Frédéric Bochart
6 articles published in Tangente
N°77Feb 18, 2021Television’s “missing” lines
The information received by our television sets is digital. Each image corresponds to a certain number of bits specifying the luminance and chrominance of each pixel (see the article “The components of our images: luminance and chrominance”). But the on-screen image is not the whole story.
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N°77Feb 18, 2021Tomorrow's ultra-high-definition TV
Our screens are taking up more and more room. And they are not done growing yet. The International Telecommunication Union (ITU) has set a new standard for tomorrow’s televisions: ITU 2020.
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N°77Feb 18, 2021Unexpected changes
Requirements for display quality are becoming increasingly stringent. Screens are growing ever wider, and their color gamut continues to expand.
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N°77Feb 18, 2021The JPEG format
By breaking each image into blocks and moving into the frequency domain, the JPEG format discards high frequencies, to which our eyes are less sensitive. This is what makes the compression effective. JPEG: vector spaces underpinning image compression!
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KnowledgeN°77Feb 18, 2021From the Fourier transform to the discrete cosine transform
How do we go from discrete digital signals to the light and color waves emitted by our screens, and how can we reduce incoming data streams as much as possible without overly degrading the images? Converting signals to a spectral representation allows them to be compressed selectively to suit our visual system.
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KnowledgeN°77Feb 18, 2021The components of our images: luminance and chrominance
Screens are now part of our daily lives—and taking up more and more space. But how are the images they display constructed? What lies behind the standards (ITU 709, etc.) and formats (4:3, 16:9, etc.) in use?
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