algorithm - Procrustes analysis / Finding the Angle Between two images represented by two sets of 2d points -

-

if have 2 sets of points can rotate 1 around procrustes analysis align 1 other.

but suppose these 2 sets of points each attached images , rotate images well. there way can rotate image, instead of rotating points? tutorial there uses dot product rotation (solve u, s, v = svd(p1', p2) , p2 . v . u', p' transposed p)

however doesn't tell me angle between images is.

the page on wikipedia calculates angle between each pair of points think.

maybe i'm asking impossible? if rotate first set of points align first, can't rotate respective images angle well? point being, angle that?

i noticed v . u' gives me 2 x 2 matrix seems rotation matrix (there's wikipedia page can't link there due posting priviledges). got sin , cos of third , first elements , used arctan2, results i'm getting kind of weird. know have transformed radians i'm not convinced i'm doing right. trying rotation gives me on gimp makes seem it's not want, i'll test more.

it seems approach correct. 2 things come mind:

1) paper linked (procrustes analysis) involves translation , scaling in addition rotation. depending on whether or not operations performed on images, may end strange results don't appear match.

2) think may overcomplicating angle calculation. v * u' appears correct rotation matrix, believe correct angle requires 1 of matrix entries in 2x2 matrix. instance, use acos() of first matrix entry. you've noticed, (depending on program) give answer in radians you'll have convert degrees if want try out rotation in gimp, etc.

hope helps!


Comments

Post a Comment

Popular posts from this blog

linux - Mailx and Gmail nss config dir -

-
i trying send mail linux command line using mailx command. can send local domain no problem want set mail send gmail account receive mail sent gmail account. after configuring mail.rc so: account gmail { set smtp=smtps://smtp.gmail.com:587 set smtp-auth=login set smtp-auth-user=username@gmail.com set smtp-auth-password=password set ssl-verify=ignore } i error: resolving host smtp.gmail.com . . . done. connecting 74.125.25.109 . . . connected. missing "nss-config-dir" variable. "/home/username/dead.letter" 11/354 . . . message not sent. after looking "nss-config-dir" here , located certn.db , keyn.db files , added mail.rc so: account gmail { set smtp=smtps://smtp.gmail.com:587 set smtp-auth=login set smtp-auth-user=username@gmail.com set smtp-auth-password=password set ssl-verify=ignore set nss-config-dir=/home/user/.mozilla/firefox/location.default } now when try send mail using command: echo "sent gmail account" | mailx -v -a
Read more

c# - Is it possible to remove an existing registration from Autofac container builder? -

-
something along lines: builder.registertype<mytype>().as<itype>(); builder.registertype<mytype2>().as<itype>(); builder.deregistertype<mytype>().as<itype>() var container = builder.build(); var types = container.resolve<ienumerable<itype>>(); assert.istrue(types.count == 1); assert.istrue(types[0].gettype == typeof(mytype2)); scenario: go through bunch of assemblies , go register types want make sure have 1 implementation of given type. need before create container. track on own nice if autofac me bit. this cannot done directly using containerbuilder , unless start on new one. mind you, having first built container should able construct new container filtering away unwanted types , reusing registrations first container. this: ... var container = builder.build(); builder = new containerbuilder(); var components = container.componentregistry.registrations .where(cr => cr.activator.limittype != typ
Read more

php - Mysql PK and FK char(36) vs int(10) -

-
i have read mysql can handle indexes , searches better if tables keys integers rather char(36) uuid's. is worth converting int(10)? note: use 1 server , have have plans use multiple databases concurrently therefore removing 1 of big reasons using uuid. our tables innodb if makes difference. thanks in advance. usually rdbms can handle integer keys pk more efficient, other datatypes. reason how build index column, yes: long dont require string (or other typed) keys, should use integers. however: char(36) , int(10) far away being equal, because int(10) much smaller, char(36). dont know, if require many different keys, should keep in mind. update, complete last paragraph: int(10) 32-bit, char(36) 36 - ^byte^ (= 288-bit). not mean, int consumes less space, means, char(36) has 4 times more different keys.
Read more