15-463 Computational Photography
"Image Blending, Warping and Mosaicing" - Oct. 29, 2007

Anna Michalska

Image Blending

Gaussian Pyramid

Called function:
[gau0 gau1 gau2 gau3 gau4] = gaussian_pyramid(image_file, number) image_file - the name of the image
number - channel - red (number = 1); green (number = 2); blue (number = )
gau0, gau1, gau2, gau3, gau4 - Gaussian pyramids for red, green or blue channel

Laplacian Pyramid

Called function:
[gau0 gau1 gau2 gau3 gau4] = laplacian_pyramid(image_file, number) image_file - the name of the image
number - channel - red (number = 1); green (number = 2); blue (number = )
lap0, lap1, lap2, lap3, lap4 - Laplacian pyramids for red, green or blue channel

Blending

Laplacian Pyramid (left)
Source: DKImages

Laplacian Pyramid (right)
Source: DKImages

Mask
Gaussian Pyramid (center)

Final image
after blending

Original image -
Laplacian Pyramid (left)Source: Aggie

Original image -
Laplacian Pyramid (right)Source: Artcone

Mask
Gaussian Pyramid (center)

Final image
after blending

Called functions:
main_blend(image1_file, image2_file, mask_file)
image1_file - the name of the image (left Laplacian Pyramid)
image2_file - the name of the image (right Laplacian Pyramid)
file_mask - the name of the mask (Gaussian Pyramid)

Image Rectification - Photos

Image Rectification - Paintings

Pierro della Francesca "Flagellation"
Source: Wikipedia

Called functions:
H = computeH(image1_points, image2_points)
H - transformation - 3 x 3 homography matrix
image1_points - n x 2 matrix of (x,y) locations of points from the first image
image2_points - n x 2 matrix of (x,y) locations of points from the second image

imwarped = warpImage('image_name', H)
imwarped - resulting warped image
'image_name' - name of the image to be warped
H - calculated 3 x 3 homography matrix

Panorama Stitching (automatic)

Source: me

Interest Point Detection - Harris corners

Adaptive Non-Maximal Suppresion

Feature Descriptor Matching

Ransac - robust method

Called function:
main_harris(image1_name, image2_name)
image1_name - name of the first image file
image2_name - name of the second image file

Image Blending and Warping

Source: Me