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Home Page of The Final Work on The Course of Images Processing

This work is based on the paper of V. Ostroeng "Facial Engraving"where he shows how to obtain digitally the results below: Introduction

Here we will define what "engraving" stands for in this work.
In this case engraving is the arte of representing a figure by lines.

Observe the example below:  This examples are figures made manually by artists , observe that in this case is necessary for one to have a lot of  techniques to made these figures.

Figures like this are relatively common in life, examples can be found on monies or postage stamps.

As there are few artists who work with these techniques, these figures becomes very difficult to design and costly.

In this work we will show how to obtain results very near that obtain by the professionals.

Description of the Problem

To make an engraving we will take a 2D-figure and will not make a 3D representation of this figure, but draw lines over the figure equally spaced in such a way that this lines "gives" the direction of the original format.

We have as example the figures below:  Tools

The tools that we will use are called "pattern" and "layers" .

Pattern - Are warping of parallels lines equally spaced .  Layers - Are places of the figure that will be filled by standards.  To make an engraving we will take a 2D-figure , and for each region selected we fill it with a standard .

Operations with Images

Operations with images are made, taking the layers in pairs and applying the necessary operation to corresponding points of the layers.

Observing that each layer covers the whole image space, however a standard can be defined only in a small region of the layer.

To combine the layers, we will define five operations :

• Add - In this operation , the resultant color at each point is the sum of the colors at that point of the two layers. • Sub - Here in each point the result is the subtraction of the colors at that point of the two layers. • Big - In this operation the result in each point is thebigger value of colors at that point of the two layers. • Small - This operation is the inverse of the Big operation , here the result in each point is the smallest value of color of the two layers. • Mult - Here the result in each point is the multiplication of the values at that point of the two layers. The layers are combined by the operations shown above, and the result is used as the dithering matrix over the original image, as can we seen in Examples .

Description of the Implementation:

The program developed here have the following characteristics :

Initial window: In the window shown above we mark on the figure, a closed curve. With the marked curve we can decide whether a region to de filled is interior or exterior relative to the curve, define the operations over the layers and pass a Gaussian filter in the original image, if we wish.

To choose a pattern we must press "Pattern", moving to the window below : To change a pattern, we use the blue and yellow control points. A green point serves as reference to change the position of the polygon.

Examples

We are going to use the image below to show the stages necessary to make an engraving: Generating the standards:     Using always the Add operation we obtain the following result: We are now going to make two versions of dithering, in which the dithering matrix is given by the image above.

• Applying a smoothing using a Gaussian in the original image we obtain : • Without smoothing: We note an improvement on the application of the Gaussian filter.

Applying to the example of the article we obtain the result:  Now the same image with gamma correction before applying the engraving.  Another example of engraving:     This program runs in the Linux environment, suffices to download the program and follow the instructions below.