add to image-util-e2e-specs.js

output_images_spec_example.js

it('should produce image results', async function () {
  const fs = require('fs/promises');
  const output_images_path = path.resolve(__dirname, '..', '..', 'build', 'output');
  try { await fs.mkdir(output_images_path); } catch (error) {}

  /* this is what works on my local setup, adjust as necessary for opencv4nodejs require */
  const packageName = 'opencv4nodejs';
  const globalPackageName = path.resolve(process.env.npm_config_prefix, 'lib', 'node_modules', packageName);
  const cv = require(globalPackageName);

  const {results, visualization} = await getImageOccurrences(originalImage, numberImage, {visualize: true, threshold: 0.8});

  const fullHighlightedImage = await cv.imdecodeAsync(visualization);
  await cv.imwriteAsync(path.resolve(output_images_path, 'full-highlights.png'), fullHighlightedImage);

  for (let i = 0; i < results.length; i++) {
    const highlightedImage = await cv.imdecodeAsync(results[i].visualization);
    await cv.imwriteAsync(path.resolve(output_images_path, `highlight-${i}.png`), highlightedImage);
  }
});