Questions tagged [grayscale]
For questions regarding Grayscale, a Bootstrap theme.
grayscale
977
questions
667
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answers
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Convert an image to grayscale in HTML/CSS
Is there a simple way to display a color bitmap in grayscale with just HTML/CSS?
It doesn't need to be IE-compatible (and I imagine it won't be) -- if it works in FF3 and/or Sf3, that's good enough ...
- 7,082
316
votes
9
answers
673k
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Display image as grayscale
I'm trying to display a grayscale image using matplotlib.pyplot.imshow(). My problem is that the grayscale image is displayed as a colormap. I need it to be grayscale because I want to draw on top ...
- 4,567
101
votes
5
answers
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Image Greyscale with CSS & re-color on mouse-over?
I am looking to take an icon that is colored (and will be a link) and turn it greyscale until the user places their mouse over the icon (where it would then color the image).
Is this possible to do, ...
- 1,850
80
votes
8
answers
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Convert RGB to Grayscale in ImageMagick command-line
How do I convert a RGB image (3 channels) to a grayscale one, using the (r+g+b)/3 method?
I look through an examples page: http://www.imagemagick.org/Usage/color_mods/#grayscale
but the desired method:...
- 4,824
69
votes
5
answers
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Greyscale Background Css Images
I've searched a lot on the web but I cannot find a cross browser solution to fade a css backgrund image to greyscale and back.
The only working solution is to apply CSS3 filter greyscale:
-webkit-...
- 1,829
67
votes
3
answers
160k
views
Read image grayscale opencv 3.0.0-dev
I am trying to read images directly as black and white.
I recently updated my OpenCv version to 3.0.0-dev, and the code that I used before does not work anymore.
img = cv2.imread(f, cv2....
- 3,103
66
votes
7
answers
177k
views
Convert an image to grayscale
Is there a way to convert an image to grayscale 16 bits per pixel format, rather than setting each of the r,g and b components to luminance. I currently have a bmp from file.
Bitmap c = new Bitmap("...
- 8,441
65
votes
5
answers
87k
views
Convert a Bitmap to GrayScale in Android
I am new to this site, and I come with a question about Android.
Is there any way to convert a Bitmap to grayscale? I know how to draw a grayscale bitmap (using canvas operations: http://www.mail-...
- 2,694
61
votes
4
answers
138k
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In OpenCV (Python), why am I getting 3 channel images from a grayscale image?
I am using Python (2.7) and bindings for OpenCV 2.4.6 on Ubuntu 12.04
I load an image
image = cv2.imread('image.jpg')
I then check the shape of the image array
print image.shape
I get (480, ...
- 2,794
49
votes
2
answers
162k
views
How can I convert a cv::Mat to a gray scale in OpenCv?
How can I convert a cv::Mat to a gray scale?
I am trying to run drawKeyPoints func from opencv, however I have been getting an Assertion Filed error. My guess is that it needs to receive a gray scale ...
- 765
41
votes
3
answers
62k
views
Android : Converting color image to grayscale [duplicate]
I am trying to convert color image into grayscale using the average of red, green, blue. But it comes out with errors.
Here is my code
imgWidth = myBitmap.getWidth();
imgHeight = myBitmap.getHeight();
...
- 1,149
39
votes
3
answers
38k
views
How can I convert an RGB image to grayscale but keep one color?
I am trying to create an effect similar to Sin City or other movies where they remove all colors except one from an image.
I have an RGB image which I want to convert to grayscale but I want to keep ...
- 82.3k
32
votes
7
answers
34k
views
Convert UIImage to grayscale keeping image quality
I have this extension (found in obj-c and I converted it to Swift3) to get the same UIImage but grayscaled:
public func getGrayScale() -> UIImage
{
let imgRect = CGRect(x: 0, y: 0, width: ...
- 718
31
votes
3
answers
55k
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How do I desaturate and saturate an image using CSS?
Update
I just realized that the desaturation is only working in Chrome. How do I make it work in FF, IE and other browsers? (Headline changed)
I'm converting a color picture to greyscale by ...
- 19.3k
26
votes
6
answers
128k
views
Convert grayscale value to RGB representation?
How can I convert a grayscale value (0-255) to an RGB value/representation?
It is for using in an SVG image, which doesn't seem to come with a grayscale support, only RGB...
Note: this is not RGB -> ...
- 24.4k
25
votes
9
answers
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How to convert a PDF to grayscale from command line avoiding to be rasterized?
I'm trying to convert to grayscale this PDF: https://dl.dropboxusercontent.com/u/10351891/page-27.pdf
Ghostscript (v 9.10) with pdfwrite Device fails with a "Unable to convert color space to Gray, ...
