Stairs and Pedestrian Crosswalks Detection Using Morphological Image Processing and Analysis in Order to Guide Visually Impaired Persons

Većina slijepih i slabovidnih osoba još ne koristi napredne sustave za pomoć pri kretanju i orijentaciji. Iako još nije vrijeme za potpuno izbacivanje ustaljenih metoda poput bijelog štapa, napredak tehnologije sada omogućava razvijanje i postupno uvođenje digitalnih mobilnih sustava za pomoć slijepima i slabovidnima. U ovoj disertaciji opisana je problematika koju mora riješiti takav sustav s naglaskom na metode navođenja prilikom kretanja korištenjem kamere i računalnom obradom slike. Ovo istraživanje usmjereno je na specifične situacije kada se osoba nalazi ispred ili na stepenicama i pješačkim prijelazima kao potencijalnim kritičnim točkama prilikom kretanja. Osim pregleda postojećih metoda detaljno su opisane tri novorazvijene metode zajedno s njihovom evaluacijom. Razvijene metode uključuju: metodu za detekciju stepenica zasnovanu na vertikalnoj i horizontalnoj analizi, multirezolucijsku metodu za detekciju pješačkih prijelaza zasnovanu na morfološkoj analizi i energiji linija, metodu za zvučno usmjeravanje slijepih i slabovidnih određivanjem prostora za sigurno kretanje. Dodatno je razvijen okvir za evaluaciju metoda usmjeravanja slijepih i slabovidnih osoba na stepenicama i pješačkim prijelazima. Testiranjem razvijenih metoda pokazane su određene prednosti u odnosu na postojeće metode po pitanju uspješnosti detekcije, mogućnosti korištenja širokokutnih ulaznih slika i robusnosti u slučajevima zaklonjenosti traženih objekata. Testiranjem brzine izvođenja razvijenih metoda pokazana je mogućnost izvođenja u realnom vremenu što je iznimno važno za pomoćne sustave koji bi se trebali koristiti u pokretu.Most of the blind and visually impaired persons are still not using advanced navigation and orientation assistance systems. Though it is not yet time to fully expel standard methods such as a white cane, advances in technology now enable the development and gradual introduction of digital mobile systems for helping the blind and visually impaired people. This dissertation describes the issues that need to be solved by such a system, focusing on navigation methods using camera and digital image processing. This research is focused on specific situations when a person is in front of or on stairs and pedestrian crosswalks as potential critical points when walking. In addition to an overview of the existing methods, three newly developed methods are described in detail along with their evaluation. Developed methods include: method for stairs detection using vertical and horizontal analysis, multiresolution method for pedestrian crosswalks detection based on morphological analysis and line energy, method for sound guidance of the blind and visually impaired by determining space for safe movement. There is also an additionally developed framework for evaluating the methods for guidance of the blind and visually impaired on stairs and pedestrian crosswalks. Testing of the developed methods has shown some advantages over existing methods regarding the accuracy, the ability to use with wide-angle input images and the robustness in cases of concealed objects. By testing the processing speed for developed methods, possibility to perform in real-time is proven, which is extremely important for the assistance systems that should be used in the movement

Single and Multi-Person Face Recognition Using the Enhanced Eigenfaces Method

This research studies and analyzes the possibility of single-person and multi-person face detection and recognition. Face detection is performed by the Viola-Jones face detection method and recognition is performed by the Eigenfaces method. Unchanged face detection and recognition methods are explained and tested to their limits. Improvement in face recognition is achieved by observing the flaws of the Eigenfaces method and their enhancement

Evaluation Framework for Computer Vision-Based Guidance of the Visually Impaired

Visually impaired persons have significant problems in their everyday movement. Therefore, some of our previous work involves computer vision in developing assistance systems for guiding the visually impaired in critical situations. Some of those situations includes crosswalks on road crossings and stairs in indoor and outdoor environment. This paper presents an evaluation framework for computer vision-based guiding of the visually impaired persons in such critical situations. Presented framework includes the interface for labeling and storing referent human decisions for guiding directions and compares them to computer vision-based decisions. Since strict evaluation methodology in this research field is not clearly defined and due to the specifics of the transfer of information to visually impaired persons, evaluation criterion for specific simplified guiding instructions is proposed.Comment: Technical paper published at 64th International Symposium ELMAR-2022, ISBN: 978-1-6654-7002-

