Visual evaluation using microcomputer-based imaging technology

Evaluafion

Printed

and Program

in the USA.

Planning,

Vol.

13, pp. 343-348,

0149-7189/90

1990 Copyright

All rights reserved.

$3.00

cc! 1990 Pergamon

+ .OO

Press plc

VISUAL EVALUATION USING MICROCOMPUTER-BASED IMAGING TECHNOLOGY*

SAM SHERRILL School of Planning University

of Cincinnati

AB!SFRACT Microcomputer-based imaging technotogy reestablishes the direct link between evaluation and environmental design b-v allowing evaluators and urban designers to visually explore and prospectively evaluate alternative simulations of design proposals. This article describes the rnicrocomputer hardware and software tised to create simulations and how these simulations are being used in planning education at the author’s university. Imaging technology is presented as a useful and promising addition to the existing repertory of evaluation techniques.

INTRODUCTION both man-made and natural, that support human goals and activities. Design professionals are concerned about human responses to designs (Bechtel, Marans, & Michelson, 1987, p. 2) just as evaluation professionals are concerned about human responses to purposive social action. From the perspective of quantitative evaluation, designs are interventions and responses are outcomes. Working together, evaluators and designers can use microcomputer-based imaging to simulate and visually present project designs to policymakers, citizen groups, and developers. For example, evaluators and urban planners could use imaging to explore with planning commissions the visual implications of zoning codes under consideration, code changes, or zoning variances. Citizen groups could explore the visual impacts of proposed construction in their communities. Working with developers, such groups might more easily and quickly agree on designs to fit a particular community or business district. In all cases, unintended visual outcomes are more likely to be identified, a difficult task in any kind of evaluation, visual or not (Sherrill, 1984).

Relatively inexpensive microcomputer imaging hardware and software can broaden the scope of evaluation by adding a new visually oriented research technique to evaluation methodology. This new technology allows images captured on film to be digitized, modified, and stored on any standard MS-DOS desktop microcomputer.’ Modified images can be used as realistic simulations of proposals having visual importance. Such simulations allow evaluations and selections to be made using realistic visual models of the alternatives. Realistic models are especially important to those who lack the designer’s ability to visualize alternative outcomes. Microcomputer-base imaging allows planners and evaluators to do visual “what ifs,” the imaging equivalent to using electronic spreadsheets to calculate the consequences of different financial assumptions. Using this technology to prospectively judge visual outcomes links evaluation to environmental design, though not for the first time (see McAllister, 1980). In the broadest of terms, environmental design is concerned with those aspects of the physical environment,

*I did most of the work on this article while a Visiting Scholar in the Department Laboratory

at the School of Architecture

and to Profe\\or

.loseph Ferreira,

also goes to Professor Communications, ‘Digitizing

William

and Planning at M.I.T.

Director

of the Computer

Meyers at the University

I am

of Urban Studies and Planning and the Computer

indebted to the University of Cincinnati

Resource Laboratory, of Cincinnati

for his support while

for his comments

1was

on evaluation

Resource

for supporting my stay at M.I.T. in residence. My appreciation

and to Thomas

Baggs of Xenac

Inc. for his on imaging.

here refers broadly to the use of the binary number system to represent all forms of verbal,

Requests for reprints should be sent to Sam Sherrill, tecture, and Planning,

University

of Cincinnati,

Associate Professor of Planning,

Cincinnati,

OH 45221.0016.

343

numerical,

School of Planning,

and visual information.

College of Design, Art, Archi-

344

SAM

SHERRILL

Imaging will contribute to decision making by allowing a greater number of alternatives to be considered in less time. Immediate changes can be made as they arise from the deliberations of the participants in planning and executive meetings. Clearly unacceptable alternatives can be quickly identified and rejected while a larger number of potentially acceptable proposals can be given further consideration and a more detailed rendering. Unlike most other ways of modeling alternates, even a detailed rendering can be done quickly. To visually simulate projects in a microcomputer environment, evaluators and designers can use any one of the small number of microcomputer boards that digitize color signals from video cameras and video (tape and disk) playback machines. The TARGA board from TRUEVISION, Inc., the most widely used in MS-DOS microcomputers, has received favorable attention from reviewers (see, e.g., Crider, 1986; Tinney, 1987).’ The TARGA board converts analog signals from video sources into digital data a microcomputer can use.’ With the companion TIPS (Truevision Image Processing Software) program from Island Graphics, Inc., a EVALUATING

