MTF mapper Activity
Status: Beta
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fvdbergh
Activity for MTF mapper
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Frans van den Bergh posted a comment on discussion General Discussion
Hi Ryan, I think the absolute minimum number of fiducials that must be visible is 5 (not counting the two central markers), if I remember correctly. But with only 5 fiducials you are unlikely to have a good estimate of the lens radial distortion parameters, so this might only work with lenses with very low distortion. I would say a reasonable number is around 10, but again this depends on their distribution across the image; measuring pitch or yaw accurately depends on having fiducials near the edges...
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Ryan posted a comment on discussion General Discussion
Hi Frans, Thank you so much for your patient and incredibly insightful analysis. I truly appreciate you taking the time to look into this and provide such clear guidance. On a separate note, I was wondering if there is a minimum requirement for the number of fiducial markers in the image when conducting the fiducial test. For example, must there be more than a certain number of fiducial markers? Regards, Ryan
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Inspirer42 posted a comment on discussion General Discussion
Hi Frans, First off, thank you very much for maintaining and sharing the MTF Mapper project — it’s an incredibly useful tool! If you find the time, it would be great if you could update the source files, test sample charts, and possibly the Ubuntu packages to the latest state. This would help users who rely on the packaged versions and example data for testing and calibration. Thanks again for your work and for keeping this valuable project available to the community! Best regards, Inspirer
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Thanks for sharing these results, they are pretty compelling! If you need to do something like this in the future, just add the --debug flag to your MTF Mapper command. This will dump some text that you can scrape, the focus offset is somewhere near the end of the output. I can share a few interesting insights: 1. I have worked with Zemax models of lenses to see what the relationship between the focus distance (camera to target) and back focus distance (lens to sensor) is. For one specific lens,...
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Pryzet posted a comment on discussion General Discussion
Hi, I did more experiments a bit of time ago but did not have time to share it here. I did use some batch script to run MTF-Mapper on hundreds of pictures collected over a long period of time. Then I used batch crop of the result pictures and batch OCR to collect the offset value form the cropped picture (did not find a way to get the offset value in a text file). With this I have been able to run long tests without wasting time collecting offset values. The first test I did was to save pictures...
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José Antonio C. posted a comment on discussion General Discussion
Hello, First of all, thanks for the excellent work on MTF-Mapper. I’d like to ask whether there is a way to manually fix the minimum and maximum Y-axis limits in MTF plots. In my workflow, I need to compare multiple plots. I’ve noticed that, in most cases, the application sets the Y axis (contrast) to 0–1, but in some plots the upper limit appears as 1.1. This variation makes visual comparison difficult. Would it be possible to Set fixed Y-axis limits in the graphical interface and/or from the command...
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discard potential fiducials that touch the image edge
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Hi Ryan, Interestingly, the failure is caused by one of the fiducials that has been cut in half by the framing. I have marked the culprit on your sample image. I just used GIMP to remove the offending fiducial, and then the chart orientation feature of MTF Mapper works as expected (see other attachment). I was not even aware of this failure mode, but the particular fiducial (the one I marked in red) is interpreted as "code 0", which is the code usually reserved for the two black fiducials (with the...
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Dear Frans, I hope you are having a productive week. We are occasionally experiencing an issue where the software reports "Fiducials not found" during operation. Before troubleshooting, we would like to confirm the system's requirements. Could you please provide guidance on the exact parameters or conditions that must be met for the software to successfully lock onto the reference points? I have also included an image of a recent occurrence for your reference. If possible, a quick review to see if...
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lorenzo del caldo posted a comment on discussion General Discussion
Hi Frans, we found ourselves coming back to this issue once again. We are now using rectangular and square slits in front of a light source to generate strong edges (four edges) in the acquisition for MTF computation. Please in the attached images two screenshots of typical acquisition for MTF measurement using these two targes. With the rectangular slit, horizontal and vertical edges can be discriminated by their length, but this is no longer possible with the square target. For this reason, we...
