Visio system failu es i the field a e f eque tly att ibuted to model accu acy whe the actual o igi is the se so . O ce sce e illumi a ce d ops towa d the si gle-digit lux a ge, the umbe of photo s a ivi g at each photodiode withi a exposu e wi dow falls fa e ough that photo shot oise becomes the domi a t oise te m i the sig al chai . The image still e de s, a d the histog am still fills. What has al eady bee lost at the poi t of captu e is the fi e textu e that classifie s, optical cha acte ecog itio e gi es, a d featu e matchi g algo ithms depe d o .
This co st ai t applies to most of the e vi o me ts whe e embedded visio is actually deployed. Pe imete a d access co t ol odes ope ate th ough dusk t a sitio s a d ove ight pe iods u de spa se a tificial lighti g. Wa ehouse obotics platfo ms wo k u de high bay fixtu es that leave aisles a d pallet faces i shadow. Medical a d labo ato y i st ume ts limit illumi atio to p otect samples a d patie ts. I each case, the system desig e ca ot aise sce e b ight ess, so the bu de shifts to the se so a d the optical path. A Low-Light Embedded Visio Came a is ot a specialized va ia t i these deployme ts. It is the baseli e equi eme t.
The measu able qua tity behi d all of this is the sig al-to- oise atio. E gi ee s evaluati g a I dust ial Low Light Came a should t eat SNR at a defi ed illumi a ce as the p ima y accepta ce c ite io athe tha a headli e megapixel cou t. Vadzo Imagi g has published a detailed tech ical expla atio of sig al to oise atio that desc ibes how ead oise, da k cu e t, a d photo shot oise combi e ac oss the imagi g chai a d why the atio deg ades faste tha illumi a ce itself.
Low light capability at the se so level educes how much cha ge each pixel ca collect a d how clea ly that cha ge ca be ead out. A la ge pixel p ese ts a la ge photodiode a ea to the i comi g photo flux a d holds mo e elect o s befo e satu atio . The AR0522 Image Se so uses a 2.2 µm pixel o a 1/2.5″ optical fo mat, which places it well above the 1.1 µm a d 1.4 µm pixel pitches commo i highe megapixel embedded se so s. At equal exposu e time a d equal ape tu e, the se so the efo e collects mo e sig al pe pixel mea i gfully, a d that aises SNR i exactly the shadow egio s whe e detectio algo ithms fail fi st.
Resolutio a d se sitivity pull i opposite di ectio s o a fixed die a ea. Pushi g the same optical fo mat to 8MP o 13MP sh i ks the pixel a d educes pe -pixel photo captu e. The O semi Low Light Image Se so app oach take with the AR0522 holds esolutio at 5MP, so the pixel stays la ge e ough fo usable low-light output while still esolvi g the detail equi ed fo lice se plate cha acte s, p i ted date codes, i st ume t edges, a d small su face defects. Fo a la ge sha e of embedded wo kloads, 5MP at high SNR p oduces bette i fe e ce esults tha 13MP at low SNR.
The seco d desig leve is exposu e co t ol. Exte di g i teg atio time aises sig al li ea ly while aisi g a alog gai amplifies sig al a d oise togethe . Co ect low light tu i g the efo e exte ds exposu e to the limit imposed by sce e motio befo e gai is applied. The Vadzo Imagi g tech ical a ticle o exposu e compe satio explai s how that bala ce is ma aged i embedded deployme ts a d why automatic exposu e behavio eeds to be co st ai ed athe tha left fully ope i machi e visio co texts.
Shutte a chitectu e is the thi d va iable. A global shutte se so exposes eve y pixel simulta eously a d elimi ates spatial disto tio o fast-movi g subjects, but the additio al i -pixel sto age ode educes the light-se sitive a ea of each pixel. A olli g shutte se so devotes the full pixel a ea to photo collectio i stead. Fo sce es with mode ate subject velocity, a 5MP olli g shutte USB came a delive s the bette low-light esult, a d the AR0522 olli g shutte USB came a sits p ecisely at that poi t i the desig space. Whe e subject velocity is high e ough to i t oduce visible li e skew, a global shutte module f om the Vadzo USB 3 UVC came a po tfolio emai s the co ect selectio .