sophisticated but friendly paint program, evaluators and designers can alter captured video images in a wide variety of ways. When images are taken from video sources, the TARGA board and the TIPS program do the work of digitizing the incoming color signals. Either flatbed or slide scanners can be used to digitize images captured on photographic film. These scanners and their accompanying software digitize the content of a photograph or 35mm slide. The software then creates an image file that can be used by TIPS, the paint software. While scanners typically produce much better results than video devices, they also produce image files larger than TIPS can handle by itself. RIO, an imaging program from AT&T that runs on a microcomputer with TIPS, enables the user to modify even the largest image file produced by a scanner.’ Focusing on the TARGA-TIPS-RIO combination, this article introduces the evaluative application of microcomputer-based imaging technology in environmental design.

VISUAL

Evaluation Methods Evaluation supports policymaking by providing the participants with information on project outcomes, the monetary and nonmonetary values and costs of those outcomes, and the distribution of values and costs. Since qualitative and quantitative research procedures together comprise most of what evaluators profess to be their methodology for outcome evaluation, only results of projects appropriately identified and represented using one or the other or both of these methods fall within the current scope of evaluation. Bounded by their methods of choice, evaluators specialize in educaREPRESENTING A complete evaluation of proposed designs would include the full range of perceptual responses to the shape, form, and color of such proposed projects as buildings, roadways, expressway entry and exit ramps, parks, and open spaces. Choices would be influenced by a comparison among projects of the difference (or ratio) of costs and values assignable to the range of perceptual outcomes of each alternative. In many cases, decisions might be influenced additionally by the distribution of values and costs. However, the first step in a comprehensive evaluation of this kind must be the sim‘TARGA is an acronym for Truevision Advanced Raster Graphic\. Now a separate company, TRUEVISION, Inc. was part of AT&T’s Electronic Photography and Imaging Center. ‘Analog representation refers to the use of a continuously variable physical quantity, the movement of mercury in a thermometer, for esample, to represent the value of a variable. such as temperature.

OUTCOMES

tional and human service program outcomes. The outcomes of these programs easily fit the methods (and, of course, this is where the money has been to finance evaluations). Projects having outcomes involving shape, form, and color do not appear in the evaluation literature. Neither the verbal models of qualitative nor the numerical-mathematical models of quantitative procedures are well suited to the identification, analysis, and presentation of projects with visual outcomes. So C‘OIIfined, evaluation cannot presently support policymaking involving visual issues.

VISUAL

OUTCOMES

ulation of possible visual outcomes, referred to as “preconstruction simulations” in environmental design ‘1KIOi\ an acronym for Ke\olution-llldependerlt. Object-Oriented ” mean) that the uer can wlcct (program). “Kc\olution-indepentlenl one 01 four level\ of rewlution to store or print an image. Of cwrw, higher rcso1utio11s produce better rcwlt\ because more pikeI\ arc bcing used to rcpvsent the contcnl of a photograph or \lide (up to the limit wt by the rcwlution of the photograph or slide itself). Ho\rcve~, the image file is larget-, creating a hard disk $toragc problem. 1.w e\ample, 3 file \nved at the highest level can tahe about 26 mcgabytc\ of hat-d di$h space. romewhat over half of a 40.megabyte hard dish found on the typical dcshtop rrlicrocotllputc,-. “Object-oriented” rct’cr\ to the treatment of images created by RIO as separate entilie:, that can bc manipulated as objects having their own unique attribute\. (H! contratt, images are treated by TIPS as a collection of pixel, and calv not be treated as distinct objects.) RIO uses a window, to display onl! part of a large image file since the file ir too big to fit into the microcomputer’\ memory at once. Once a part of the image is picked, TIPS ih loaded by RIO so that TIPS.5 paint tools can be used to modify the selected part of the whole image.

