How to Join Stereo Pairs for cross-eye free-viewing, using Gimp, by Disney Wizard
[crosseye stereograph, see 3D with your right eye on the left image, and left on right.]
Click and watch YouTube to learn
HOW TO JOIN STEREO PAIRS Using Gimp by Disney Wizard
A Tale from the Dark Side
This new 10 minute video supersedes the previous one because it now incorporates "DUPLICATE" which preserves EXIF data from the camera, protects the original image from accidental alteration as well as both saving time and easing of dealing with directories and saving the resulting images.
Right click the left image and select PROPERTIES to name it,
highlight the entire name CTRL-A
copy the name to the text clipboard CTRL-C
ENTER to save the name change.
Open the image in Gimp by dragging it into the Gimp tool-bar, have open desktop space in the lower right so it opens there.
CTRL-A to select the entire left Image
CTRL-C to copy the left image into the image clipboard
CTRL-Z to clear any changes to the left image that will soon be minimized after the visual cross eye inspection, and closed at the end, but we are done with processing it.
Open the right-hand image in Gimp by dragging it into the Gimp tool-bar, have open desktop space in the lower left so it opens there.
Visually inspect the unjoined pair by crossing your eyes. Inspect for latency, alignment and rotation issues - but don't change them yet.
Minimize the first image,
Duplicate the second image ALT-I, D
Minimize the second image
The new, untitled, right image should be in the lower right of the desktop.
Drag the upper left corner of the new right image across the screen to the left.
Resize the canvas: ALT-I, V to open the Set Image Canvas Size control box.
At Ratio X,Y, off the right side, click the "chain link" to break the "constrain Aspect Ratio" because we want to double the width and not double the height along with it.
Type "2" into the X box and enter. The bottom shape indicator should reflect image on left and empty on right. Click OK.
SHIFT-I flattens the image.
CTRL-V pastes the left image into the center of the duplicated right image, displayed on the left.
Drag the pasted image into place (if something else happens when you click, kill that, then type M or click the select rectangular regions in the Gimp toolbar.) When you drag it into place, it doesn't need to be precise, it's a nice bonus if it is.
ALT-V, B will add scroll bars.
CTRL-+,+,+,+ will zoom in.
Drag the image to close the gap all around, the 'dancing ants' indicating the selection should be right up to the edge all around. Often the pairs were not precisely aligned in the camera. Find a spot near the center of the stationary image that both image share, and move the scroll bar so the spot touches the top edge. In this image, the high contrast top curve of the large is an excellent choice, points of triangles also work well. Go to the floating image side and drag the image up and down until the shared spot also touches the top edge, It is easy to misalign to the right or left by a pixel or two when dragging up and down for horizontal alignment, so go to the center, or right edge and trim up the gap with a short drag. I tend to skip this trim by aligning the cursor on the right edge before I click to drag, and make sure the cursor is the same trim from the right edge as I drag it up and down for the horizontal alignment step.
My camera pair doesn't attach to the bar correctly, and there is a 2.5 degree slope
CTRL-T, image Transform, rotate allows me to correct this slant out. Drag the grid to the correct alignment and change the sign of the number box to snap it level.
Often, If the image was snapped in zoom, that zoom was not precisely matched, so scaling the image is necessary.
When you are ready to lock in the image, type F to Fill the screen, for a final crosseye image check. Then click anywhere outside the floating image to anchor it.
Occasionally an image pair will be mismatched in time of shutter trigger, an arm will be out of place, or eyes blink. Copy small areas of the opposite image to the other for a visual match.
Shift-I to flatten the image.
CTRL-S to save. Your text clipboard should still have the image filename in it, CTRL-V will paste it into the filename save box, and, if you are saving as a JPEG you can also paste that name into the comments box.
The Title in the image above was constructed by creating the actual title in another image window, copied and pasted into this one, twice. The Horizontal alignment is critical, use the method above to match them up. Sliding the text left and right brings it forward and back visually. I like to match it up to a spot shared by both images before tweaking it forward and back visually with a small left/right shift.
Small samples from the original image, that we minimized for temporary storage at the beginning of this exercise, can be used to paste over the applied text to further the illusion. The ball on the right is closer than the spire behind it. By pasting the edge of the ball over the text, the alignment of the title between them by visual parallax is enhanced. The subtitle is visually attached to the smaller spire by first pasting the back ground of the text into place, copying the spire over it, and finally the foreground text over that.
Remember to save your work.
Good luck -- Wiz.
[ dsc00173, 2008.11.08 00.22, 3Dti, California, Anaheim, Disneyland®, Tomorrowland, view of Astro Orbiter, from Plaza, night, aligned, with Text, inverse, anaglyph ]