Philippine Journal of Science 150 (3): 883-893, June 2021 ISSN 0031 - 7683 Date Received: 29 Oct 2020

Crowd Estimation of the Procession in ,

Darius Joseph R. Diamante*, Alerik Ezekiel C. Ruiz, Rex Emmanuel M. Apad, John Paul Aloveel C. Ferrer, and Alexis M. Fillone

Civil Engineering Department, De La Salle University Manila Malate, Manila 1004 Philippines

Developments in crowd counting and estimation are currently in demand brought about by the increasing population and corresponding improvements in public safety planning. Various crowd counting methodologies are successful in addressing challenges and limitations, such as occlusions and wide density variations. However, none have tackled the risky dynamic scenario of the annual Black Nazarene Procession in Manila City, Philippines. Extreme densities are reached as participants follow a moving subject. Yearly reported crowd estimates vary greatly as estimation methods used for this event remain undisclosed, undefined, or unpublished. Considering the strengths of both detection-based and regression-based crowd counting methods, a novel pedestrian estimation method is proposed to appropriately provide an accurate pedestrian estimate. Using video graphics, a static grid analysis is performed to systematically capture and evaluate actual participant density. From the recorded pedestrian densities, functions were developed to estimate densities at varying distances ahead and behind the carriage. A pedestrian joining density function was established to account for devotees who merge with the crowd way ahead of the procession. The 2019 event involved a moving carriage faithfully followed by thousands of devotees as it traveled along a 6.94-km route for 21.35 hours. Employing a 95% confidence interval for the density function intercepts and coefficients, 176,086 to 484,215 active pedestrian devotees during the procession were estimated using the developed systematic pedestrian estimation method. The social value of a more accurate crowd estimation method lies in providing policymakers with reliable crowd estimates that will enable the authorities to deploy the appropriate number of security personnel for crowd management, as well as medical staff for emergency situations during mass gatherings of similar nature to the Black Nazarene Procession.

Keywords: crowd counting, mass gathering, microscopic analysis, pedestrian dynamics, pedestrian safety, religious gathering

INTRODUCTION to touch or kiss the image of the Black Nazarene at the Quirino Grandstand in . A parade concludes the The Feast of the Black Nazarene is an annual nine-day nine-day feast, where the image is paraded on a carriage celebration that regularly gathers throngs of devotees in along a 6.5-km route in the City of Manila. It attracts the City of Manila, Philippines. Reports show that millions large crowds from Rizal Park to the Minor Basilica of of devotees participate in the events, such as the novena Quiapo for long hours. The voluminous groups that travel masses and “pahalik” – where devotees queue for hours continuously along the route are seemingly unmatched by *Corresponding Author: [email protected] other local religious events. A report stated a 5% increase