Microcomputer-Based

(Bosselmann & Craik, 1987, p. 167). Just the visual component of perceptual outcomes is examined here because only this component involves microcomputer-based imaging. My concern here is identifying and presenting possible visual outcomes using imaging to do preconstruction simulations. Estimating the values and costs of these outcomes is not discussed, even though it is essential to decision making. Simulating visual outcomes entails the creation of models using multidimensional representations of structures in either physical or electronic media.5 Unlike their verbal and mathematical counterparts in evaluation, these models are scaled, isomorphic replications of the projects they represent. Designers traditionally have used architectural sketches and drawings done by hand, more realistic artists’ renderings, or scale models built of wood, cardboard, or plastic foam, to convey a visual sense of how a proposed project will look, how it will fit into its site, and into the surrounding area. However, in place of and as supplements to drawings and sketches, designers are now using CADD (computerassisted design/drawing) programs running on computers, especially desktop microcomputers, to generate machine drawings. In addition to CADD software, mini- and mainframe computers can be used to animate design proposals. Animation sequences can be used to create the visual sensation of driving or flying by the proposed structure and through the surrounding area. The same effect has also been created by video filming movement through a scale model. Visual Models Designers and evaluators can use verbal, mathematical, or visual models. While most decision making participants could probably create a mental image based on a verbal description, the images are likely to vary owing to the ambiguity of language and the participants’ own uneven abilities to visualize. Difficulty in agreeing on a common image would lengthen the time needed to reach a final decision and would make the process more complex. Few, if any, could visualize from a mathematical model. The visual model comes closer to giving participants the feeling of seeing and being in the finished project. These are important reactions because the simulation elicits responses that are proxies for responses to the project’s real counterpart. Hence, the quality of decision making is a partial but important function of the closeness between the simulated project and the real one. While visual models are preferable to their qualitative and quantitative counterparts, each of the various media used for visual modeling has its respective advantages and disadvantages. ‘Cinematography is a potential simulation method. However, the expense of special effects and hand-drawn animation makes it an impractical alternative.

Imaging

Technology

345

Though still useful and in use, hand-sketched and drawn models are giving way to the more efficient CADD drawings produced by computers.6 CADD drawings can be more quickly modified than hand drawings and a plotter can produce the drawing while the designer moves on to other tasks. While faster, and as realistic in appearance as hand drawings, CADD models still fall short of photographic realism. Major disadvantages of the scale model are time, resources, and specialized skill needed for its creation and alteration. Such a model is not easily transported, nor can it be easily or quickly altered. The difficulty of construction and alteration rises as a direct function of the model’s size and realistic detailing. Its major advantage is the holistic and true three-dimensional perception it provides observers. Even this is a mixed advantage because of the observers’ unique “birdseye” perspective. The view is roughly equivalent to flying over an area at a relatively low altitude. While an interesting and unique way of seeing the project in question, this is not the way those who live and work in the actual area are going to experience it from the ground. Video filming movement through a scale model at street level can convey a sense of what the structures and area are like from a more realistic and dynamic perspective. To some degree, having the model on film also makes the model more mobile since only the film needs to be moved. However, since the film can be altered only as quickly as the model itself, video-filmed models are no more flexible than the models themselves. In addition, this kind of filming requires highly specialized equipment. Advanced computer simulations are dynamic, geometrically accurate, and increasingly realistic. However, such simulations can only be produced and altered on expensive machines (mini-, mainframe, or even supercomputers) requiring an advanced knowledge of graphics programming to operate. Unlike microcomputers, including those used for imaging, the advanced simulation environment is not directly accessible to the vast majority of evaluators and designers. The microcomputer-based TARGA-TIPS-RIO imaging combination is another option. It is interactive and accessible to any user who has learned how to use word-processing or spreadsheet software. And, it can be used to combine CADD drawings, video film, still photographs, and slides to create realistic static models of alternative designs. Also available are AT&T’s Topas Modeler and more advanced ProModeler, three-dimen‘This replacement should not be overdrawn, so to speak. Miller (1988) maintains that in design education and practice, computers must be integrated with more traditional tools such as sketching and drawing. For example, sketching remains important in the formative stages of the design process where ideas are still being conceived and tested against important constraints. Used at this stage, CADD models could mistakenly convey a greater degree of completion and agreement than actually exists, a point that applies equally to imaging.

