c# - True pixel quantity -


i know question littel strange need realy help. have algorithme calculate true pixel quantity in binary image. example how work:

binary image :

0 0 1 0 0 1 1 1 1 1 0 1   1 1 1 1 1 1 1 1 0 0 0 1 0 1 0 0 0 1

her result :

18 15 11 8 6 5 16 13 9  7 5 4 11 9  6  5 4 3 5  4  2  2 2 2 2  2  1  1 1 1

and how work :

result (i,j) = result (i+1, j) + result (i, j+1) - result(i + 1, j + 1) + image(i,j)

her example 18 value: 

18 = 16 + 15 - 13 + 0

my question : name of algorithm because need more information it?

thank help.

this called integral image, or summed area table. used speedup box filtering, among others. 2d generalization of prefix sum.


Comments

Post a Comment

Popular posts from this blog

rdbms - what exactly the undo information lives in oracle? -

some docs says, there "undo tablespaces" implies should create tablespace undo imformation. some docs says, there "undo segment" implies undo information lives in normal tablespaces , use of it's segment. so, undo information lives , organized? earlier releases of oracle database used rollback segments store undo. oracle9i introduced automatic undo management, simplifies undo space management eliminating complexities associated rollback segment management. oracle recommends (oracle 9i , on words) use undo tablespace (automatic undo management) manage undo rather rollback segments. when creating undo tablespace, these automatically created: n undo segments (based on sessions parameter value) named _syssmun$ owned public (usable ops configuration) not manually manageable
Read more

bash - How do you programmatically add a bats test? -

i'd have bats test created every file in directory, i'm not sure best way done is. approach below creates single test when there many files in directory. #!/usr/bin/env bats in $(ls) @test "testing $i" { pwd } done to extract ls output not batter solution go wrong on filenames spaces. you can below shopt -s nullglob file in /dir/* //test command on $file done shopt -u nullglob you can using find command also find /some/directory -maxdepth 1 -type f -exec cmd option {} \;
Read more

clojure - 'get' replacement that throws exception on not found? -

i'd access values in maps , records, throwing exception when key isn't present. here's i've tried. there better strategy? this doesn't work because throw evaluated every time: (defn get-or-throw-1 [rec key] (get rec key (throw (exception. "no value.")))) maybe there's simple method using macro? well, isn't it; has same problem first definition, if evaluation of throw happens later: (defmacro get-or-throw-2 [rec key] `(get ~rec ~key (throw (exception. "no value.")))) this 1 works letting get return value (in theory) never generated other way: (defn get-or-throw-3 [rec key] (let [not-found-thing :i_would_never_name_some_thing_this_021138465079313 value (get rec key not-found-thing)] (if (= value not-found-thing) (throw (exception. "no value.")) value))) i don't having guess keywords or symbols never occur through other processes. (i use gensym generate special value of...
Read more