<div dir="ltr">Hello Users,<div><br></div><div>I have two images that are essentially aligned that I am using to experiment with the Similarity Transform with Regular Step Gradient Descent Optimizer (I am using example 7). The fixed image is a traced black and white boundary image of moving image. I am having trouble understanding the results.</div>
<div><br></div><div><p style="margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Monaco">Result = </p>
<p style="margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Monaco"> Scale = 4.15432</p>
<p style="margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Monaco"> Angle (radians) 0.00397598</p>
<p style="margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Monaco"> Angle (degrees) 0.227807</p>
<p style="margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Monaco"> Center X = 374.818</p>
<p style="margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Monaco"> Center Y = 361.912</p>
<p style="margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Monaco"> Translation X = -0.171362</p>
<p style="margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Monaco"> Translation Y = -0.684359</p>
<p style="margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Monaco"> Iterations = 500</p>
<p style="margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Monaco"> Metric value = 1337.12</p><p style="margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Monaco"><br></p><p style="margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Monaco">
I am surprised to see a scaling factor introduced. I have set the optimizerScales to 1 (scale) and 1 (angle). And indeed the moving image is scaled down by about a factor of 4. Can anyone shed any light on this for me? </p>
<p style="margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Monaco"><br></p><p style="margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Monaco">Also, can anyone recommend a good reference book that is an introduction to registration techniques and would explain from an application viewpoint the pros and cons of particular transformations. I have Terry Yoo's book but I would like something more introductory. I have also read the itk software guide but would like to find another reference. </p>
<p style="margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Monaco"><br></p><p style="margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Monaco">Thanks for any help you can give. </p><p style="margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Monaco">
Maureen</p></div></div>