883 Philippine Journal of Science Diamante et al.: Crowd Estimation of the Black Vol. 150 No. 3, June 2021 Nazarene Procession in the number of participants during the 2019 parade gatherings. These large-scale events are internationally compared to the previous year’s estimate. observed by religious communities as well as during concerts, sports fests, political gatherings, and cultural Despite the social, cultural, and economic significance events (Gayathri et al. 2017). Among these, religious of mass religious gatherings like the Black Nazarene processions are found to be the largest in scale. Inherent Procession, such events bear health and safety risks. crowd characteristics – such as the number of participants, Field reports reveal that the frequency of injuries is high safety ratings, and frequency – are a few parameters that due to immense crowd densities during these gatherings vary across these events. (Bettencourt et al. 2007). Furthermore, various agencies and news outlets disclose significantly dissimilar figures Studies have been undertaken to evaluate crowd dynamics pertaining to the estimated number of attendees during the in mass gatherings relating to public safety (Gayathri et procession, justifying the need to further study the event. al. 2017; Johansson et al. 2012). For instance, reports on the 2012 Kumbh Mela Pilgrimage in the Northern Risk management efforts are constrained due to a lack Indian state of Uttar Pradesh reveal an attendance of of systematic studies on such events. Because of annual around 30 million pilgrims; this is recorded as the largest increases in participants and inadequate studies on religious and mass gathering in human history (Philipson pedestrian characteristics in events similar to the Black 2015). The Philippines, meanwhile, has the third-largest Nazarene Procession, the researchers seek to analyze Catholic population in the world – amounting to 75 million the pedestrian characteristics to develop a systematic people (Barooah 2017). Filipino Catholics are known for estimation method that may be applied to similar local and having sincere, enormous, and extreme expressions of international mass gatherings. The study aims to quantify piety. Mass religious gatherings of this sort have gained the pedestrian density in the procession with respect to critical attention due to the rise in injury and mortality the distance from the carriage and to provide an estimated cases caused by stampedes, chaotic behavior, and other number of pedestrian devotees during the procession based health risks. One of the main causes of high injury and on a novel method. death rates is the poor quality of crowd management. A As organized, the paper contains a literature review of partial list of mass religious gatherings around the world previous estimation methods followed by a discussion is presented in Table 1. of current methods used for the study. The analysis In evaluating the quality of health protocols in place of results and development of the novel pedestrian during religious mass gatherings, Karampourian et al. estimation method and relevant conclusions, as well as (2019) identified key factors that influence preparedness. recommendations, are then presented. One is inter-organizational coordination in developing The rate of urbanization in developed cities has caused a a unified policy. Inter-agency collaboration is likewise surge in population densities. Part of the influx of people mandatory in order to establish a comprehensive data towards highly urbanized cities may be ascribed to mass registration system. Another is the preparedness of

Table 1. Tabulated information on local and international religious mass gatherings. Estimated Religious festival Location Description participants The Feast of the Cebu City, • Celebrated annually every January 1.5 million Santo Niño Philippines • Involves parading an old image of the child Jesus dating back to 1521 Peñafrancia Festival Naga City, • Celebrates two festivals consecutively: The Feast of Divino Rostro 1.8–2 million Philippines (land procession) and Our Lady of Peñafrancia (fluvial procession) The Procession of Manila, • Involves parading a black image of Jesus Christ through 6.5 km from 1.35–6 million the Black Nazarene Philippines Rizal (Luneta) Park to the Minor Basilica of Quiapo Procesión Señor y Salta, Argentina • A primitive cross, a painting of Virgen de las Lágrimas, and images of 800,000 Virgen del Milagro Virgen and then the Señor y del Milagro are paraded every September from the Cathedral of Salta to Parque 20 de Febrero, then back to the Cathedral. Each way is 2.3 km long. The Procession Lima, Peru • Usually reaching 24 h, the image of the Lord of the Miracles is paraded More than 100,000 of the Lord of the from Las Nazarenas Church to La Merced Church. Around 4,300 Miracles bearers alternately carry the image through 80 m for 15 min. Iztapalapa Passion Mexico City, • The Crucifixion is reenacted after an 8-km uphill procession to the 2 million Play Mexico summit of Cerro de Estrella. Among hundreds of actors, the main role is given to an individual who carries the cross and is attached to it.