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Gray-Box posted a comment on discussion General Discussion
Dear Frans, Thank you for all your advice. I was just writing various scripts this morning to batch process a large amount of data. I learned a lot by comparing various MTF output results and line-of-resolution data. It's very exciting and fun. I was also able to confirm that the qualitative evaluation based on the analysis results and the subjective quantitative evaluation results tend to coincide. I'm really looking forward to comparing the many lenses I have at hand. Thank you for creating and...
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Hi Gray-Box, It sounds like you already have solutions to some of your questions, but I'll try to address them: * Adding a way to fix the scale for chromatic aberration or the 2D grid plots via the GUI is possible, and something that would not take a huge amount of work, so I might consider it; * I don't have access to any cameras to produce pixel-shifted images, so I'm hesitant to implement any corrections. But remember that pixel shifting increases the sample density only, it does not alter the...
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Dear All, I'm sorry to ask a question after I've already done so, but I've read the help and understood a lot of things. What I wanted to do was use command line mode and I was able to automate some of the tasks by renaming on the command line. I'm going to keep using command line mode for a while. I'll ask again if there's anything I can't solve on the command line. Thank you. Gray-Box
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Dear Author, I recently started using MTF Mapper. I'm very impressed with this product, which allows for stable, quantitative data acquisition with simple settings. I'm grateful for this product because it allows everyone to accumulate data by setting the same conditions. Thank you. I have a few questions after using it, and I would appreciate your advice. Is it possible to set the scale to a fixed value to make it easier to compare lens performance? I would particularly like to set the scale of...
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hugo rodriguez posted a comment on discussion General Discussion
Hi Frans, I'm back after a few days of vacation. I've done several tests with the different images into Imatest, ImageJ and MTFM and will share them with you. It's quite interesting.
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Hi Fizz, You are already on the right track: what you are observing, namely that the results improve when you move further away from the test chart, is what I would expect if print quality was a limiting factor. To answer your questions: 1. Slanted-edge measurements are the product of three parts: MTF_measured = MTF_target * MTF_lens * MTF_sensor. At some point your chart magnification is low enough that the MTF_target part no longer has a measurable impact. If you start with a very high quality...
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Leopold Fizz posted a comment on discussion General Discussion
Dear Author, First and foremost, thank you for your invaluable contribution. Your software has greatly simplified lens resolution testing for individual users like myself. However, I’ve encountered some inconsistencies in my tests and would appreciate your expertise. Test Setup: Equipment: Nikon Z6 with Z 24-70mm f/4 lens. Charts: A commercially printed ISO 12233-2000 chart (high-quality, slightly smaller than A1). A self-printed lengrid-A1 chart (provided by you). While its slanted edges appear...
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Hi Frans, Thank you for your detailed answer. I end up using the A2 chart on A3 paper because I though the software was struggling with my "low resolution" sensor (compared to most DSLRs). But I face the same focus shift issue with A3 chart on A3 paper with all fiducial markers visible. Regarding your question about the MTF measurements meeting my needs. To be honest I did not try this a lot as I a currently most interested in the focus feature. Then I may spend some time measuring MTF of my lenses...
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Hi Frans, Thank you for your detailed answer. I end up using the A2 chart on A3 paper because I though the software was struggling with my "low resolution" sensor (compared to most DSLRs). But I face the same focus shift issue with A3 chart on A3 paper with all fiducial markers visible. Regarding your question about the MTF measurements meeting my needs. To be honest I did not try this a lot as I a currently most interested in the focus feature. Then I may spend some time measuring MTF of my lenses...
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Hi Frans, Thank you for your detailed answer. I end up using the A2 chart on A3 paper because I though the software was struggling with my "low resolution" sensor (compared to most DSLRs). But I face the same focus shift issue with A3 chart on A3 paper with all fiducial markers visible. Regarding your question about the MTF measurements meeting my needs. To be honest I did not try this a lot as I a currently most interested in the focus feature. Then I may spend some time measuring MTF of my lenses...
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Hi Pryzet, Here's a quick follow-up to illustrate what I meant by looking for shifts in the 3D surface consisting of the (x, y) pixel coordinates and the corresponding MTF50 measured at that location. Note that MTF Mapper "slides" a small window along the long edges of the black bar targets, thus computing many MTF50 values along each long edge, producing the 3D dataset like the 0raw_points.txt I shared yesterday. I have attached the script (thanks ChatGPT) that is a minimal implementation of what...
