If nothing else, taking a look at the RGB decomposition is important to give you an idea of where the important information is in your image, and where the noise is. Very often the green channel contains an excellent B&W version of the image. Often the blue channel has the most noise, but not in this case. You can see that the red channel contains most of the luminance information as well as a lot of noise, the green channel has the least noise, and the blue channel has shadows and noise. Here you can see the three channels: red (top), green (middle) and blue (bottom). Right-click on the original image and select Image -> Mode -> Decompose. Each one can be represented as an independent grayscale image. Via Decompose RGB ¶Ī third method is to consider the red/green/blue channels of the image. The reason is that we are getting more blue and red channel noise, whereas in the grayscale mode change operation the algorithm is giving us a remix of 60% of the clean, detailed green channel. You can see a lot more noise in the desaturated zoomed view (examine the blurred area below the spikes). Also, compare the 100% zoom views at right and in the previous grayscale example.
The result is visually different note the increased contrast in the scales. Unlike the grayscale mode change above, the channels are not remixed in different percentages, so we should expect different results. Duplicate the original image ( Ctrl+D) and right-click on the copy. Here is what I get if I use desaturate instead. My experiments with the Channel Mixer (more on this below) support this. This formula does a pretty nice job in the general case, but some images do not work as well with it, particularly if the green channel component is not strong. Supposedly this mix accounts for the eye’s sensitivity to different colors. I don’t know how this conversion works in GIMP, but I have read that Photoshop uses a standard mix of the RGB channels for their grayscale conversion: RED=30%, GREEN=59% and BLUE=11%. Here is what I get if I use the standard mode change to grayscale from RGB.ĭuplicate the original image ( Ctrl+D) and right-click on the copy. I thought it might look nice as a black and white image. Here is an example image, loaded into GIMP. decomposing to LAB and using the Lightness (L) channel.decomposing to HSV and using the Value (V) channel.decomposing to RGB and using any one of the channels.the “standard” grayscale conversion operation.In this tutorial I’ll show you some different ways to convert color RGB images to B&W: Jeschke and may not be used without permission of the author.
Michael co-owns internet agency Restruct Web, where he develops websites & apps (web & iPhone/Android).Text and images Copyright (C) 2002 Eric R. Manytools is a project by Michael van Schaik, a webdeveloper from Rotterdam (NL). Manytools is a collection of tools to automate the repetitive jobs involved in webdevelopment (or any other job). (Starting October 2017, Chrome (version 62) will show a “NOT SECURE” warning when users enter text in a form on an HTTP page, and for all HTTP pages in Incognito mode.) Today we finally got around to upgrading the site to run on HTTPS. Happy to inform that Manytools is now fully Chrome-62-ready, thanks Google! A secure connection had been due for a very long time. Our apologies for the inconvenience it has caused. This seemed like a nice way to support this website, but turned out to be far too much of a burden to our visitors. Thank you for your feedback on our (brief) test with browser based bitcoin mining. SeptemExit Coinhive (in-browser bitcoin mining) In case you notice any problems or irregularities I'd be happy if you notify me so I can check on them. You may/should notice some speed improvements. So, ManyTools has now been moved to a shiny new hosting cluster. JPhasing out hosting server after (almost) 10 yearsĪfter having been running steadily on the previous server for almost ten(!) years, it became time to retire that machine. These intermittent errors were a byproduct of the recent server move and have now been fixed. The past few weeks you may have seen a server error or two on the steganography tool. AugSteganography tool fixed (server errors) In case there's a reason for these attacks, do let me know. So if you take it down it will simply be unavailable for a lot of legitimate users. I have no resources nor interest to fight back. AugTo the person(s) attacking this site: please stop
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