Comments for imatest https://www.imatest.com Image Quality Testing Software & Test Charts Tue, 07 Apr 2020 20:16:28 -0600 hourly 1 https://wordpress.org/?v=5.3 Comment on Testing a macro lens using Checkerboard and Micro Multi-slide by Henry Koren https://www.imatest.com/2016/12/testing-macro-lens-using-checkerboard-micro-multi-slide/#comment-40620 Wed, 20 Feb 2019 17:33:15 +0000 http://www.imatest.com/?p=17382#comment-40620 Great question. The simple answer is that I made a mistake in the capture process, and left a downsampling option enabled on the camera. Oops!

I am most concerned about how this may have impacted the 1x magnification tests, which were the only ones where the MTF50 reached high enough that the image resolution would have significantly limited the measurement. These maxed out at 1595 LW/PH or 0.437 cycles / pixels which is getting pretty close to the downsampled Nyquist frequency. If there was a flat spot where the MTF peaked out I would be even more concerned. Even if some additional MTF response were available at full resolution on the 1x magnification, the sensor we used does have an anti-aliasing filter which could also impact the “lens-only” performance.

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Comment on Testing a macro lens using Checkerboard and Micro Multi-slide by JL https://www.imatest.com/2016/12/testing-macro-lens-using-checkerboard-micro-multi-slide/#comment-40619 Wed, 20 Feb 2019 07:43:44 +0000 http://www.imatest.com/?p=17382#comment-40619 Why were the images downsampled to 5 megapixels?

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Comment on Singapore Imatest Training Course – March 2019 by Gage https://www.imatest.com/2019/01/singapore-imatest-training-course-march-2019/#comment-40618 Thu, 14 Feb 2019 14:49:16 +0000 http://www.imatest.com/?p=24721#comment-40618 Hi Willson, thanks for your question. The training is not only focused on how to use the software. Most of the training is teaching on key image quality factors and the importance of them, how they can be tested and interpreted in Imatest software, and some guidelines on how to set up your lab to get accurate measurements. I hope that answers your question. Please let me know if it didn’t and I can share more information.

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Comment on Singapore Imatest Training Course – March 2019 by Willson https://www.imatest.com/2019/01/singapore-imatest-training-course-march-2019/#comment-40617 Thu, 14 Feb 2019 09:56:41 +0000 http://www.imatest.com/?p=24721#comment-40617 Hi i would like to know during these 2 days training you will be touch on how to use your software only or will there be training thought to us how you all implement these function as well?

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Comment on Considerations when evaluating a Near Infrared camera by Christan Taylor https://www.imatest.com/2018/10/considerations-for-evaluating-a-near-infrared-camera/#comment-40610 Fri, 05 Oct 2018 17:27:07 +0000 http://www.imatest.com/?p=23496#comment-40610 Hey Meyer,

The camera was not refocused for the NIR lighting condition. My guess would be that the optics are the major cause in the drop in quality. Refocusing and repeating this analysis would certainly provide a better understanding of the sensors performance.

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Comment on Considerations when evaluating a Near Infrared camera by Meyer Ben Ari https://www.imatest.com/2018/10/considerations-for-evaluating-a-near-infrared-camera/#comment-40609 Fri, 05 Oct 2018 05:41:25 +0000 http://www.imatest.com/?p=23496#comment-40609 Re Visible vs NIR MTF50 data
Was the camera re-focused for the NIR measurement? Interesting to know how much of such a large drop was caused by the sensor and how much by the optics.

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Comment on Beijing, China Training Course and Seminar by Gage Hollen https://www.imatest.com/2016/04/beijing-china-training-course-and-seminars/#comment-40603 Tue, 27 Mar 2018 15:31:17 +0000 http://www.imatest.com/?p=12219#comment-40603 Hi Haimanot,

You may visit here to sign up online: Beijing, China Training Course

We look forward to having you! Let us know if you have any additional questions.

All the best,
Imatest team

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Comment on Beijing, China Training Course and Seminar by Haimanot Alemeye https://www.imatest.com/2016/04/beijing-china-training-course-and-seminars/#comment-40602 Tue, 27 Feb 2018 12:14:40 +0000 http://www.imatest.com/?p=12219#comment-40602 I would like to participate this seminar how to get it?

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Comment on Reading an Imatest Plot: Tonal Response, White Balance, and Gamma by Henry Koren https://www.imatest.com/2017/03/reading-an-imatest-plot-tonal-response-white-balance-and-gamma/#comment-40582 Tue, 06 Jun 2017 17:20:33 +0000 http://www.imatest.com/?p=18446#comment-40582 Hi Mark

Pixel level ranges from 0-255 for 8 bits per pixel images (such as 24bit RGB color images). Levels range from 0-65535 for 16 bit images. We divide by the maximum of the range to obtain a normalized pixel level from 0-1.

Log means Log base 10, so log(x) is equal to the exponent of 10 required to obtain x, I.e.: log(1/255) = -2.4065, log(255/255) = 0. This is the same thing as saying 10^-2.4065 = 1/255, 10^0 = 1. Hope that helps! -Henry

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Comment on Reading an Imatest Plot: Tonal Response, White Balance, and Gamma by Mark Chen https://www.imatest.com/2017/03/reading-an-imatest-plot-tonal-response-white-balance-and-gamma/#comment-40581 Sun, 04 Jun 2017 16:15:13 +0000 http://www.imatest.com/?p=18446#comment-40581 i have little confuse .
what do log(pixel level / 255 ) mean ?
and 0 -0.2 -0.4 -0.6 …. ?
could you explain ?
please .

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