Apparatus and method for creating video images including soft-edge processing

• US 5,408,593 A
• Filed: 10/18/1993
• Issued: 04/18/1995
• Est. Priority Date: 01/07/1991
• Status: Expired due to Term

• Current Assignee: Shima Seiki Manufacturing Limited
• Original Assignee: Shima Seiki Manufacturing Limited
• Inventors: Nagashima, Hiroshi, Kotaki, Kenji
• Primary Examiner(s): Powell, Mark R.
• Assistant Examiner(s): HUYNH, BA
• Application Number:
  US08/137,216
• Time in Patent Office: 547 Days
• Field of Search: 395/117, 395/118, 395/122, 395/143, 395/146-148
• US Class Current: 345/422
• CPC Class Codes: G06F 3/04845 for image manipulation, e.g. dragging, rotation, expansion or change of colour
• CPC Class Codes: G06T 11/001 Texturing; Colouring; Generation of texture or colour inpainting G06T5/77

Abstract

Soft-edge processing of a video color image is effected in accordance with a stylus nib pressure. Initially, a display circle unit is determined having center coordinance corresponding to display coordinance of a stylus and having a radius corresponding to a nib pressure of the nib stylus. A display region is set encompassing the display circle unit, the display region having a plurality of pixels. A distance from each pixel located outside the circle unit within the display region to the circle unit is determined. This distance is then used as the basis for determining a Z value of the pixel which is indicative of the relative illumination of the pixel to effect soft-edge processing of the image.

Claims

1. An imaging apparatus comprising:

an input device for generating display coordinates and nib pressure values of a stylus pen operated by a user;

a display device;

a frame memory for storing pixel illumination data for said display device;

a painting data memory for storing colorizing data for the display device;

a painting front-end processor, receiving said display coordinates and said nib pressure values from said input device, for calculating a display line of successive interpolated circle units each having a center coordinate and a radius in accordance with said display coordinates and said nib pressure value generated by said input device;

a painting operation processor for generating addresses to said frame memory corresponding to pixel locations of said display device at display regions respectively corresponding to said circle units of said display line calculated by said painting front-end processor;

a main processor for controlling said painting front-end processor and said painting operation processor in accordance with input commands applied thereto;

a Z-operation processor for calculating, for each pixel location within each display region defined by said circle units, a first distance from said each pixel to the center coordinate of the corresponding circle unit, and for calculating a difference between said first distance and said radius of said corresponding circle unit, and for determining a value Z from said difference based on a predetermined relation between a value of said difference and said value Z, wherein said Z value is indicative of a relative illumination of the corresponding pixel location to effect soft-edge processing of an image; and

,

an anti-aliasing processor for receiving said pixel illumination data and colorizing data of a corresponding pixel location, for varying a relative illumination of said pixel illumination data and said colorizing data in accordance with said Z value of said corresponding pixel, and for combining the thus varied pixel illumination data and colorizing data and writing the resultant combined pixel data in said frame memory at an address of said corresponding pixel location.

2. An imaging apparatus as claimed in claim 1, wherein plural different sets of said predetermined relation between said value of said difference and said Z value are stored in advance, and wherein any one of said plural sets is selectable in response to an input command.

3. An imaging apparatus as claimed in claim 1, wherein an effective range of said value of said difference in which a corresponding Z value is obtained is variable.

10. An imaging apparatus as recited in claim 1, wherein a coordinate system of said input device is finer than that of said display device.

11. An imaging apparatus as recited in claim 2, wherein a coordinate system of said input device is finer than that of said display device.

12. An imaging apparatus as recited in claim 3, wherein a coordinate system of said input device is finer than that of said display device.

4. An method of forming a video image comprising:

generating display coordinates and nib pressure values of an input device in accordance with a display line formed by a stylus pen operated by a user;

storing pixel illumination data of the display line for a display device in a frame memory;

storing colorizing data of the display line for the display device in a painting memory;

calculating, as the display line, successive interpolated circle units each having a center coordinate and a radius in accordance with said display coordinates and said nib pressure generated in said generating step;

generating addresses to said frame memory corresponding to pixel locations of said display device at display regions respectively corresponding to said circle units of said display line calculated in said calculating step;

calculating, for each pixel location within each display region defined by said circle units of said display line, a first distance from said each pixel to the center coordinate of the corresponding circle unit, and calculating a difference between said first distance and said radius of said corresponding circle, and determining a value Z from said difference based on a predetermined relation between a value of said difference and said value Z, wherein said Z value is indicative of a relative illumination of the corresponding pixel location to enable soft-edge processing of the video image; and

,

receiving said pixel illumination data and colorizing data of a corresponding pixel location, varying a relative illumination of said pixel illumination data and said colorizing data in accordance with said Z value of said corresponding pixel, and combining the thus varied pixel illumination data and colorizing data and writing the resultant combined pixel data in said frame memory at an address of said corresponding pixel location.

