Computer forensics

First let us discuss what animation is. Animation refers to make anything come alive by producing some movement in the pictures. Animation is not only concerned with the movement but is also related to the changes in the color or shape of the picture. Today computers play a vital role in the field of animation by providing the still pictures motion, color and shape. This is referred to as computer animation.

There are various devices which produce these moving pictures. The movie projector, CRT screens whose pixels change rapidly and LCDs. Functioning of each of these devices differ. The animated movies refer to the drawn pictures and not the movies which are enacted by the actors in the real world. The techniques for the animation have evolved very rapidly with the use of the latest and best technology and equipment for the production to be fast and economical. And the latest tool in the area is computer animation which has good graphical capabilities.

In the conventional method of creating animation a series of the pictures was drawn according to the story and this is called a storyboard. Then several individual pictures were created in form of frames. Now the key frames were drawn by the animators in reference to the storyboard. The key frames were spread time wise according to the storyboard for the development of motion between the pictures. Then the gaps between the adjacent frames were filled with the in between frames.

The work remains the same but now the animators are not needed. Today the in between frames are drawn by the computer which has made the work easier and less expensive. The key frames can be entered into a computer through animation paint system and the graphic tablet allows the user to trace the key frames. The computer animation system produces the drawing in the sequence of strokes. The animator enters the key frames by drawing all the strokes. If the animator asks the computers the number of in between frames to be produced, the computer does the interpolation in order to turn all the strokes in first frame to the strokes of the second frame. For this it is necessary that both the strokes consist of the same number of strokes.

The number of points in the two strokes may differ even if they appear to be same to the eye. So when there is the need for the transformation of one stroke to the other the picture will never be correctly drawn. So the points will have to be equalized in order to remove the difference between the two strokes.

Special techniques are used to distribute the added points within the intervals for the equalization. Once the interpolated points in the two strokes become equal well then the two points can be interpolated. The linear interpolation may appear jerky so the curvilinear interpolation may be needed So that the end points get connected. Determination of the interpolated slope at an intermediate point is done by computing the distance from the endpoints. The jerkiness must be avoided in time to make the motion slow more of the in between frames are needed. For the faster motion, fewer frames are needed.

Whenever there is and need for speeding up or slowing down the in between frames specifications for the creation of these should be given correctly. This can be achieved through curvilinear interpolation. And so the animator can be given control for maintaining the motion of the speed between the two key frames. The computer animation system can also be given specifications regarding distance ratios by clicking on a scale.

The other technique uses moving point constraints in which the animator explicitly has to specify the points along the curves. The stroke sequence is connected through a number of points which are equal. These are the moving points. The system will Figure out transformations which may be translations, rotations and scaling that gradually transform the first frame to the second, in such a way that the end points move along these moving points, and the other points take the movement along the path given by these transformations. So now the animator has more control over the time interval.

If we see the case of a movie, then all the frames must be colored which can be done by the computers easily in the current times. When the area is to be filled up with the color then the computer animation uses a seed fill but for this the boundary or the outline must be defined by the solid lines. The computer needs to know the starting point or the seed point within the area that is to be filled or colored. If the computer is provided with the corresponding seeds of the key frames by the animator then the computer can automatically color although the in between frames as the in between seed points will always lie inside the in-between areas.

This doesn?t mean that whatever the system produces has to be accepted. The animator has the final verdict in creating computer animations as the lines can be deleted or inserted manually. The animator can also make the changes or do corrections in the in-between frames if to adjust the details in the computer created animations that the automation cannot easily do.

In the computer animations the features like speed, ease of entry, user friendliness is very important. But still the computer animations are easy to produce in less time and with little experience.

The kind of animation discussed here is two-dimensional so there are things which the system cannot do as all objects are flat. For this there are real time computer animation systems. The real time animation will be discussed in the second part of this.