Image providing method and device

1. An image-providing device comprising:

a fish-eye image input device inputting fish-eye image;

a fish-eye image storage device storing said input fish-eye image;

a visual-field information input device inputting in real-time visual-field information including information on sight-line direction (theta, phi) and on field angle (gamma) in visual-field area of said fish-eye image;

a drawing area calculation device for calculating in real-time, using said input visual-field information, each pixel of a drawing area in a plane which is orthogonal to said sight-line direction and has an extent determined by said field angle; and

a dewarping processing device determining a pixel position in said fish-eye image which corresponds to each pixel position in said calculated drawing area to form in real-time a dewarped image from the fish-eye image with its distortion removed.

2. An image-providing device according to claim 1 , wherein said fish-eye image is a moving image.

3. An image providing device according to claim 1 wherein said fish-eye image is an image derived from an object imaged on a hemispherical surface of a virtually established hemisphere being developed on a plane, said drawing area calculating device calculates a plane tangent to said hemispherical surface as the drawing area, said dewarping processing device comprises:

a three-dimensional position computation device computing, for each pixel in said calculated drawing area, its three-dimensional position in a three-dimensional coordinate system with an origin at a center of a bottom circle of said hemisphere; and

a non-linear mapping device calculating a zenithal angle theta s and an azimuthal angle phi s of an axis passing through said origin and a three-dimensional position of each pixel in said calculated drawing area, and using the zenithal angle and the azimuthal angle as a basis to determine a pixel position in said fish-eye image.

4. An image providing device according to claim 1 , wherein said drawing area calculating device calculates pixel positions at four corners of said drawing area, said dewarping processing device calculates each pixel position in said drawing area from the pixel positions at the four corners in said drawing area by interpolation processing.

5. An image providing device according to claim 1 , wherein said fish-eye images are divided into a plurality of blocks, each of which is separately accessible, said image providing device further comprises to-be-read block calculating device calculating said blocks to be read from said calculated drawing area, and said fish-eye image input device only inputs said calculated block to be read.

6. An image providing device according to claim 1 , wherein said fish-eye image includes right and left two-system images for stereo display, said drawing area calculating device calculates a drawing area for each of said two-system fish-eye images based on said input visual-field information, and said dewarping processing device forms, for each of said calculated two-system drawing areas, a dewarped image from each fish-eye image.

7. An image providing method comprising:

inputting a fish-eye image and storing it in a storage device;

inputting in real-time visual-field information including information on sight-line direction (theta, phi) and on field angle (gamma) in visual-field area of said fish-eye image;

calculating in real-time, using said input visual-field information, each pixel of a drawing area in a plane which is orthogonal to said sight-line direction and has an extent determined by said field angle; and

determining a pixel position in said fish-eye image which corresponds to each pixel position in said calculated drawing area to form in real-time a dewarped image from the fish-eye image with its distortion removed.

8. An image providing method according to claim 7 , wherein said fish-eye image is a moving image.

9. An image providing method according to claim 7 , wherein said fish-eye image is an image derived from an object imaged on a hemispherical surface of a virtually established hemisphere being developed on a plane, said step of calculating a drawing area in real-time calculates a plane tangent to said hemispherical surface as the drawing area, and said step of forming a dewarped image in real-time comprises:

computing, for each pixel in said calculated drawing area, its three-dimensional position in a three-dimensional coordinate system with an origin at a center of a bottom circle of said hemisphere; and

calculating a zenithal angle theta s and an azimuthal angle phi s of an axis passing through said origin and a three-dimensional position of each pixel in said calculated drawing area, and using the zenithal angle and the azimuthal angle as a basis to determine a pixel position in said fish-eye image.

10. An image providing method according to claim 7 , wherein said step of calculating a drawing area in real-time calculates pixel positions at four corners of said drawing area, and said step of forming a dewarped image in real-time calculates each pixel position in said drawing area from the pixel positions at the four corners in said drawing area by interpolation processing.

11. An image providing method according to claim 7 , further comprising:

dividing said fish-eye images into a plurality of blocks, each of which is separately accessible; and

calculating said blocks to be read from said calculated drawing area.

12. An image providing method according to claim 7 , wherein said fish-eye image includes right and left two-system images for stereo display, said step of calculating a drawing area in real-time calculates a drawing area for each of said two-system fish-eye images based on said input visual-field information, and said step of forming a dewarped image in real-time forms, for each of said calculated two-system drawing areas, a dewarped image from each fish-eye image.