Given an image in PGM format and the task is to invert the image color (making negative) content in PGM format.
PGM image represents a gray scale graphic image. PGM is the abbreviation of Portable Gray Map. This image file contains one or more PGM images file.
Significance of data chunks: The data which are used to create PGM image listed below:
- P2 is the type of image that is grey image
- 4 4 is the image dimension
- 255 is the maximum grey level
- Since, the image data are stored in matrix format and each row indicates the image row and the value indicates the grey level of corresponding pixel. The maximum value (255) is used for white and minimum value (0) is used for black.
P2 4 4 255 255 0 255 0 0 255 0 255 100 200 150 100 50 150 200 0
The input image looks like:
How to invert the image data?
Invert the grey image means change the grey level of an image using (255 – grey lavel) i.e. if grey level of a pixel is 150 then grey level in negative image is (255 – 150) = 105. It means 255 will changes with 0 and 0 will change with 255. It is changing of proportion of black and white present in grey.
P2 4 4 255 0 255 0 255 255 0 255 0 155 55 105 155 205 105 55 255
The output image looks like:
Negative (Invert) Image
- C program to write an image in PGM format
- Image Processing in Java | Set 4 (Colored image to Negative image conversion)
- C program to print characters without using format specifiers
- C program to print the length of a String using %n format specifier
- Image Processing in Java | Set 6 (Colored image to Sepia image conversion)
- Image Processing in Java | Set 3 (Colored image to greyscale image conversion)
- C program to Check Whether a Number is Positive or Negative or Zero
- OpenCV C++ Program to blur an image
- OpenCV Python Program to blur an image
- Node Jimp | invert
- Python | OpenCV program to read and save an Image
- Python PIL | logical_xor() and invert() method
- OpenCV C++ Program to create a single colored blank image
- Image Processing in Java | Set 5 (Colored to Red Green Blue Image Conversion)
- Python Program to detect the edges of an image using OpenCV | Sobel edge detection method
If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to email@example.com. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.