884 Philippine Journal of Science Diamante et al.: Crowd Estimation of the Black Vol. 150 No. 3, June 2021 Nazarene Procession medical infrastructures in terms of manpower allocation. low resolution and high occlusion during high-density This requires knowledge of the participant population to scenarios, providing a sound estimate (Ma et al. 2015). sufficiently estimate the required number of specialist teams to be deployed during the event. This concern may Regression-based Crowd Counting Methods be adequately addressed through further studying crowd In developing crowd counting methods, studies have estimation methods. shifted to regression-based methods. Pedestrian counts and Studies also sought to define crowd management from detections are estimated from mapped features (Chan and crowd control. Based on structured interviews among Vasconcelos 2009). After features are extracted through crowd managers, the latter entails enacting procedures at developed methods such as in Marana et al. (1998), crowd the onset or after the crowds have become uncontrollable. estimates are mapped using various techniques such as On the other hand, crowd management is proactively linear regression (Paragios and Ramesh 2001), piecewise setting measures to prevent unforeseen circumstances linear regression (Chan et al. 2008), Gaussian process from taking place. This includes proper resource allocation regression (Chan and Vasconcelos 2012), and neural while stressing the significance of monitoring and network (Sindagi and Patel 2018). As regression-based prediction (Martella et al. 2017). Notable past events in methods sought to address the problems of high clutter various countries brought light upon the chaotic incidents and occlusion, they however fail to consider significant during mass religious gatherings, further highlighting the spatial information when regressing from the global count strong need to scientifically evaluate crowd dynamics (Sindagi and Patel 2018). (Gayathri et al. 2017). Over time, innovations in crowd counting have been There are emerging in-depth methods used in analyzing developed. One of which is the developed crowd density pedestrian space-time dynamics that are meant to improve estimation system of Hussain et al. (2011) that uses disaster risk and management measures during mass edge detection and background removal and passes the gatherings. Estimating the number of people – or crowd processed digital image to a neural network that generates counting – plays a significant role in urban planning and a crowd density estimate. Evaluating texture patterns have risk management (Wu et al. 2020). Simpler methods have also been explored. With low-density crowds showing been used in other studies, such as that in Aros-Vera et al. coarse textures and high-density crowds displaying fine (2020), where a geographic information system software patterns, crowd densities can be estimated by using this was initially used to estimate the area of the event. To information and feeding such data to neural networks obtain the crowd count estimate, a uniform density of four (Marana et al. 1998). persons per m2 was assumed across the whole area. Crowd Figures on pedestrian estimates for the Black Nazarene counting has been a popular topic of interest, and significant Procession over the years have varied greatly due to vague contributions to its development have been abundant. estimation methods that were published to be used for this event. Existing estimation methods vary per source. Detection-based Crowd Counting Methods According to NCR police Chief Carmelo Valmoria, a Direct crowd observation methods operate under the sample 1 m x 1 m pedestrian density is taken, then is assumption that the crowd is made up of independent multiplied by the area of a particular location. This is subjects or persons (Yuan et al. 2020). Early studies on the done at various locations along the route to consider matter rely mostly on manual detection of each person in the influx of pedestrians and “to take into account that a crowd using key features, such as the person’s head and particular area’s dimensions.” Furthermore, several shoulders (Saleh et al. 2015) through a sliding window methods were suggested by a national news agency to that bounds the region of interest (ROI) being observed enable independent sources to generate crowd estimates (Dollar et al. 2012). Karthika et al. (2018) manually without depending on authorities. These include obtaining detected pedestrians during the Kumbh Mela as they an average pedestrian count from a determined number occupy a certain geometric pore. Parts-based detection of pixels in an image then multiplying the figure with methods (Enzweiler and Gavrila 2009) develop trainable the total number of pixels of the image, and dividing the systems that identify body parts as a component of a area into grids then taking a sample grid density to be body. Further developments have incorporated pattern multiplied with the location’s area (GMA News Online recognition (Viola et al. 2003) and random forest (Gall 2014). However, these methods can only estimate certain et al. 2011) to a degree of success. The system developed portions of the route instantaneously. by Viola et al. (2003) feeds two consecutive frames to a detector to analyze appearance and pattern information Moreover, local authorities in Quiapo, Manila; the Metro in order to detect walking individuals. These methods Manila Development Authority; and the Department of likely proved to be significant for extreme instances of Public Works and Highways mentioned having used

