1.1 Technical Specification VC nano 3D-Z

Owned by Wilhelm Scheermann
Last updated: Dec 08, 2022
3 min read

1.1.1 Framerate calculation

The framerate can be calculated by following these subcalculations:

  1. Calculate the time for a video line: TLine = HMAX*13.468 ns.

  2. Calculate the time for storing the captured image: TCapt = (DY + 33 +  FPGADelay)*TLine + 3.3us.

  3. Calculate the total time: TTotal = ShutterTime + TCapt.

FPGADelay in NrOfProcessingLines, between 7 and 38, depending on the filter configuration; main impact has the bgSubKy setting (see the libvclinux documentation).

HMAX vs. DX

DX

HMAX

TLine (us)

DX

HMAX

TLine (us)

1408

370

4.983

1344

350

4.713

1280

330

4.444

1216

320

4.310

1152

300

4.040

1088

290

3.906

1024

270

3.636

960

250

3.367

896

240

3.232

640

240

3.232

320

240

3.232

The following tables show some examples.

frame time (ms) at NrOfProcessingLines=7, shutter=1us

DY/DX

1408

1344

1280

1216

1152

1088

1024

960

896

640

320

DY/DX

1408

1344

1280

1216

1152

1088

1024

960

896

640

320

1080

5.584

5.283

4.981

4.830

4.529

4.378

4.076

3.774

3.623

3.623

3.623

1024

5.305

5.019

4.732

4.589

4.302

4.159

3.872

3.586

3.442

3.442

3.442

960

4.986

4.717

4.448

4.313

4.044

3.909

3.640

3.370

3.236

3.236

3.236

800

4.189

3.963

3.737

3.623

3.397

3.284

3.058

2.832

2.718

2.718

2.718

512

2.754

2.605

2.457

2.382

2.234

2.159

2.011

1.862

1.788

1.788

1.788

256

1.478

1.399

1.319

1.279

1.199

1.159

1.080

1.000

0.960

0.960

0.960

128

0.840

0.795

0.750

0.727

0.682

0.659

0.614

0.569

0.546

0.546

0.546

frame time (ms) at NrOfProcessingLines=38, shutter=1us

DY/DX

1408

1344

1280

1216

1152

1088

1024

960

896

640

320

DY/DX

1408

1344

1280

1216

1152

1088

1024

960

896

640

320

1080

5.739

5.429

5.119

4.964

4.654

4.499

4.189

3.879

3.724

3.724

3.724

1024

5.460

5.165

4.870

4.722

4.428

4.280

3.985

3.690

3.543

3.543

3.543

960

5.141

4.863

4.586

4.447

4.169

4.030

3.752

3.475

3.336

3.336

3.336

800

4.344

4.109

3.874

3.757

3.522

3.405

3.171

2.936

2.819

2.819

2.819

512

2.908

2.751

2.594

2.516

2.359

2.280

2.123

1.966

1.888

1.888

1.888

256

1.633

1.545

1.457

1.413

1.325

1.280

1.192

1.104

1.060

1.060

1.060

128

0.995

0.941

0.888

0.861

0.807

0.781

0.727

0.673

0.647

0.647

0.647

maximum frame rate (fps) at NrOfProcessingLines=7, shutter=1us

DY/DX

1408

1344

1280

1216

1152

1088

1024

960

896

640

320

DY/DX

1408

1344

1280

1216

1152

1088

1024

960

896

640

320

1080

179

189

201

207

221

228

245

265

276

276

276

1024

188

199

211

218

232

240

258

279

290

290

290

960

201

212

225

232

247

256

275

297

309

309

309

800

239

252

268

276

294

304

327

353

368

368

368

512

363

384

407

420

448

463

497

537

559

559

559

256

676

715

758

782

834

863

926

1000

1042

1042

1042

128

1190

1258

1333

1375

1466

1516

1628

1758

1830

1830

1830

maximum frame rate (fps) at NrOfProcessingLines=38, shutter=1us

DY/DX

1408

1344

1280

1216

1152

1088

1024

960

896

640

320

DY/DX

1408

1344

1280

1216

1152

1088

1024

960

896

640

320

1080

174

184

195

201

215

222

239

258

269

269

269

1024

183

194

205

212

226

234

251

271

282

282

282

960

195

206

218

225

240

248

266

288

300

300

300

800

230

243

258

266

284

294

315

341

355

355

355

512

344

363

385

397

424

439

471

509

530

530

530

256

612

647

687

708

755

781

839

906

943

943

943

128

1005

1062

1126

1162

1239

1281

1376

1485

1547

1547

1547

  • The measurements were done without any other CPU load.
    Parallel image processing tasks may lead to a lower framerate.

  • These values are only reachable if image capturing is deactivated.