Character recognition based on region pixel concentration for license plate identification

Budući da je postalo moguće izvoditi digitalnu obradu slike u kratkom vremenu, njezina uporaba u tehničkim sustavima postaje sve češća. Automatsko prepoznavanje registarskih oznaka jedan je takav primjer. Koristeći digitalnu obradu slike moguće je automatski detektirati i prepoznati znakove s registarske oznake vozila. Koraci u ovom procesu su predprocesiranje slike, detekcija pločice, segmentacija i prepoznavanje znakova. Ovaj proces obavlja algoritam koji uzima digitalne slike kao ulaz i daje tekstualni oblik znakova s registarskih oznaka kao izlaz. Postoji nekoliko metoda koje se koriste za izvođenje ovog procesa. Ove metode su objašnjene u ovom radu i jedna od njih je implementirana u C# programskom jeziku. Rezultati pokazuju da algoritam radi dobro u slučajevima bez puno deformacija ulazne slike. Međutim, još uvijek postoje slučajevi u kojima nepredvidiva priroda ulazne slike može uzrokovati neuspješnu detekciju ili prepoznavanje.Since it has become possible to perform digital image processing in a short period of time, its usage in technical systems is getting more common. Automatic license plate recognition is one such example. By using digital image processing it is possible to automatically detect and recognize characters on vehicle license plates. The steps taken in this process are image preprocessing, plate detection, character segmentation and recognition. This process is performed by the algorithm which takes the digital image as an input and gives textual form of license plate characters as an output. There are several methods used to perform this process. These methods are explained in this paper and one of them is implemented in C# programming language. The results show that the algorithm works fine in cases without much deformation of an input image. However, there are still cases where unpredictable nature of an input image can cause unsuccessful detection or recognition

Single and Multi-Person Face Recognition Using the Enhanced Eigenfaces Method

This research studies and analyzes the possibility of single-person and multi-person face detection and recognition. Face detection is performed by the Viola-Jones face detection method and recognition is performed by the Eigenfaces method. Unchanged face detection and recognition methods are explained and tested to their limits. Improvement in face recognition is achieved by observing the flaws of the Eigenfaces method and their enhancement

The Role of Endothelin-1 and Nitric Oxide in the Pathogenesis of Hypertension in Diabetic Patients

The pathogenesis of renal hypertension has not yet been fully clarified. As the potential role of endothelin-1 (ET-1) and nitric oxide (NO) has been postulated, their concentrations were determined in plasma and urine of diabetic patients. The study included 30 diabetic patients (both IDDM and NIDDM) with initial or advanced diabetic nephropathy (decreased endogenous creatinine clearance, proteinuria) and 20 healthy control subjects. The correlation with blood pressure and other renal function parameters was monitored and compared with the control group. Also, the effect of ACE inhibitors (ACEI) on ET-1 and NO patterns was monitored in correlation with arterial hypertension. In diabetic patients that did not receive ACEI therapy, the increase in plasma ET-1 was associated with both systolic and diastolic blood pressure elevation, whereas in those administered ACEI the increase in plasma ET-1 was associated with a systolic blood pressure decline. In addition, the increase in plasma NO was accompanied by a statistically significant decline of both systolic and diastolic blood pressure in diabetic patients receiving ACEI

