Featured post

c# - Usage of Server Side Controls in MVC Frame work -

-
i using asp.net 4.0 , mvc 2.0 web application. project requiremrnt have use server side control in application not possibl in noraml case. ideally want use adrotator control , datalist control. i saw few samples , references in codepleax mvc controllib howwver found less useful. can tell how utilize theese controls in asp.net application along mvc. note: please provide functionalities related adrotator , datalist controls not equivalent functionalities thanks in advace. mvc pages not use normal .net solution makes use of normal .net components impossible. a normal .net page use event driven solution call different methods service side mvc use actions , view completly different way handle things. also, mvc not use viewstate normal .net controlls require. found article discussing mixing of normal .net , mvc.
3 comments

optimization - Retrieving the most significant features gained from SIFT / SURF -

-

i'm using surf extract features images , match them others. problem images have in excess of 20000 features slows down matching crawl.

is there way can extract n significant features set?

i tried computing mser image , use features within regions. gives me reduction anywhere 5% 40% without affecting matching quality negatively, that's unreliable , still not enough.
additionally size image down, seems affect quality of features severely in cases.
surf offers few parameters (hessian threshold, octaves , layers per octave) couldn't find on how changing these affect feature significance.

after researching , testing have found hessian value each feature rough estimate of it's strength, using top n features sorted hessian not optimal.
achieved better results when doing following until number of features below target of n:

  • size image down, if overly large
  • only features lie in mser regions considered
  • for features lie close each other, feature higher hessian considered
  • of n features per image want save, 75% features highest hessian values
  • the remaining features taken randomly remainder, weighted distribution of hessian values computed through histogram

now need find suitable n, around 1500 seems enough currently.


Comments

Post a Comment

Popular posts from this blog

c# - Usage of Server Side Controls in MVC Frame work -

-
i using asp.net 4.0 , mvc 2.0 web application. project requiremrnt have use server side control in application not possibl in noraml case. ideally want use adrotator control , datalist control. i saw few samples , references in codepleax mvc controllib howwver found less useful. can tell how utilize theese controls in asp.net application along mvc. note: please provide functionalities related adrotator , datalist controls not equivalent functionalities thanks in advace. mvc pages not use normal .net solution makes use of normal .net components impossible. a normal .net page use event driven solution call different methods service side mvc use actions , view completly different way handle things. also, mvc not use viewstate normal .net controlls require. found article discussing mixing of normal .net , mvc.
Read more

ios - Very simple iPhone App crashes on UILabel settext -

-
i have simple application. have button , label in ib. have ibaction onclick calls settext on label. there's outlet label. connected in ib. crashes app first time in simulator. when launch again, sets text. crashes again next time. crashes on actual device. should simple, i'm not sure i'm doing wrong. thanks. in .h file : #import <uikit/uikit.h> @interface untitledviewcontroller : uiviewcontroller { iboutlet uilabel *label; iboutlet uibutton *button; } @property (nonatomic, retain) uilabel *label; -(ibaction) onclick1: (id) sender; @end and in .m: - (ibaction) onclick1: (id) sender { //[label settext:@"hello world!"]; label.text = @"hello world!"; //[button settitle:@"clicked" forstate:uicontrolstatenormal]; } sorry, i'm new site. how crash log , stack? thanks. edit : while answer technically correct, doesn't answer question @ :( sorry < warning - guess > if you're...
Read more

mysql - Why there can be only one TIMESTAMP column with CURRENT_TIMESTAMP in DEFAULT clause? -

-
why there can 1 timestamp column current_timestamp in default or on update clause? create table `foo` ( `productid` int(10) unsigned not null, `addeddate` timestamp not null default current_timestamp, `updateddate` timestamp not null default current_timestamp on update current_timestamp ) engine=innodb; the error results: error code : 1293 incorrect table definition; there can 1 timestamp column current_timestamp in default or on update clause this limitation, due historical, code legacy reasons, has been lifted in recent versions of mysql: changes in mysql 5.6.5 (2012-04-10, milestone 8) previously, @ 1 timestamp column per table automatically initialized or updated current date , time. restriction has been lifted. timestamp column definition can have combination of default current_timestamp , on update current_timestamp clauses. in addition, these clauses can used datetime column definitions. more information, see automati...
Read more