So I’m doing some testing with my drones, and I created an aerial target this weekend- it’s 2’ x 2’, with 1’ x 1’ black and white checkerboard. In the center of each white square, I placed a small black target (1" square on one, 2" square on the other) so that I could verify that the pixel resolution that I claim was what I am actually capable of producing.
The target showed up in my test flights just fine, but I find that the white just overpowers the camera. Because of the amount of light reflected back, each white section of the target looks to be about 2" larger in all dimensions than the black sections are. This, of course, completely drowns out the smaller “pixel” targets.
Does anybody have any suggestions for a decent high-contrast pairing that might not be so overwhelming to the digital camera? I thought about going with a red-green target, or maybe a purple-yellow, though I think the purple-yellow may have the same issues as black-white.
I’ve also considered making the target with a short-pile carpet, to reduce some of the glare from a flat, painted surface. I’ll probably still try that just to see what happens.
If you are verifying the resolution of a camera, why not use a USAF resolution test chart or similar? Measuring the size of a circle is not a very good way to measure resolution.
If the issue is the white is too bright, why not use 18% gray instead of white? That’s the standard neutral brightness for photography.
The targets are square, for measurement purposes. Exactly 2’ x 2’, made of two 1’ x 1’ black squares and two 1’ x 1’ white squares, with a small 2" black square set in the center of one white panel, and a small 1" square set in the other.
The targets serve two purposes- One, I’ll survey in the central point (intersection of all four large squares) to position the target XYZ for doing mosaicking and photogrammetry, and two, to verify that if I say I have a 1"-per-pixel resolution, that I really can resolve something at one inch or greater.
The grey may work as well- I considered that as well as a beige of some sort. Thanks!
I’m wondering if what kind of CCDs you have matters. That is, if it’s a 3 CCD camera, you might want the light squares to register in each of the CCDs (R, G, B). So, either a gray or a muddy orange?