1 x 1.8 aspect ratio target
Status: Beta
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fvdbergh
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Frans,
I have created this version of the chart to match the aspect ratio of our camera. Can you please confirm if this is chart will work? Also, can I add more targets near the perimeter, any advice?
Hi,
Some feedback:
1. Yes, this chart will work, but the "chart orientation" measurement feature in MTF Mapper may no longer work as expected. The position of those circular fiducial patterns are hard-coded into both the code that generates the chart, and in the MTF Mapper code that interprets the fiducials. I did notice, however, that you appear to have discarded some of the fiducials, and MTF Mapper recognised the fiducial sequence, so maybe you did not move the fiducials, but just clipped the existing ones to fit inside your new aspect ratio box. So maybe the chart orientation feature will work after all...
2. Just running your png image through MTF Mapper produced ok results with regards to edge orientations. I did notice that the top left and bottom right trapezoids were a little bit close to those L-shaped polygons in the chart corners. If your camera captures at a high enough resolution, so that the gap between the trapezoid and the L-shape is greater than 32 pixels, then this will not be an issue. But you may as well remove the L-shaped polygons altogether, as they are only used to help with rough alignment when setting up the chart (MTF Mapper ignores them completely)
3. Yes, you are welcome to add more trapezoids closer to the perimeter --- this will be even easier if you drop those L-shaped polygons. I assume that you have been editing the chart generator code to produce the above chart, so if you are stuck, just send me your modified code and I can take a look myself (my email address is fvdbergh@gmail.com).
4. On the other hand, if you have been editing the chart by hand from the .svg, then you could simply clone a few trapezoids to fill the perimeter. Save the .svg as a png (like above), blur it slightly (Photoshop, GIMP, ImageMagick, or whatever), and run it through MTF Mapper. Check the angles of your newly cloned trapezoids, and rotate them a little if necessary until all the MTF50 annotations show up with cyan text in the annotated output image. You can verify the OSF (see the SFR/MTF curve output in the GUI by clicking on the cyan annotations in the annotated output, the OSF is in the table below the SFR curve, and should be 8.0).
Regards,
Frans
This is a raster to keep the file size down, the art is a vector file.