Digital cartoon and animation process

• US 6,061,462 A
• Filed: 03/07/1997
• Issued: 05/09/2000
• Est. Priority Date: 03/07/1997
• Status: Expired due to Fees

• Current Assignee: Phoenix Licensing, LLC
• Original Assignee: Phoenix Licensing, LLC
• Inventors: Marrero, Noel M., Cook, Robert A., Gardner, Justin L., Moran, Mark R., Tostevin, Nicole H.
• Primary Examiner(s): Chang, Jon
• Assistant Examiner(s): Patel, Jayanti K.
• Application Number:
  US08/813,859
• Time in Patent Office: 1,159 Days
• Field of Search: 382/100, 382/107, 382/118, 382/153, 382/154, 382/162, 382/167, 382/190, 382/210, 382/206, 382/216, 382/236, 382/255, 382/256, 382/260-264, 382/266, 382/269, 382/274 , 382/283, 382/291, 382/294, 382/296, 382/298, 382/299, 382/300, 382/308, 345/425-441, 345/112-115, 345/473, 348/574, 348/586, 40/426, 40/427, 40/430-431, 352/39-69, 368/229, D21/592
• US Class Current: 382/100
• CPC Class Codes: G06T 15/02 Non-photorealistic rendering

Abstract

A digital cartoon or animation creation process, alternately describable as digital rotoscoping. Images are obtained in digital format by set-up steps (32, 44), image capture steps (34-36 and 46), and image storage (38, 48). The rotoscoping process (10) includes an image to line art rendering sub-process (14) which optionally may be followed by a specialized line art rendering sub-process (16) or a coloring sub-process (18). The line art rendering sub-process (14) includes a series of filters, particularly including a high-pass filter (68) using a gaussian blur convolution matrix. The specialized rendering sub-process (16) has particular use for carrying image regions having particularized detail through into final images in a manner that such detail is not lost, and the coloring sub-process (18) permits creation of colorized final images.

Claims

1. An image rendering process, comprising:

(a) obtaining an original image into an image channel; and

(b) scrubbing said image channel, to enhance lines which will appear as transitions at borders of a subject in said line art representation;

(c) scaling said image channel up in size, to render said lines more finely;

(d) creating an alpha channel from said image channel, to denote key content appearing in said original image;

(e) creating a monochrome channel from said image channel;

(f) applying levels filtering to said monochrome channel, to increase contrast of low and mid-range information and thereby obtain further visual definition of said lines;

(g) applying high-pass filtration to the monochrome channel, to filter out low frequency spatial information and thereby obtain further visual definition of said lines;

(h) increasing contrast in said monochrome channel, to obtain further visual definition of said lines;

(i) darkening said monochrome channel, to strengthen visual definition of said lines;

(j) converting said monochrome channel to final size;

(k) lining said monochrome channel, to produce consistent thin appearance of said lines; and

(l) removing noise from said monochrome channel, thereby rendering said image channel into a rotoscope channel and producing a line art representation of said original image.

2. The image rendering process of claim 1, further comprising:

using a color-key background while obtaining said original image in step a of claim 1; and

using said alpha channel of step c of claim 1 to exclude said color-key background when denoting said key content of said original image.

3. The image rendering process of claim 1, wherein step g comprises:

applying median filtration to said monochrome channel, to blur out noise; and

applying further levels filtering to said monochrome channel, to increase contrast.

4. The image rendering process of claim 1, wherein step h comprises:

applying further median filtration to said monochrome channel, to blur out noise; and

applying further levels filtering to said monochrome channel, to darken said lines.

5. The image rendering process of claim 1, wherein step i comprises:

scaling said monochrome channel down in size; and

clipping said monochrome channel in at least one orthogonal dimension.

6. The image rendering process of claim 1, wherein step j comprises:

converting to a consistent size said lines which are at said borders of said subject; and

placing a consistent thickness line around said borders of said subject.