SAM SHERRILL

346

sional modeling programs that have many of the same features as CADD software (plus the ability to accept images from video and photographic sources). There is

IMAGING

HARDWARE

TRUEVISION offers eight different boards, ranging from one that does screen displays only to the TARGA 32 board that captures and displays at a screen resolution of 5 12 (horizontal) by 482 (vertical) pixels using a palette of 32 million colors. The newest offering, the VISTA board, has the same number of colors as the TARGA 32 but offers, among other features, much higher resolution. The TARGA 16 is the most widely used board. It plugs into either an eight-bit or sixteenbit slot in a standard desktop XT- or AT-compatible microcomputer. It accepts either color composite or analog RGB video input and produces either as output.’ Output can go only to an analog RGB monitor, composite video monitor, or a television set via an RF modulator. Output does not go to the standard digital color monitor found on many microcomputers because this type of monitor cannot produce as many colors as the TARGA board.X TIPS and RIO require DOS 2.0 and above, a minimum of 512K RAM, and a hard disk of at least

DESIGN

also a Topas animation program than can be used to put models and images in motion.

AND SOFTWARE 40-megabytes capacity. Only hard disks of this size or more will accommodate RIO files (that can run up to 20 MB per file or more) plus the programs themselves. Full-screen manipulation and the use of the UNDO function in TIPS (that erases and restores images) require expanded memory of at least 1.5 MB using the LIM (Lotus-Intel-Microsoft) memory management standard. This is RIO’s minimum requirement as well, though four megabytes enables the program to be used more efficiently. Selections from TIPS’s icon-based menus and RIO’s verbal menus are made with a pointing device, either a mouse or a digitizing tablet using a puck or pen. The TARGA-TIPS-RIO combination accepts image input from digital scanners, video slide scanners, video cameras, video playback machines, CADD programs (after the CADD file is converted to a format acceptable to TIPS and RIO), and television sets. Output can go to printers, 35mm film recorders, video recorders, analog monitors, and television sets.

AND EVALUATIVE

In the School of Planning at the University of Cincinnati, we are using imaging technology to evaluate alternative design proposals having community and public policy importance.’ We have used a video camera and a video slide scanner to bring photographic images into TIPS and RIO. Though these are convenient input devices, the resulting image quality is not good enough for the detailing and realism demanded by a growing number of our projects. We are now relying more on a digital 35mm slide scanner that produces images over a dozen times the quality of either our video camera or video slide scanner. Output goes either to our color thermal printer or high resolution 35mm film recorder.

‘KGB stands for red, green, and blue. Using these three colors, an RGB monitor separately controls the on-screen creation of all other colors in a way that produces a much sharper image than a compositc monitor or the standard color television set. ‘An analog RGB monitor can produce as many colors as the TARCiA board. Its color range plus its RGB quality are the two reasons this kind of monitor is used. “The School recently created a microcomputer-based environmental simulation laboratory to experiment with and extend imaging technology into planning education and practice. Students are taught to use the traditional tools of urban design such as drawing and scale model construction. They are also being taught to use CADD and how to hring CADD structures into TIPS, RIO, and Topas. They gain practical experience by participating in School projects.

APPLICATIONS

The following are several examples of recent imaging projects undertaken by Planning faculty and students. Before making recommendations, community planners wanted to see how the appearance of a three-story building in their central business district would look with a new coat of paint, an expanded sidewalk, and trees planted along the expanded walk. A 35mm slide photograph of the building was taken (using a special lens to correct for vertical distortion) and scanned. TIPS was used to repaint the building and its trim and to expand the walk. A slide photo of the type of tree to be planted was taken and scanned also. The tree was downsized to the appropriate height and width and saved on the hard disk as a digital file. Once loaded into TIPS and RIO, the tree was replicated several times. The replicates were then “planted” in the appropriate spots on the newly expanded sidewalk. In another community, planners and a citizens group wanted to see how a new sign would look on a parcel of land to be cleared of several trees and trimmed’back by the widening of an adjacent street. A 35mm slide of the site was scanned. Using TIPS, the trees were removed, the sign created, and the street expanded using the surface texture of the street in the photograph. Merchants in a neighborhood business district were interested in seeing how a proposed three-story building

Microcomputer-Based would affect the appearance of adjacent storefronts if it replaced the existing one-story structure. First, a three-dimensional wire frame model of the building was created. Next, brick, wood, and concrete textures scanned from photographs were mapped onto the surfaces of the model. Then the existing building was replaced with the texture-mapped model in a scanned photograph of the site and adjacent buildings. Other projects very similar to the three described above have also been conducted. In all of these cases, original plans were carried out, approved, or approved with modest modifications. The time needed for planning and decision making was shortened since all those involved worked from and evaluated the same simulations. In another community that wished to preserve the historic style of architecture in its central business district, imaging was used to help modify codes governing architectural styles of proposed buildings, modifications or existing structures, and signage. Simulations enabled the city manager and the city’s principal planner to prospectively evaluate the impact of alternative codes on