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Hi Pryzet, There are quite a few potential factors that could affect stability. For now, let's focus (pardon the pun) only on the RGB results: 1. The MTF Mapper test chart orientation estimation is not perfect, partly because a regular camera calibration requires multiple poses of the planar calibration target in order to estimate the lens intrinsic parameters, in particular focal length and radial distortion, but MTF Mapper has to do the same job with only a single target pose. In addition to that,...
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Hi Jonathan, The MTF Mapper GUI is not really well suited to a workflow that requires combining multiple result sets from multiple images into a single output. Keep in mind that the GUI is really calling the command-line MTF Mapper in the background. I know that other MTF Mapper users have performed analyses like you are interested in, e.g., you capture a sequence of through-focus images and then extract the best result from each part of the field to build a composite result. This requires some scripting,...
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Jonathan Leavitt posted a comment on discussion General Discussion
When you focus on the center of a flat test pattern using a lens that has noticeable field curvature, the measured sharpness always tapers off from the center because it is going progressively out of focus towards the edges. You would need to re-focus the lens at various points from the center and somehow incorporate those results into the data. How can one do that? For example the attached Zeiss Biotar does not improve at the edges between F2 and F8. I assume this is field curvature, because stopping...
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Hi, I'm trying to use MTF Mapper Focus chart to measure the focus shift of IR corrected lenses (CCTV lenses) from different manufacturers between white LEDs and IR 850nm lighting. The phenomenon I want to measure is the same as the chromatic aberrations we can notice between Red Green and Blue channels on and RGB picture. My goal is to do a rough focus on the chart with white LEDs, note down of the estimated chart distance and MTF peak position, then turn off the white LEDs and turn on the IR 850nm...
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Hi, I'm trying to use MTF Mapper Focus chart to measure the focus shift of IR corrected lenses (CCTV lenses) from different manufacturers between white LEDs and IR 850nm lighting. The phenomenon I want to measure is the same as the chromatic aberrations we can notice between Red Green and Blue channels on and RGB picture. My goal is to do a rough focus on the chart with white LEDs, note down of the estimated chart distance and MTF peak position, then turn off the white LEDs and turn on the IR 850nm...
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I'll be out for a few days, will reply you when I'm back :)
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Yes, MTF Mapper will directly process raw Bayer images. You can start with a raw camera file such as a .NEF or .CR2, and the MTFM GUI will call dcraw (or libraw) to render the image to a grayscale Bayer-mosaic Tiff file. This only happens when you set the Bayer channel option in the settings, and you'll see an icon next to the filename in the MTFM results list to indicate what type of channel interpretation was used (RGB, single channel grayscale, or Bayer red, green or blue). If you are using the...
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Aha, I understand. I¡ll try to make some tests with other angles but 5º. With distortion I really meant other angles but 5º instead of curved edges, which is hard to find unless you test some fisheye lens or othe really distorted (though these days are quite common as many manufacturers as you know hide that under the 'manufacturer profile'). And in the first paragraph you already answered that. Ok, so to make readings is better to correct the vignetting (even roughly) than to keep the image 'as-is'....
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Hmm. I don't want to go into too many details regarding SE_MTF since I have never looked at the code myself. But I do suspect that SE_MTF may not handle edge orientations larger than 5 degrees correctly; the earlier versions of the ISO 12233 standard simply required the edge to be at roughly 5 degrees, and many implementations just assume you stick to those parameters. It is entirely possible to use most other edge orientation angles with some minor changes to the algorithm. So that could explain...
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Hi again, Hugo! Try mtf_generate_rectangle.exe -m 1.0 -n 0 -o sharp.png in the directory where mtf_mapper.exe lives. For converting between c/p and lp/mm, I use c * (1000 / p) where c is the c/p value and p is the sensor pitch in micron, e.g., 0.442 * (1000 / 5.97) = 74.04 lp/mm, which is close enough to your value to show your formula is correct (exact dimensions of the sensor and number of pixels explain the remaining differences). There are a great number of details that affect the accuracy of...