- 275
25
votes
3
answers
62k
views
CSS filter grayscale image for IE 10
Is there a way to make grayscale image filter work on IE 10 without JavaScript or SVG?
I've been using the following code successfully in all browsers except IE 10.
img{
filter:url("data:image/svg+...
- 253
24
votes
2
answers
17k
views
Is it possible to turn an entire webpage to grayscale using CSS?
I would like to turn an entire website to grayscale. Of course, I can manually edit the CSS and adjust every single color, background-color & co. property, and I can adjust every single image in ...
- 145k
24
votes
2
answers
21k
views
What grayscale conversion algorithm does OpenCV cvtColor() use?
When converting an image in OpenCV from color to grayscale, what conversion algorithm is used? I tried to look this up in the source code on GitHub, but I did not have any success.
The lightness ...
- 2,794
18
votes
3
answers
44k
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how to make smooth grayscale on hover using CSS
I have logo in my website, it is grayscaled on hover i want it to be colored smoothly. it is working but not smoothly. i am using CSS transition.
This is my code
<img alt="TT ltd logo" src="./img/...
- 303
18
votes
2
answers
18k
views
Convert JPG image from grayscale to RGB using imagemagick
I am trying to convert gray scale images to RGB using the imagemagick command-line tools.
It is working fine for PNG images, using:
convert image.png -define png:color-type=2 result.png
(taken from ...
- 537
17
votes
2
answers
44k
views
Python Pil Change GreyScale Tif To RGB
I have a greyscale TIF File. I need to convert it to RGB/ read from it in a way I can work with it.
img = Image.open(GIF_FILENAME)
rgbimg = img.convert('RGB')
for i in range(5):
print rgbimg....
- 1,198
17
votes
2
answers
32k
views
CSS filter grayscale not working in Firefox
I'm having troubles doing a transition from grayscale to colored, it works in chrome, but that is it.
Here is the HTML:
<div id="post" style="background-image:url('bg.png');background-repeat:no-...
- 2,345
15
votes
2
answers
16k
views
Python numpy subtraction no negative numbers (4-6 gives 254)
I wish to subtract 2 gray human faces from each other to see the difference, but I encounter a problem that subtracting e.g. [4] - [6] gives [254] instead of [-2] (or difference: [2]).
print(type(...
- 6,052
14
votes
4
answers
14k
views
Is it possible to have black and white and color image on same window by using opencv?
Is it possible to have black-and-white and color image on same window by using opencv libraray? How can I have both of these images on same window?
user991511
14
votes
4
answers
26k
views
Convert a QImage to grayscale
I have a QImage and I need to convert it to grayscale, then later paint over that with colors. I found an allGray() and isGrayScale() function to check if an image is already grayscale, but no ...
- 77.1k
14
votes
5
answers
18k
views
how to read a png file in color and output as gray scale using the Go programming language?
How do I read in a color .png file in the Go programming language, and output it as an 8-bit grayscale image?
- 2,191
14
votes
3
answers
19k
views
display two png images simultaneously using pylab
I want to open two png image files and display them side by side for visual comparison.
I have this code for opening one png file (which I got from unutbu on stackoverflow.com):
import numpy as np
...
- 259
13
votes
1
answer
17k
views
Converting RGBA image to Grayscale Golang
I'm currently working on a program to convert and RGBA image to grayscale.
I asked a question earlier and was directed to the following answer -
Change color of a single pixel - Golang image
Here is ...
- 379
12
votes
4
answers
64k
views
Turning a Large Matrix into a Grayscale Image
I have a NumPy array of 3,076,568 binary values (1s and 0s). I would like to convert this to a matrix, and then to a grayscale image in Python.
However, when I try to reshape the array into a 1,538,...
user748176
12
votes
4
answers
44k
views
Conversion to grayscale using emguCV in C#
I am new to EmguCV. I want to convert an rgb image into gray scale. For the conversion I have used the code
Image<Gray,byte> grayImage = ColordImage.Convert<Gray, byte>();
Now when i ...
- 1,425
12
votes
2
answers
12k
views
Ghostscript color detection
I seem to be unable to find whether Ghostscript is able to simply detect whether job is color or grayscale. I use Ghostscript for conversion of print jobs to PNG, but I also need to have information ...
- 1,819
12
votes
1
answer
10k
views
Image conversion to Grayscale using ImageMagick is very dark
I converted a bunch of "normal" JPG photos via
convert infile -colorspace Gray outfile
to monochrome. However the result is for all images very dark. Here a sample conversion: original photo and ...
