What is the use of cvGetRows() function in OpenCV? -


when should use function. can explain me example?

according documentation, itreturns array row or row span. returns rows specified.

i explain of python terminal:

load image in grayscale mode , check width , height.

>>> import cv2.cv cv >>> img = cv.loadimage('approx2.jpg',0) >>> img <iplimage(nchannels=1 width=300 height=300 widthstep=300 )>

see, image 300x300 size. below image.

enter image description here

taking sum pixels,

>>> cv.sum(img) (1252271.0, 0.0, 0.0, 0.0)

now apply our first function, cv.getrow()

>>> row = cv.getrow(img,150) >>> row <cvmat(type=42424000 8uc1 rows=1 cols=300 step=300 )> >>> cv.sum(row) (14279.0, 0.0, 0.0, 0.0)

i took 150th row , took sum of elements in row. see resulting image has height = 1.

now taking function cv.getrows().

>>> rows = cv.getrows(img,0,150) >>> rows <cvmat(type=42424000 8uc1 rows=150 cols=300 step=300 )> >>> cv.sum(rows) (802501.0, 0.0, 0.0, 0.0)

i took rows upto 150th. see height 150. check out image below:

enter image description here

now there fourth argument on function delta_row can used increment. select rows increment of step size mentioned, skipping in between. ie if specified, the function extracts every delta_row -th row start_row , (but not including) end_row .

>>> rows = cv.getrows(img,0,300,5) >>> rows <cvmat(type=42420000 8uc1 rows=60 cols=300 step=1500 )>

see, height 30 because extracts every 5th row.

result below :

enter image description here

similar case cv.getcol() , cv.getcols().


Comments

Post a Comment

Popular posts from this blog

javascript - backbone.js Collection.add() doesn't `construct` (`initialize`) an object -

<!doctype html public "-//w3c//dtd xhtml 1.0 strict//en" "http://www.w3.org/tr/xhtml1/dtd/xhtml1-strict.dtd"> <html> <head> <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js"></script> <script src="http://documentcloud.github.com/underscore/underscore-min.js"></script> <script src="http://documentcloud.github.com/backbone/backbone-min.js"></script> </head> <body> <button id="cmd_create_event" name="cmd_create_event" type="button">create new `event`</button> <script type="text/javascript"> var eventmodel = backbone.model.extend({ initialize : function() { console.log("`event` initialized. id: " + this.cid); this.bind("change:status", function() { console.log(this.get("status") + " value `status`"); }); this.bind("error", function(model, e...
Read more

c++ - Accessing inactive union member and undefined behavior? -

i under impression accessing union member other last 1 set ub, can't seem find solid reference (other answers claiming it's ub without support standard). so, undefined behavior? the confusion c explicitly permits type-punning through union, whereas c++ ( c++11 ) has no such permission. c11 6.5.2.3 structure , union members 95) if member used read contents of union object not same member last used store value in object, appropriate part of object representation of value reinterpreted object representation in new type described in 6.2.6 (a process called ‘‘type punning’’). might trap representation. the situation c++: c++11 9.5 unions [class.union] in union, @ 1 of non-static data members can active @ time, is, value of @ 1 of non-static data members can stored in union @ time. c++ later has language permitting use of unions containing struct s common initial sequences; doesn't permit type-punning. to determine whether union type-punning is allowe...
Read more

php - Get uncommon values from two or more arrays -

is there function in php give array of uncommon values 2 or more arrays? for example: $array1 = array( "green", "red", "blue"); $array2 = array( "green", "yellow", "red"); .... $result = function_needed($array1, $array2,...); print_r($result); should give output: array("blue", "yellow", ...); use array_diff , array_merge : $result = array_merge(array_diff($array1, $array2), array_diff($array2, $array1)); here's demo. for multiple arrays, combine callback , array_reduce : function unique(&$a, $b) { return $a ? array_merge(array_diff($a, $b), array_diff($b, $a)) : $b; } $arrays = array( array('green', 'red', 'blue'), array('green', 'yellow', 'red') ); $result = array_reduce($arrays, 'unique'); and here's demo of that.
Read more