In the first part of this tutorial, you will discover what pixels are (i.e., the building blocks of an image). So, totally 270,000 numerical values in the NumPy array.Looking for the source code to this post? Jump Right To The Downloads Section OpenCV Getting and Setting Pixels

For a gray scale image, each pixel will hold 1 value.

So, totally 270,000 * 3 numerical values in the NumPy array.

For a color image (RGB) image, each pixel will hold 3 values.

Given that the pixel value only needs to be in the range we normally use an 8-bit unsigned integer to represent each color intensity.

To create a pure red color, we would fill up the red bucket (and only the red bucket) up completely: (255, 0, 0) .įIGURE 4: HERE WE HAVE THREE EXAMPLES OF COLORS AND THE “BUCKET” AMOUNTS FOR EACH OF THE RED, GREEN, AND BLUE COMPONENTS.

Then, to create a black color, we would empty each of the buckets out: (0, 0, 0) - since black is the absence of color.To construct a white color, we would fill each of the red, green, and blue buckets completely up, like this: (255, 255, 255) - since white is the presence of all color.We then combine these values into a RGB tuple in the form (red, green, blue) . Figure 3: The RGB cubeĮach of the three Red, Green, and Blue colors are represented by an integer in the range 0 to 255, which indicates how “much” of the color there is. The grayscale gradient image above demonstrates darker pixels on the left-hand side and progressively lighter pixels on the right-hand side.Ĭolor pixels, however, are normally represented in the RGB color space - one value for the Red component, one for Green, and one for Blue, leading to a total of 3 values per pixel. The values in between 0 and 255 are varying shades of gray, where values closer to 0 are darker and values closer 255 are lighter: FIGURE 2: IMAGE GRADIENT DEMONSTRATING PIXEL VALUES GOING FROM BLACK (0) TO WHITE (255). In a grayscale image, each pixel has a value between 0 and 255, where zero is corresponds to “black” and 255 being “white”. Most pixels are represented in two ways: grayscale and color. Overall, there are 600 x 450 = 270,000 pixels in our image. This means that our image is represented as a grid of pixels, with 600 columns and 450 rows. The image above has a resolution of 600 x 450, meaning that it is 600 pixels wide (width) and 450 pixels tall (height). Normally, a pixel is considered the “ color” or the “ intensity” of light that appears in a given place in our image. There is no finer granularity than the pixel. Pixels are the raw building blocks of an image. If we think of an image as a grid, each square in the grid contains a single pixel. We will understand the building blocks of an image - the pixel.

Color 0 to 255 white or black