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Images are matrices

Images are matrices of pixels. Image analysis is basically matrices manipulations and analysis.

• 8-bit greyscale images: each pixel can take an integer value

Image format

The format in which is saved is highly relevant for image analysis. Two big classes of image classes exist. The loosless format do not loose information when savng the images. The lossy format, usually compressed format, will modify the pixels values to reduce the size of the image (and therefore loose informations.

In a perspective of image analysis, lossy format must be avoided at all cost. Using successive lossy compression (or save successively the same image in a lossy format), will cause loss and/or modification of the informtion contained in the image.

Different type of images:

• JPEG
  • lossy compression
  • loss of informations
  • light
  • DO NOT USE
• TIFF
  • no compression
  • NO loss of informations
  • heavy
• PNG`
  • lossless compression
  • NO loss of informations
  • light

More info:

Minervini, M. et al. (2015) The significance of image compression in plant phenotyping applications. Funct. Plant Biol. Website. PDF