Speed for IMU data

SDV

I am trying to obtain an estimated speed from the IMU data stream of an OAK-D-POE camera. The basic math is simple: velocity = acceleration/dt, in theory, is the average velocity of the camera (on a specific axis) over the time interval dt relative to the previous period dt.

If acceleration is negative, the speed in the interval dt will be negative and vice versa.

Thus, the velocity relative to the ground is the sum of the relative speeds.

Obviously, this approach can produce errors derived from inaccurate data produced by the IMU, and so filters and corrections must be introduced, such as setting the speed to zero when there is no lateral or vertical acceleration, which indicates that the camera is stationary.

However, from the tests I have done, I get absolutely incorrect data.

Has anyone tried and found a solution?

jakaskerl

SDV
dvelocity = acceleration*dt
Generally, you are integrating over time, so little errors in measurements will cause drift over time.

SDV when there is no lateral or vertical acceleration, which indicates that the camera is stationary.

Or moving at the same velocity.

Can you demo the data? How quickly are the results completely wrong?

Thanks,
Jaka

SDV

`Hi. Im using this code:

#!/usr/bin/env python3

import cv2

import depthai as dai

import time

import numpy as np

import csv

# Create pipeline

pipeline = dai.Pipeline()

# Define sources and outputs

imu = pipeline.create(dai.node.IMU)

xlinkOut = pipeline.create(dai.node.XLinkOut)

xlinkOut.setStreamName("imu")

# enable ACCELEROMETER_RAW at 500 hz rate

imu.enableIMUSensor(dai.IMUSensor.LINEAR_ACCELERATION, 500)

# enable GYROSCOPE_RAW at 400 hz rate

imu.enableIMUSensor(dai.IMUSensor.GYROSCOPE_CALIBRATED, 400)

# it's recommended to set both setBatchReportThreshold and setMaxBatchReports to 20 when integrating in a pipeline with a lot of input/output connections

# above this threshold packets will be sent in batch of X, if the host is not blocked and USB bandwidth is available

imu.setBatchReportThreshold(1)

# maximum number of IMU packets in a batch, if it's reached device will block sending until host can receive it

# if lower or equal to batchReportThreshold then the sending is always blocking on device

# useful to reduce device's CPU load and number of lost packets, if CPU load is high on device side due to multiple nodes

imu.setMaxBatchReports(10)

# Link plugins IMU -> XLINK

imu.out.link(xlinkOut.input)

# Function to write data to CSV

def write_to_csv(data, filename='imu_data.csv'):

with open(filename, mode='a', newline='') as file:

    writer = csv.writer(file)

    writer.writerow(data)

# Write CSV header

write_to_csv(['Timestamp (ms)', 'Delta t (ms)', 'Accel X (m/s²)', 'Accel Y (m/s²)', 'Accel Z (m/s²)', 'Velocity X (km/h)', 'Velocity Y (km/h)', 'Velocity Z (km/h)'])

# Pipeline is defined, now we can connect to the device

with dai.Device(pipeline) as device:

def timeDeltaToMilliS(delta) -> float:

    return delta.total_seconds() \* 1000

# Output queue for imu bulk packets

imuQueue = device.getOutputQueue(name="imu", maxSize=50, blocking=False)

baseTs = None

velocity = np.array([0.0, 0.0, 0.0])

lastTs = None

while True:

    imuData = imuQueue.get()  # blocking call, will wait until new data has arrived

    imuPackets = imuData.packets

    for imuPacket in imuPackets:

        acceleroValues = imuPacket.acceleroMeter

        acceleroTs = acceleroValues.getTimestampDevice()

        if baseTs is None:

            baseTs = acceleroTs

        acceleroTs = timeDeltaToMilliS(acceleroTs - baseTs)

        # Calculate time difference

        currentTs = acceleroTs / 1000.0  # convert to seconds

        if lastTs is not None:

            dt = currentTs - lastTs

            # Read acceleration

            acceleration = np.array([acceleroValues.x, acceleroValues.y, acceleroValues.z])

