Tremble and drift

For philosopher Henri Lefebvre, rhythms are influenced by their context. They also vary. The waves on the sea provide an obvious example. Perturbations across water involve counter movements, complex overlays of movement, and the patterns rely on the shape and materials of the shore, the tides, weather conditions, and water traffic. He contrasts rhythm with…More

Visualising 2D Discrete Cosine Transforms

I’m interested in the Discrete Cosine Transform (DCT) method as a means of hiding one image inside another. It’s also a key technique in image compression. I’ve implemented the DCT method on an Excel spreadsheet. The image below is an 8×8 grid of pixel values, in grey ranging from 0 = black to 255 =…More

COVID-19 Rhythmanalysis

Rhythms permeate the city, and these rhythms overlap, combine, aggregate and interfere with one another. That’s the gist of Henri Lefebvre’s book entitled Rhythmanalysis. By my reading the concept fits within the genre of research concerned with everydayness, the quotidian, which implies a concern with ordinary things and everyday phenomena that repeat. (See post: Time…More

Beyond averages: DCT graphics

The visual field is full of smooth curves. Shadows don’t have sharp edges but fade out. Colours blend, sometimes imperceptibly. At some level of detail, most things transition smoothly, but to varying degrees. The variation across such transitions is noticeable in a high quality digital photograph, i.e. a pixel image. Here is a random row…More