grayscale

rgbImage = grayImage / max(max(grayImage)); or rgbImage = grayImage / 255; Which of the above is right,and reason? To convert a grayscale image to an RGB image , there are two issues you have to address: Grayscale images are 2-D, while RGB images are 3-D, so you have to replicate the grayscale image data three times and concatenate the three copies along a third dimension. Image data can be stored in many different data types , so you have to convert them accordingly. When stored as a double data type, the image pixel values should be floating point numbers in the range of 0 to 1. When stored

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: width, height: height) let colorSpace = CGColorSpaceCreateDeviceGray() let context = CGContext(data: nil, width: Int(width), height: Int(height), bitsPerComponent: 8, bytesPerRow: 0, space: colorSpace, bitmapInfo: CGBitmapInfo(rawValue: CGImageAlphaInfo.none.rawValue).rawValue) context?.draw(self.cgImage!, in: imgRect) let imageRef = context!.makeImage() let newImg = UIImage(cgImage: imageRef!) return newImg

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? Yes it is, here is an example, expaination in the comments: import cv #open color and b/w images im = cv.LoadImageM('1_tree_small.jpg') im2 = cv.LoadImageM('1_tree_small.jpg',cv.CV_LOAD_IMAGE_GRAYSCALE) #set up our output and b/w in rgb space arrays: bw = cv.CreateImage((im.width,im.height), cv.IPL_DEPTH_8U, 3) new = cv.CreateImage((im.width*2,im.height), cv.IPL_DEPTH_8U, 3) #create a b/w image in rgb space cv.Merge(im2, im2, im2, None, bw) #set up

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 -> grayscale, which is already answered in another question, e.g. Converting RGB to grayscale/intensity ) The quick and dirty approach is to repeat the grayscale intensity for each component of RGB. So, if you have grayscale 120, it translates to RGB (120, 120, 120). This is quick and dirty because the effective luminance you get depends on the actual luminance of the R, G and B subpixels of the

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 toGrayScale() or similarly-named function. Right now I'm using this code, but it's does not have a very good performance: for (int ii = 0; ii < image.width(); ii++) { for (int jj = 0; jj < image.height(); jj++) { int gray = qGray(image.pixel(ii, jj)); image.setPixel(ii, jj, QColor(gray, gray, gray).rgb()); } } What would be the best way, performance-wise, to convert a QImage to grayscale? UmNyobe Rather