PCD file format xyzrgb

Hello everyone,

I still don´t get how the rgb information is encoded in the pcd file. I would like to be able to seperately extract "xyz" and "rgb.

When I open a pcd file with rgb values, I get for example:

1.28125 577.09375 197.9375 1.8807908e-038
828.125 599.03125 491.375 1.8807908e-038
358.6875 917.4375 842.5625 1.8807908e-038

I assume the first three rows are xyz and the last contains rgb. Now before You throw Your eggs/pies/spears, I looked into http://docs.pointclouds.org/1.3.0/structpcl_1_1_r_g_b.html, but I don´t get it.

int rgb = ...;
uint8_t r = (rgb >> 16) & 0x0000ff;
uint8_t g = (rgb >> 8)  & 0x0000ff;
uint8_t b = (rgb)     & 0x0000ff;

^Is that how the last row is built?

1.28125 577.09375 197.9375 1.8807908e-038

So the RGB is encoded in the

1.8807908e-038

, right?

I would like to know how the color is encoded in this number. Am I even looking into the right direction?

It's bitshifted (http://www.functionx.com/cpp/Lesson11.htm skip to Bit
Shift Operators: The Left Shift <<)

The RGBA information is available either as separate r, g, b, or as a
packed uint32_t rgba value. To pack it, use:

 int rgb = ((int)r) << 16 | ((int)g) << 8 | ((int)b);

To unpack it use:

 int rgb = ...;
 uint8_t r = (rgb >> 16) & 0x0000ff;
 uint8_t g = (rgb >> 8)  & 0x0000ff;
 uint8_t b = (rgb)     & 0x0000ff;


On 26 January 2012 14:18, goekhan <[hidden email]> wrote: _______________________________________________
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Thank You koen buys-2 !

I obviously didn´t know about bitshifting.

you are probably asking, "Why the hell do I need to know this?" and my answer is, "I have no idea" but you ain't got no choice; ain't no one else gonna learn this stuff for you

Hi,
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Soz to necro post but it applies to this question.

Is this a good value for a color: 1.00511523e-038

???

Hi,

> Is this a good value for a color: 1.00511523e-038

yeah this should be fine, its rgb packed into a float value: so

1.00511523e-038 = 0x006D7286

Channel Hex Dec
R =            6D = 109
G =            72 =115
B =            86 = 134

Should be something grayish. I'm not 100% sure its RGB and not BGR as OpenCV
uses it.

Alex
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