1University of Aizu, Graduation Thesis. March, 2013 s1170002AbstractTechnical illustrations are important forunderstanding objects in space. Technical illustrationsare used to communicate information of technicalnature. This paper demonstrates that illustrations thatshow a performer’s point of view will be easier tounderstand with body position as a constantfactor. Specifically, it is hard to understandmovement of body positions described as an oralstatement and in text, leading readers to mentally tryand animate the performance. This paper argues thatcanonical body positions and depth perceptions acrossthe fields of display are easier to comprehend.The experiment, as reported in this thesis aims tounderstanding how common people understandimages that are shown from different perspectives andcamera positions. The study remains inconclusivebecause no trend with the variety of the body tasks,height and angular combinations could be established.However, results show high levels of proficiency inidentifying action-height-angular images whenimages from top views are matched with imagesshown from body height.1 IntroductionMental imagery is an experience and an importantaspect of our general understanding of how differentobjects functions in space without direct visualization.In a complex spatial world, mental imagery canpresent some complex cases of comprehensioninvolving mental rotation. Mental rotation is theability to rotate two-dimensional and three-dimensional objects in space but as an internalrepresentation of the mind. It is basically about howthe brain moves objects in the physical space in amanner that helps with positional understanding(including structural and functional) of objects inspace. Research in psychology [1,2] has providedmuch literature demonstrating how people developand customize mental models and perform mentalrotation towards performing procedural actions inspace. This is where technical illustrations canactually help develop guidelines in a way that might help users perform mental rotations in a predefined orexpected sequence.Technical illustration is the use of illustration tovisually communicate information of a technicalnature. Illustrations should demonstrate visual imagesthat are accurate in terms of dimensions andproportions, and should provide enough visual cuesfor the reader to understand exactly how any physicaltask is to be completed in a given 2-d space.Therefore showing body positions in an illustrationlead to exact information and help you make animage. Further, depth perception is the visual abilityto perceive the world in three dimensions and thedistance between and within objects. People arebetter at judging distances directly across the displayplane.Visual information becomes necessary for anyphysical action when it comes to learning a motorskill by observing it. Visual information is importantfor experiencing how a physical task needs to becompleted. Illustrations are important for novicelearners at an early stage of learning when it is hard tounderstand external physical movements, actionsequences and patterns of movement, one thatsomeone has not yet experienced directly andrepeatedly. Technical illustrations might helpcomprehend the exact style of movement, pressurepoints, actions and reactions; etc could be initiallyunderstood using a manual.Mental rotation can be separated into the followingcognitive stages :1 Create a mental image of an object2 Rotate the object mentally until acomparison can be made3 Make the comparison4 Decide if the objects are the same or not5 Report the decisionThe experiment as reported in this article has beendesigned to differentiate between these cognitivestages and then recognize three-dimensionalmovements shown in a 2-d environment.Interestingly, research in technical communicationrelated to the aspect of understanding task-based bodymovements and ability for mental rotation couldprovide an interesting perspective into thecomprehensive knowledge of how physical objects inPerception of Objects in Technical Illustrations:A Challenge in Technical CommunicationYu Arai s1170002 Supervised by Prof. Debopriyo Roy
2University of Aizu, Graduation Thesis. March, 2013 s1170002space could be shown for various tasks. This specificarea of applied research in technical communicationis still at its infancy and plenty of questions stillremain unanswered. This research aims atcontributing to the field by testing a set of hypothesesthat could be directly used towards developing designguidelines for static technical illustrations.The specific research questions for the experimentas reported in this study include the following:o For a two-dimensional illustration beingshown for a task completed in a three-dimensional space, would the readers preferan object centered view or a performer-centered view?o For a two-dimensional illustration beingshown for a task completed in a three-dimensional space, would the readers preferobjects being shown with maximumviewpoints across the display plane or into thedisplay plane?o Should the primary object related to the taskbe shown below the camera position or atdirectly horizontal to the camera position?o Is there any significant difference in theefficiency with which tasks are understood,based on type of task, height at which the tasktakes place with relation to the human body,and