1. Gabatarwa
Auna nisa da laser ta hanyar lokacin tafiyar bugun jini shine ginshiƙi na zamani na samun bayanan sararin samaniya. Duk da haka, daidaitonsa yana fuskantar ƙalubale a asali lokacin da ƙafar laser ta yi hulɗa da sassa masu rikitarwa, waɗanda ba su ci gaba ba. Wannan binciken ya magance Tasirin Gabaɗaya na Pixels Gudaɗɗa, wata hanyar kuskure da ta haɗa da nakasar ƙafar laser da ke rufe nisa daban-daban. Ya ƙunshi tsohuwar tasirin pixels gudaɗɗa (daga katsewar zurfi a cikin tantanin ƙuduri) da kuma tasirin kusurwar faɗuwa (daga tsawaita ƙafar laser ta hanyar lissafi). Takardar ta gabatar da sabon tsarin gyara da ya haɗa ilimin kimiyyar lissafi da lissafi da kuma tsarin aiki mai ƙarfi don kimanta sigogi don maido da amincin auna nisa, wanda aka tabbatar a kan kayan aiki na kasuwanci kamar Trimble M3 DR da Topcon GPT-3002LN.
2. Bayanin Ka'idar
2.1 Tasirin Gabaɗaya na Pixels Gudaɗɗa
Babbar matsalar ita ce ƙafar bugun laser guda ɗaya tana dawo da bayanan nisa masu shakku saboda tana haskaka sassa a nisa daban-daban. Wannan tasirin "gabaɗaya" ya haɗa abubuwa biyu daban-daban a ƙarƙashin haɗin gwiwar ƙafar guda ɗaya, mara daidaituwa, wanda ke haifar da son rai na tsari. Girman kuskuren ya dogara da kayan aiki saboda ƙa'idodin sarrafa siginar mallakar kamfani, wanda ke sa gyara gabaɗaya ya zama ƙalubale.
2.2 Tasirin Pixels Gudaɗɗa
Yana faruwa ne lokacin da tabon laser ya ratsa gefe ko katsewar zurfi (misali, kusurwar gini). Idan bambancin zurfi ya yi ƙasa da ƙudurin nisa na kayan aiki $\Delta R = c \cdot \tau / 2$ (inda $c$ shine saurin haske kuma $\tau$ shine faɗin bugun), mai auna nisa yana karɓar siginar guda ɗaya, gurɓatacce. Mai kimanta lokaci yana yaudarwa, yana ba da rahoton nisa mara daidaituwa, sau da yawa matsakaicin nauyin nisoshi.
2.3 Tasirin Kusurwar Faɗuwa
Lokacin da katakon laser ya bugi wani sashi a kusurwar da ba ta daidaita ba $\theta$, ƙafar zagaye tana tsawaita zuwa ellipse tare da babban axis $D / \cos(\theta)$, inda $D$ shine diamita na katako. Wannan ƙafar da ta lalace ta hanyar lissafi tana ɗaukar samfurin nisa daban-daban a tsawonsa. Haɗe da watsawa na Lambertian, wanda ke rage ƙarfin siginar kamar $\cos(\theta)$, bugun dawowa yana faɗaɗa lokaci kuma yana raguwa, wanda ke haifar da son rai na auna nisa.
3. Hanyoyin Aiki
3.1 Tsarin Aiki na Harka Biyar
Binciken ya ƙirƙiri tsarin aiki na matakai biyar na tsari: 1) Siffanta bazuwar katako, 2) Aiwatar da karkatar da tsakiya don rage tasirin pixels gudaɗɗa, 3) Tsara tasirin kusurwar faɗuwa, 4) Kimanta kusurwoyin faɗuwa da ba a sani ba a cikin bayanan filin ta hanyar maimaitawa, da kuma 5) Ƙirƙira da aiwatar da tsarin gyara gudaɗaya.
3.2 Kimanta Kusurwar Bazuwa & Karkatar da Tsakiya
An gabatar da hanyar don kimanta ingantacciyar bazuwar katako. Ta hanyar karkatar da wurin da ake nufi daga gefuna da gangan, ana iya sanya ƙafar ta fi rufe sashi guda ɗaya, don haka kawar da ko rage gudummawar pixels gudaɗɗa.
