CODEWITHSUNDEEP
c++image-processing
Mus
Mus

Reputation: 7540

C++ - Image Conversion

I am new to C++ and would like to know how to read in a .jpg image and then convert it to binary (black and white/bi-level/two-level)?

Thank you.

Upvotes: 0

Views: 4733

Answers (3)

josephthomas
josephthomas

Reputation: 3276

There is the option for libpng, which as been used on many projects. For additional reading on how to write a grayscale image, take a look at this chapter from their website.

Upvotes: 0

log0
log0

Reputation: 10947

Your better choice is probably boost Gil.
Boost libraries are not especially for beginner, but they are often well designed.

#include <boost/gil/image.hpp>
#include <boost/gil/typedefs.hpp>
#include <boost/gil/extension/io/jpeg_io.hpp>

int main() {
  using namespace boost::gil;

  rgb8_image_t img;
  jpeg_read_image("test.jpg",img);

  gray8s_view_t view(img.dimensions());
  color_converted_view<gray8_pixel_t>(const_view(img), view);

  jpeg_write_view("grey.jpg", view);
 }

Upvotes: 3

Andreas Magnusson
Andreas Magnusson

Reputation: 7434

You can use DevIL to read the image. It supports a lot of different formats.

To convert it to pure black and white, you then go through the whole image data and compute the intensity or light contribution of each pixel and if it falls below a certain threshold you'll output a black pixel otherwise a white pixel.

You could do it as simply as check the RGB-values of each pixel against a threshold of RGB(0.5, 0.5, 0.5). But you might get better results if you convert the image to HSI and use the intensity value for each pixel, but that's more work.

Upvotes: 1

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