visual angles / perspectives, or somecombination of all of the these factors?2 Literature ReviewMental imagery is a unique phenomenon incognitive psychology and is considered an innerexperience that plays an important role for memoryand thinking. Mental imagery has always been acentral character in the research related to classicaland modern philosophy. An important challenge andthe central focus for this discussion are centered onhow the human mind processes mental images.Literature on mental rotation suggests mentalrotation as the brain’s ability and way of movingobjects in order to understand what they are andwhere they belong [3, 4, and 5]. Mental rotationrefers to how the mind recognizes objects and itspositions in space. Researchers call these objectsstimuli. A stimulus then would be any object or imageseen in the person’s environment that has been alteredin some way. Mental rotation then takes place for theperson to figure out what the altered object is.Why is it that different people understand differentphysical procedures in a 2-D environment withdiffering ability? Besides issues related to designefficiency, the answer probably lies in differinglearning processes which emphasize visual, auditory,and kinesthetic systems of experience and preferencesin learning styles . One possible response could bethought of in terms of an individual’s ability formental rotation towards comprehending any physicalaction. But the ability for mental rotation is alsodependent on what people see and cannot see in thepresented scene.2.1 Display Plane DynamicsFrom a design perspective, people will performdifferently with objects or its angles when shown intoversus across the display plane . For objects intothe display plane, there will be a question of how wellreaders can judge the distance between angles andobject areas. This is because the vision will beobscured by bodies or objects on the line of sightresulting in lack of judgment related to depth cues.On the contrary, objects shown across the displayplane show the maximum number of objects andvisual angles across the line of sight making it easierto judge objects, and the need for judging depth cuesare reduced. However, what needs to be showndepends on the task and the priority.What does this literature mean for a technicalcommunicator and an illustrator who wants to drawobjects for explaining a physical procedure in a 3-dprint or online environment? The first question thatcould be explored in this context is to ask howtechnical illustrators should demonstrate physicalorientation to explain procedures. Another importantquestion for technical communicators would be tounderstand the characteristics of the display plane forvisualizing procedures.2.2 Object-Body-Centered PerspectiveFrom a readers’ perspective, imagining someonedoing a physical action has more positive influenceon physical task completion, when compared to nomental practice . The important question aboutmental practice is related to whether the mentalpractice should be based on the spectator’s point ofview or the performer’s point of view. There isextensive research done by Krull with the suggestionthat graphics for physical tasks need to take intoaccount the needs of users who will carry out actionsin a physical environment. Research suggests thatgraphics need to show tasks from the users viewpoint,and need to make clear how tools are to be used andthe direction in which actions are to be exerted. Anillustration with an object-centered point of viewpositions objects across a display plane . This
3University of Aizu, Graduation Thesis. March, 2013 s1170002viewpoint, which could also be called a spectator’sview, allows objects to be placed so as to directviewers’ attention without obscuring important partsof objects .Psychological research has concurred thatcanonical views showing two-dimensionalrepresentations of physical actions that are held in athree dimensional world are best represented whenillustrations are shown with objects in a three-quarterview from slightly below the camera position.Although canonical views (slightly rotated viewpointto show maximum angles) are always preferred, whenit comes to replicating a task, the choice between aspectators viewpoint (seeing the action as an observerand not as a doer) and object-centered viewpoint(seeing the action as a doer and not as an observer) israther obscure and more context-driven. However, ifthe focus is simply to adapt an object-centeredperspective, the visual could be shown from the backwithout much thought going into how the task shouldbe completed. This is important to understandbecause there are individual differences in the waypeople prioritize objects in space vis-a-vis theorientation of their bodies in space and with differentinterpretations of visual information and withdifferent performance levels on the task [11, 12].Hypotheses: The review of the literature pointstowards the following set of hypotheses for the study.• Illustrations showing natural movements based onactor’s own preference are easier to emulate, andstimulate activation of a strong mental image(Kosslyn et al., 1973, 1998, 1994).• Canonical views showing three-quarter views areeasier to understand.