3.3 Tsarin Tasirin Kusurwar Faɗuwa & Kimanta Maimaitawa
An tsara tasirin kusurwar faɗuwa bisa ga lissafin ƙafar laser da ilimin kimiyyar watsawa. Wani sabon abu mai mahimmanci shine tsarin kimanta maimaitawa don kusurwar faɗuwa $\theta$ a wuraren da ake nufi, wanda sau da yawa ba a san shi ba a cikin yanayin bincike na yau da kullun. Dabarar daidaitawa ta haɗa da duk rashin tabbas na lura.
3.4 Ƙirƙirar Tsarin Gyara Gudaɗaya
An haɗa tsarin kuskure na kowane mutum cikin cikakkiyar lissafin gyara: $\Delta R_{total} = f(\Delta R_{mix}, \Delta R_{angle}, \phi, \theta, D, ...)$. Ana kimanta sigogi ta hanyar tsarin daidaitawa wanda ke la'akari da rashin tabbas na lura.
4. Sakamakon Gwaji & Bincike
4.1 Tsarin Gwaji & Kayan Aiki
An gudanar da gwaje-gwaje ta amfani da tashoshi guda biyu na kasuwanci: Trimble M3 DR 2" da Topcon GPT-3002LN. An saita maƙasudai akan sassa marasa ci gaba da kuma a kusurwoyin faɗuwa daban-daban don haifar da tasirin pixels gudaɗɗa na gabaɗaya.
4.2 Kimanta Aiki
An yi amfani da hanyar gyara da aka gabatar akan bayanan auna nisa na danye. Sakamakon ya tabbatar da raguwa mai mahimmanci a cikin kurakurai na tsari. Tsarin aiki ya maido da ingancin auna nisa cikin nasara, yana nuna tasirinsa a cikin nau'ikan kayan aiki daban-daban. Kimanta kusurwa ta hanyar maimaitawa ya tabbatar da ƙarfi a cikin yanayi kamar na filin.
Sakamako Mai Muhimmanci: An warware kurakurai na tsari saboda tasirin pixels gudaɗɗa na gabaɗaya yadda ya kamata, tare da kiyaye daidaito na ƙasa da santimita inda ma'aunin gargajiya ya nuna son rai na decimeter.
5. Tattaunawa & Hanyoyin Gaba
Fahimta ta Asali: Haɓaka na gaske na wannan takarda ba wai kawai wani ƙarin tsarin kuskure ba ne; shine sanin hukuma da haɗa kananan hanyoyin kuskure guda biyu na LiDAR waɗanda ake bi da su daban-daban a ƙarƙashin laƙabin "nakasar ƙafar laser." Marubutan sun gano daidai cewa yanayin baƙar fata na firmware na mai auna nisa na kasuwanci shine babban shinge ga gyara gabaɗaya, kuma sun yi wayo ta hanyar karkata shi da hanyar daidaitawa ta waje wacce ta dogara da ilimin kimiyya.
Kwararar Ma'ana: Ma'ana tana da inganci: ayyana matsalar (tasirin gabaɗaya), raba ta (pixels gudaɗɗa + kusurwar faɗuwa), kai hari ga kowane da hanyoyin da suka dace (karkatar da tsakiya, kimanta kusurwa ta hanyar maimaitawa), da sake haɗa su cikin tsarin gudaɗaya. Tsarin aiki na harka biyar yana ba da tsari mai bayyanawa, mai aiki ga masu aiki.