5. An imaging apparatus comprising:

painting means for generating display coordinates and a nib pressure value of a stylus pen operated by a user;

preprocessing means, receiving said display coordinates and said nib pressure value from said painting means, for calculating a circle painting unit having center coordinates and a radius respectively in accordance with said display coordinates and said nib pressure value generated by said painting means;

display means for displaying an image composed of plural pixels;

a frame memory, having plural memory elements having addresses corresponding to respective pixels of said display means, for storing pixel illumination data for said display means;

a painting operation processor for generating addresses to said frame memory corresponding to pixel locations of said display means at a display region corresponding to said circle painting unit calculated by said preprocessing means and for generating frame memory addresses denoting each pixel location within said display region;

Z-operation means for calculating, for each pixel location within said display region defined by said circle unit, a first distance from said each pixel to the center coordinate of the circle unit, and for calculating a difference between said first distance and said radius of said circle unit, and for determining a value Z from said difference based on a prestored table denoting a predetermined relation between a value of said difference and said value Z, wherein said Z value is indicative of a relative illumination of the corresponding pixel location to effect soft-edge processing of an image;

painting information generating means, responsive to said painting means, for generating colorizing information to be applied to an image displayed by said display means; and

,

an anti-aliasing processor for receiving said pixel illumination data and colorizing information of a corresponding pixel location, for varying a relative illumination of said pixel illumination data and said colorizing information in accordance with said Z value of said corresponding pixel, and for combining the thus varied pixel illumination data and colorizing information and writing the resultant combined pixel data in said frame memory at an address of said corresponding pixel location.

6. An imaging apparatus as claimed in claim 5, wherein said Z value is a constant value for each pixel located within said circle painting unit, and wherein said Z value decreases in value as said first distance increases outside said circle painting unit.

7. An imaging apparatus as claimed in claim 5 or 6, wherein said preprocessing means is further for calculating a display line of successive interpolated circle units each having a center coordinate and a radius in accordance with plural display coordinates and said nib pressure generated by said input device.

8. An imaging apparatus as claimed in claim 5 or 6, wherein said display region is a square region having sides encompassing said circle unit and having a center corresponding to said center coordinates of said circle unit.

9. An imaging apparatus as claimed in claim 7, wherein said display region is a square region having sides encompassing said circle unit and having a center corresponding to said center coordinates of said circle unit.

13. An imaging apparatus as recited in claim 5, wherein a coordinate system of said painting means is finer than that of said display means.

14. An imaging apparatus as recited in claim 6, wherein a coordinate system of said painting means is finer than that of said display means.

15. An imaging apparatus as recited in claim 7, wherein a coordinate system of said painting means is finer than that of said display means.

16. An imaging apparatus as recited in claim 8, wherein a coordinate system of said painting means is finer than that of said display means.

17. An imaging apparatus as recited in claim 9, wherein a coordinate system of said painting means is finer than that of said display means.

18. An imaging apparatus comprising:

an input device for generating signals denoting position coordinates and nib pressure values of a stylus pen operated by a user;

a display device for displaying an image by a plurality of pixels;

a frame memory, having a plurality of memory elements designated by addresses corresponding to respective pixels, for storing pixel image data displayed by the display device;

a painting front-end processor, responsive to the signals from the input device, for calculating a center coordinate and a radius defining a circle painting unit in accordance with the position coordinates and a nib pressure value, and for generating signals denoting the center coordinate and values;

a Z-table having Z values each representing a contribution degree which decreases approximately in accordance with an increase in distance from a reference position;

a painting address processor, responsive to the signals from the painting front-end processor, for determining a pixel region which includes the defined circle painting unit on the display device, and for generating signals denoting addresses of the memory elements of the frame memory corresponding to each pixel location in the determined pixel region;

a Z-operation processor, responsive to the signals from the painting front-end processor and the painting address processor, for calculating a first distance from the coordinate of the pixel corresponding to the frame memory address to the center coordinate of the corresponding circle painting unit, and for reading a contribution degree Z based on the reference position out of the Z-table in a case where the first distance is smaller than the radius of the circle painting unit, for reading a contribution degree corresponding to a second distance calculated as a difference between the first distance and the radius in a case where the first distance is larger than or equal to the radius, and for generating signals denoting the thus read contribution degree Z; and

,

an anti-aliasing processor, responsive to the signals from the Z-operation processor and to the signals from the painting address processor, for executing a predetermined anti-aliasing process by applying the contribution degree Z for the image data read from the frame memory.

19. An image apparatus as claimed in claim 18, wherein the painting front-end processor interpolates data to the position coordinates and the nib pressure values of the stylus pen expressed by the signals from the input device when the stylus pen is moved by manipulation, and calculates center coordinates and radii defining circle painting units for this interpolated data, and generates signals denoting the center coordinates and the radii.

20. An imaging apparatus as claimed in claim 19, wherein the painting front-end processor, the Z-table, the Z-operation processor, and the anti-aliasing processor execute operation processes by using a coordinate system which is finer than the coordinate system used to locate pixels on the display device.

21. An imagining apparatus as claimed in claim 19, wherein the painting front-end processor interpolates the data with a pitch corresponding to 1/n of a radius of a circle painting unit, where n is greater than 1.