AMBULATORY PROCEDURES IN DAY SURGERY DEPARTMEN

Jednodnevna i ambulantna kirurgija dva su modaliteta izvanbolničkog liječenja koje se provodi u dnevnoj kirurškoj bolnici. Svrha ovog istraživanja, provedenog u Dnevnoj bolnici Kirurške klinike, bila je prikupiti i analizirati pokazatelje strukture bolesnika, dijagnoza, učinjenih zahvata i organizacije ambulantne kirurgije. Studija analizira 3409 ambulantnih kirurških zahvata i histoloških dijagnoza odstranjenog tkiva kod 2736 bolesnika (1457 ženskog i 1279 muškog spola). Specijalist dermatolog uputio je 408 (14,9%) bolesnika, a ostali su došli prema preporuci liječnika primarne zdravstvene zaštite. Prema uputnoj dijagnozi, benigne promjene imala su 2522 (92%) bolesnika, displastične 47 (2%), a maligne njih 167 (6%). Prosječna životna dob bila je 52,8 godina. Bolesnici s benignom novotvorinom bili su znatno niže prosječne dobi (44,2) od onih s malignom (66,5). Najčešća uputna dijagnoza bila je D22 – melanocitni madež. Od ukupno 38, deset najčešćih čini 87% svih uputnih dijagnoza. Prema 10. reviziji Međunarodne klasifikacije bolesti (MKB-10), to su: D22 (33,9%), D23 (21,3%), D21 (13,4%), D17 (6,9%), D21.0 (3,2%), C44 (2,4%), D21.1 (1,7%), L02 (1,6%), L08 (1,6%) i B07 (1,3%). Od kirurških postupaka najčešće su izvođeni ekstirpacija, ekscizija i biopsija pigmentne promjene ili novotvorine kože. Kada su ambulantni zahvati rađeni zbog sumnje na benignu bolest, patohistološka je dijagnoza potvrdila 94,6% uputnih i samo 48% sumnji na malignu novotvorinu. Od bolesnika upućenih s dijagnozom benigne novotvorine 114 (4,5%) imalo je maligni tumor kože. Malignih novotvorina ukupno je bilo 219 (8,0%), a melanoma 24 (0,8%). Od ukupno 16 anatomskih regija ljudskog tijela tri čine 56% svih lokalizacija izvođenja zahvata. To su leđa (750), glava (520) i prsište (260). Zahvate je radilo dvadeset i dvoje liječnika različitih specijalizacija, najčešće specijalisti opće kirurgije (64,2%). Specijalisti plastične i rekonstruktivne kirurgije ukupno su operirali 458 (16,0%) bolesnika. Dječji kirurzi operirali su 381 (13,9%), a ostali 130 (4,8%) bolesnika. Ambulantna je kirurgija kirurgija kože, potkožja i mekih tkiva koja su redovito zahvaćena benignim tumorima ili pigmentnim promjenama, pretežito lokaliziranim na trupu i glavi. Samo je 43,8% bolesnika s dokazanim malignitetom bilo klinički prepoznato, što uz veću pojavnost malignih histoloških (8%) nego uputnih dijagnoza (6%) upućuje da dobar dio bolesnika nije prošao temeljit dijagnostički postupak.Day surgery and ambulatory surgery are two modalities of outpatient treatment carried out in day surgery department in Croatia. The purpose of this study, conducted in day surgery department, was to collect and analyze indicators of patient structure, diagnoses, performed procedures and organization of ambulatory surgery. This study analyzes 3409 ambulatory procedures and histological diagnoses of removed tissue in 2736 patients (1457 female and 1279 male). The indications for treatment were in 408 (14.9%) cases set by dermatologists while others were referred by primary healthcare physicians. According to the referral diagnosis, 2522 (92%) patients had benign, 47 (2%) dysplastic, and 167 (6%) malignant changes. The average patient age was 52.8 years. Patients with benign changes were, in average, significantly younger (44.2) than those with malignant ones (66.5). The most common referral diagnosis was D-22 melanocytic nevus. From a total of 38, 10 most common diagnoses constitute 87% of all referral diagnoses. According to International Classification of Diseases, Tenth Edition (ICD-10), these are: D22 (33.9%), D23 (21.3%), D21 (13.4%), D17 (6.9%), D21.0 (3.2%), C44 (2.4%), D21.1 (1.7%), L02 (1.6%), L08 (1.6%), B07 (1.3%). The main surgical procedures include extirpation, excision and biopsy of pigmented changes or skin neoplasms. When a procedure was performed because of a suspected benign lesion, pathohistological diagnosis confirmed 94.6% of such referral diagnoses as benign, whereas only 48% of clinically suspected malignant neoplasms were pathohistologically malignant. Out of patients referred with a clinically diagnosed benign lesion, 114 (4.5%) patients had a pathohistologically confirmed malignant skin tumor. The total number of malignant neoplasms was 219 (8.0%), and of melanoma 24 (0.8%). Out of 16 anatomical regions of the human body surgical procedures performed in three localizations make 56% of all localizations of performed procedures. These are: back (750), head (520) and chest (260). The procedures were performed by 22 physicians of various specialties, mostly by general surgeons (64.2%). Plastic and reconstructive surgeons performed 458 (16%), pediatric surgeons 381 (13.9%) and others 130 (4.8%) procedures. Ambulatory surgery is the surgery of skin, subcutaneous and soft tissue, usually affected by benign tumors or pigmentary changes, located mostly on the head and trunk. Only 43.8% of patients with verified malignancy were clinically recognized, which indicates, along with the higher incidence of malignancy in pathohistological (8%) than referral (6%) diagnoses, that a significant number of patients did not undergo a thorough diagnostic procedure