885 Philippine Journal of Science Diamante et al.: Crowd Estimation of the Black Vol. 150 No. 3, June 2021 Nazarene Procession secondary data such as the local population of areas along included in the estimate. Thus, the crowd estimate considers the procession route. In addition, the total devotees who those only found within a defined threshold along the route attended at the starting point in Quirino Grandstand and at visible in the frame. This means not everyone in the scene the end in who did not join the procession or image is necessarily included, such as those considered were added to the count. This might have included non- in benchmark datasets. participants, leading to an overestimation of the number of participants during the procession. This justifies the need for a thorough study of this event in order to develop an estimation system fitting for its Confusion further arose as the accounts from various dynamic nature. In attempting to address such, we propose sources (see Table 2) inadequately reported whether the a novel systematic pedestrian estimation method that figures correspond to the number of participants during the incorporates the use of detection-based concepts paired procession only, which corresponds to the study’s scope, with a regression-based method to provide a sound or throughout the nine-day festival as a whole. estimate of the pedestrians along the whole route of the Black Nazarene Procession. Table 2. Varying estimated number of participants from different sources. Black Nazarene Estimates Procession year MATERIALS AND METHODS 2020 2.5 million The data gathering method employed was a video- 2019 800,000; 1.35 million; 4 million; 5 million graphic survey. Video cameras were used to record the 2018 850,000; 1.4 million; 4 million; 6 million actual procession. Camera locations along the procession route were earlier identified through ocular inspection. 2017 1.4 million The following criteria were used to assess the location 2016 1.5 million suitability: 1) a facility along the procession route can accommodate a camera setup, or a local government unit (LGU) has available CCTV (closed-circuit television) Considering the use of existing crowd counting methods cameras; 2) the location is accessible to the researchers; alone to the Black Nazarene Procession is constrained by and 3) the camera location can provide an elevated view of two important limitations. First, existing methods only the observed road segment during the video-graphic survey estimate the number of people in a crowd encompassed (Ravishankar and Nair 2018). Four cameras were set up at within a frame of a still image. Using such methods strategic points along the procession route. An additional 15 will require video footage or images of the whole CCTV footage sets were collected from the Metropolitan procession route, which is challenging both logistically Manila Development Authority and LGU barangay halls. and economically. Furthermore, the second limitation of Furthermore, distances were noted between fixed points using existing methods alone is the non-integration of visible from the camera field of view to calibrate the video crowd movement direction to the estimation process. The footage sets during the video analysis. pedestrians found in benchmark datasets used by previous studies are composed of images of pedestrians traveling Pedestrian Estimation Method in random directions (Chan et al. 2008; Chen et al. 2012; Despite the advancements and availability of automatic Zhang et al. 2015, 2016) or having one fixed subject of counters, Ray et al. (2020) highlight the advantages of interest, such as a stadium (Indrees et al. 2013). Pedestrian using manual counting methods. These consider valuable movement direction is immaterial to the crowd estimation contextual data such as the pedestrian dynamics that heavily process. However, the dynamic movement of the high- influence the crowd behavior during the particular event. density crowd during the Black Nazarene Procession on In this case, the Black Nazarene Procession demonstrates the last day of the nine-day feast along the procession route unusual dynamics as pedestrians continuously move along is a significant factor in the estimation process. Pedestrian a designated route while following a moving carriage. The movement during the Black Nazarene Procession is density-distance analysis applied in Apad et al. (2019) was considered dynamic since participants continuously move adopted in this study. It evaluates the pedestrian density along a designated route while following a moving subject, ahead and behind the carriage relative to the distance particularly the carriage. Taken into consideration is the from the carriage. variation in pedestrian densities at different distances from the moving carriage. Pedestrians considered in the In analyzing the video footage, a mesh of 2 m x 2 m square estimation method are limited to those actively participating grids was laid out across the image frame. Two columns in the procession along the whole route. Pedestrians spilling of grids were set perpendicular to the traffic movement over adjacent streets, on bridges, and on buildings are not