            # Integrate acceleration to get velocity

            velocity += acceleration \* dt

            # Convert velocity to km/h

            velocity_kmh = velocity \* 3.6

            imuF = "{:.1f}"

            print(f"Delta t: {imuF.format(dt \* 1000)} ms")

            print(f"Accelerometer [m/s^2]: x: {imuF.format(acceleroValues.x)} y: {imuF.format(acceleroValues.y)} z: {imuF.format(acceleroValues.z)}")

            print(f"Velocity [km/h]: x: {imuF.format(velocity_kmh[0])} y: {imuF.format(velocity_kmh[1])} z: {imuF.format(velocity_kmh[2])}")

            # Write data to CSV

            write_to_csv([currentTs \* 1000, dt \* 1000, acceleroValues.x, acceleroValues.y, acceleroValues.z, velocity_kmh[0], velocity_kmh[1], velocity_kmh[2]])

        lastTs = currentTs

    if cv2.waitKey(1) == ord('q'):

        break\`

And this is part of the data collected:

Timestamp (ms),Delta t (ms),Accel X (m/s²),Accel Y (m/s²),Accel Z (m/s²),Velocity X (km/h),Velocity Y (km/h),Velocity Z (km/h)

7.3629999999999995,7.3629999999999995,1.41015625,0.0234375,-0.0625,0.037378729687499994,0.0006212531249999999,-0.001656675

9.718,2.3549999999999995,1.453125,0.015625,-0.44140625,0.0496983234375,0.0007537218749999999,-0.005398917187499999

12.235,2.5170000000000003,0.42578125,-0.21484375,-0.609375,0.0535564125,-0.0011930203125000002,-0.0109205859375

14.815999999999999,2.581,0.31640625,-0.19921875,-0.546875,0.0564963328125,-0.00304408125,-0.0160019296875

17.194999999999997,2.3789999999999956,-1.046875,-0.09765625,-0.87890625,0.047530476562500014,-0.0038804484374999984,-0.02352923437499999

19.754,2.5590000000000055,-1.5625,0.015625,0.18359375,0.033136101562499985,-0.003736504687499998,-0.021837895312499984

22.226,2.4719999999999986,-1.4921875,0.0234375,0.19921875,0.019856826562499992,-0.003527929687499998,-0.020065007812499983

24.621000000000002,2.3950000000000014,-1.2734375,0.04296875,0.1015625,0.008877248437499987,-0.003157453124999998,-0.019189335937499982

28.909,4.287999999999997,0.27734375,-0.0859375,0.58203125,0.013158548437499985,-0.0044840531249999965,-0.010204635937499991

31.405,2.4960000000000053,1.203125,0.1171875,-0.1796875,0.023969348437500006,-0.003431053124999994,-0.011819235937499993

37.138999999999996,5.733999999999996,1.52734375,0.10546875,-0.29296875,0.05549738906249998,-0.0012539249999999958,-0.017866814062499993

54.576,17.437,-1.12109375,0.078125,0.0,-0.014877253125000026,0.003650231250000005,-0.017866814062499993

64.731,10.154999999999998,1.28125,0.109375,0.05859375,0.03196268437499997,0.007648762500000004,-0.015724743749999992

78.067,13.336,-0.9453125,0.07421875,0.2109375,-0.013421390625000034,0.011211975000000004,-0.005597718749999991

89.89800000000001,11.831000000000008,1.26171875,-0.01953125,-0.19140625,0.040317229687500004,0.010380107812500003,-0.013750017187499996

99.652,9.754,-1.20703125,-0.0390625,-0.03125,-0.002066948437499989,0.009008451562500004,-0.014847342187499998

113.319,13.666999999999998,1.5625,0.09375,-0.30078125,0.0748099265625,0.013621064062500002,-0.029646140624999994

