15-463

Sylvia Han (sylviah)

IMAGES OF THE RUSSIAN EMPIRE


Due: 11:59pm on Monday, September 10, 2012


Overview

The goal of this assignment is to take the digitized Prokudin-Gorskii glass plate images and use image processing techniques to automatically produce a color image with as few visual artifacts as possible.

Approach

In order to create a colorized image, the three color channel images must be extracted and aligned on top of each other to form a single RGB image. The alignment is determined using normalized cross-correlation to determine the closeness of an image and a template. If the images were large, gaussian pyramids were used in since the NCC sliding dot product can be very time and memory costly.

After using gaussian pyramids, the large images were still not properly aligned. The borders of the image were cropped out in order to improve the alignments. The alignment improved greatly after the borders were removed.

Problems

There is one image in which NCC did not result in a good alignment. This might possibly be because the image contained trees on top of a cliff which might confuse the algorithm because the pixels displaying the trees are very "messy" and sporadic. One part of the tree can possibly be mistaken for another part.

Another possibility is that the window of possible offsets the NCC was performed on were too small for the image. This could mean that the best offset was not in the window and therefore could not be found.



COLORIZED IMAGES

R(y, x) G(y, x) indicates the offset of the green (G) and red (R) channel on the blue channel by x pixels on the horizontal axis and y pixels on the vertical axis.

R(9, -1) G(4, 1)


R(5, 5) G(2, 3)



R(12, 0) G(6, 1)


R(4, 3) G(2, 2)



R(14, 4) G(6, 2)



R(13, -1) G(1, -1)



R(4, 2) G(1, 1)



R(11, 1) G(5, 1)



R(6, 0) G(2, 0)


R(91, 33) G(39, 15) -- [TIF]



R(107, 55) G(47, 38) -- [TIF]


R(51, 38) G(35, 25) -- [TIF]



R(87, 32) G(42, 5) -- [TIF]


R(6, 4) G(14, 6) -- [TIF]



R(125, 33) G(57, 25) -- [TIF]


R(42, 4) G(16, 2) -- [TIF]



R(11, 17) G(-17, 10) -- [TIF]


R(65, -34) G(28, -16) -- [TIF]



R(72, 33) G(24, 20) -- [TIF]


R(105, -47) G(53, 4) -- [TIF]



R(107, 32) G(48, 20) -- [TIF]


R(111, 0) G(50, 4) -- [TIF]



R(106, -40) G(49, -18) -- [TIF]