Dimensional Sketch Research Articles

Second Stage of Visual Perception and Picasso’s Cezannian Cubism

Palmer (1999) describes a sequence of four basic stages for visual perception: an im-age-based phase that deals with extracting image structure (primal sketch), a surface-based level which concerns itself with recovering surfaces in depth (2.5-dimensional—henceforth two*-dimensional—sketch), an object-based stage that covers the description of three-dimensional objects (volumetric descriptions), and a category-based phase that handles the identification of objects in terms of known categories. Each of these levels is defined by a different kind of output representation and by the processes that are required to compute it from the input representation. This article points at an interesting parallelism between the surface-based and object-centered stages of vision, and Picasso's two different phases of Cézannian Cubism. In general terms, it is fascinating to see how an artist's intuitive approach to pictorial representation appears to mirror scientific research on vision. Cézanne’s influence becomes clear in the spring of 1908 when the Spaniard started applying the familiar Frenchman’s postulates to his work. Despite the fact that the compositions were strictly inscribed on the picture’s flat surface, none of the object’s corporeality was lost, so that one can often speak in terms of “flat relief.” A change occurred between the end of 1908 and the beginning of 1909 when depicted objects became more solid and roundly modeled, and when pure surface representation yielded to attempts at presenting objects in the round. To that extent, we may speak of an object-based stage in Picasso’s output.

Imaging three dimensional objects with ultrasound

The ultrasound imaging laboratory provided students with the opportunity of determining what an unknown three dimensional object was from two-dimensional images. Armed with a portable diagnostic ultrasound imaging system, and internal calipers for quantification, students were given unknown objects from the creepy crawly collection. Each object was immersed in a small tub of opaque fluid. Students could adjust the imaging system to give different cross-sections or cut planes through the object. From this information and linear calipers, they were to determine what the object was and provide a quantitative three dimensional sketch. This experience gave them a taste of the chief difficulty in diagnostic imaging of the body: deciphering and recognizing tissue structures and organs from partial views. Other imaging exercises included the use of imaging phantoms to measure spatial and temporal resolution as a function of depth and other controls.

Water electrolyzer for renewable energy systems

The article is devoted to the features of the alkaline water electrolyzers use in power plants with a hydrogen energy storage systems based on renewable energy sources. The technology of nickel–cobalt electrodes electrochemical formation according to a printed 2–dimensional sketch is proposed. A new technique for the synthesis of diaphragms with a zirconium hydroxide hydrogel as a hydrophilic filler is considered. The current–voltage characteristics of an electrolytic cell located inside outer containment shell, designed for pressures up to 160 atm, are investigated.

Physical analog models in architectural design

The contribution presents design approaches based on analog models and experiments in architecture and science and on the works of Frei Otto and his teams, in particular. Starting with the classification of self-forming processes, three thesis are described to show the influence of the physical experiment on the quality of the design. The first thesis - the design tools define the architecture - opposes T-square and compass versus self-forming physical experiments, tracing back the invention of the grid shell to the search for a tool to define the proper shape of compression stressed shell structures. The second - in working with self-forming processes, the will to design a particular shape is linked to the understanding of the influence of boundary conditions - emphasizes that the use of self-forming processes never holds you from making design decisions. The third - in shapes, defined by self-forming processes, the balance of power according to the principle of minimal energy expenditure results in a harmony of form - reflects on the esthetical quality of shapes, deriving from self-forming processes. The verification is given by an example of evidence: describing the design process for a tent according to the form of a minimal surface the interplay between willful decisions and inherent laws within the shape are show. The choice of suitable boundary conditions results in a shape which does equal justice to the original design ideas and the structural specifications. Finally its shown that the role of physical design models in times of computer-based virtual 3D models appear as three dimensional sketches.

Towards Hands-On Computing in Design: An Analysis of the Haptic Dimension of Model Making

Model making plays a crucial part in the early stages of architectural design. It captures spatial percepts and allows for three dimensional thinking and evaluation, hence establishing a direct connection between the body and the object. In the context of architectural design, model making enables exploration of the formal and the spatial qualities of a design through the contrasts in different aspects such as form, size, color or material. The easily revisable nature of the conceptual models helps architects to search for the design alternatives (Knoll and Hechinger, 2007, 19). Architectural scale models are design tools that promote thinking and the communication between the designer and the design (Smith, 2004). Models in the making, aside from serving the material undertaking of a design idea, act as sketches just as two dimensional sketch drawings do. Gursoy (2010) has recently discussed model-making as a form of preliminary design sketching, and the possible contribution of its inherent ambiguities to the design process. Model sketches are objects in becoming, subject to the designer’s spatial perception and intellect. They are continually open to discoveries.

Some computational aspects of low-level computer vision

Some computational aspects of low-level computer vision are addressed, discussing the following example problems: 2-1/2 dimensional sketch, shape from shading, and optical flow. The existence and uniqueness of the solutions, schemes for optimal solutions, reliable and efficient algorithms for the computation, discretization errors, and coping with discontinuities are studied.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

A computer implementation of a theory of human stereo vision.

Recently, Marr & Poggio (1979) presented a theory of human stereo vision. An implementation of that theory is presented, and consists of five steps. (i) The left and right images are each filtered with masks of four sizes that increase with eccentricity; the shape of these masks is given by delta 2G, the Laplacian of a Gaussian function. (ii) Zero crossings in the filtered images are found along horizontal scan lines. (iii) For each mask size, matching takes place between zero crossings of the same sign and roughly the same orientation in the two images, for a range of disparities up to about the width of the mask's central region. Within this disparity range, it can be shown that false targets pose only a simple problem. (iv) The output of the wide masks can control vergence movements, thus causing small masks to come into correspondence. In this way, the matching process gradually moves from dealing with large disparities at a low resolution to dealing with small disparities at a high resolution. (v) When a correspondence is achieved, it is stored in a dynamic buffer, called the 2 1/2-dimensional sketch. To support the adequacy of the Marr-Poggio model of human stereo vision, the implementation was tested on a wide range of stereograms from the human stereopsis literature. The performance of the implementation is illustrated and compared with human perception. Also statistical assumptions made by Marr & Poggio are supported by comparison with statistics found in practice. Finally, the process of implementing the theory has led to the clarification and refinement of a number of details within the theory; these are discussed in detail.

A new method of preparing carboncoated copper electron microscope grids.

Abstract A new method for the preparation of carbon-coated copper grids for standard electron microscope applications is described. It is relatively simpler, faster, more efficient and less expensive than traditional procedures, and is particularly suited for quantity output. Mica sheets are used for the preliminary substrates. A specially designed grid holder and lifter which can recover 35 grids in one movement is used. Dimensional sketches of the grid holder and lifter are given.