886 Philippine Journal of Science Diamante et al.: Crowd Estimation of the Black Vol. 150 No. 3, June 2021 Nazarene Procession direction. Moreover, multiple rows of grids were laid out carriage, multiplying them with the corresponding road parallel to the traffic movement until the total grid width width provides an estimate of the number of pedestrians. was less than or equal to the road width (see Figure 1). Summing up these values would then provide the Frames were extracted from the video footages every 4-m cumulative number of pedestrians that took part in the distance the procession moved forward. Six frames ahead procession. of the carriage and six frames behind the carriage were obtained, collecting a total of twelve snapshots for each Given the high-density scenarios and high occlusion video footage. For each frame, the pedestrian headcount captured with the relatively low-resolution cameras within each grid was divided by the grid area to obtain available, manual detection of pedestrian heads were the pedestrian density. A density map was generated to employed providing the critical variation in densities and graphically illustrate the pedestrian densities at varying accounting for spatial considerations. To further estimate distances from the carriage. the cumulative number of active participants throughout the procession, the density variations at different distances In order to systematically obtain an estimated number from the carriage were regressed. To consider the of participants during the procession, the active length dynamic behavior of the crowds and to generate a sound of the parade was first established. The active length of estimation technique, the novel pedestrian estimation the parade is the observable extent of participants within system integrates the use of both detection-based and which the pedestrians are actively participating in the regression-based concepts. procession. It was identified that the length of the parade has two main sections – the area behind and ahead of the carriage. By using the pedestrian density data obtained from the grid analysis, functions were developed using RESULTS AND DISCUSSION regression analysis where the density of the pedestrians behind and ahead of the carriage are functions of the Pedestrian Density distance from the carriage. With the parade length being The Black Nazarene Procession held on 09 Jan 2019 constant, the only varying parameter needed to obtain the traveled a total of 6.938 km from Quirino Grandstand number of participants in each segment is the road width to Plaza Miranda at the Minor Basilica of Quiapo (see with respect to its distance from the carriage. With the Figure 2). The procession commenced at 5:09:00 AM and varying densities of each meter behind and ahead of the

Figure 1. Pedestrian density set-up of a frame from Camera 08.

887 Philippine Journal of Science Diamante et al.: Crowd Estimation of the Black Vol. 150 No. 3, June 2021 Nazarene Procession

Figure 2. Procession route with camera locations and road segment labels in the City of Manila. concluded at 2:30:00 AM on 10 Jan 2019. Throughout the m2. Passive participants who only intended to follow 21-h and 21-min duration of the parade, the procession the procession throughout the parade were found further attracted large crowds, which played certain roles in behind, generating lower densities. On the other hand, the event. pedestrian densities ahead of the carriage show a less distinct pattern. As observed during the event, rope holders Apad et al. (2019) explained the three categories of displayed turbulent swaying motions, causing the ordinary participants: pushers, rope holders, and ordinary devotees. devotees to clear the area to avoid injuries. This created The pushers are those who push the carriage from behind patches of low-density areas ahead of the carriage. The in the instances of stoppage along the route. The rope minimum density recorded is 0.75 ped/m2 situated right holders situated ahead of the carriage tug two ropes behind a high-density grid. to facilitate the forward movement and to manage the carriage direction. The ordinary devotees are neither pushers nor rope holders. Their main goal is to approach Pedestrian Estimation Method and touch the image of the Black Nazarene mounted on It should be noted that the pedestrians considered in this the carriage. This often leads to risky maneuvers due to the study are limited to those actively participating in the aggressive behavior of the ordinary devotees. Moreover, procession along the parade route. Pedestrian observers they may be situated ahead, by the side, or behind the found on adjacent streets, atop bridges, or on buildings carriage throughout the procession. are not considered in the count. Data from five cameras were utilized in the study. As By evaluating the pedestrian densities at varying distances, seen in Figure 3, pedestrian densities vary as the distance functions were developed where the average density of from the carriage increases. Behind the carriage, it can pedestrians is estimated as a function of the distance from be observed that pedestrian densities generally decrease the carriage. Considering the pedestrian density behind the as distance increases. High densities can also be found carriage, a logarithmic behavior was observed (see Curve at locations behind the carriage, particularly within an 2 in Figure 4a and Equation 2 in Table 3). The function 8-m range from the carriage. This is where the pushers was linearized to be appropriately subjected to simple were situated. The high number of pushers occupying linear regression analysis. A 95% confidence interval a small area when they compress to push the carriage was set for the coefficients to provide a threshold for a from behind caused the large pedestrian densities. The statistically sound estimate. Functions that correspond to maximum density recorded is 12.5 ped (pedestrians) per the minimum (see Curve 1 in Figure 4a and Equation 1

888 Philippine Journal of Science Diamante et al.: Crowd Estimation of the Black Vol. 150 No. 3, June 2021 Nazarene Procession

Figure 3. Pedestrian grid density map showing variations in densities at relative distances ahead and behind the carriage.