AMBULATORY PROCEDURES IN DAY SURGERY DEPARTMEN

Jednodnevna i ambulantna kirurgija dva su modaliteta izvanbolničkog liječenja koje se provodi u dnevnoj kirurškoj bolnici. Svrha ovog istraživanja, provedenog u Dnevnoj bolnici Kirurške klinike, bila je prikupiti i analizirati pokazatelje strukture bolesnika, dijagnoza, učinjenih zahvata i organizacije ambulantne kirurgije. Studija analizira 3409 ambulantnih kirurških zahvata i histoloških dijagnoza odstranjenog tkiva kod 2736 bolesnika (1457 ženskog i 1279 muškog spola). Specijalist dermatolog uputio je 408 (14,9%) bolesnika, a ostali su došli prema preporuci liječnika primarne zdravstvene zaštite. Prema uputnoj dijagnozi, benigne promjene imala su 2522 (92%) bolesnika, displastične 47 (2%), a maligne njih 167 (6%). Prosječna životna dob bila je 52,8 godina. Bolesnici s benignom novotvorinom bili su znatno niže prosječne dobi (44,2) od onih s malignom (66,5). Najčešća uputna dijagnoza bila je D22 – melanocitni madež. Od ukupno 38, deset najčešćih čini 87% svih uputnih dijagnoza. Prema 10. reviziji Međunarodne klasifikacije bolesti (MKB-10), to su: D22 (33,9%), D23 (21,3%), D21 (13,4%), D17 (6,9%), D21.0 (3,2%), C44 (2,4%), D21.1 (1,7%), L02 (1,6%), L08 (1,6%) i B07 (1,3%). Od kirurških postupaka najčešće su izvođeni ekstirpacija, ekscizija i biopsija pigmentne promjene ili novotvorine kože. Kada su ambulantni zahvati rađeni zbog sumnje na benignu bolest, patohistološka je dijagnoza potvrdila 94,6% uputnih i samo 48% sumnji na malignu novotvorinu. Od bolesnika upućenih s dijagnozom benigne novotvorine 114 (4,5%) imalo je maligni tumor kože. Malignih novotvorina ukupno je bilo 219 (8,0%), a melanoma 24 (0,8%). Od ukupno 16 anatomskih regija ljudskog tijela tri čine 56% svih lokalizacija izvođenja zahvata. To su leđa (750), glava (520) i prsište (260). Zahvate je radilo dvadeset i dvoje liječnika različitih specijalizacija, najčešće specijalisti opće kirurgije (64,2%). Specijalisti plastične i rekonstruktivne kirurgije ukupno su operirali 458 (16,0%) bolesnika. Dječji kirurzi operirali su 381 (13,9%), a ostali 130 (4,8%) bolesnika. Ambulantna je kirurgija kirurgija kože, potkožja i mekih tkiva koja su redovito zahvaćena benignim tumorima ili pigmentnim promjenama, pretežito lokaliziranim na trupu i glavi. Samo je 43,8% bolesnika s dokazanim malignitetom bilo klinički prepoznato, što uz veću pojavnost malignih histoloških (8%) nego uputnih dijagnoza (6%) upućuje da dobar dio bolesnika nije prošao temeljit dijagnostički postupak.Day surgery and ambulatory surgery are two modalities of outpatient treatment carried out in day surgery department in Croatia. The purpose of this study, conducted in day surgery department, was to collect and analyze indicators of patient structure, diagnoses, performed procedures and organization of ambulatory surgery. This study analyzes 3409 ambulatory procedures and histological diagnoses of removed tissue in 2736 patients (1457 female and 1279 male). The indications for treatment were in 408 (14.9%) cases set by dermatologists while others were referred by primary healthcare physicians. According to the referral diagnosis, 2522 (92%) patients had benign, 47 (2%) dysplastic, and 167 (6%) malignant changes. The average patient age was 52.8 years. Patients with benign changes were, in average, significantly younger (44.2) than those with malignant ones (66.5). The most common referral diagnosis was D-22 melanocytic nevus. From a total of 38, 10 most common diagnoses constitute 87% of all referral diagnoses. According to International Classification of Diseases, Tenth Edition (ICD-10), these are: D22 (33.9%), D23 (21.3%), D21 (13.4%), D17 (6.9%), D21.0 (3.2%), C44 (2.4%), D21.1 (1.7%), L02 (1.6%), L08 (1.6%), B07 (1.3%). The main surgical procedures include extirpation, excision and biopsy of pigmented changes or skin neoplasms. When a procedure was performed because of a suspected benign lesion, pathohistological diagnosis confirmed 94.6% of such referral diagnoses as benign, whereas only 48% of clinically suspected malignant neoplasms were pathohistologically malignant. Out of patients referred with a clinically diagnosed benign lesion, 114 (4.5%) patients had a pathohistologically confirmed malignant skin tumor. The total number of malignant neoplasms was 219 (8.0%), and of melanoma 24 (0.8%). Out of 16 anatomical regions of the human body surgical procedures performed in three localizations make 56% of all localizations of performed procedures. These are: back (750), head (520) and chest (260). The procedures were performed by 22 physicians of various specialties, mostly by general surgeons (64.2%). Plastic and reconstructive surgeons performed 458 (16%), pediatric surgeons 381 (13.9%) and others 130 (4.8%) procedures. Ambulatory surgery is the surgery of skin, subcutaneous and soft tissue, usually affected by benign tumors or pigmentary changes, located mostly on the head and trunk. Only 43.8% of patients with verified malignancy were clinically recognized, which indicates, along with the higher incidence of malignancy in pathohistological (8%) than referral (6%) diagnoses, that a significant number of patients did not undergo a thorough diagnostic procedure

