Applications
Applications
Small software instruments, free and sober.
Alongside its industrial work, image4D builds small software instruments: free applications, sober by design, with no ads, no accounts and no data collection. Each one does a single thing, carefully. They are our design laboratory, and our way of giving something back to the public domain they draw from.
Grain
The weather, told by literature.
Grain looks at the sky above you and finds someone in the books who has already written it: a fine drizzle by Verlaine, a storm by Shakespeare, a hard frost by Tolstoy. Over 550 excerpts chosen one by one from public domain works, from Gilgamesh to Colette, checked against reference editions. The corpus is French literature, enriched with early public domain translations; the app itself is in French.
Temps de pose
The earliest photographs, at their original speed.
Temps de pose presents thirteen historical photographs, from Niépce to 1927, which develop on screen at the true pace of their exposure time, driven by ambient light and the steadiness of your hand. An instrument for physically experiencing what taking a photograph once meant. No permissions, no network: everything happens on the device.
Zone V
Previsualising the print before releasing the shutter.
Zone V lets you handle Ansel Adams and Fred Archer's Zone System on a 1941 Adams photograph in the public domain. You meter the scene with a spot meter and write your intention on the film holder; two constraints suffice: this shadow on zone III, this light on zone VII. Exposure becomes a translation, development a slope, and the negative then the print take shape before your eyes. A contemplative workshop, with no account and no data collection. Android application available on Google Play.
Invisible Center
The camera that knows itself.
Invisible Center tells the story of the three numbers every measuring photograph depends on: f, cx, cy, the camera's internal geometry. Three interactive chapters: the instrument laid bare, around an 1898 Meydenbauer camera; what a few pixels of error cost, on the stone of a building; and a genuine least-squares calibration converging before your eyes, down to the measurement noise and no further. There is no exact result, only acceptable residuals. In four languages, with no account and no data collection. Android application in preparation.
Straight
Lines are only straight once corrected.
Straight tells the story of radial lens distortion and of the theorem that undoes it exactly, published in Sensors in 2016. Four chapters to handle: you bend a composition of straight lines, calibrate a lens by eye as Brown did with his plumb lines, watch the inverse series collapse or diverge, and leave with a Metashape/OpenCV conversion tool and its Python code, offered. The mirror's coefficients even hide the Fuss-Catalan numbers. In four languages, with no account and no data collection. Android application in preparation.
No Points
Orienting a world without measuring a single point.
No Points tells the story of the logical bundle adjustment published in IJITEE in 2020 with Mohamed Ben Ellefi: orienting spheres and cameras without extracting a single point, by reasoning on occlusions alone. You handle Allen's algebra, watch “a bit on the right” become “north-east”, then follow the machine orienting eight cameras by successive consistencies. The final chapter embeds a real SPARQL engine (Oxigraph in WebAssembly) running the paper's very query, locally. In four languages, with no account and no data collection.