IMPLICATIONS

OF VIDEO-IMAGING

Though this is not the place to enter the debate over qualitative and quantitative approaches to evaluation, imaging does seem to have some of the characteristics of both (as described by Reichardt & Cook, 1976).‘O Imaging can be prospective or retrospective, experimental without experimental and control groups, holistic yet particularistic, case study-oriented yet generalizable to other settings. Evaluators and urban designers moderately skilled with TIPS and RIO, can quickly create preconstruction simulations to support design planning, evaluation, and policymaking. In less time, compared to other techniques or media, more options can be reviewed and prospectively judged before final choices are made. Completed projects could be examined and modified as part of the same process. Unacceptable features could be replaced to see whether a similar project under con-

Imaging Technology

347

the appearance of the business district. Not only was the pace of decision making quickened, but substantial code changes were made as well. The School of Planning is currently creating a comprehensive CADD model of the entire campus of the University of Cincinnati. Once completed and combined with the imaging software, review will be required of all proposed new construction as well as modifications of existing buildings. Every proposal will have to pass this image-based visual evaluation. A similar proposal is being prepared for the city of Cincinnati Design Review Board. The most ambitious project undertaken so far is the creation of an animation videotape (using AT&T’s Topas Animator program) to explore the dynamic design and evaluative applications of microcomputer-based animation. Unlike still image simulations, animation may provide an additional dimension of realism by allowing the viewer to move (at street level, for example) through an entire area, viewing both existing and proposed structures.

TECHNOLOGY

FOR EVALUATION

struction, but having different attributes, might be more visually acceptable. Attributes can be selectively added and removed one at a time to determine experimentally which is more appealing. Particular structures with different attributes can be examined in the larger environmental context by combining slides or video film of the actual site with the alternative structures under consideration. Site-specific projects are essentially case studies but, with selective modification, can be a source of general observations about other similar projects. Overall, microcomputer-based imaging is a promising potential addition to the existing repertory of evaluation techniques. It will allow evaluators to participate in urban design planning and policymaking, thus reuniting environmental design and evaluation. Because it has some of the characteristics of both evaluation paradigms, it should appeal to the proponents of each.

REFERENCES BECHTEL, troduction:

R.B., MARANS, R.W., & MICHELSON, W. (1987). InEnvironmental design research. In R.B. Bechtel, R.W.

‘“1 am not entirely comfortable with the qualitative versus quantitative distinction in evaluation, often billed as the clash of the paradigms. 1 agree with Meyers (1981) on two points: First, evaluation does not have the scientific standing (nor the intellectual substance) to characterize itself as engaged in such an epochal struggle; and, second, there is so much overlap and interdependence that the distinction is not dichotomous but one of degree. However, none of the methods I am aware of address visual issues. No matter how they are classified or cross-classified, the deficiency remains and is the one addressed here.

Marans, & W. Michelson (Eds.), Methods in environmental havioral research. New York: Van Nostrand Reinhold Co.

and be-

BOSSELMANN, P., & CRAIK, K.H. (1987). Perceptual simulations of environments. In R.B. Bechtel, R.W. Marans, & W. Michelson (Eds.), Methods in environmental and behavior research. New York: Van Nostrand Reinhold Co. CRIDER, 294-299.

B. (1986, October).

TARGA’s

MCALLISTER, D.M. (1980). Evalualion Cambridge, MA: The MIT Press.

Video Vision. PC World, pp.

in environmentalplanning.

SAM

348 MEYERS, W.R. (1981). CA: Jossey-Bass. MILLER, Academic

The evaluation

enterprise.

San Francisco,

Frank C. (1988). Architectural design and solid modeling. Computing, 2(4), 10-13, 54-56.

REICHARDT, C.S., & COOK, T.D. (1976). Beyond qualitative versus quantitative methods. In T.D. Cook & C.S. Reichardt (Eds.),

SHERRILL

Qualitative and quantitative Hills, CA: Sage.

methods

in evaluation

research. Beverly

SHERRILL, S. (1984). Identifying and measuring unintended comes. Evaluation and Program Planning, 7(l). 27-34. TINNEY, R. (1987, March). AT&T’s TrueVision system. Byte Magazine, pp. 215-217.

out-

image processing