121.965,8.646,-0.33984375,-0.14453125,-0.6640625,0.0642320859375,0.009122442187500003,-0.050315484375

129.46699999999998,7.501999999999967,-1.515625,0.0859375,-0.04296875,0.023299298437500178,0.011443373437499993,-0.05147594999999999

136.97799999999998,7.511000000000018,1.0859375,0.06640625,0.33984375,0.05266261406250025,0.013238971874999996,-0.042286710937499965

144.459,7.481000000000016,0.73046875,-0.0078125,-0.06640625,0.0723353062500003,0.013028568749999997,-0.044075137499999965

160.09,15.631000000000006,-0.0234375,-0.046875,0.62109375,0.0710164406250003,0.010390837499999996,-0.009125198437499954

171.66400000000002,11.574000000000002,0.578125,-0.19921875,-0.3125,0.09510482812500029,0.0020901093749999943,-0.022145948437499955

179.61599999999999,7.951999999999987,-1.48046875,0.01171875,0.1640625,0.05272315312500036,0.002425584374999994,-0.017449298437499962

191.409,11.792999999999997,1.421875,0.05859375,0.01953125,0.11308857187500036,0.0049131703124999935,-0.016620103124999966

192.086,0.6770000000000109,1.421875,0.05859375,0.01953125,0.11655396562500041,0.005055974999999995,-0.016572501562499963

209.376,17.29,-1.48828125,0.01171875,0.2578125,0.02391738750000041,0.005785396874999994,-0.0005252203124999636

221.906,12.529999999999985,1.55859375,0.13671875,0.0546875,0.09422243437500033,0.011952506249999988,0.0019416234375000336

238.209,16.30300000000001,-0.78125,0.05859375,0.16015625,0.0483702468750003,0.01539142031249999,0.011341321875000039

256.839,18.62999999999998,-0.38671875,-0.16015625,-0.58984375,0.022433793750000323,0.004650060937500002,-0.02821831874999992

274.304,17.465000000000007,1.81640625,0.05859375,-0.17578125,0.1366385203125004,0.008334084375000004,-0.039270389062499925

289.566,15.261999999999997,-1.44921875,0.05859375,-0.0625,0.05701380468750041,0.011553412500000002,-0.04270433906249993

296.78900000000004,7.2230000000000345,1.3671875,0.046875,0.1875,0.0925645078125006,0.012772293750000009,-0.0378288140624999

316.753,19.96399999999998,-1.3359375,0.09765625,0.1015625,-0.003449854687499325,0.019790887500000003,-0.03052947656249991

339.51,22.756999999999973,-1.8515625,0.01953125,0.2734375,-0.15513948281249915,0.0213909890625,-0.008128054687499938

359.321,19.81100000000002,-0.47265625,-0.2109375,0.1015625,-0.18884913749999918,0.006347010937499982,-0.0008846578124999297

374.20799999999997,14.886999999999983,-0.23046875,0.046875,-0.234375,-0.20120069531249915,0.00885919218749998,-0.013445564062499917

379.108,4.9000000000000155,2.09375,0.078125,0.1484375,-0.16426694531249902,0.010237317187499984,-0.010827126562499907

386.581,7.473000000000008,-1.0,-0.02734375,0.3984375,-0.19116974531249906,0.009501693749999984,-0.0001080421874998969

403.961,17.380000000000006,2.1875,0.02734375,-0.81640625,-0.05430224531249899,0.011212537499999986,-0.051188948437499916

421.554,17.592999999999968,-1.36328125,0.0546875,0.9453125,-0.14064539062499884,0.01467615937499998,0.008682229687499975

439.448,17.89400000000002,-1.48828125,-0.05859375,-0.0625,-0.23651808749999897,0.010901643749999976,0.00465607968749997

452.866,13.417999999999985,3.04296875,0.171875,-1.26953125,-0.08952809062499911,0.01920403124999997,-0.05666837343749997

