Raw image file format


#1

Does anyone know the format description of the .lzf files Skanect uses to store depth images? It seems to have to do with LZF compression (see a library at http://oldhome.schmorp.de/marc/liblzf.html), but that is a generic compression algorithm, not image compression, so more information is needed to decode the files. Better yet, does anyone have code to write/read these files?

Best,

Carlo

P.S. There is a related post on the “meta” forum, with no answer.


Raw data from Skanect?
#2

@tomasi I believe our format, after LZF decompression, is:

int32_t height
int32_t width
float32_t[width*height] depth_values_in_meters

@nburrus Can you confirm?


#3

Skanect can use different depth storage format, but I assume @tomasi is talking about the depth16bits.lzf files. If you are indeed talking about files with 16bit in the name, then the depth values will actually be 16 bit unsigned short values representing the depth in mm.

int32_t height
int32_t width
uint16_t[width*height] depth_values_in_millimeters

So to read them, just apply an LZF decompression, and read these fields directly in binary.


#4

Thanks to all. I was indeed referring to depth16bits.lzf

On Wed, Dec 17, 2014 at 12:22 PM, nburrus <structure@occipital.com> wrote:


nburrus
December 17

Skanect can use different depth storage format, but I assume @tomasi is talking about the depth16bits.lzf files. If you are indeed talking about files with 16bit in the name, then the depth values will actually be 16 bit unsigned short values representing the depth in mm.

int32_t height
int32_t width
uint16_t[width*height] depth_values_in_millimeters

So to read them, just apply an LZF decompression, and read these fields directly in binary.


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#5

How do I apply LZF decompression?


#6

@Astralink, the library referenced above is meant to be incorporated into an application. A quick search didn’t turn up any general purpose apps using the library, but there may be some.

-Jim


#7

Hi Jim and thank you for the replay.

I am not sure witch library are you referring.

Let me elaborate. I wish to work on the raw depth & RGB images recorded via Skanect (OpenNI).

Having a batch of “depth16bits.lzf” files, how do I access them?

Thanks,


#8

I’m referring to the library mentioned by @tomasi st the top of this thread. Generally meant to be built into an application.

However, a quick google search for “decompress lzf files” turned up the following that may offer a command line option for you:

-Jim