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All these is because I'm helping a friend, the man behind this website that specializes in lens testing: www.digitalcamaralens.com Actually I'm comparing this particular lens: https://www.digitalcamaralens.com/Html/Objetivos/Yongnuo/100_2.0/Yongnuo-100_2_Analisis.htm He needs to optimize the workflow for testing because it takes so much time in boring tasks. I'm trying to convince him to use MTFM instead of ImageJ with SE_MTF_2xNyquist. But he is worried by seeing how different are the results specially...
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Ok, I'm sending you the files I used through WeTransfer for this test as well as some RAW from a Tamrom 16-30mm with a SONY a7R II at all apertures. Please confirm me that you receive the email. It will expire in 3 days, but don't worry if you can't download it. I can also upload then to GDrive if you need.
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Hi Frans! Thanks for such a detailed response. Well, all that you explained is the same as I already knew, so I think we are talking the 'same language', great then :) I couldn't create that image with that code as I'm no expert with command line. I wrote this into the program files/MTF mapper: mtf_mapper.exe mtf_generate_rectangle -m 1.0 -n 0 -o sharp.png But got and error... any help will be welcomed :) Regarding the differences between Imatest, sfrmat and MTFMapper I found an article of a friend,...
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Hi Hugo! Please send the file to fvdbergh@gmail.com, and I will take a look when my travels are over. But to get back to the cycles/pixel issue, I really did mean one cycle fits into a pixel. If you had a perfect lens then the sensor will simply capture a 50% gray value ... but that is only for a very literal interpretation of 1.0 cycle per pixel. If you look at the slanted-edge method then the SFR is just the contrast as a function of spatial frequency, and we have now chosen to represent spatial...
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Hi Frans, That's right, and that's exactly what I always thoughit was: a cycle is the same as a pair of lines. I also did a research in Imatest documentation and confirmed what I did know: a cycle is the same as a pair of lines. Anyway, when you say that " If one line pair is the same width as a pixel, we have one line pair per pixel, which is also one cycle per pixel" I guess you mean a 'pair of pixels' instead of a single pixel because it's simply impossible to have a cycle per pixel. Or maybe...
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one line pair is a black line and a white line; this can also be interpreted as one cycle, if you place two line pairs next to each other, then the distance from the middle of the first black line to the middle of the second black line is one cycle, however, this is the same distance as yhe width of a black line and a white line together. In other words, a line pair is the same thing as a cycle. when we measure in line pairs per mm, we are talking about physical line pairs as the lens would project...
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Hi Frans, thanks a lot for your kind reply. 1) Well, I don't know the sensor model but I used RAWDigger to dig into the manufacturer metadata and there I found the value I was looking for: 6080 photo detectors. I assume it's right. Not a big difference, though, between 6016. 2) Regarding Imatest, I've just realized that when I entered 5.96um as the pixel pitch, the units were 'pixel per inch' instead of 'microns per pixel' which I think is the right one. See attached image. However, this didn't made...
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Hi Hugo, The best source for the pixel pitch is the sensor datasheet if you know the sensor model number. Next best is if the camera manufacturer posts this number, or perhaps a reputable review site. The least accurate method is to calculate it yourself, mostly because you cannot assume that the sensor dimensions are exactly equal to the nominal format size. Having said that, if you do not have an accurate pitch number, then any approximation is reasonable, meaning that a small error in your calculated...
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Hi Frans, thanks for your kind reply. Ok, I guessed that cycles and line pairs give the same values to my understanding. In the end, a complete cycle goes to full white, then to full black and to the starting point... like a pair of lines. But I'll research a bit for more information, I could be wrong. I still have a few questions if you don't mind: 1) Ok, so pixel pitch. To calculate it what data do I exactly need: the final effective pixels or photodetectors? For the D610, with 6016 px width and...
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Hi Frans, thanks for your kind reply. Ok, I guessed that cycles and line pairs give the same values to my understanding. In the end, a complete cycle goes to full white, then to full black and to the starting point... like a pair of lines. But I'll research a bit for more information, I could be wrong. I still have a few questions if you don't mind: 1) Ok, so pixel pitch. To calculate it what data do I exactly need: the final effective pixels or photodetectors? For the D610, with 6016 px width and...