468.518,15.652,-1.39453125,0.15234375,0.42578125,-0.16810602187499912,0.027788174999999967,-0.03267679218749996

476.21599999999995,7.697999999999983,2.58203125,0.21875,-0.96875,-0.09655070624999929,0.03385034999999996,-0.059523567187499904

494.28,18.064000000000025,-2.140625,0.14453125,1.81640625,-0.23575640624999947,0.04324927499999997,0.05859805781250026

503.908,9.628000000000025,3.078125,0.11328125,-1.515625,-0.1290661312499992,0.047175693749999977,0.006065282812500121

511.344,7.435999999999998,-1.74609375,-0.23046875,-0.88671875,-0.17580836249999918,0.04100613749999998,-0.017671823437499873

531.3919999999999,20.047999999999956,1.65625,-0.01171875,-1.0078125,-0.056272162499999424,0.040160362499999984,-0.0904084734374997

597.305,65.913,0.30078125,0.10546875,-0.46484375,0.01509925781250057,0.06518670468749999,-0.2007097593749997

647.981,50.67600000000005,0.609375,0.0078125,-0.75390625,0.12626973281250067,0.06661196718749998,-0.33824759062499987

658.712,10.730999999999934,2.015625,-0.3671875,-2.0390625,0.2041365515625002,0.052426926562500066,-0.4170198374999994

673.918,15.206000000000053,-0.58984375,0.0625,-0.171875,0.17184756093750012,0.05584827656250008,-0.4264285499999994

694.723,20.804999999999964,-0.58984375,0.15234375,2.76171875,0.1276694437500002,0.06725851875000005,-0.21958133906249977

711.073,16.349999999999977,-1.5,-0.328125,-0.9453125,0.03937944375000033,0.047945081250000084,-0.27522243281249975

723.533,12.460000000000026,-0.03125,0.15234375,-0.41796875,0.03797769375000033,0.0547786125000001,-0.29397083906249977

733.524,9.990999999999971,2.96484375,0.0859375,-1.9453125,0.14461600781250003,0.05786957812500009,-0.3639390609374996

746.26,12.73600000000008,-1.3359375,0.2578125,0.39453125,0.08336380781249964,0.06969017812500017,-0.3458499609374995

753.544,7.283999999999957,2.734375,-0.0390625,-1.2734375,0.15506568281249922,0.06866586562500018,-0.3792425484374993

760.985,7.441000000000031,1.91796875,-0.14453125,0.36328125,0.20644346249999942,0.06479422031250016,-0.3695111156249993

772.745,11.759999999999993,0.2890625,0.08203125,-0.0859375,0.21868121249999942,0.06826709531250016,-0.3731493656249993

778.3919999999999,5.646999999999958,1.8984375,0.015625,-1.0,0.25727492812499914,0.06858473906250015,-0.3934785656249991

795.9209999999999,17.529000000000018,-3.234375,0.1015625,0.79296875,0.05317163437499892,0.07499377968750016,-0.34343874843749905

807.79,11.869000000000018,1.8359375,-0.203125,1.03125,0.13161830624999907,0.06631457343750015,-0.299375085937499

819.5519999999999,11.76199999999994,-2.48828125,0.09375,0.46484375,0.026256515624999605,0.07028424843750013,-0.27969211406249916

843.433,23.881000000000043,-3.05078125,0.12109375,0.75390625,-0.23602402968750083,0.08069487187500014,-0.21487758749999902

850.829,7.395999999999958,1.10546875,-0.078125,-0.203125,-0.20659026093750102,0.07861474687500015,-0.22028591249999901

858.428,7.599000000000022,1.98828125,-0.21484375,1.10546875,-0.15219804375000084,0.07273739531250013,-0.19004426718749892

878.398,19.97000000000004,1.484375,0.02734375,-0.76171875,-0.04548335625000062,0.07470319218750014,-0.24480575156249904