Figure 4. Average pedestrian densities at varying distances a) behind and b) ahead of the carriage. The green curves represent the function for maximum densities, the red curve represents the function for minimum densities, and the blue curve represents the functions fitted to the actual data. in Table 3) and maximum (see Curve 3 in Figure 4a and and Equation 5 in Table 3). After linearizing the function, Equation 3 in Table 3) pedestrian density estimates behind a 95% confidence interval was set for the equation the carriage were developed accordingly. coefficients. Generated were functions for the minimum (see Curve 1 in Figure 4b and Equation 4 in Table 3) and Similarly, the average pedestrian densities ahead of the maximum (see Curve 3 in Figure 4b and Equation 6 in carriage were plotted against the distance. The curve Table 3) pedestrian density estimates ahead of the carriage. displayed an exponential trend (see Curve 2 in Figure 4b

889 Philippine Journal of Science Diamante et al.: Crowd Estimation of the Black Vol. 150 No. 3, June 2021 Nazarene Procession

Table 3. Functions estimating the minimum, nominal, and maximum pedestrian densities behind and ahead of the carriage. Pedestrian density behind the carriage Minimum density (1)

Nominal density (2)

Maximum density (3)

Pedestrian density ahead of the carriage Minimum density (4)

Nominal density (5)

Maximum density (6)

2 In Equations 1–6, di (measured in ped/m ) is the density 2. the active length of the procession is constant along of the pedestrians at a distance i (measured in m) behind the route; and the variation in pedestrian densities at or ahead of the carriage. After obtaining the density at a different distances from the carriage is similar along ℓ certain distance, it is multiplied by the road width Rwi the route. (measured in m) to obtain the number of pedestrians per m length. Taking the summation of the number of As observed from the video footage, the average length pedestrians from distance = 1 m to the total length of the of the parade behind the carriage was found to be parade behind or ahead the carriage measured in meters approximately 80 m with a standard deviation of 8.111 (L) the total number of pedestriansℓ behind and ahead the m, while the extent of the parade ahead the carriage was carriage can be obtained as shown in Equations 7 and 8, estimated at 50 m according to the first assumption. Thus, respectively. Lbehind = 80 m and Lahead = 50 m. To obtain the estimated range of pedestrian devotees, Equations 1 and 4 were used to obtain the minimum (7) pedestrian estimate while Equations 3 and 6 were used to obtain the maximum pedestrian estimate in Equations 7 and 8, respectively. For the first 130 m of the procession (8) route, the number of devotees actively participating in the procession was estimated using Equation 9. Considering the varying road widths of the procession route, the minimum and the maximum number of active devotees Since a person is a discrete entity, the obtained number of within the first 130 m of the route were estimated to be pedestrians at each iteration was rounded up to the nearest about 14,874 to 28,802. As the procession moved forward, integer. Furthermore, the total number of pedestrians it was perceived that the density of pedestrians joining the in the parade at an instant can thus be calculated using active devotees ahead of the parade was constant. The Equation 9. densities of the joining pedestrians were obtained using (9) Equations 4 and 6, considering a length of 51 m ahead of the carriage. This yields a minimum and maximum joining pedestrian density of about 1.78 and 5.12 ped/m2, In developing the system that generated the total estimate respectively. The number of joining pedestrians per meter of the participants in the procession, the following traveled by the procession was, thus, approximated by assumptions were taken into consideration: multiplying the joining density with the road width of the road section 51 m ahead of the carriage. As the number of 1. the ropes attached in front of the carriage are joining pedestrians accumulated throughout the remaining straightened at the instant of estimating the number 6,808 m of the procession route, the total number of of pedestrians ahead of the carriage; thus, the length pedestrian devotees that actively participated in the parade of the parade ahead of the carriage is the length of the was estimated to range from 176,086–484,215. Aside from rope which is 50 m; the estimated range, no other sound comparison can be