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Hi Hugo, Apologies for the delay, I'm travelling so my responses may be a bit spotty. I think we have to sort out the different units first. Imatest is reporting cycles per pixel, which are very different from the line pairs per mm you are reporting on via MTF Mapper. In MTF Mapper you can just change the units in the settings (untick lp/mm units). For the lp/mm units to function correctly you also need to set the pixel pitch correctly (I think it should be 5.97 micron for the D610). But for comparing...
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As you can see, with Imatest I get 41.8 lp/mm, about 39 with ImageJ and 92 with MTF Mapper. I thought it could be a simple matter of doubling numbers (lines instead of pairs) but there is still a difference...
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Thanks for replying so fast, Frans. However, I think I explained myself badly: what I really wanted to say is that after linearizing I got the same results that I already got, so the discrepancies with Imatest and ImageJ are still there. This confirms that the software linearizes the images in the first stages, that was what I was referring for... Regards,
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Thanks for replying so fast, Frans. However, I think didn't I explained myself well: what I really wanted to say is that after linearizing I got the same results that I already got, so the discrepancies with Imatest and ImageJ are still there. This confirms that the software linearizes the images in the first stages, that was what I was referring for... Regards,
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Glad to hear you have resolved the discrepancies! Feel free to ask more questions if you have any. Regards, Frans
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I tried linearizing the image and the results are the same in MTF mapper, so it confirms what you explained, Frans
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Hi there, I was about to start a new thread but maybe this one applies to me. I've just discovered MTF Mapper and I'm impressed with the job you did. Well done! However, I was checking with ImageJ and Imatest Master and I find different values, so I'm not sure what's happening here... I'm loading the attached image captured with a Nikon D610 (24Mpx) and I'm getting: * 92.58 lp/mm in MTF Mapper (see attached capture) * 41.8 C/P (which I guess is the same) in Imatest (see capture) * About 0.41 in ImageJ...
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Balazs posted a comment on discussion General Discussion
Thanks Frans, this is exactly what I needed! As for the possible inaccuracies, I haven't noticed any discrepancies so far, but I will keep an eye on it. Thank you again :)
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Hi Balazs, The quick-and-dirty solution is to do the following: mtf_mapper --chart-orientation DSC_1972.tiff out --debug --logfile test.log and then look in test.log for the line that looks like this: Tait-Bryan angles: 0.424339 45.626967 0.734844 where the angles are listed in roll-yaw-pitch order. You have to remember to pass the --debug flag. I should warn you, though, that I have received reports of inaccurate chart orientation estimates. I only tested over a small range of distances, and it...
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First of all, thanks for this brilliant software, Frans. Would it be possible to output the Euler angles into a text file from the chart-orientation option rather than just putting them on the image? This would help me automating the process. Otherwise, I'll have to use some sort of OCR to extract this data, but that would be a bit silly as the information is already there in MTF mapper. Thanks, Balazs
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fixed up polygon output for generate_rectangle
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1. switched svg page over to using floating point coordinates
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added multi-pattern slide target type
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Ok, thank you very much. I get it.
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Hmm, I plotted the full SFR curve for your initial image lowvalue.png, as well as an edge from 350mm.png that also happens to have an MTF50 value of 0.08. You can see that the SFR curves are very similar until the contrast drops below 0.1, so it is not surprising that the MTF50 values are similar. By the way, you can get more precision out of MTF Mapper if you process the outputs with a script, but I don't know if you will necessarily get improved accuracy. Is the difference between 0.075 and 0.08...
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There are still some question, like the photo below, which is much vaguer than the first one mentioned in the topic, but the result of his edge mtf50 analysis is still 0.08.
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Ok, I also see values of about 0.24 cycles/pixel in 150mm.png. Not sure if you still have a question, or if I have answered it already?
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yes,For the focus of the picture, it is indeed able to reach 0.2-0.3 cycles/pixel ,Take the picture below
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I quickly ran MTF Mapper on the image you provided above (not ideal, but I also got 0.08, so it should be representative), and extracted the attached Edge Spread Function. A sharp edge should rise from black to white over a very short distance, perhaps a distance on the order of 1 pixel or less. From the ESF extracted from your image the rise distance looks to be about 8 pixels, so the edge really does appear to be quite blurry. The SFR curve has a "bounce" in it, which suggests that the lens was...
