I have this strange problem where certain JPEG images are not visible in Adobe Form while others are. What could be causing this?
Thank you in advance,
Joshua
This problem is related to the colorspace of the JPEG image. Convert the JPEG to the YCbCr colorspace to fix it. You can do so with ImageMagick for example. This Linux command would do the trick:
mogrify -colorspace YCbCr <your_image.jpeg>
Related
I am seeing the following image in a paper:
However, when I download the associated dataset with the paper, the images are like this:
How can I make the almost black images in the dataset looking like the one in the paper?
link to dataset: http://www.cs.bu.edu/~betke/research/HRMF2/
link to paper: http://people.bu.edu/breslav/084.pdf
The contents of this dataset is saved as 16 png data. But ordinary display has only 8bit dynamic range. So we cannot display them without windowing. Please try to use ImageJ, it can map 16bit data into visible 8bit data.
https://imagej.nih.gov/ij/index.html
It can show as following.
As the other answers rightly say, the images are in 16-bit PNG format. You can convert one to a conventionally scaled, viewable JPEG with ImageMagick which is installed on most Linux distros and is available for macOS and Windows.
So, in Terminal:
magick 183.png -auto-level 183.jpg
If you would like to convert all 800 images to JPEGs in one go, you can use ImageMagick's mogrify like this:
magick mogrify -format JPEG -auto-level *png
Note that if your ImageMagick is the older v6 (as opposed to the v7 commands I used) the two commands become:
convert 183.png -auto-level 183.jpg
mogrify -format JPEG -auto-level *png
The images in this dataset have high dynamic range of 16-bits per pixel. Image viewer you are using is mapping 16-bit pixels to 8-bit ones, in order to display them (most displays can only effectively handle 8 or 10 bits of brightness). Most image viewers will just truncate the least significant 8 bits, which in your case produces nearly black image. To get better results, use ImageJ (Fiji distribution is the easiest way to get started), which displays this:
I'm looking for a database with a lot of high-resolution CIE Lab* images. Do you know where can I find it? I found RGB images only.
There are not many formats that are able to store images in CIE Lab colourspace, in fact the only one I know of is TIF and I believe CIE Lab colourspace is actually only an extension that not all software is able to handle.
I can only suggest you find a suitable database in another format and convert it yourself. You can do that painlessly with ImageMagick which is included in most Linux distros and is available for macOS and Windows. So, to convert a single hi-res PNG file to CIE Lab colourspace and save as TIF, you could run this in Terminal:
magick input.png -colorspace Lab result.tif
If you had hundreds of PNGs, you could do them all in one go with:
magick mogrify -colorspace Lab -format TIF *png
If you are using ImageMagick v6 or older, use:
convert input.png -colorspace Lab result.tif # for single image
mogrify -colorspace Lab -format TIF *png # for multiple images
I am completely new to Imagemagick and I need to convert different types of images to the LAB colorspace.
I Am currently using this command:
magick convert "input4.tif" -flatten +profile tiff:37724 -colorspace Lab -auto-orient -intent Absolute -compress LZW "output4.tif"
The problem is that this command does not seems to work for ECI-RGB images and CMYK images.
If I convert a CMYK image to LAB, the image looks completely oversaturated in magenta and cyan.
If I convert an ECI-RGB image to LAB, it is a bit darker than the original.
Help would be greatly appreciated,
Thanks
ALL,
I have an XPM image with the size of 10x10. What I would like to do is to scale it so that the size becomes 16x16.
Does anybody knows how I can do that?
Thank you.
With ImageMagick, which is installed on most Linux distros, and is available for macOS and Windows:
convert small.xpm -scale 16x16 bigger.xpm
How can I set a transparent background on JPEG image? This is a doubt of many colleagues of mine.
What would be the solution using Paint on Windows?
What are the other simple alternatives?
You can't make a JPEG image transparent. You should use a format that allows transparency, like GIF or PNG.
Paint will open these files, but AFAIK it'll erase transparency if you edit the file. Use some other application like Paint.NET (it's free).
Edit: since other people have mentioned it: you can convert JPEG images into PNG, in any editor that's capable of working with both types.
If you’re concerned about the file size of a PNG, you can use an SVG mask to create a transparent JPEG. Here is an example I put together.
JPEG can't support transparency because it uses RGB color space. If you want transparency use a format that supports alpha values. Example PNG is an image format that uses RGBA color space where (r = red, g = green, b = blue, a = alpha value). Alpha value is used as an opacity measure, 0% is fully transparent and 100% is completely opaque. pixel.
JPG does not support a transparent background, you can easily convert it to a PNG which does support a transparent background by opening it in near any photo editor and save it as a.PNG
How can I set a transparent background on JPEG image?
If you intend to keep the image as a JPEG then you can't. As others have suggested, convert it to PNG and add an alpha channel.
JPG doesn't support transparency
Just wanted to add that GIF "transparency" is more like missing pixels. If you use GIF then you will see jagged edges where the background and the rest of the image meet. Using PNG, you can smoothly "composite" images together, which is what you really want. Plus PNG supports highly quality images.
Don't use "Paint". There are many high quality art applications for doing art work. I think even the cell phone apps (Pixlr is pretty good and free!) and web-based image editting apps are better. I use Gimp - free for all platforms.
While a JPEG can't be made transparent in and of itself, if your goal is to reduce the size of very large image areas for the web that need to contain transparent image areas, then there is a solution. It's a bit too complicated to post details, but Google it. Basically, you create your image with transparency and then split out the alpha channel (Gimp can do this easily) as a simple 8-bit greyscale PNG. Then you export the color data as a JPG. Now your web page uses a CANVAS tag to load the JPG as image data and applies the 8-bit greyscale PNG as the Canvas's alpha channel. The browser's Canvas does the work of making the image transparent. The JPEG stores the color info (better compressed than PNG) and the PNG is reduced to 8-bit alpha so its considerably smaller. I've saved a few hundred K per image using this technique. A few people have proposed file formats that embed PNG transparency info into a JPEG's extended information fields, but these proposal's don't have wide support as of yet.