• Object zones shown into the display plane areharder to comprehend when objects are shownacross the display plane.3 MethodsSample and Context: Forty-one students who arenon-native speakers of English (native Japanesespeakers) participated in this study.3.1 ProceduresThe experiment aims to understand how commonpeople understand images and relates them to imagesshown from different perspectives and camerapositions. We asked test subjects to evaluate bodyimages via matching tasks and asked them to ratetheir confidence in their choices.3.2 Methods41 subjects took part in the experiment and eachsubject rated 40 image types, divided into two blocksof 20 each. As part of its robust design, theexperiment considered two sets of images. For theexperiment, we generated images of body positionsfor two kinds of activities: a man holding a ball and aman throwing a ball. The purpose for using twodifferent types of objects relates to the exploration ofwhether object types influences how decisions aboutdepth perceptions and display planes and viewpoints(object-centered or performer-centered) are made.This paper only discusses the results generated fromthe image set related to the man with the ball. Theother set (man with bat) has been discussed as part ofanother paper .Each participant was handed out two different setsas part of an in-class graded assignment, with each sethaving 20 test sheets. Each participant was firsthanded out an instruction sheet in Japanese, and theywere orally explained in Japanese as to what isexpected of them from the experiment.3.3 InstrumentsUsing a computer program that sustains accuratethree-dimensional relationships among body parts, theexperimenter produced variations of viewpoints andbody positions. Each position included two heightsfor each activity: Chest and Waist. The man-holding-the-ball is shown as holding a ball centered in front ofhis chest or waist with the hands gripping the ballfrom both sides. The man-throwing-the-ball versionshows him throwing a ball with his left hand at thechest or waist height. These action gestures werecaptured for five positions where the body moveswith the camera position remaining constant: Front -0 degrees (the man holding/throwing the ball andfacing the camera head on), 1/3 Side - 30 degrees,Side - 90 degrees, 1/3 Back - 120 degrees, Back - 180degrees. For all these images, the camera waspositioned slightly above the waist height.Each set had five images and there were 4 sets intotal. Every set was rotated in five angles asmentioned before. The first set showed a man holdinga ball at chest height; the second set showed throwingat chest height. Two other sets showed a man holdingand throwing a ball at waist height respectively.Once these images were generated, the camera wasthen positioned to capture images from the top for theabove-mentioned sets. A matching top image wasgenerated for each image generated from the setsabove, with a displacement along the y and z-axis to
4University of Aizu, Graduation Thesis. March, 2013 s1170002position the camera exactly on top of the head. Eachof the images generated for the 4 sets were tested tosee whether readers could identify the same whenshown from the top. Each test sheet had an imagefrom the above sets, with three top views out ofwhich only one top view correctly represents the viewshown from slightly over the waist height. Each testsheet had three questions and question 1 and 3 wereanswered using a Likert scale.1. Identify the most appropriate picture shownfrom the top that matches the picture shownfrom the waist height. (Three options provided).2. Which illustration shown from the top standsthe second best?3. How confident are you about your response?3.4 Data AnalysisDuring data sorting, each test sheet for the giventask was reported to be accurately identified andgiven a score of either 1 or 0. The data was entered inSPSS statistical software for data analysis. If a persondid not answer a question (test sheet), he/she wasassigned a grade of 0 for the task. For the questionson confidence, a score in the range of 1-5 wasreported for each test sheet. A score of 0 was assignedwhen the question on confidence was observed as 0(not answered). The answers were divided into fourdifferent blocks of information.1 Man Holding Ball - Chest Height (Front,1/3rd Side, Side, 1/3rd Back, Back)2 Man Holding Ball - Waist Height (Same)3 Man Throwing Ball - Chest Height (Same)4 Man Throwing Ball - Waist Height (Same)4 FindingsOverall findings suggest that readers across thedifferent body position types, rotations and heightsused, did quite well with mean values indicating 85 ~90% accuracy.Table1 shows the following accuracy types witheach combination having 5 images:Mean Accurate Responses for the following:• 5 Angular Rotations Man with Ball -Holding - Chest Height• 5 Angular Rotations for Man with Ball -Holding - Waist Height• 5 Angular Rotations for Man with Ball -Throwing - Chest Height• 5 Angular Rotations for Man with Ball -Throwing - Waist HeightTable 1: Descriptive Statistics for Man with BallMeanStd.DeviationFrequency0 1Holding Chest Front .85 .358 6 35Cochrans Q= 17.968Holding Chest 1/3side .90 .300 4 37Holding Chest Side .85 .358 6 35Holding Chest 1/3back .90 .300 4 37Holding Chest Back .90 .300 4 37Throwing Chest Front .93 .264 3 38Throwing Chest 1/3side .93 .264 3 38Throwing Chest Side .93 .264 3 38df = 19Throwing Chest 1/3back .83 .381 7 34Throwing Chest Back .88 .331 5 36Holding Waist Front .83 .381 7 34Holding Waist 1/3side .88 .331 5 36Holding Waist Side .88 .331 5 36Holding Waist 1/3back .88 .331 5 36Asymp. Sig.