Image Compare Quick Start
Image Compare is a tool that aids in comparing the images of two coins, medals, or similar items. It is available as a Windows Application installer and as source code. This quick guide assumes you've already setup the Image Compare project.
Step 1: Start the Image Compare Application
On Windows image compare is found in the start menu under the Image Compare folder. On Linux run the imagecomp program from the command line.
Step 2: Load Your Images
Step 3: Take a Look at Your Images

The tab labled "Image 1" should be selected. If not, select it. The medal is probably not in view because only the top-left corner of the image fits in this window.

Move both scrollbars around to see parts of the image.

Press the "Fit" button at the bottom of the window. This will shrink the image to fit the window.

Notice the blue circle that is centered on the medal. This is used to line up the two images. The next section will explain how.

Press the "Full" button at the bottom of the window. This will return the iamge to its full size.

Step 4: Take a Look at The Comparison

Click on the tab labeled "Compare" and scroll the image so that the item is visible in the window.

The two images have not been aligned so the comparisons we do in this step will look terrible. In the next step we will align the images.

The first way to compare the two items is to flip between them. Click the button labeled "Flip" at the left of the window. Click it again. This will flip between the two images. If you're using the two sample images from above they are almost aligned, but the comparison still appears to jump.

The second way to compare the images is to use the "x-ray" or "port hole" window. Just move the cursor over the image. A square view of the underlying image is shown. Move this window by moving the cursor.

Click the "Fit" and "Full" buttons at the bottom of the window to zoom in and out of the image.

If you're using the sample images look at the small ribbon at the bottom of the wreath. It is slightly different between the two images. Also, to the right of the wreath there is the initials "AK" in the second image. There are no initials in the first.

Step 5: Align the Images

The images are aligned by finding the item's center and diameter, and then specifying how it should be rotated to be exactly upright.

Image Compare offers an automatic mechanism this works most of the time, and a manual mechanism that will always work.

For the automatic mechanism press the "Find" button at the left of the window. The blue circle should snap to the edge of the item and fit snugly. If it does not fit correctly you can use the manual method. There are options you can use to tweek how the computer finds the item which might help. These options are described at the end of this quick start guide.

For the manual mechanism you will set the X, Y and Radius values in the boxes at the left side of the window. Their values are initially set assuming the item is centered in the image and exactly touch the top and bottom edges of the image. Click on the up/down arrows next to each value, or type in the value you want to use.

Having applied either the automatic or manual method to both items we've found the item in each image but we haven't matched their rotation. If you're using the sample images you're pretty close.

On the tabs labeled "Image 1" and "Image 2" notice the blue line starts at the center of the item and runs straight up to the edge of the item. This line may be obscured by a green line. Don't worry, that shouldn't cause any problem in practice.

To align the two image's rotation we will move that blue line by changing the value in the field marked "Rotate" at the left of the window. Click the up/down arrows in that field and watch the blue line move in one degree increments. You can make finer adjustments by typing a value into the field (such as "3.5").

Pick a landmark on the two items to match. This will be the default "Top" of the items. They will be rotated in the Compare window to have that point at the top. If you're landmark isn't really at the top you can rotate both images together in the Compare tab.

For the example images you can use the eye of the small bird as a landmark.

If you're using the sample images you should have gotten settings close to the following:

ParameterImage 1Image 2
X 2151.6 2166.8
Y 1457.0 1449.6
Radius 1406.1 1411.6
Rotate 357.5 356.7

Step 6: Compare Your Images

Use the Compare tab as described in step 4.