Application Of Computer Vision To Measure Recognition And Localization In The Space

The main focus of the thesis is to explore the application of computer vision to quantitively measure recognition and localization in the space. It is based on the concept to evaluate spaces. Such kind of ability of recognition and localization in architectural and urban study filed is explained as legibility by Kevin Lynch. Discussion and controversy on legibility mainly focuses on two aspects: First, whether the legibility of environment should be treated as a subjective category, dependent on a particular recipient, or as an objective feature of space. Second, to what extend should we emphasis on and expect such term in a built environment. That discussion relates to other concept of human’s perception and cognition mapping process, as well as other evaluation standard. Legibility comes from linguistic study. In the words of the Oxford English Dictionary, a text that is ‘legible’ is defined as one that is “plain, easily made out”, and “accessible to readers, easy to read, readable”.

Kevin Lynch transformed such idea to the ease or difficulty of ‘reading’ — and after that locating oneself within the urban environment. In his book the Image of the City, Lynch argues that people in urban situation orient themselves by means of mental maps so that he evaluates cities by legibility (imageability and visibility). It means the extent to which the cityscape can be “read” and people can engage in way-finding through visual sense. Based on that, he translated an environmental image into three components: identity (recognizing urban elements as separate entities), structure (relation between elements and to the observer), and meaning (images’ practical and emotional value to the observer). By social surveys and interviews, he collected a large number of maps and categorizes people’s perceptions towards city into five elements as a qualitative method of analyzing legibility including path, edge, node, district and landmark have a clear role. Lynch was convinced that the legibility of space is a factor determining the visual and functional quality of a city. It provides grounds for any spatial activity undertaken by the city inhabitants, generating a sense of security and identification with the surrounding space. Based on that, Lynch recommended that, in the process of design, the elements of the perceptive structure should be considered to provide the legibility and clarity of city space. Imageability is a synonymous term coined by Lynch together with legibility, “is the quality of a physical object, which gives an observer a strong and vivid image. It might also be called legibility”. The word “image” however has different meanings for different people; a kind of experience or a concept, plan, map. For example, Yadav (1987) demonstrates “Image has also been used to describe conceptions of the city, either in terms of images or such as the city as an important tower, a giant switch board, a clover-leaf intersection etc. ”and “An image is an internalized representation and, regarding the environment, it is “an individual’s mental representation of parts of the external reality known to him via any kind of experience”, including indirect experiences”.

To further discuss the idea of evaluation of the built environment, Jack L. Nasdar emphasizes on the idea that “legibility may be necessary but is not sufficient for a likeable environment”. In his book the Evaluative Image of the City, to extand Lynched work, he proposes the evaluation of likability by the definition of “the probability that an environment will evoke a strong and favorable evaluative response among the groups or the public experiencing it”. ” Should be guided by a ‘visual’ plan: a set of recommendations and controls. Concerned with visual form on the urban scale’”. Through those two cases of Knoxville and Chattanooga, one can tell the fact that citizens share large areas of agreement about what makes their cities look good, particularly when it comes to the broader scope of visual perception: five desirable features are naturalness, upkeep, order, and historical significance. Besides, different interviewing methods give inspiration of stages of human’s perception. Meanwhile, since the concept of legibility comes out, human-centered discussion about legibility leads to a more subjective explanation: “such ability to “comprehend” the built environment also treats it as a subjective category, dependent on a particular recipient, and not as an objective feature of space”. Chris- tian Norberg-Schulz has expressed that man’s perception and comprehension of space make up his sense of “being in the world, ” yet the fundamental factor constituting this sense of being is habitation and handling of space, thus, his active participation in the creation and use of space.

In Searching for Legible City Form: Kevin Lynch’s Theory in Contemporary Perspective, legality is demonstrated as a notion understood in a humanistic sense: The concept of legibility assumes the relevance of the spatial message to the comprehension and needs of the recipients — users of space. The legibility of a city does not seem to be a function of the physical or morphological characteristics of a city’s spatial structure. Instead, it is more related to the early years of childhood that we become conditioned to understand spatial relationships in certain ways. That nearly automatic conditioning (outside of a rational thought process) becomes a key to the way we understand the physical world around us later in our lives. Another concept relates to legibility is perception, which is a process placed in the center of any environmental behavior. On one hand, recognizing the environment requires recognition of elements and spaces, on the other hand, requires awareness of the way of linkage and relation between them. The process of how human percept surrounding environment is far more than merely seeing and feeling an environment. It is related to complex environmental stimuli comprising perception, emotion, implication, and worth aspect.

In Analysis of Urban Spaces Naghizadeh states hierarchy of the perception- intellectual perception, illusory perception, and imaginary perception. Legibility works with perception from a more visual and imaginary way. Except for evaluating human’s perception, legibility correlate to wayfinding, a basic human need in built environment. Maps are wayfinding aids that help people know and remember their environment. In the absence of these way-showing tools, humans and other animals use their acquired knowledge of environment assorted in their memories – their ‘cognitive map’. And such mapping process is via visual features and linkages, determined by legibility.

From my perspective, this term is more like an objective feature of space, while being subjective perceptee under personalized experiences and understanding of the built environment. Thus, most of the interview based methodology regarding legibility and similar term only looks at the output/results given by the participants, which, in some sense, neglects personal perception behind their opinions.