The grid is a blue/green. The work is in a black ink, and has a fair bit of variety of pressures, which I want to retain.
Here's a link to a small selection.
I have Photoshop v3
My attempts have involved using Select, Color Range, and sampling some grid, then inverting.
Is there a better way?
I also have some experience with Python and PIL, if that's a useful alternative.
This is a Photoshop answer, rather than a programming answer, but that seems to match your question's needs.
I applied a Black and White filter, and enabled a Blue filter, then set the Blue channel sensitivity to 300%, like this in Photoshop CC.
and got pretty good results like this:
In an older vsersion of Photoshop, you may need to go to Image->Mode->Lab Color and then go into the Channels palette and deselect Lab leaving just a and b channels selected, then use Select->Color Range to get the blues (or maybe the blacks!!!!) before going back to RGB mode.
Related
My question might be off topic, but I didn't a better forum to ask.
I need to change the color of a product on an eCommerce website. We have many styles and many colours, so taking a picture of every combination is out of question (about 100 styles and colours, which will result in 10,000 pictures. We just don't have time to take that many pictures or process them manually). However, I could take a picture of every product and and a picture of one style in every colours and then make a program which generate all the missing pictures. I was thinking using something like OpenCV (and probably python) which provide lots classic computer vision algorithm off the shelf, to do so. Before doing it, I'm sure this is a classic image processin problem. Does it have a name or is there any algorithm or resources on the topic ?
In other world, there are apps and program which allows you to change the colour of our dress or clothes. Does any body knows how it works or have usefull resources related to this problem ?
You separate intesity from colour information. Then you change the colour information and merge both back together.
This will give you an image with changed colours but maintained brightness. So shadows, highlights and so on stay untouched.
You have to convert your RGB touples to a colour space that has separate coordinates for intensity and colour.
https://en.wikipedia.org/wiki/Lab_color_space as one example
Of course you may restrict these operations to your "product" so anything else remains unchanged.
in an iOS application I need to recognize colors through camera, but analyzing the problem, I noticed that different kinds of light make the colors observed in the captured picture a little bit different from the real ones. For example, under a high neon light a light blue seems like a gray.
What is the cause and what kind of approch I could follow to solve this problem of "fake colors"?
The colors are not fake, they are just different than what you expect them to be. As #Piglet said this has a lot to do with the physics of light and white balance may help.
If you want to read more about it look at:
Color Rendering Index
Color Metamerism
Sensitivity Metamerism Index
Color Constancy
These all refer to the physics behind why different illuminations create different colors. There is also the camera color pipeline that contributes its share, so you can also read about white balance and tone mapping...
I am in my final year of BS Computer Science. I have chosen a project in the image processing domain. But I really don't know where to start from! Here is a rough draft of my project idea:
Project Description:
Often people are faced with the problem of deciding which colors to choose to paint their walls, doors and ceilings. They want to know how their rooms will look like after applying a certain color. We want to design a mobile application that can give people the opportunity to preview their rooms/walls/ceilings, etc, with a certain color before applying the color. Through our application the user can take photos of their rooms/walls/ceilings, etc, and change their colors virtually and preview them. This will give them a good estimate about the final look of their house.
Development will be in java using open CV libraries.
Can anyone provide some help?
For starting OpenCV with android you can follow the tutorial here.
And as your above description, I think you need to do the following...
Filter out the color of room's wall or ceiling color.
Replace with your preview color.
But as your room's color is not unique, you may need to mark the color manually and segment it. Here watershed algorithm might be helpful.
And one more thing is that there might be a chance of lighting variation, so you should use HSV color space instead of RGB.
And finally this is not the full solution, but you will get some idea about how to start with your project.
ImageMagick as a famous image processing library.You may look that one too.It can perform numerous operations with images
Thanks
I want to replace the particular color of an image with other user selected color. While replacing color of image, I want to maintain the gradient effect of that original color. for example see the attached images.
I have tried to do so with CoreGraphics & I got success to replace color. But the replacing color do not maintain the gradient effect of the original color in the image.
Can someone help me on this? Is the CoreGraphics is right way to do this?
Thanks in advance.
After some struggling almost with the same problem (but with NSImage), made a category for replacing colors in NSImage which uses ColorCube CIFilter.
https://github.com/braginets/NSImage-replace-color
inspired by this code for UIImage (also uses CIColorCube):
https://github.com/vhbit/ColorCubeSample
I do a lot of color transfer/blend/replacement/swapping between images in my projects and have found the following publications very useful, both by Erik Reinhard:
Color Transfer Between Images
Real-Time Color Blending of Rendered and Captured Video
Unfortunately I can't post any source code (or images) right now because the results are being submitted to an upcoming conference, but I have implemented variations of the above algorithms with very pleasing results. I'm sure with some tweaks (and a bit of patience) you might be able to get what you're after!
EDIT:
Furthermore, the real challenge will lie in separating the different picture elements (e.g. isolating the wall). This is not unlike Photoshop's magic wand tool which obviously requires a lot of processing power and complex algorithms (and is still not perfect).
I'm trying to convert hundreds of images that
Have an unknown subject centered in the image
Have a white background
I've used ImageMagick's convert utility in the following way
convert ORIGINAL.jpg -fuzz 2% -matte -transparent "#FFFFFF" TRANSPARENT.png
The problem is, some of my subjects are within the "white" scale, so, just like the weatherman wearing a green tie, some of my subjects seem to be disitegrating.
Is there any way to solve this via ImageMagick? Are there any alternative solutions? Scripting GIMP?
As you said, GIMP has a magic wand tool that can be used to select continuous areas of the same color, and so it can avoid the "green tie syndrome". The problem is that it may introduce a problem if there is something like a human hair crossing the image (that will seperate some of the white areas). Another common problem, especially with pictures of people, is when they put their hand next to the body and between the hand and the body there is a small hole.
Basically, it is not too hard to create a GIMP script that opens in batch many images, uses the magic wand to select the pixel at some corner (or if desired, in several known fixed places, not just one) and then removes the selection.
If it's hard to find a white area at a fixed spot, it is possible to do a search inside - meaning that the script searches for a white pixel on the borders, and it goes inside gradually in a spiral untill it finds some white pixel. But this is very very unefficient in the basic scripting engine, so I hope you don't need this.
If any of the suggested options above is OK, tell me and I'll create a gimp script for it. It will be even better if you can post some samples images, but I'll try to help even without these.