iphone - Cropping UIImage like camscanner -


i stuck in application feature. want cropping feature similar cam scanner cropping. screens of cam-scanner are: have created similar crop view.

enter image description here

enter image description here

i have obtained cgpoint of 4 corners. how can obtained cropped image in slant.

please provide me suggestions if possible.

this perspective transform problem. in case plotting 3d projection in 2d plane.

as, first image has selection corners in quadrilateral shape , when transform in rectangular shape, either need add more pixel information(interpolation) or remove pixels.

so actual problem add additional pixel information cropped image , project generate second image. can implemented in various ways:

<> can implement own applying perspective tranformation matrix interpolation.

<> can use opengl .

<> can use opencv. .. , there many more ways implement it.

i had solved problem using opencv. following functions in opencv achieve this.

  1. cvperspectivetransform

  2. cvwarpperspective

first function calculate transformation matrix using source , destination projection coordinates. in case src array have values cgpoint corners. , dest have rectangular projection points example {(0,0)(200,0)(200,150)(0,150)}.

once transformation matrix need pass second function. can visit thread.

there may few other alternatives opencv library, has collection of image processing algorithms.

ios application opencv library available @ eosgarden.


Comments

Post a Comment

Popular posts from this blog

basic authentication with http post params android -

i doing basic authentication passing username , password , using basicnamevaluepair sending post params response service. my method: public stringbuilder callservicehttppost(string username, string password, string type) { // create new httpclient , post header httpclient httpclient = new defaulthttpclient(); httppost httppost = new httppost(webservice + type); httpresponse response = null; stringbuilder total = new stringbuilder(); try { url url = new url(webservice + type); /*string base64encodedcredentials = base64.encodetostring((username + ":" + password).getbytes(), base64.url_safe | base64.no_wrap);*/ string base64encodedcredentials = "basic " + base64.encodetostring( (username + ":" + password).getbytes(), base64.no_wrap); httppost.setheader("auth...
Read more

vb.net - Virtual Keyboard commands -

i wondering difference between virtual these keyboard commands is: keyeventf_extendedkey , keyeventf_keyup is. everywhere have looked gives me description based off integers , not want know each of them does. you've tagged question vb.net, these have nothing @ vb.net. they're constants defined in windows header files, use win32 api functions. as far difference, can't tell looking @ values. individual values not particularly important, that's why named identifiers used. what's important used , documentation functions tells mean. the first one, keyeventf_extendedkey , used keybdinput structure (which used along e.g. sendinput function) pass information synthesized keyboard input. if flag used, means scan code should interpreted extended key. technically, means scan code preceded prefix byte value 224 (&he0 in hexadecimal notation). the second one, keyeventf_keyup , 1 of flags available use structure. means key being released (going up)...
Read more

css - Firefox for ubuntu renders wrong colors -

Image
i've got following problem: i'm developing website, while testing around i've noticed firefox , chromium display css bar in different colors. when switched between several machine come conclusion firefox ubuntu problem. on other devices i've tested website. it's fine. the differences between chrome , firefox rendering: firefox: chromium: note: firefox ubuntu problem. does knows why , came solution? https://bugzilla.mozilla.org/show_bug.cgi?id=655637 bug 629312 - firefox displays wrong colors on image (only linux) open about:config , rechange gfx.color_management.mode 2 0.
Read more