Stairs and Pedestrian Crosswalks Detection Using Morphological Image Processing and Analysis in Order to Guide Visually Impaired Persons

Većina slijepih i slabovidnih osoba još ne koristi napredne sustave za pomoć pri kretanju i orijentaciji. Iako još nije vrijeme za potpuno izbacivanje ustaljenih metoda poput bijelog štapa, napredak tehnologije sada omogućava razvijanje i postupno uvođenje digitalnih mobilnih sustava za pomoć slijepima i slabovidnima. U ovoj disertaciji opisana je problematika koju mora riješiti takav sustav s naglaskom na metode navođenja prilikom kretanja korištenjem kamere i računalnom obradom slike. Ovo istraživanje usmjereno je na specifične situacije kada se osoba nalazi ispred ili na stepenicama i pješačkim prijelazima kao potencijalnim kritičnim točkama prilikom kretanja. Osim pregleda postojećih metoda detaljno su opisane tri novorazvijene metode zajedno s njihovom evaluacijom. Razvijene metode uključuju: metodu za detekciju stepenica zasnovanu na vertikalnoj i horizontalnoj analizi, multirezolucijsku metodu za detekciju pješačkih prijelaza zasnovanu na morfološkoj analizi i energiji linija, metodu za zvučno usmjeravanje slijepih i slabovidnih određivanjem prostora za sigurno kretanje. Dodatno je razvijen okvir za evaluaciju metoda usmjeravanja slijepih i slabovidnih osoba na stepenicama i pješačkim prijelazima. Testiranjem razvijenih metoda pokazane su određene prednosti u odnosu na postojeće metode po pitanju uspješnosti detekcije, mogućnosti korištenja širokokutnih ulaznih slika i robusnosti u slučajevima zaklonjenosti traženih objekata. Testiranjem brzine izvođenja razvijenih metoda pokazana je mogućnost izvođenja u realnom vremenu što je iznimno važno za pomoćne sustave koji bi se trebali koristiti u pokretu.Most of the blind and visually impaired persons are still not using advanced navigation and orientation assistance systems. Though it is not yet time to fully expel standard methods such as a white cane, advances in technology now enable the development and gradual introduction of digital mobile systems for helping the blind and visually impaired people. This dissertation describes the issues that need to be solved by such a system, focusing on navigation methods using camera and digital image processing. This research is focused on specific situations when a person is in front of or on stairs and pedestrian crosswalks as potential critical points when walking. In addition to an overview of the existing methods, three newly developed methods are described in detail along with their evaluation. Developed methods include: method for stairs detection using vertical and horizontal analysis, multiresolution method for pedestrian crosswalks detection based on morphological analysis and line energy, method for sound guidance of the blind and visually impaired by determining space for safe movement. There is also an additionally developed framework for evaluating the methods for guidance of the blind and visually impaired on stairs and pedestrian crosswalks. Testing of the developed methods has shown some advantages over existing methods regarding the accuracy, the ability to use with wide-angle input images and the robustness in cases of concealed objects. By testing the processing speed for developed methods, possibility to perform in real-time is proven, which is extremely important for the assistance systems that should be used in the movement

