Chase Hendrick
Claude Opus 5.5 (1M context)
Unroll 1.7.0: Live sheet, stream any public segment and volume and see the volume on the sheet
7391956 unverified | # Live sheet | |
| `live.html` streams one traced sheet (a tifxyz segment) and one scan volume (OME-Zarr: CT, or a 3D ink prediction) | |
| straight from the Vesuvius Challenge open data bucket and shows the volume on the sheet in 3D. Nothing is packed | |
| ahead of time and nothing is uploaded: your browser fetches only the rows of the segment inside the crop (HTTP Range) | |
| and only the zarr chunks the samples touch, then samples and draws. | |
| ## The sampling rule | |
| Each node of the segment grid gets one value: the volume's voxels along the node's normal over plus or minus | |
| **Depth** level-0 voxels, reduced by **max** or **mean**, reading the nearest voxel of the chosen pyramid **level** | |
| (numpy rounding). This is the rule of `kit sheetview` in [ChaseHendrick/Scrolls](https://github.com/ChaseHendrick/Scrolls), | |
| which writes the same mesh for Neuroglancer, and the two agree: on the PHerc0139 w045 preset (119,301 points) the | |
| largest difference was 6e-6, and on a blosc-compressed 3D ink volume (350,761 points) it was 0. **Refine grid** | |
| adds bilinear midpoints (a new node is valid when its cell's four corners are). Holes (-1) stay holes. | |
| ## Inputs | |
| | Field | URL parameter | Meaning | | |
| | --- | --- | --- | | |
| | Segment | `seg` | a tifxyz folder URL (`x.tif`, `y.tif`, `z.tif`, `meta.json`), uncompressed float32 in strips; the voxel size comes from the `-NNum.tifxyz` folder name | | |
| | Volume | `vol` | an OME-Zarr v2 root in the segment's voxels, raw or blosc, uint8 to float32 | | |
| | Crop | `crop=r0,r1,c0,c1` | rows and columns of the segment grid | | |
| | Volume level | `level` | pyramid level; 1 halves the reads | | |
| | Depth | `depth` | voxels each side of the sheet | | |
| | Refine grid | `up` | 1 to 4 | | |
| | Along the normal | `reduce` | `max` or `mean` | | |
| | Colors | `palette` | `gray` or `ink` | | |
| | | `autoload=1` | load at once | | |
| Example: `/live.html?crop=500,650,700,900&level=1&depth=4&up=2&reduce=mean&autoload=1`. | |
| The presets are PHerc0139 w045 only, a public scan off the prize lists. Any public segment and volume in the bucket | |
| work, since the bucket answers CORS for GET and HEAD. | |
| ## Outputs | |
| - **Download VTK**: the mesh with its values as ASCII VTK, the format Neuroglancer's `vtk://` source and ParaView read. | |
| - **Volume in neuroglancer**: the hosted Neuroglancer on the same volume. | |
| An ink prediction shown here is model output, not a reading. | |
| ## For agents | |
| ```js | |
| await liveSheet.load({ seg, vol, crop: [r0, r1, c0, c1], level: 1, depth: 4, up: 2, reduce: 'mean' }); | |
| liveSheet.state(); // params, vertices, triangles, chunks, samplesPerVertex, volume | |
| liveSheet.values(); // the value of every grid node (NaN at holes) | |
| liveSheet.turn(30); // orbit the camera, degrees | |
| liveSheet.screenshot(); // PNG data URL | |
| ``` | |
| `lib/livesheet.js` has no DOM and runs in Node too: `readSegment`, `upsample`, `normals`, `openVolume`, | |
| `sampleSheet`, `sheetMesh`, `toVTK`. Tests: `node tests/livesheet.mjs` (no network). | |
| ## Limits | |
| Zarr v3 volumes, zarr filters, compressed or tiled TIFFs are refused with a message. A crop of about 150 by 200 nodes | |
| refined twice is about 120,000 points and loads in about 15 s; the raw PHerc0139 CT at level 1 reads about 600 MB for | |
| it, so prefer level 2 for wide crops. | |