886.02,7.622000000000018,-0.078125,-0.26953125,-1.22265625,-0.047627043750000625,0.06730747031250012,-0.27835446093749916

903.433,17.41300000000001,1.140625,-0.0234375,-0.13671875,0.02387508749999942,0.06583824843750011,-0.28692492187499913

920.848,17.414999999999957,-1.67578125,0.10546875,3.40234375,-0.08118634218750033,0.0724505062500001,-0.07361838281249965

936.812,15.963999999999977,-0.171875,-0.0390625,-0.90625,-0.09106406718750032,0.0702055687500001,-0.12570093281249958

955.748,18.936000000000064,0.875,0.0,-0.08203125,-0.03141566718750012,0.0702055687500001,-0.13129297031249962

963.6289999999999,7.880999999999916,1.66015625,-0.26953125,-0.76171875,0.01568562187499938,0.06255853593750019,-0.15290414999999938

975.7679999999999,12.13900000000001,-0.28515625,0.046875,0.01953125,0.0032241796874993662,0.0646069921875002,-0.15205062656249937

991.317,15.549000000000035,-1.609375,0.046875,-0.9296875,-0.08686283906250084,0.0672308859375002,-0.20409118593749948

1015.6400000000001,24.323000000000093,0.22265625,0.0078125,0.71875,-0.06736643437500077,0.0679149703125002,-0.14115542343749923

1034.039,18.39899999999983,2.453125,0.0,-1.76953125,0.09511973437499774,0.0679149703125002,-0.25836280312499815

1043.08,9.041000000000077,-1.359375,-0.10546875,-0.78515625,0.05087534062499737,0.06448221562500017,-0.2839177546874984

1053.598,10.518000000000027,0.8046875,-0.01171875,1.19921875,0.08134467187499744,0.06403848750000017,-0.23850957656249827

1060.4560000000001,6.858000000000031,2.828125,-0.01171875,0.5,0.15116768437499775,0.06374916562500017,-0.2261651765624982

1069.37,8.913999999999866,-2.01953125,-0.125,-0.046875,0.08636011874999872,0.05973786562500023,-0.2276694140624982

1078.0590000000002,8.689000000000169,-0.859375,0.3515625,0.328125,0.05947852499999819,0.07073488125000044,-0.21740553281249797

1100.688,22.629000000000012,-1.37890625,0.19921875,1.41796875,-0.052853245312501865,0.08696411718750044,-0.10189155937499791

1116.377,15.688999999999842,-0.34765625,-0.2578125,-0.765625,-0.07248900937500168,0.0724027640625006,-0.14513436562499749

1122.9530000000002,6.576000000000359,-2.0859375,-0.01171875,-0.515625,-0.12187065937500438,0.07212533906250058,-0.15734106562499817

1133.193,10.239999999999583,1.33984375,-0.078125,0.8671875,-0.0724786593750064,0.0692453390625007,-0.12537306562499947

1147.934,14.741000000000115,-2.5078125,0.0078125,0.77734375,-0.20556225000000744,0.0696599296875007,-0.08412129843749913

1157.883,9.948999999999986,0.10546875,0.07421875,0.03125,-0.20178473906250743,0.0723181781250007,-0.08300203593749914

1167.249,9.365999999999985,0.1796875,-0.1953125,-0.77734375,-0.19572610781250743,0.06573270937500071,-0.1092122015624991

1180.39,13.14100000000007,-0.421875,0.21875,1.40625,-0.21568400156250755,0.07608124687500077,-0.04268588906249875

1197.7930000000001,17.403000000000056,-1.0546875,-0.15234375,-0.11328125,-0.2817610171875078,0.06653678906250073,-0.04978304999999877

1217.501,19.707999999999835,-0.21875,-0.14453125,-0.66015625,-0.2972810671875077,0.05628247031250082,-0.09662034374999838

1232.778,15.276999999999985,-0.40234375,0.16015625,1.1953125,-0.31940884687500765,0.06509061562500082,-0.030881503124998433

