command line), or to use something like SLIME (for emacs or xemacs) as a development environment. If you don't know what they are, look them up. You may wish to use Cygwin to install xemacs, which will give you access to a range of linux-ish tools.
2) Require is, IIRC, a part of the standard. ASDF is technically not, it is a library that operates to make libraries work more conveniently. ASDF has a bunch of features that you will eventually want if you really get into writing large Lisp programmes.
3) Question unclear, pass.
4) See 1a) - do your tests and modifications in a running instance, thus avoiding the need to load the library more than once (just as you would in Python - you found the python repl, right?). In addition, when your programme is complete, you can probably dump an image which has all of your libraries pre-loaded.
Edit: additional answers:
5) Yes
6) Once you have dumped the image, you will still need to distribute the lisp binary to load the memory image. To make this transparent to the user, you will also have to have a loader script (or binary) to run the lisp binary with the image.
You don't have to start the lisp from scratch and load everything over again each time you want to run a simple test. For more efficient development, interactively evaluate code in the listener (REPL) of a running lisp environment.
For distribution, I use Zachary Beane's Buildapp tool. Very easy to install and use.
Regarding distribution -
I wrote a routine (it's at home and unavailable at the moment) that will write out the current image as a standard executable and quit. It works for both CLISP and SBCL.
I can rummage it up if you like.
I have a binary file. I don't know how it's formatted, I only know it comes from a delphi code.
Does it exist any way to analyze a binary file?
Does it exist any "pattern" to analyze and deserialize the binary content of a file with unknown format?
Try these:
Deserialize data: analyze how it's compiled your exe (try File Analyzer). Try to deserialize the binary data with the language discovered. Then serialize it in a xml format (language-indipendent) that every programming language can understand
Analyze the binary data: try to save various versions of the file with little variation and use a diff program to analyze the meaning of every bit with an hex editor. Use it in conjunction with binary hacking techniques (like How to crack a Binary File Format by Frans Faase)
Reverse Engineer the application: try getting code using reverse engineering tools for the programming language used for build the app (found with File Analyzer). Otherwise use disassembler analysis tool like IDA Pro Disassembler
For my hobby project I had to reverse engineer some old game files. My approaches were:
Have a good hex editor.
Look for readable words in the binary file. Note how their distribution is. If the distance between them is constant you know it is a listing.
Look for 2-3 consequent zeros. Might indicate an int32 value.
Some dwords might be pointers into the file.
Try to identify reoccurring patterns in the file.
Seeing lots of C0-CF might indicate RLE compressed data.
I've developed Hexinator (Window & Linux) and Synalyze It! (macOS) exactly for this purpose. These applications allow you to see the binary files like in other hex editors but additionally you can create a "grammar" with the specifics of a binary file format. The grammar contains all the building blocks and is used to parse the file automatically.
Thus you can keep the knowledge you gain in the analysis and apply it to multiple files simultaneously. You can also color-code the bits and pieces of file formats for a quick overview in the hex editor.
The parsing results are displayed in a tree view where you can also modify the files easily (applying endianness et cetera).
Reverse engineering a binary file when you have some idea of what it represents is a very time consuming process. If you have no idea what it is then it will be even harder.
It is possible though, but you have to have a pretty good reason for doing so.
The first step would be to open it up in a hex editor of your choice and see if you can find any English text to point you in the direction of what the file is even supposed to represent. From there, Google "Reverse Engineering binary files", there are much more knowledgeable people than me that have written guides about it.
The "strings" program from GNU binutils is very useful. It will print the strings of printable characters in a file, quite often giving a clue to what a file contains or a program does.
If the data represents serialized Delphi objects, you should start reading about the Delphi serialization process. If that's the case, I think your best bet would be to load it using Delphi and continue your analysis from the IDE. Some informations about Delphi serialization can be found here.
EDIT: if the file does contain serialized delphi objects, then you should write a small delphi program that loads it, and "convert" the data yourself to something neutral, like xml. If you manage to do this, you should check and see if delphi supports serializing to xml. Then, you could access those objects from any language.
The unix "file" command is really useful - I don't know if there is anything like it in windows. You run it like this:
file myfile.ext
And it spits out a text description based on the magic numbers and data contained therein.
Probably it is contained within cygwin.
If you have access to the application that creates the file, you can apply changes to the application, then save the file and see the effects (Keep in mind that numbers are probably stored in little endian):
First create the file repeatedly. If the files are not binary equal, the current date/time is probably stored in the area where hte differences occur.
Maybe you want to repeat that with the software running under different environments, to see if OS version etc are stored, but this is rather unusual.
Next you can try to change single variables and create several files that only differ in the value of this variable. This helps you identify where this variable is stored.
That way you can also exclude variables that are not stored in the file: If you change them, but the files created are identical, they are not stored.
In order to test the hypotheses you worked out with the steps above, edit one of the files and have the application read it.
If you don't have access to the application itself, I suggest that you forget about it and find another way to solve your problem. There is a very high probability that it will be faster...
If file does not give a meaningful answer, you may want to try TRiD by Marco Pontello to determine whether your data is stored in a known format.
Get the Delphi application and open it in IDA Pro freeware version, and find where it writes the file, and decode how it writes the file that way.
Unless it's plan text.
Do you know the program that uses it? If so you can hook that programs write to file function and get an idea of what data its writing, the size of the data and where.
More Info: http://www.codeproject.com/KB/DLL/Win32APIHooking_Trouble.aspx
Unlike traditional hex editors which only display the raw hex bytes of a file, 010 Editor can also parse a file into a hierarchical structure using a Binary Template. The results of running a Binary Template are much easier to understand and edit than using just the raw hex bytes.
http://www.sweetscape.com/010editor/
Try to open it in a hex editor and analyse.
I want to study the .vce format. It's a binary format and it seems more complicated than a simple object serialization. Does it exist any tool or technique to analyze a binary format?
You might need to "Reverse-Code-Engineer" a programm using this file format (http://www.openrce.org/). Tools used for this kind of analysis are: brain, disassembler (IDA Pro for example) and Debugger (OllyDBG for example). But beware - the way for successfull reverse engineering a file format is veeeeeerrry hard.
And reversing an application might be illegal depending on where you live!
You'll have to get a library that can read the format (or create one yourself).
Here is some of the microsoft office binary format specifications
I believe it would only be possible through some nasty reversed-engineering. It would be very useful to have access to application that uses mentioned format, so that you can generate few simple files and compare them in hex editor. You cannot get far with this method, but you might be able to figure out the header.
It would also be useful to study some binary format mechanisms, such as encryption and compression. If you're talking about Visual CertExam file format, than it is likely that useful data will be strongly encrypted.
My 2 cents:
Start by reversing the application reading the files themselves. Particularly android applications are helpful, as the resulting java source is easier to read (you might want to try A+ vce reader for android for example). This program indicates that vce uses/embeds sqlite in the file (in line with what is hinted here: Reverse Engineer a File Format).
Where to go from here? You might want to explore sqlite file carving tools to see if there might be a way to programatically identify the patterns in the file. Good luck!