7. The image rendering process of claim 1, wherein step j comprises:

determining a subject size by relating said subject to said monochrome channel;

converting to a plurality of consistent sizes instances of said lines which are located at said borders of said subject, based upon said subject size;

placing a consistent thickness line around said borders of said subject; and

applying further levels filtering to said monochrome channel, based upon said subject size, to better visually define smaller instances of said subject.

8. The image rendering process of claim 1, wherein step k includes:

despeckling said monochrome channel by removing stray pixels.

9. The image rendering process of claim 1, further comprising:

optimizing quality of said line art representation by selectively processing only portions of said monochrome channel which are designated by said alpha channel.

10. The image rendering process of claim 1, further comprising:

optimizing speed of the image rendering process by selectively processing only portions of said monochrome channel which are designated by said alpha channel.

11. The image rendering process of claim 1, after step k further including:

(l) creating a face channel from said monochrome channel, which is the size of said rotoscope channel;

(m) creating a little alpha channel form said alpha channel, which is the size of said rotoscope channel;

(n) removing unwanted content from said rotoscoped channel;

(o) reviewing and cleaning up said rotoscoped channel by an artist;

(p) isolating at least one key region in said face channel;

(q) enhancing the contrast of said key regions in said face channel;

(r) integrating said face channel into said rotoscoped channel, based upon the state of said little alpha channel; and

(s) cleaning up said rotoscoped channel by an artist, to thereby render said rotoscope channel into an enhanced line art representation of the original image.

12. The image rendering process of claim 11, wherein step n includes:

searching said rotoscope channel for clusters of pixels smaller than a user specified size; and

blanking corresponding pixels in said little alpha channel, to thereby flag said clusters of pixels for later removal from said rotoscope channel.

13. The image rendering process of claim 11, wherein step n includes:

reviewing and selecting problem areas in said rotoscope channel by an artist; and

blanking corresponding pixels in said little alpha channel, to thereby flag said problem areas for later removal from said rotoscope channel.

14. An improved rotoscoping process of the type in which an original image is used to produce an image channel and also a rotoscope channel containing a line art representation of the original image, wherein the improvement comprises:

(a) creating a monochrome face channel from said rotoscope channel;

(b) creating an alpha channel from said image channel;

(c) removing unwanted content from said rotoscope channel;

(d) reviewing and cleaning up by an artist of said rotoscope channel;

(e) isolating at least one key region in said face channel;

(f) enhancing the contrast of said key regions in said face channel;

(g) integrating said face channel into said rotoscope channel, based upon the state of pixels in said alpha channel; and

(h) cleaning up by an artist of said rotoscope channel, to thereby render an enhanced line art representation of the original image.

15. The image rendering process of claim 14, wherein step c includes:

searching said line art representation for clusters of pixels smaller than a user specified size; and

blanking corresponding pixels in said alpha channel, to thereby flag said clusters of pixels for later removal from said rotoscope channel.

16. The image rendering process of claim 14, wherein step c includes:

reviewing and selecting problem areas in said rotoscope channel by an artist; and

blanking corresponding pixels in said alpha channel, to thereby flag said problem areas for later removal from said rotoscope channel.

17. The image rendering process of claim 14, further comprising:

coloring said enhanced line art representation.

18. The image rendering process of claim 14, further comprising:

optimizing quality of said enhanced line art representation by selectively processing only portions of said rotoscope channel which are designated in said alpha channel as representing key content.

19. The image rendering process of claim 14, further comprising:

optimizing speed of the image rendering process by selectively processing only portions of said rotoscope channel which are designated in said alpha channel as representing key content.

20. The image rendering process of claim 14, further comprising coloring said rotoscoped channel.

21. A cartoon image having an enhanced line art representation prepared in accordance with the image rendering process of claim 14.

22. A motion picture animation having a plurality of sequential enhanced line art representations prepared in accordance with the image rendering process of claim 14.