J = imadjust( I ) maps the intensity values in grayscale image I to new values in J . By default, imadjust saturates the bottom 1% and the top 1% of all pixel values. This operation increases the contrast of the output image J .

I = rgb2gray( RGB ) converts the truecolor image RGB to the grayscale image I . The rgb2gray function converts RGB images to grayscale by eliminating the hue and saturation information while retaining the luminance. If you have Parallel Computing Toolbox™ installed, rgb2gray can perform this conversion on a GPU.

A grayscale image is a data matrix whose values represent intensities of one image pixel. While grayscale images are rarely saved with a colormap, MATLAB uses a colormap to display them. You can obtain a grayscale image directly from a camera that acquires a single signal for each pixel.

BW = im2bw( I , level ) converts the grayscale image I to binary image BW , by replacing all pixels in the input image with luminance greater than level with the value 1 (white) and replacing all other pixels with the value 0 (black).

uint8 or uint16 Data. Indexed. Image is an m-by-n array of integers in the range [1, p]. Colormap is a p-by-3 array of floating-point values in the range [0, 1]. Image is an m-by-n array of integers in the range [0, p –1].

Because it is a one layer image from 0-255 whereas the RGB have three different layer image. So that is a reason we prefer grey scale image instead of RGB.

Change a picture to grayscale or to black-and-white

1. Right-click the picture that you want to change, and then click Format Picture on the shortcut menu.
2. Click the Picture tab.
3. Under Image control, in the Color list, click Grayscale or Black and White.

The Average method takes the average value of R, G, and B as the grayscale value. Grayscale = (R + G + B ) / 3. Theoretically, the formula is 100% correct.

You can binarize an image with cv2. threshold() . If type is set to cv2. THRESH_BINARY , any value greater than the threshold thresh is replaced with maxval and the other values are replaced with 0 .

Variables in MATLAB® of data type (class) uint16 are stored as 2-byte (16-bit) unsigned integers. For example: y = uint16(10); whos y. Name Size Bytes Class Attributes y 1×1 2 uint16. For more information on integer types, see Integers.

imshow( BW ) displays the binary image BW in a figure. For binary images, imshow displays pixels with the value 0 (zero) as black and 1 as white. imshow( X , map ) displays the indexed image X with the colormap map . imshow( filename ) displays the image stored in the graphics file specified by filename .

rgb2gray converts RGB values to grayscale values by forming a weighted sum of the R, G, and B components: 0.2989 * R + 0.5870 * G + 0.1140 * B These are the same weights used by the rgb2ntsc (Image Processing Toolbox) function to compute the Y component.

The im2gray function accepts grayscale images as inputs and returns them unmodified. The im2gray function converts RGB images to grayscale by eliminating the hue and saturation information while retaining the luminance.

To display the image, use a grayscale colormap with 256 values. This avoids the need to scale the data-to-color mapping, which is required if you use a colormap of a different size. Use the imagesc function in cases where the colormap does not contain one entry for each data value. Now display the image in a new figure using the gray colormap:

Input black and white values, specified as a 2-element numeric vector. Values in input image A that are less than or equal to amin are mapped to the value 0 in the intensity image, I. Values in A that are greater than or equal to amax are mapped to the value 1 in I.