Ƙarfi & Kurakurai: Babban ƙarfin shine aikace-aikacen aiki. Hanyar ba ta buƙatar samun damar bayanan siginar danye, wanda sau da yawa mallakar kamfani ne. Ta amfani da nisoshi da kusurwoyi kawai da ake iya gani, tana ba da mafita bayan sarrafawa. Kimanta kusurwoyin faɗuwa ta hanyar maimaitawa yana da wayo musamman don binciken duniya ta zahiri. Kuskuren, kamar yadda yake da yawancin hanyoyin da suka dogara da tsari, shine dogaronsa ga ingantaccen farawa na sigogi da zaton cewa tsarin kimiyyar jiki na asali (kamar watsawa na Lambertian) suna da gaskiya. Sassa masu haske sosai ko masu mayar da haske na iya karya tsarin. Bugu da ƙari, tabbatarwa akan nau'ikan kayan aiki guda biyu kawai, duk da yake tabbatacce, ya bar tambayoyi game da aikin sa a cikin mafi girman yanayin na'urorin sikanan laser, gami da LiDAR na hannu da na sama, inda waɗannan tasirin suka fi bayyana.
Fahimta Mai Aiki: Ga ƙwararrun sararin samaniya, wannan aikin wajibi ne don daina yin watsi da ma'auni na gefe da na karkata. Binciken ya ƙididdige kuskuren, wanda zai iya zama mai mahimmanci. Dabarar karkatar da tsakiya ita ce abin da za a iya amfani da shi nan take, mai rahusa ga ma'aikatan filin da ke bincika sassa masu rikitarwa. Ga masana'anta, binciken ya nuna wani yanki don inganta firmware: bayyana rahoton ingantattun sigogi na katako da yuwuwar tsare-tsaren gyara na ciki don waɗannan tasirin. Makomar ta ta'allaka ne cikin haɗin kai mafi ƙarfi. Ya kamata sikanan na zamani na gaba su saka irin waɗannan tsare-tsaren a ciki, ta amfani da binciken siginar na ainihin lokaci kamar ci gaban da aka samu a cikin sarrafa LiDAR cikakken siginar don gandun daji (duba, misali, aikin Mallet & Bretar (2009) a cikin Jaridar ISPRS na Hotuna da Bincike ta Nesa). Haɗa wannan tare da koyon inji don rarraba nau'in saman da kuma hasashen halin watsawa daga siginar dawowa zai iya haifar da tsarin auna nisa da laser masu daidaitawa, masu gyara kansu. Ka'idodin a nan suma suna da alaƙa kai tsaye da fagen da ke tasowa na LiDAR mai ƙarfi da tsararrun SPAD (Single-Photon Avalanche Diode) a cikin motoci masu cin gashin kansu, inda pixels gudaɗɗa a gefunan abu suke zama ƙalubale mai mahimmanci ga aminci.
Aikace-aikace na Gaba: Hanyar aiki tana da tasiri kai tsaye ga binciken injiniya mai madaidaicin madaidaici (misali, sa ido kan nakasar sassa masu rikitarwa), takaddun al'adun gargajiya, da tsarin fahimtar motoci masu cin gashin kansu inda daidaitaccen ma'aunin nisa a iyakokin abu yake da mahimmanci ga aminci. Aikin gaba zai iya haɗa wannan tsarin cikin bututun SLAM (Sarrafa Wuri da Taswira na Lokaci guda) na ainihin lokaci ko haɓaka nau'ikan da ke tafiyar da AI waɗanda ke koyon sigogi na gyara daga bayanai, rage dogaro ga tsarin jiki na zahiri.
6. Nassoshi
- Abshire, J. B., et al. (1994). Pulse timing estimators for laser rangefinders. Proceedings of SPIE.
- Adams, M. D. (1993). A review of laser rangefinding technology. Journal of Surveying Engineering.
- Herbert, M., & Krotkov, E. (1992). 3D measurements from imaging laser radars. Image and Vision Computing.
- Soudarissanane, S., et al. (2009). Incidence angle influence on the quality of terrestrial laser scanning points. ISPRS Workshop Laserscanning.
- Typiak, A. (2008). Methods of eliminating the influence of mixed pixels in laser rangefinders. Reports on Geodesy.
- Xiang, L., & Zhang, Y. (2001). Analysis of mixed pixel in laser radar range finding. Optical Engineering.
- Mallet, C., & Bretar, F. (2009). Full-waveform topographic lidar: State-of-the-art. ISPRS Journal of Photogrammetry and Remote Sensing, 64(1), 1-16.