trying to understand some bits i found in Opencv & c++

Question

Hey peeps am studding opencv and running through some tutorials, i came across these attributes well I think they are that the problem really I dont know what they are tried google it but with no luck:

So these are the bits that i have no idea what they are have a look maybe someone can explain these to me so the tutorials will have more sense to me:

vector<Vec4i>() //I know what vector is :) but Vec4i....?
CV_8UC1 // <------- ?

Vec4i is a type, CV_8UC1 looks like a macro

billz
– billz

2013-02-04 02:19:53 +00:00
Commented Feb 4, 2013 at 2:19 — billz
– billz, Commented Feb 4, 2013 at 2:19

Walfie · Accepted Answer · 2013-02-04 02:24:07Z

4

The OpenCV basic structures page (under the Vec section) explains that Vec4i is a typedef, equivalent to Vec<int, 4>, a vector of 4 integers.

Additionally, on the same page (under the Mat section), it explains that CV_8UC1 is an 8-bit single-channel matrix. Specifically:

8 indicates the bit depth
U indicates that it is unsigned
C1 indicates that there is a single channel.

Here's a page with more information about OpenCV naming conventions.

answered Feb 4, 2013 at 2:24

Walfie

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4 Comments

Tomazi Over a year ago

Thank you so much great just wont i need to know and wonted

Fantastic Mr Fox Over a year ago

@Tomazi Just for future reference, what and wanted are spelt with an 'a' and not an 'o'. Also nice answer Walfie, +1

Tomazi Over a year ago

Hey again just one quick question C1 single channel means the stored image will be Grayscale or black an white where C3 would be used for color images...?#

Walfie Over a year ago

@Tomazi Yes, single-channel matrices are suitable for storing greyscale images, and three-channel matrices for colored images (the three channels being red, green, and blue)

Fantastic Mr Fox · Accepted Answer · 2013-02-04 02:24:41Z

1

Vec4i is just a typedef of a a vector:

typedef Vec<int, 4> Vec4i; from here.
CV_8UC1 is a #Define which helps with initialization of OpenCV matrices:

e.g.

CV_8UC1 means 8-bit single-channel matrix,

If you ever need OpnenCV type advice look at the documentation.

It is very helpful.

answered Feb 4, 2013 at 2:24

Fantastic Mr Fox

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