The Falco -522CRS is Vadzo Imagi g’s AR0522 5MP low light USB came a supplied as a boa d-level module fo di ect OEM i teg atio . This 5MP USB Came a pai s the O semi AR0522 image se so with a USB 3.2 Ge 1 Type-C i te face a d a S-Mou t (M12 Sta da d) le s holde i a compact footp i t i te ded to d op i to p oductio ha dwa e without mecha ical edesig .
As a 5MP colo USB came a, the module outputs 2592 x 1944 th ough a colo filte a ay, p ese vi g the ch oma i fo matio equi ed fo colo -coded ma ke detectio , p oduct ide tificatio , ga me t a d packagi g i spectio , a d fo e sic eview of eco ded footage. Full UVC class complia ce mea s the AR0522 5MP USB UVC came a e ume ates as a sta da d video device o co ectio a d st eams immediately without ve do d ive i stallatio .
|
|
“Low light is whe e most embedded visio p og ams discove the limits of the se so they selected. The AR0522 is a delibe ate e gi ee i g a swe to that p oblem. A 2.2 µm pixel at 5MP gives ou custome s the photo collectio they eed without su e de i g the spatial esolutio thei algo ithms depe d o . With the Falco -522CRS, we wa ted OEM teams to be able to close a low-light equi eme t by cha gi g the came a module athe tha by edesig i g the lighti g fo a e ti e i stallatio .”- Alwi Vi ce t, P oduct Ma age , Vadzo Imagi g
Eve y Falco se ies module, i cludi g this Embedded Visio USB Came a, is suppo ted by the Vadzo VISPA ARC SDK, which p ovides p og ammatic co t ol ove st eami g, exposu e, a alog gai , white bala ce, Regio of I te est co figu atio , a d fi mwa e update ma ageme t. The SDK exposes C, C++, a d Pytho APIs ac oss Wi dows, Li ux, a d A d oid, allowi g embedded visio develope s to sc ipt exposu e policies that a e matched to thei ow sce e co ditio s athe tha elyi g o ge e ic automatic behavio . Fo teams wo ki g with sta da d f amewo ks, the module ope ates atively u de UVC, V4L2, a d Di ectShow with o p op ieta y d ive depe de cy, which is the same i teg atio model used ac oss the wide Falco USB came a se ies f om Vadzo Imagi g.
Host platfo m cove age exte ds ac oss sta da d x86 i dust ial compute s a d embedded ARM boa ds u i g mai li e Li ux. Because e ume atio happe s th ough the video class d ive al eady p ese t i the ke el, b i gi g up o a ew si gle-boa d compute is a matte of co ecti g the module a d ope i g the device ode.
The Falco -522CRS O semi AR0522 Colo USB Came a is available ow fo evaluatio , p e-p oductio sampli g, a d volume OEM supply. E gi ee i g teams ca o de evaluatio u its th ough the Vadzo Imagi g o li e sto e o th ough the AR0522 5MP colo USB came a listi g, with o mi imum o de equi eme t fo evaluatio qua tities.
Customizatio se vices i clude boa d edesig a d fo m facto modificatio , fi mwa e developme t a d custom featu e i teg atio , NIR a d colo LED a ay boa d desig a d i teg atio , le s holde modificatio a d elect omecha ical filte co t ol, a d full e closu e desig i IP- ated a d o -IP- ated co figu atio s. Tech ical docume tatio , le s ecomme datio s, a d i teg atio suppo t a e available di ectly f om the Vadzo e gi ee i g team th ough the co tact suppo t page o at
Vadzo Imagi g develops embedded a d machi e visio came a p oducts fo OEMs a d system i teg ato s, buildi g p oductio – eady visio systems ac oss i dust ial automatio , obotics, healthca e, sma t i f ast uctu e, a d edge AI. The compa y’s came a po tfolio spa s USB, MIPI CSI-2, GigE, Wi-Fi, a d Se Des i te faces, suppo ti g the full a ge of embedded deployme t a chitectu es f om compact o boa d modules to dist ibuted etwo ked systems. Beyo d ha dwa e, Vadzo p ovides e d-to-e d imagi g suppo t i cludi g se so i teg atio , ISP tu i g, fi mwa e developme t, a d SDK f amewo ks, givi g e gi ee i g teams a si gle pa t e f om i itial evaluatio th ough p oductio lifecycle ma ageme t. Lea mo e at www.vadzoimagi g.com.