Stairs and Pedestrian Crosswalks Detection Using Morphological Image Processing and Analysis in Order to Guide Visually Impaired Persons

Većina slijepih i slabovidnih osoba još ne koristi napredne sustave za pomoć pri kretanju i orijentaciji. Iako još nije vrijeme za potpuno izbacivanje ustaljenih metoda poput bijelog štapa, napredak tehnologije sada omogućava razvijanje i postupno uvođenje digitalnih mobilnih sustava za pomoć slijepima i slabovidnima. U ovoj disertaciji opisana je problematika koju mora riješiti takav sustav s naglaskom na metode navođenja prilikom kretanja korištenjem kamere i računalnom obradom slike. Ovo istraživanje usmjereno je na specifične situacije kada se osoba nalazi ispred ili na stepenicama i pješačkim prijelazima kao potencijalnim kritičnim točkama prilikom kretanja. Osim pregleda postojećih metoda detaljno su opisane tri novorazvijene metode zajedno s njihovom evaluacijom. Razvijene metode uključuju: metodu za detekciju stepenica zasnovanu na vertikalnoj i horizontalnoj analizi, multirezolucijsku metodu za detekciju pješačkih prijelaza zasnovanu na morfološkoj analizi i energiji linija, metodu za zvučno usmjeravanje slijepih i slabovidnih određivanjem prostora za sigurno kretanje. Dodatno je razvijen okvir za evaluaciju metoda usmjeravanja slijepih i slabovidnih osoba na stepenicama i pješačkim prijelazima. Testiranjem razvijenih metoda pokazane su određene prednosti u odnosu na postojeće metode po pitanju uspješnosti detekcije, mogućnosti korištenja širokokutnih ulaznih slika i robusnosti u slučajevima zaklonjenosti traženih objekata. Testiranjem brzine izvođenja razvijenih metoda pokazana je mogućnost izvođenja u realnom vremenu što je iznimno važno za pomoćne sustave koji bi se trebali koristiti u pokretu.Most of the blind and visually impaired persons are still not using advanced navigation and orientation assistance systems. Though it is not yet time to fully expel standard methods such as a white cane, advances in technology now enable the development and gradual introduction of digital mobile systems for helping the blind and visually impaired people. This dissertation describes the issues that need to be solved by such a system, focusing on navigation methods using camera and digital image processing. This research is focused on specific situations when a person is in front of or on stairs and pedestrian crosswalks as potential critical points when walking. In addition to an overview of the existing methods, three newly developed methods are described in detail along with their evaluation. Developed methods include: method for stairs detection using vertical and horizontal analysis, multiresolution method for pedestrian crosswalks detection based on morphological analysis and line energy, method for sound guidance of the blind and visually impaired by determining space for safe movement. There is also an additionally developed framework for evaluating the methods for guidance of the blind and visually impaired on stairs and pedestrian crosswalks. Testing of the developed methods has shown some advantages over existing methods regarding the accuracy, the ability to use with wide-angle input images and the robustness in cases of concealed objects. By testing the processing speed for developed methods, possibility to perform in real-time is proven, which is extremely important for the assistance systems that should be used in the movement