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The edge of the graph looks good, but the value of the software analysis is only about 0.08, what caused this
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Vasyl Shynkar posted a comment on discussion General Discussion
Dear Frans van den Bergh, Thank you for creating this wonderful tool, MTF Mapper. I would like to use it to test the lenses of my camera. For this purpose, I need to adapt the field of view to be approximately 13 times smaller than the A4 format and to have a different aspect ratio. Additionally, there are cases where the field of view is not rectangular but circular or oval. At the moment, I don't fully understand all the details about how the code functions. I have a few questions: Should the chart...
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Guido modified a comment on discussion General Discussion
Is it only me having this problem with saving data with the save buttons on windows PCs?
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Is it only me having this problem with saving data with the save buttons on windows PCs?
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Is it only me having this problem with saving data with the save buttons on windows PCs?
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That worked perfekt. Thank you very much Frans! Instead of cropping the picture I put a white rectangle over the two black horizontal lines. Though I can not save the results on my three windows PC with the save buttons in mtf mapper. One of them is windows 11 and two are windows 10. It is not working with mtfmapper 0.7.38 or 0.7.40. I found the data in: C:\Users\Guido\AppData\Local\Temp\mtfmappertemp_0 So at least I was able to copy the data from there.
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rjm posted a comment on discussion General Discussion
Hi Frans, Last week I've calibrated three of my lenses to match my camera. MTF Mapper was super helpful in the process, as it makes determining the amount of defocus very straightforward. Essentially, the biggest problem I had was sticking the A0 poster on the wall by myself. Given that every single shot contains some uncertainty in the focus position, I wanted to do a regression of AF Tune Value versus focus mismatch. As far as I could find, exporting the results from the UI does not give you the...
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That worked perfekt. Thank you very much Frans! Instead of cropping the picture I put a white rectangle over the two black horizontal lines. Though I can not save the results on my three windows PC. One of them is windows 11 and two are windows 10. It is not working with mtfmapper 0.7.38 or 0.7.40. I found the data in: C:\Users\Guido\AppData\Local\Temp\mtfmappertemp_0 So at least I was able to copy the data from there.
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Hi Guido, I have found the underlying reason why MTF Mapper's --imatest-chart option was not working with your images. I think my code was based around an older Imatest chart type that did not have those bright white squares inside the centre column, second row block. Those blocks were brighter than the white background of the chart, causing all kinds of trouble. I have released MTF Mapper 0.7.40 to fix the problem, your test images should now work correctly (maybe with a little adjustment of the...
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MTF mapper released /windows/mtfmapper-0.7.40-win64.exe
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version bump
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improved Imatest chart cropping to handle trimodal histograms
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Hi Guido, Sure! To deal with the image brightness problem you could try adjusting the Threshold parameter (in the GUI, Settings->Preferences, the Threshold field under the "Input Flags" group). Or on the command line, try the -t option, I found -t 0.3 worked with your 139.jpg. For dealing with Imatest charts there is the --imatest-chart command line option, and the corresponding File->Open Imatest image GUI menu item. Except I noticed that this is not working correctly with your input images. I have...
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Dean Goff posted a comment on discussion General Discussion
Hi Frans, Thanks again for your response. In the paper they convolve the slit with the presample blur of the sensor and then sample it. Having reread the paper I think this is what I need to do - I was hoping that mtf_generate_rectangle might offer a shortcut for doing this, but from your explanation above, I don't think that it will. I've attached the paper for your interest. Kind regards, Dean.
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Hi Frans, I'm have trouble with pictures from an Imatest chart. Only if I make the picture brighter I get results. Even with the brighter picture I only get results in the center but not on the top and bottom line. Any idea what could cause the problem? Kind regards Guido
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Hi Dean, I found the paper on Google scholar, but scholar did not find an open-access PDF, so I only have the abstract to go on. If I understand correctly (based on other similar papers) the idea is to use a slit instead of a point light source (too few photons, requires some magnification optics). The slit will have a rect() function impulse response across the narrow part of the slit, compared to the step() impulse response of the slanted-edge method. I suppose if you knew the width of the slit...