1245.1970000000001,12.41900000000018,-1.015625,-0.2421875,0.36328125,-0.3648158156250083,0.05426280000000065,-0.014639779687498198

1262.575,17.377999999999894,2.14453125,0.0625,-1.00390625,-0.23065222500000915,0.05817285000000064,-0.07744495781249781

1272.086,9.511000000000047,-1.9453125,-0.00390625,-0.515625,-0.2972589468750095,0.05803910156250064,-0.0950997515624979

1285.155,13.068999999999997,1.1875,-0.00390625,0.69140625,-0.24138897187500946,0.05785531875000064,-0.06257019374999791

1295.698,10.542999999999969,-0.8515625,-0.12890625,0.390625,-0.2737098562500094,0.052962707812500655,-0.04774409999999795

1311.107,15.409000000000006,2.0390625,0.04296875,-0.91796875,-0.1605981656250093,0.05534628750000065,-0.09866602968749798

1322.545,11.43800000000006,0.18359375,-0.30859375,-0.796875,-0.15303836250000927,0.04263938437500059,-0.13147879218749814

1332.675,10.129999999999972,-0.44140625,0.1484375,1.78125,-0.16913556562500923,0.04805260312500057,-0.06652016718749831

1346.958,14.283000000000046,-0.9765625,-0.2890625,0.1640625,-0.2193492375000094,0.03318935625000053,-0.058084270312498285

1357.845,10.886999999999869,-2.0703125,0.29296875,0.69921875,-0.3004914093750084,0.04467173906250039,-0.030679649999998615

1373.612,15.767000000000087,-2.1953125,-0.0234375,-0.7578125,-0.4250999812500091,0.04334139843750038,-0.07369399687499885

1382.679,9.066999999999936,-1.07421875,0.25390625,0.3671875,-0.4601637703125088,0.05162920312500032,-0.061708556249998936

1393.0739999999998,10.394999999999932,2.11328125,-0.015625,0.32421875,-0.38108055937500934,0.05104448437500033,-0.04957564218749901

1402.414,9.340000000000126,-2.30859375,0.109375,0.66796875,-0.4587047156250104,0.054722109375000376,-0.027115860937498713

1420.389,17.974999999999852,0.3125,-0.29296875,-1.03515625,-0.4384828406250106,0.03576410156250053,-0.09410082187499816

1440.01,19.62100000000011,3.45703125,0.1015625,-1.4765625,-0.19429336406250922,0.04293802968750057,-0.19839869999999876

1444.884,4.874000000000045,2.0,-0.13671875,-0.91015625,-0.1592005640625089,0.04053910781250055,-0.21436866562499893

1467.433,22.54899999999993,2.9375,0.03515625,-1.88671875,0.07925511093749038,0.04339296562500054,-0.3675257015624985

1475.497,8.064000000000071,-2.08984375,0.03515625,-0.76953125,0.018586110937489842,0.04441356562500055,-0.38986550156249866

1498.54,23.042999999999925,-0.328125,-0.1015625,1.68359375,-0.008633432812510071,0.035988468750000585,-0.2502033187499991

1514.921,16.38099999999998,1.73046875,0.0625,-1.19140625,0.0934150781249898,0.03967419375000058,-0.32046245156249903

1533.6860000000001,18.765000000000143,-1.53515625,0.1953125,0.16796875,-0.010290867187510992,0.05286833437500068,-0.30911549062499893

1556.975,23.288999999999895,-1.92578125,0.1484375,2.87890625,-0.17174913750001025,0.06531339375000063,-0.06774683906250005

1562.229,5.254000000000092,0.3515625,0.01171875,0.265625,-0.16509954375001012,0.06553504687500064,-0.06272270156249997

1572.1719999999998,9.942999999999813,2.75390625,0.12109375,-1.8984375,-0.06652402031251199,0.06986957343750055,-0.1306768921874987

