I am on MAC OSX.
How to convert an gray scaled image to the RGB format.
Can i use the CIFilters for converting? Or any other way
And also i want to reverse the operation. i.e., convert the RGB format to Gray scaled format.
Regards,
Dhanaraj.
You can draw the grayscale image into an RGB-color context and export that image. Of course, the ability to draw a grayscale image into a non-grayscale context means you probably don't need to convert the image in the first place, since it will be done for you on-the-fly.
Core Image requires RGB images as input and produces them as output. I think it will convert a non-RGB image for you, so you could just use some simple filter in its identity configuration, but that's unnecessary.
What are you really trying to do that requires you to convert the image?
Related
Hi i am uisng MITK Workbench 2016.11.0. I want to save image in PNG or JPEG or TIFF using MITK. But there are only 5 options available: NRRD, NIFTI, VTK, VTK LEGACY IMAGE.
Only 2-d images can be saved in classic 2-d image formats such as PNG, BMP, JPEG, or TIFF and only if the pixel format is supported by the image format.
If you seem to have a 2-d image for which the 2-d options are not available, it's most probably a 3-d image with a single slice. A 3-d image can't be saved as 2-d image even with a single slice as important 3-d meta-data like 3-d origin and orientation in 3-d space would be lost.
I need to detect an image is a color image or black&white image. But don't understand what will be the process or there have any function to detect it. If there have no function to detect it then what will be the process?
Image file has mode, which tells if it is RGB, grayscale or B&W.
I assume you know that and you are trying to examine a RGB image to see if it only has black / white color. In this case you can calculate the histogram of the image in all R/G/B channels, the black and white will have two sharp peaks in all three channels.
Please use a image editing software like GIMP and experiment.
I have a problem with a binarization method.
I have images with text, which I want to binarize.
I want the text ends up being white, but there are images with the text darker than the background and there are images with text less dark than the background.
I want to binarize images like these, but I want the text in white color in the binarized images.
By the way, I am binarizing images with this code. This code is good for images with text darker than the background but it isn't good for text less darker than the background. I think I need a method to know if the text is more or less dark than the background for to invert or no invert the binarization.
umb = graythresh(originalImage);
binaryImage =(~im2bw(originalImage,umb));
How can I do it?
Thanks a lot for the help
there are 2 possible solutions which I had in mind:
solution1:
generate a grayscale image using rgb2gray function.
generate a histogram from the grayscale image, and ignore the transparent pixels. you can use imhist function.
check what is the histogram maximal value. if the value is high - the background is probably light and the text should be darker than the background. in this case - take the negative image (for example, by using imcomplement), and then binarize it. otherwise - you can binarize it as is.
solution 2:
the solution asserts that the image is simple enough, i.e. doesn't have a lot of connected components other than the letters.
binarize the input image.
divide the image into connected components using bwconncomp function.
for each connected component find it's representative value, it can either be 0 or 1
check what is the most common represantative value. if it is 1 - the letters are dark. in this case take the negative image and than binarize. otherwise - binarize the input image as is.
good luck!
I want to use imagesc to crop and display a black and white (grayscale?) image. However, it keeps displaying the image in rgb, making it look like it came from an infra-red camera! Any tips for preserving the original colors?
You need to change the color map. After you run imagesc use colormap('Gray'). You can set default colormap to current colormap using colormap('default')
I have original RGB image.
then, I convert it to gray scale.
then, I assign new threhold value into some pixel.
then, I need to convert the gray scale image from step#3 to RGB image.
I am trying on the step#4. Could you help to advise?
Check out rgb2hsv and hsv2rgb in matlab. Then threshold on the value matrix. This makes more sense to me.
Another possibility is to convert to grey scale but keep the original colour image. Then create a mask by thresholding the grey scale image and use that mask to discard the pixels above/below your threshold on the colour matrix.