= .525Holding Waist Back .93 .264 3 38Throwing Waist Front .90 .300 4 37Throwing Waist 1/3side .88 .331 5 36Throwing Waist Side .83 .381 7 34Throwing Waist 1/3back .90 .300 4 37Throwing Waist Back .93 .264 3 38Data shows that there is not much differencebetween the mean values for any position/heightcombination type. The overall average mean valuesshows 90% accuracy with which readers couldidentify any given illustration at the body height andmatch it with the top view.The frequency chart further corroborates the meanaccuracy results by showing that in all casesparticipants with accurate responses count up tobetween 34~38, while participants who answeredwrongly measured up to between 3~7.Further, statistically I wanted to explore if thesimilarity in mean accuracy between body positionsalso indicates that there is an insignificant differencebetween all the 20 body positions combined.I then performed a non-parametric statisticalanalysis called the Cochran Test. This test enables usto identify whether there is a statistically significantdifference between all the treatments carried out.The Cochran test is performed for conditions wherethe values are binary. In this experiment, the accuracy
5University of Aizu, Graduation Thesis. March, 2013 s1170002values for each body position were recorded as 1 =correct, and 0 = incorrect. This treatment helps usunderstand if the “k” treatments have identical effects.Overall, Cochran’s Q Value for the 5 AngularRotations, Height and Ball Action shows Q = 17.968,with Asymp. Sig = .525. This sig. value goes on toshow that p > .05, suggesting an insignificantdifference between the results.I then wanted to test if there is any significantdifference between responses / accuracy scores in thematching task, between the illustrations rotating at 5angles showing holding a ball at chest height.The Confidence data shows a mean score around3.68 ~ 3.80 in a 1 ~ 5 scale. The highest meanconfidence score is reported for three of the fivepositions, reportedly front, 1/3rdside and 1/3rdbackpositions at 3.80. We see a touch lower mean scorefor 1/3rdside and back positions, but the differencemight not be significant. Data shows that for the 5rotations of throwing chest positions, there isrelatively lower level of confidence for the throwingchest positions in the range of 3.53 ~ 3.85. We seerelatively lower confidence levels for the frontposition and 1/3rdside positions, but the meanconfidence does pick up for the side and backpositions. The highest reported confidence is seen forthe 1/3rdback position at 3.85.Data shows high mean confidence levels for theholding waist positions. High mean confidence scoresare recorded for front, 1/3rdside and 1/3rdbackpositions at over 3.90 while we see a relatively lowerlevels of confidence for side and back positions at3.80 and 3.73 respectively.Show a relatively high level of confidence for allthe five positions for throwing –waist in the range of3.78~3.95. We see a comparatively high confidencescore for the front position at 3.95 when compared toother front positions for action-height combinations.A non-parametric analysis with the Friedman testfor the confidence levels for the 20 different body –height – action combinations was considered to judgeif any significant difference exists between theconfidence levels when considered together. Resultsshowed a Chi-square value of 25.172 with an Asymp.Sig. value = .155 > .05. This goes on to show thatthere is no significant difference between theconfidence levels as reported for 20 differentillustrations.Further, we tested the vicariate correlation betweenthe mean accuracy scores and confidence levels. Datashows a few significant correlations, although in mostcases no significant correlations were observed.The data shows the significant correlation values.This data is not conclusive and indicative of any pattern, but there are some indications that non-canonical viewpoints show a strong correlationbetween actual accuracy scores and confidence.5 DiscussionData in this specific application context clearlynegates the null hypotheses that canonical viewsshowing multiple viewpoints and maximum angles ofvisibility have a distinct advantage when compared tofull front or back views where the viewpoints areexpected to be obscured from direct vision. Thisspecific context where readers had time to workthrough the matching tasks, clearly demonstrated thatside, 1/3rdback, 1/3rdside views did not have anydistinct and statistically significant advantage whencompared to other frontal or back views. This study isdifferent from previous studies because it allowedreaders time to explore the task, whereas earlierstudies conducted by myself were performed in acontext with lesser stake and more random set ofparticipants demonstrating the fact that canonicalviews are more beneficial when decisions are neededto made quickly and without reconsideration andmore intricate thoughts going in to the process.Further, data do not support and demonstrate anysignificant difference and lowered mean accuracy andconfidence levels when objects are shown in thedisplay plane versus across the display plane. Finally,we did not specifically test what is a “naturalmovement” in the selected sample, but data on firstlook