Methods and apparatus for rendering an image with depth-of-field display

• US 7,068,275 B2
• Filed: 08/27/2003
• Issued: 06/27/2006
• Est. Priority Date: 03/01/1999
• Status: Expired due to Term

• Current Assignee: Dropbox, Inc.
• Original Assignee: Sony Computer Entertainment Incorporated (Sony Group Corp.)
• Inventors: Cuthbert, Dylan Simon, Nakamura, Tadashi
• Primary Examiner(s): Jankus, Almis R.
• Application Number:
  US10/649,295
• Publication Number:
  US 20040036687A1
• Time in Patent Office: 1,035 Days
• Field of Search: 345/428, 345/581, 345/582, 345/606, 345/609, 345/611, 345/646, 345/647
• US Class Current: 345/428
• CPC Class Codes: G06T 15/20 Perspective computation
• CPC Class Codes: G06T 3/4007 based on interpolation, e.g. bilinear interpolation image demosaicing G06T3/4015; edge-driven or edge-based scaling G06T3/403
• CPC Class Codes: H04N 13/128 Adjusting depth or disparity

Abstract

A depth of field rendering apparatus, method and program displays a sense of distance using a Z buffer to establish a depth direction of objects in an image and generating an image in a just-in-focus state while writing a Z value of each of dots in the image into the Z-buffer. A blurred image is produced from the just-in-focus image and portions of the blurred image are selectively overwritten on the just-in-focus image by comparing a preset Z value to the Z value of each of the data in the Z buffer.

Claims

1. A rendering apparatus for showing depth of field in an image, comprising:

(a) a Z buffer operable to establish a depth value of objects in an image;

(b) an image generator unit to generate an image in a just-in-focus state while writing a Z value of each of dots in the image into the Z buffer;

(c) a blurring unit operable to produce a blurred image of the image in the just-in-focus state; and

(d) an overwriting unit operable to selectively overwrite portions of the blurred image on the image in the just-in-focus state by comparing a preset Z value to the Z value of each of the dots in the Z buffer.

2. A rendering apparatus as claimed in claim 1, wherein the preset Z value is changed arbitrarily and continuously with time such that an image field of the objects that are in the just-in-focus state is correspondingly changed.

3. A rendering apparatus as claimed in claim 1, wherein the blurring unit is operable to produce reduced images and to magnify the reduced images to generate out-of-focus images.

4. A rendering apparatus as claimed in claim 3, wherein the blurring unit uses a pixel-interpolation algorithm to produce the reduced images.

5. A rendering apparatus as claimed in claim 4, wherein the pixel-interpolation algorithm comprises a bilinear filter algorithm.

6. A rendering apparatus as claimed in claim 1, wherein the overwriting unit is operable to selectively mask objects corresponding to the preset Z value and to overwrite all un-masked objects with corresponding ones of the out-of-focus images such that objects located farther and nearer than the preset Z value are out of focus.

7. A rendering apparatus as claimed in claim 1, further comprising a video random access memory (VRAM) having a rendering area and a texture area, wherein the blurring unit is operable to produce sequentially reduced images in the VRAM and to magnify the reduced images to generate a plurality of different levels of out-of-focus images.

8. A method for showing depth of field in an image, comprising:

(a) establishing a depth value of objects in an image;

(b) generating an image in a just-in-focus state while writing a Z value of each of dots in the image into a Z buffer;

(c) producing a blurred image of the image in the just-in-focus state; and

(d) selectively overwriting portions of the blurred image on the image in the just-in-focus state by comparing a preset Z value to the Z value of each of the dots in the Z buffer.

9. A method as claimed in claim 8, wherein the preset Z value is changed arbitrarily and continuously with time such that an image field of the objects that are in the just-in-focus state is correspondingly changed.

10. A method as claimed in claim 8 wherein the blurred image is produced by reduced images and magnifying the reduced images to generate out-of-focus images.

11. A method as claimed in claim 10, further comprising using a pixel-interpolation algorithm to produce the reduced images.

12. A method as claimed in claim 11, wherein the pixel-interpolation algorithm comprises a bilinear filter algorithm.

13. A method as claimed in claim 8, objects are selectively masked corresponding to the preset Z value and all un-masked objects are overwritten with corresponding ones of the out-of-focus images such that objects located farther and nearer than the preset Z value are out of focus.

14. A method as claimed in claim 8, wherein the blurring is executed in a video random access memory (VRAM) having a rendering area and a texture area, including producing sequentially reduced images in the VRAM and magnifying the reduced images to generate a plurality of different levels of out-of-focus images.

15. A storage medium for storing an image-generating program capable of execution by a microprocessor to perform steps for showing depth of field in an image, the steps comprising:

(a) establishing a depth value of objects in an image;

(b) generating an image in a just-in-focus state while writing a Z value of each of dots in the image into a Z buffer;

(c) producing a blurred image of the image in the just-in-focus state; and

(d) selectively overwriting portions of the blurred image on the image in the just-in-focus state by comparing a preset Z value to the Z value of each of the dots in the Z buffer.

16. A storage medium as claimed in claim 15, further comprising the step of arbitrarily and continuously changing the preset Z value with time such that an image field of the objects that are in the just-in-focus state is correspondingly changed.

17. A storage medium as claimed in claim 15, wherein the step of producing a blurred image produces reduced images and magnifies the reduced images to generate out-of-focus images.

18. A storage medium claimed in claim 17, wherein the step of producing a blurred image uses a pixel-interpolation algorithm to produce the reduced images.

19. A storage medium as claimed in claim 18, wherein the pixel-interpolation algorithm comprises a bilinear filter algorithm.

20. A storage medium as claimed in claim 15, wherein the step of selectively overwriting selectively masks objects corresponding to the preset Z value and overwrites all un-masked objects with corresponding ones of the out-of-focus images such that objects located farther and nearer than the preset Z value are out of focus.

21. A storage medium as claimed in claim 15, wherein the step of blurring is executed in a video random access memory (VRAM) having a rendering area and a texture area, including producing sequentially reduced images in the VRAM and magnifying the reduced images to generate a plurality of different levels of out-of-focus images.