Conventional Animation Research Articles

Computer-assisted coloring by matching line drawings

An approach to automatically color line drawings based on feature matching is proposed. The motivation is that coloring 2D animation is still a labor-intensive process in current cartoon film production. The objective of our work is to investigate how to automatically color an image in a cartoon sequence on the basis of the previous frame. Our method first establishes the matching relationship of two images, after which it automatically paints one of them with the color information of the other using a region-matching algorithm. The region-matching algorithm is based on feature correspondences. The results show that the proposed algorithm can straightforwardly and robustly realize our objective and has a promising future for our next step to further automate conventional animation.

A low-overhead technique for dynamic blackboarding using morphing technology

We present a simple, low-overhead method for “dynamic blackboarding”, using inexpensive, commercially available morphing technology. The method, which allows rapid production of animated presentations for classroom use, requires the user to construct a storyboard using a conventional graphical editor, and then link the storyboard frames into a QuickTime animation using the morphing software. The technique requires less effort to produce satisfactory simple animations than conventional algorithm animation techniques, and also requires less training. (Note to readers: Since this paper makes extensive reference to animations, it is best to view the accompanying animations at the appropriate points while reading the paper. These animations are available on the World Wide Web; their URLs are given at the appropriate points in the paper.)

新映像メディアとその応用 ３次元ＣＧ技術を用いたセルアニメタッチ映像の動きの表現法

Computerization of cell-touch animation production started in the 1970s. Most computer systems used 2D computer graphics technology. Even now there are very few systems which use 3D computer graphics technology. The authors have proposed methods and algorithms to produce cell-touch animation image using 3D computer graphics technology such as generation of character lines and an animation spreadsheet. We propose a method to create freer camera motion for cell-touch animation production. We first construct a world in the computer where elements such as camera, lights, objects and cell layers are deployed. 2D characters are mapped on a transparent plate as a layer. Then motion paths and camera directions are set using spline curves. The views can be previewed with wireframes and rendered images. Many camera motions that used to be impossible with conventional cell-animation or 2D-based animation production methods can be achieved with less effort and sometimes automatically.

最先端画像映像生成処理技法 セルアニメタッチ画像生成のための３次元ＣＧ画像の２次元化アルゴリズム

This paper describes a series of algorithms which makes 3D image data look like conventional cell animation images. The techniques of producing cell animation have not changed much from when movies were invented. It has essentially been a typical labor-intensive manual industry. That industry started to disappear in the 70s in the USA because of the rising cost of labor. The same thing happened in Japan in the 80s. Digital ink and paint systems were introduced to the industry in the late 80s, but the system was not yet powerfull enough to bring back the jobs that had once fled from the USA, Europe and Japan. This research started when PCs became cheaper and fast enough with a variety of 3D software packages. Making cell animation-like images by using 3D image generation software would not be practical at all if PCs were still expensive and available 3D software were slow and complicated for artists to operate.

Composition of multiple figure sequences for dance and animation

Insights gained from an interdisciplinary study of the creative processes involved in dance composition are the basis for the development of computer based tools to support dance composition and animation. The system which has been developed (COMPOSE) provides an interactive hierarchical environment where the user can reduce the complexity of the task by flexibly switching between spatial and temporal views of the composition. Realistic animation of the final result is also available. COMPOSE, which is implemented on IRIS and Macintosh workstations, has proven itself to be of real value in dance composition. It is now being tested as the front-end of a conventional animation system for use in the animation of multiple articulated figures.

Merging and transformation of raster images for cartoon animation

The task of assembling drawings and backgrounds together for each frame of an animated sequence has always been a tedious undertaking using conventional animation camera stands and has contributed to the high cost of animation production. In addition, the physical limitations that these camera stands place on the manipulation of the individual artwork levels restricts the total image-making possibilities afforded by traditional cartoon animation. Documents containing all frame assembly information must also be maintained. This paper presents several computer methods for assisting in the production of cartoon animation, both to reduce expense and to improve the overall quality. Merging is the process of combining levels of artwork into a final composite frame using digital computer graphics. The term “level” refers to a single painted drawing (cel) or background. A method for the simulation of any hypothetical animation camera set-up is introduced. A technique is presented for reducing the total number of merges by retaining merged groups consisting of individual levels which do not change over successive frames. Lastly, a sequence-editing system which controls precise definition of an animated sequence, is described. Also discussed is the actual method for merging any two adjacent levels and several computational and storage optimizations to speed the process.

SoftCel - an application of raster scan graphics to conventional cel animation

The system described uses frame buffers to provide digital analogues to the traditional processes of copying pencil drawings onto cels, painting them, and photographing them. The copying process is replaced by scanning the pencil drawings with a television camera and digitizing the video signal. Several image processing operations are performed on the digitized drawings to condition them for the next step, interactive painting of the drawings mediated by a computer program. The painted drawings are then combined with each other and painted backgrounds for frame by frame recording on film or video tape.

The problems of computer-assisted animation

In the last few years several systems have been written for aiding in the conventional two-dimensional animation process. The main purpose of these systems has been to let the computer produce missing drawings based on extreme drawings produced by animators. While there has been some success and a great deal of optimism, the promise of higher output and quality using a computer has not been realized. The transition from simple drawings optimized for use on the computer to the complicated and detailed drawings of quality conventional animation has been much harder than expected. The principle difficulty is that the animators drawings are really two dimensional projections of three dimensional characters as visualized in the animators head, hence information is lost, ie. one leg obscures another. The problem of making a program infer the original object from its projections is akin to extremely difficult artificial intelligence problems. Efforts to overcome this by drawing skeletons or increasing the number of overlays require more manual intervention thereby offsetting the gains of using the computer. One way to analyze an approach is to determine the average time required of an artist or operator at all stages of animation for every frame. A second problem not generally recognized is that a production animation system requires the management of hundreds of thousands of drawings, hence data base management techniques not normally found in experimental animation systems.

Computer-Generated Key-Frame Animation

Special animation languages have been developed for specifying an image sequence to be generated by a computer. Although this approach to computer animation has provided some form of organization and control of the specification of image sequences, the computer remains out of reach to most animators because of the communication difficulty. An animator's ideas involve mainly pictures and their motion. Thus it is appropriate that the communication of ideas between the animator and the computer should be largely through pictures. An interactive computer-controlled graphical system allows the animator to develop pictorial sequences directly on a cathode-ray tube display, without forcing the animator to become a computer programer. The implementation of computer-generated key-frame animation is based on techniques that have been developed for conventional cel animation. Key frames are created and stored on a suitable medium such as digital magnetic tape or disc. In addition to the picture, information about the kind of motion and the number of frames from the previous key frame is specified. During playback of this sequence, the in-between frames are computed by interpolating between key frames and are displayed at the cine rate on the cathode-ray display. Thus previewing is available in seconds.

Methods and Procedures for the Production of Fully-Animated Cartoon Films Using New Animascope® Automatic Animation Processes

Today's production costs and the shortages of animation artists have made it almost impossible to produce fully-animated cartoon films. While some methods did develop the outline drawings of the character by various chemical or optical means, all of the early methods required the making of large, transparent “cels” for each frame, which had to be hand-colored and retouched before being re-photographed by conventional animation techniques. The new system produces not only the most complex character outline drawings but also the flat, cartoon-style coloring directly onto 35mm film by means of simple laboratory printing and processing. An automatic traveling matte is used to combine these images with the backgrounds. Production procedures parallel those of normal live-action filming. The principles involved for each production and laboratory step are described and illustrated.