RO116685B1 - Process for replacing the background in shots - Google Patents

Abstract

The invention relates to a process for replacing the background in shots and can be used in making animated scenes for advertising, feature films, interactive games etc. According to the invention, the process for replacing the background in shots consists in shooting the subject in any conditions, the outline of the subject being kept unchanged from one photogram to another. After shooting, the film is loaded into the memory of a computer and is divided into photograms. In the first photogram, the subject is selected by making a mask of its outline, then each photogram is border-changed and intersected with the next photogram, converted into a black and white image, and the resulting image is soft-edged; afterwards, the colours of the subject and/or background may be independently modified and the film may be reassembled.

Description

The present invention relates to a process for replacing the background in a filmed material and may be used in the production of animated sequences for advertising, artistic film, interactive games, etc.

In order to replace the background in a material, a process is known consisting of:

- filming the subject on a blue background, followed by its replacement with any other background corresponding to the theme, thus obtaining the image of the subject (filmed in the first phase) on the new background.

This procedure has the following disadvantages:

- requires special lighting equipment, the blue background must be specially designed to avoid unwanted reflections;

- certain subjects (eg live animals) cannot be easily filmed using the procedure described above.

Also known is a process described in US Pat. No. 5469536, for replacing the background of an image, consisting mainly of the following steps;

- storing the image on the computer;

- the computer identifies the edges of the subject based on the color information (mainly based on the color difference between the subject and the background);

- Obtaining a mask that identifies the subject;

- digital image processing.

This procedure is difficult to apply in the case of filmed sequences; applying this procedure would involve processing each frame, which would have imperfections on the subject's outline (the outline trembles from one image to another).

The process of replacing the background in a filmed material, according to the invention, removes the disadvantages mentioned by the fact that the filming of the subject can be done under any conditions and the contour of the subject is preserved exactly from one frame to another, after filming the material the film loading into memory. to the computer, after which the film is divided into the component frames, in the first frame selecting the subject, by making a mask according to its outline, after which each frame is applied the border transformation and intersects with the next frame transformed into black and white, and to the image thus obtained the soft edge transformation is applied, after which the colors of the subject and / or the background can be changed independently, and the film can be reassembled.

The process of replacing the background in a filmed material according to the invention has the following advantages:

- does not require special lighting and filming conditions;

- it is easy to process on the computer, each frame being applied the same sequence of operations.

An example of the invention is given below. In order to carry out the procedure, the subject is first filmed, which can be static or moving, under ordinary conditions, but without necessarily having the blue background in the known process; any video camera can be used for shooting.

The new procedure for replacing the background in a filmed material consists of the following steps:

- the image taken is inserted into the computer, being digitized in the FRAMEBUFFER module specific to the computer (this is in fact an analog / digital converter);

RO 116685 Bl

- dividing the material into the component frames;

- in the first frame, the contour of the subject is selected and the surface, within the frame, delimited by this contour we will call it a mask;

- for each of the following frames (2, 3, ... n), the following 50 transformations and processes are applied:

- take the mask of the frame m-1 (where 2 <m <n-1) and save it separately in the computer memory;

- to this mask is applied the transformation of border as, for example, in the program

PfotoStyler. with a variation of 5-20 pixels depending on the speed of the subject; 55

- copy the frame m and convert it to black / white;

- adjust the brightness and contrast of this image;

- the mask of the transformed m-1 frame, intersects with the black / white, corrected image of the m-frame;

- the intersected image is applied to the soft edge transformation, for example, from 6o PhotoStyler or PhotoShop.

Next, the subject being background delimited (the delimitation obtained with the help of the mask), we can change the colors of the background or of the subject independently.

finally, the images processed in the previous stage are reassembled, obtaining the desired effect, namely changing the colors of the background and / or the subject or even 65 changing the total background.

claims

Claims (2)

1. Process for replacing the background in a filmed material, characterized by the fact that the filming of the subject is done under any conditions, and the contour of the subject is preserved exactly from one frame to another, after filming the material the film being loaded into the memory of a computer and being divided into the component frames, after which, in a first stage, the subject from the first frame is selected, by making a mask according to its outline, in a second stage, each frame is applied to the large border and is transformed. intersects with the next frame, transformed into black, in a third stage, each image obtained is applied to the softedge transformation, and in a last stage, the colors of the subject and, optionally, of the background are independently modified, and reassembled. the movie. 2. Process according to claim 1, characterized in that, in the last 80 steps, the background itself can be modified, after which the film is reassembled.