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Hi Dean, I found the paper on Google scholar, but scholar did not find an open-access PDF, so I only have the abstract to go on. If I understand correctly (based on other similar papers) the idea is to use a slit instead of a point light source (too few photons, requires some magnification optics). The slit will have a rect() function impulse response across the narrow part of the slit, compared to the step() impulse response of the slanted-edge method. I suppose if you knew the width of the slit...
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Hi Dean, I found the paper on Google scholar, but scholar did not find an open-access PDF, so I only have the abstract to go on. If I understand correctly (based on other similar papers) the idea is to use a slit instead of a point light source (too few photons, requires some magnification optics). The slit will have a rect() function impulse response across the narrow part of the slit, compared to the step() impulse response of the slanted-edge method. I suppose if you knew the width of the slit...
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Hi Frans, Thank you very much for this, as well as the ChatGPT tip, as I have struggled to get Gawk working on Windows. One further question... One of my aims is to replicate the work described in "Comparison of tilted slit and tilted edge supperresolution MTF techniques" by Olson et al. (2007). My plan is to create a narrow slit using the generator - do you think this will work? Thanks in advance, Dean.
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Hi Dean, I have attached a sample of the usaf1951r.txt file, but also included some AWK scripts for generating more such charts. I also found the siemens.txt file, so I included the scripts for generating more of these too. I know you mentioned that you are working on Windows, but with some kind of Windows-Subsystem-for-Linux (WSL) you might be able to run AWK. Otherwise, I'm sure you can try to ask ChatGPT to convert the AWK scripts into Python. Regardless, it is pretty simple to generate these...
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Hi, I've been using mtf_generate_rectangle to generate rectangles, but I'd like to generate more complex charts and see usaf1951r.txt mentioned in your blog. However, I cannot find this file in the distribution or on SourceForge and think it would act as a good starting point for my own charts. Can you supply this and the Siemens example? Thanks, Dean. PS I'm working on Windows.
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Hi Daniel, Those lensprofile charts are indeed wild! If you still have them, would you mind sending me a sample image of the "bad" lighting orientation? I should be able to use that to improve the sanity checks (involving each slanted-edge measurement) to prevent such disasters in the future. First prize would be if I can generate an appropriate warning, but I cannot promise that just yet. Regards, Frans
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Daniel Zielinski posted a comment on discussion General Discussion
Outlandish values were creating huge loops in the lines produced. Could not read the values on the Y axis. Was driving me nuts, but then I tried changing the angle of the light on the chart and...problem solved! The chart I'm using is printed on photopaper and it has a gloss. Get the lighting angle wrong and the lensprofile chart has a fit. Other charts look mostly normal. The chart orientation numbers were all less than 0.10. That doesn't matter if the lighting angle is creating some kind of reflection...I...
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Hi Franz, we really missed the additional data on the edge corner in the edge_mtf file. it's straight forward this way. thanks a lot, Lorenzo.
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Hi Lorenzo, It is a bit clunky, but the quickest way to obtain the geometric edge orientation is to compute the vector between the "edge centroid" and the "nearby corner" coordinates listed in edge_mtf_values.txt (assuming you ran MTF Mapper with the -q -v 2 options). The non-comment lines in edge_mtf_values.txt and edge_sfr_values.txt match one-to-one, so you can safely join the information across the two files. Then take x=$2 - $5 and y=$3 - $6, where $n represents column number n from edge_mtf_values.txt,...
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p.s. we are aware that your code is able to discriminate between sagittal and meridional edges, but also on that we could not understand how it is done. but it could be added to the discussion since honestly, it could possibly be even more useful than horizontal and vertical discrimination. we're providing here one of our test images on which we're trying to compute the mtf. to explain the problem we found that our optical system has some different astigmatism in the two directions. we then use a...
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hello, we're using the software for mtf measurement on an SFRplus chart provided by IMATEST. we would need to be able to discriminate between horizontal and vertical edges but we are having a hard time in understanding how to do it from the output data and if it is even possible. Basically we're looking at the "slanted edge orientation" angle and the "edge orientation relative to radial line to centre" angle, as they are called in the output file "edge_sfr_values.txt". about the first one: as far...