- 9,734
12
votes
3
answers
20k
views
16 bit grayscale png
I'm trying to write (using libpng) an 16-bit grayscale image where each point color equals to sum of its coordinates. The following code should produce a 16-bit PNG, but instead produces 8-bit like ...
- 125
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2
answers
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views
How can I grayscale a canvas image in JavaScript?
I have an image inside of an HTML5 canvas with the size of 28x28 pixels. I get the imageData of the canvas as an array of RGBA (red, green, blue, alpha) values using this code:
canvas = document....
- 161
11
votes
2
answers
64k
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How to convert a grayscale matrix to an RGB matrix in MATLAB?
rgbImage = grayImage / max(max(grayImage));
or
rgbImage = grayImage / 255;
Which of the above is right,and reason?
- 62.7k
11
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2
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views
How to turn ImageIcon to gray on Swing
I would like to know if there is some way in Swing to turn an ImageIcon to gray scale in a way like:
component.setIcon(greyed(imageIcon));
- 5,661
11
votes
1
answer
8k
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Set individual pixels in .NET Format16bppGrayScale image
I'm trying to render a small Bitmap in memory with .NET that needs to be 16 bit Grayscale. The bitmap's format is set to PixelFormat.Format16bppGrayScale. However, Bitmap.SetPixel takes a Color ...
- 149k
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votes
7
answers
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How can I convert a color image to grayscale in MATLAB?
I am trying to implement an algorithm in computer vision and I want to try it on a set of pictures. The pictures are all in color, but I don't want to deal with that. I want to convert them to ...
- 125k
10
votes
2
answers
5k
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Use python wand to grayscale image
I want to use the Python API binding for ImageMagick http://wand-py.org to directly manipulate images. I am however not able to deduce from the documentation how to use a grayscale transformation. Can ...
- 111
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6
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Detecting grayscale images with .Net
I am scanning documents to JPG images. The scanner must scan all pages as color or all pages as black and white. Since many of my pages are color, I must scan all pages as color. After the scanning ...
- 1,721
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votes
2
answers
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openCV - draw color contours on greyscale image
I'm working on a segmentation algorithme for medical images and during the process it must display the evolving contour on the original image.
I'm working with greyscale JPEG. In order to display the ...
- 454
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votes
3
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6k
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Counting colonies on a Petri dish
I have a bunch of Petri dishes full of dots which I'd like to count in Matlab. Can this be done reliably and in batches?
E.g. This plate has 352 colonies
I've tried ImageJ but need to do quite a ...
- 2,233
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4
answers
20k
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Grayscale image with CSS on Safari 5.x
I am trying to show some images on a page where they should be shown in grayscale, except on mouse hover when they smoothly transition into color. I've made it work nicely on IE, Chrome and Firefox, ...
- 3,015
9
votes
4
answers
46k
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Convert HSV to grayscale in OpenCV
I'm a newbie in OpenCV. I'm learning the Segmentation by Watershed algorithm and I have a problem.
I have to convert the image color to grayscale for using Watershed.
When I use the BGR color space, ...
- 160
9
votes
1
answer
7k
views
ImageMagick Reduces Colorspace to Gray
I convert RGB and CMYK TIFF images to RGB JPEGs using
convert a.tif -colorspace rgb a.jpg
If the TIFF image contains only gray pixels, the colorspace of the resulting JPEG is gray, not RGB.
How can ...
- 2,377
9
votes
1
answer
19k
views
Image does not load as grayscale (skimage)
I'm trying to load an image as grayscale as follows:
from skimage import data
from skimage.viewer import ImageViewer
img = data.imread('my_image.png', as_gray=True)
However, if I check for its ...
- 706
9
votes
2
answers
6k
views
MonoTouch convert color UIImage with alpha to grayscale and blur?
I am trying to find a recipe for producing a a blurred grayscale UIImage from a color PNG and alpha. There are recipes out there in ObjC but MonoTouch does not bind the CGRect functions so not sure ...
- 424
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votes
2
answers
5k
views
How to create Bitmap from grayscaled byte buffer image?
I am trying to get frame image to process while using new Android face detection mobile vision api.
So I have created Custom Detector to get Frame and tried to call getBitmap() method but it is null ...
- 357
8
votes
1
answer
22k
views
BufferedImage - getting the value of a pixel in grayscale color model picture
I have an BufferedImage transformed to grayscale using this code. I usually got the pixel values by BufferedImage.getRGB(i,j) and the gor each value for R, G, and B. But how do I get the value of a ...
- 2,246