890 Philippine Journal of Science Diamante et al.: Crowd Estimation of the Black Vol. 150 No. 3, June 2021 Nazarene Procession made because the methods employed in the previous Black Based on data from the density-distance analysis, results Nazarene Processions were not disclosed, explained, nor showed a 130-m active length of the pedestrian parade: published. 80 m behind and 50 m ahead of the carriage. With the use of this active length and its corresponding densities Pedestrian dynamics of the Black Nazarene Procession on the new estimation approach, it was determined that in terms of density is evaluated and represented through the estimated number of active devotees that participated this paper. By integrating detection-based and regression- in the 2019 Black Nazarene Procession ranges from based crowd counting concepts, a novel approach 176,086–484,215 pedestrians; this considers a 95% level is developed to provide better crowd estimates that of confidence for the function intercepts and coefficients. significantly influence this large-scale event. Accurate The novel method adapts the strengths of both detection- crowd estimates aid in crowd management planning based and regression-based crowd counting methods. for local and international events with similar nature to the Black Nazarene Procession by allocating sufficient The novel estimation method may also be utilized on security and medical personnel for the forecasted crowd other local and international mass gatherings that share a population. For the 2018 Black Nazarene Procession, the similar nature of having a massive crowd follow a moving Manila Police increased the number of policemen from subject along a designated route, such as the Fluvial 5,000 the previous year to 6,500 deployed during the said Procession of Our Lady of Peñafrancia in Naga City, the event (Remitio 2018). Efficient and adequate personnel Solemn Procession of Señor Santo Niño in Cebu City, allocation may further be optimized to support the crucial the Procesión Señor y Virgen del Milagro in Salta, the stage of crowd management planning using improved Procession of the Lord of the Miracles in Lima, and the crowd estimation techniques. Iztapalapa Passion Play in Mexico City. Accurate crowd estimation techniques are important so that the proper It is important to note that the developed pedestrian number of security personnel for crowd management and density curves are specific to the 2019 Black Nazarene medical staff during health emergencies can be allocated. Procession. Given its novelty, the replicability of using the same curves to future Black Nazarene Processions The study of crowd estimation has found relevance during are subject to further evaluation. Furthermore, the use of the current pandemic the world is experiencing (Rezaei such curves to similar-natured events aside from the Black and Azarmi 2020) where social distancing is enforced Nazarene Procession is not advisable as factors – such as to limit the number of persons occupying a given space pedestrian behavior, route conditions, or event mechanics the will help control the spread of the virus (Saidan et – may vary greatly. Aside from presenting these curves al. 2020). as tools to estimate future Black Nazarene Processions and other similar-natured events, the study proposes the As the study was bound by time and budget constraints, the development of a system as a whole in order to generate method can be further improved by using drones to capture sound crowd estimation techniques. The system consists images from better angles, limiting challenges caused by of data gathering through pedestrian counting and density occlusion. Using high-definition video cameras instead calculation with respect to the moving subject of interest, of the available low-definition CCTV cameras may also model generation from the obtained actual densities, and provide higher quality images for better data quality. This crowd estimation by applying the model throughout the permits the use of other more established methods, such whole procession route. as integrating neural networks, in estimating the densities at established grids or ROI relative to the moving subject of interest in similar-natured processions.

CONCLUSION AND RECOMMENDATIONS STATEMENT ON CONFLICT OF On the last day of the 2019 Feast of the Black Nazarene, INTEREST the image was paraded on a carriage for 21.35 h along a 6.9-km route in the City of Manila. The heterogeneity The authors declare that they have no known competing of the crowd was categorized into three groups based on financial interests or personal relationships that could their roles – pushers, rope holders, and ordinary devotees. have appeared to influence the work reported in this paper. To address the inconsistent approach of different agencies in reporting the estimated number of participants in the procession, a novel method was developed for a more systematic estimate.

891 Philippine Journal of Science Diamante et al.: Crowd Estimation of the Black Vol. 150 No. 3, June 2021 Nazarene Procession

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