did not show any evidence in support of thehypotheses. However, unless “natural movement” isdefined clearly and tested as two specific groups,testing this hypothesis is probably beyond the scopeof the analysis. This paper has just provided someinitial indications of the phenomenon.This study is interesting because it allows us to seethe accuracy with which readers are able to judgepositions which are manipulated based on threedifferent factors; reportedly body height, rotationangles, and actions. These three variations whenhappening at once, presents multiple confoundingvariables that should be considered towardsinterpreting the results. The fact that the matchingtask was conducted for a static camera angle shownfrom the top for all the combinations, allowed us tosee how these body positions, otherwise seen at bodyheight would appear from the top and then performthe matching task accordingly. The purpose behindshowing the camera angles from the top was to putbody zones/areas into the display plane at the verticalaxis (seen from top), thereby intentionally attemptingto negate the difference in judgments that could arise
6University of Aizu, Graduation Thesis. March, 2013 s1170002when body positions are shown at body height. Atbody height with such variations in rotation, heightand action, more diverse visual cues should benaturally available when compared to top views.The most interesting finding that could be reportedfrom this study is the fact that there is a large amountof similarity among the mean accuracy scores fordifferent body height – action – rotation combinations.The Cochran’s test goes on to show that there is astatistically insignificant difference between the meanscores for the 20 different combinations. Further, theCochran’s test within the height-action combinations(5 illustrations/per combination) goes on to show thatthere is an insignificant difference. One probablereason for such an outcome might be the fact thatreaders spent some quality time judging the possiblematching illustration, as this was a graded assignmentfor the class and everyone wanted to do well. Thatprobably explains the high levels of accuracy withalmost every single matching task. But the differencebetween accuracy sores, however insignificant stillgoes on to show that it was the character of theillustration that prompted a response and judgmenttowards accuracy or inaccuracy. In other words,variations in judgments could also have been causedby the position of the body as it looks from a top view.6 ConclusionThis has been an interesting study because itallowed us to explore the effects of different bodyrotations, height and action. This experiment probablyhas been conducted under very strict conditionswhere the purpose of the experiment was wellexplained, the exercise was handled as part of a classassignment, and participants were allowed a lot oftime to think through the exercise. It is possible thatparticipants might have referred back and forthbetween matching tasks towards making judgmentsand that might have increased their accuracy levels.That makes for an interesting argument as to whetherwe want participants to make judgments based onfirst instinct or if readers are allowed to actually makethoughtful decisions towards the response they thinkappropriate. This should be considered as anexploratory analysis, as a lot more needs to be tested(e.g., different experimental conditions) for thesematching tasks with the same set of variables.7 References Z. W. Pylyshyn, “What the minds eye tells theminds brain: A critique of mental imagery,”Psychological Bulletin, vol. 80, no. 1, pp. 1-24,Jul. 1973. R. N. Shepherd and J. Metzler, “Mental rotationof three dimensional objects," AmericanAssociation for the Advancement of Science,Vol. 171, No. 3972, pp. 701-713, 1971. A. M. Johnson, “Speed of Mental Rotations aFaction of Problem-Solving Strategies,”Perceptual and Motor Skills, vol. 71, no. 3, pp.803-806, Dec. 1990. B. Jones and T. Anuza, “Effects of sex,handedness, stimulus and visual fieldon ”mental rotation”,” Cortex, vol. 18, no. 4, pp.501-514, Dec. 1982. C. Hertzog and B. Rypma, “Age difference incomponents of mental rotation taskperformance,” Bulletin of the PsychonomicSociety, vol. 29, no. 3, pp. 209-212, 1991. H. Gardner, Frames of Mind: The Theory ofMultiple Intelligences. New York: Basic Books,1983. R. Krull et al., “User perceptions and point ofview in technical illustrations,” Proc. STC’s50thAnnual Conference Proceedings, Dallas,TX, May, 2003, pp. 205-210. J. A. Verbunt et al., “Mental practice-basedrehabilitation training to improve arm functionand daily activity performance in strokepatients: a randomized clinical trial,” BMCNeurology, 8:7 doi: 10.1186/1471-2377-8-7April 2008. R. Krull, “Comparative Assessment ofDocument Usability With Writing QualityMeasures,” STC Proceedings, 1994. R. Krull et al., “Canonical Views in ProceduralGraphics,” Professional CommunicationConference, 2003. IPCC 2003. Proceedings,IEEE International, 2003. A. D. Milner and M. A. Goodale, The VisualBrain in Action. Oxford University Press, 1995. J. M. Zacks et al., “Selective disturbance ofmental rotation by cortical stimulation,”Neuropsychologia, vol. 41, pp. 1659-1667,2003. M. Nozawa, “Efficacy of Technical Illustrationsin a Technical Communication Environment,”University of Aizu graduation thesis 2013.