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added readme for docker, tweaks to container building
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basic docker container for arm64, plus a Python watcher/processor
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Tom Kwasnitschka posted a comment on discussion General Discussion
Thank you Frans, I will contact you directly and hope to report back to this discussion! Best greetings Tom
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Hi Tom, Yes, there are at least two implementations that I have spun off as closed source that are nearly real time, meaning 3 to 5 frames per second while processing 5 MP images, running on arm64 processors. Since one version belongs to my current employer, and the other was implemented under contract, I am not able to make these available to third parties. I might be able to help you with some scripting to automate the process a little bit; depending on how much processing power you have available,...
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Dear Frans, Is there a real time version of MTF mapper that does not require loading files but accepts a WDM or V4L source, or any other real time video signal capture? We are (finally) in the process of internally shimming a series of water corrected underwater optics we developed with Zeiss, and would like to speed up the process which is pretty tedious working on a file by file base... Feel free to reach out off list if appropriate! Many thanks! Tom Kwasnitschka GEOMAR Helmholtz Centre for Ocean...
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Hi Frans, Thank you very much for your help. I have now obtained the desired results through fiducial_correspondence.txt！ Regarding the issue of chart orientation you mentioned, I am currently testing with an A3-sized chart at 30 cm, and the results appear to be reliable. I plan to use MTF Mapper to test sharpness in the automated testing of a camera's production，I've just started learning about this area, so there's a lot of knowledge I'm still missing. There are some documents where I could use...
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Hi Rany, Some answers: 1. When you run mtf_mapper with the --chart-orientation option (I'm referring to command-line operation) it produces a file called fiducial_correspondence.txt which provides both the image space coordinates (in pixels) and the chart space coordinate (in mm) of the circular fiducial targets. The chart space coordinates are simply the expected x and y positions for a given target design, so you can use the contents of fiducial_correspondence.txt to perform any camera calibration...
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Dear [Developer/Support Team]: I hope this message finds you well. I am writing to inquire about certain features of MTFMapper and to seek guidance on its compilation under the Windows operating system: 1. Firstly, I am interested in knowing whether MTFMapper can not only generate a marked chart for chart orientation results but also export additional data such as the center distance between two symbols on the chart, along with the Pitch, Roll, and Yaw values, into a text file simultaneously. 2....
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Dear [Developer/Support Team]: I hope this message finds you well. I am writing to inquire about certain features of MTFMapper and to seek guidance on its compilation under the Windows operating system: 1. Firstly, I am interested in knowing whether MTFMapper can not only generate a marked chart for chart orientation results but also export additional data such as the center distance between two symbols on the chart, along with the Pitch, Roll, and Yaw values, into a text file simultaneously. Secondly,...
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Solene posted a comment on discussion General Discussion
Hi, Sorry for answering this late, I put my project aside for a bit. Thank you so much for answering my message. Even if I am a beginner, I have succeeded to reach my aim thanks to your help. Thank you again for your work. I wish you well
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Hi! Yes, this is certainly possible. Let's assume that you have mtf_mapper.exe on your PATH (see this tutorial, and you have a cmd.exe window open (or powershell). Let's also assume you have a file called sample.png (I attached one) in the current directory. Then you can run the command mtf_mapper -v 2 -q sample.png . which will produce an output file called edge_sfr_values.txt in the current directory. This file contains some comments, i.e., lines starting with a "#" symbol, which describe the meaning...
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Hi, I'm using MTF Mapper gui and I like the efficiency of the software comparing to other tool ! I would like to make it even more easier for my purpose. I'm analysing a Camera and I'm looking for the resolution at 100lp/mm. With the "User manuals for individual application" I was wondering if it was possible to write a script that can give me this value only by ginving him an Image and the size of the pixel (without looking to all the curve). I know my question will seems basic, but I am a beginner...
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Jeff posted a comment on discussion General Discussion
Frans, Thank you so much for the explanation. I have recalculated the MTF from the same single edge images using lp/mm for the specific pixel pitch of each sensor (X-H2=3.04, X-H2S=3.76). Now I see an expected result with the higher resolution 40mp sensor showing consistently greater resolving power in terms of actual line pairs.
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