1584.6180000000002,12.44600000000018,-1.7578125,0.41796875,0.1796875,-0.14528386406251315,0.08859691406250082,-0.1226258859374986

1599.672,15.0539999999999,2.1796875,0.1015625,-1.2109375,-0.027157007812513914,0.09410103281250079,-0.18825191718749817

1617.299,17.62700000000006,1.5703125,0.0234375,-0.328125,0.07249062656248642,0.0955883109375008,-0.20907381093749824

1627.2949999999998,9.995999999999894,-1.171875,-0.03515625,-0.90625,0.03032000156248687,0.0943231921875008,-0.2416857609374979

1646.695,19.400000000000084,2.62109375,0.04296875,-1.65234375,0.21337718906248768,0.09732412968750082,-0.3570854484374984

1666.4730000000002,19.778000000000073,0.65625,0.05078125,-0.0546875,0.26010271406248786,0.10093979531250083,-0.3609792421874984

1679.519,13.045999999999891,-0.28125,-0.03515625,-0.80078125,0.24689363906248799,0.09928866093750084,-0.3985884140624981

1699.598,20.078999999999958,2.6015625,0.078125,-1.3046875,0.43494602343748756,0.10493587968750083,-0.4928969671874979

1722.182,22.58400000000016,1.40234375,0.0625,-0.67578125,0.5489599359374884,0.11001727968750087,-0.5478396046874984

1754.434,32.251999999999946,1.7265625,0.0390625,-0.80078125,0.749426273437488,0.11455271718750087,-0.6408160734374981

1766.987,12.553000000000036,-2.140625,0.05078125,0.453125,0.6526897171874877,0.11684756250000088,-0.6203389921874981

1792.265,25.277999999999913,-2.19921875,0.109375,0.109375,0.4525590515624885,0.12680077500000084,-0.6103857796874982

1810.617,18.351999999999926,-0.59765625,-0.140625,-0.5625,0.41307357656248866,0.11751007500000087,-0.647548579687498

1829.9959999999999,19.379000000000033,1.49609375,0.0859375,-0.6875,0.5174476593749888,0.12350545312500087,-0.6955116046874982

1845.65,15.654000000000057,-1.7578125,0.0703125,-0.16015625,0.41838719062498847,0.1274678718750009,-0.7045371140624982

1861.674,16.024000000000036,0.53125,-0.0546875,-0.3515625,0.4490330906249886,0.12431314687500086,-0.7248174890624982

1876.757,15.082999999999958,-1.5,0.03125,-0.1796875,0.36758489062498884,0.12600998437500086,-0.7345743046874983

1892.618,15.860999999999903,-0.46484375,-0.12109375,-0.59375,0.34104249843748896,0.1190955796875009,-0.768477192187498

1896.993,4.375000000000018,-1.38671875,-0.07421875,-0.14453125,0.3192016781249889,0.11792663437500088,-0.770753559374998

1916.786,19.79300000000017,0.3125,-0.10546875,-0.37109375,0.34146880312498906,0.11041147968750081,-0.7971957703124982

1931.846,15.059999999999851,-0.140625,0.10546875,-0.02734375,0.33384467812498914,0.11612957343750076,-0.7986782390624984

1946.961,15.11499999999999,-0.6015625,-0.03515625,-0.515625,0.30111125624998913,0.11421658125000075,-0.8267354578124982

1964.143,17.18200000000003,0.94921875,0.17578125,-0.53515625,0.3598253718749893,0.1250895656250008,-0.8598376546874983

1971.6149999999998,7.471999999999701,0.26953125,-0.12109375,-0.44921875,0.367075546874989,0.1218322406250009,-0.8719212796874978

1982.586,10.971000000000286,-0.83984375,0.0703125,0.18359375,0.33390541406248814,0.12460927500000099,-0.8646701343749976

1998.955,16.369000000000078,0.109375,0.04296875,-0.4296875,0.34035070781248816,0.127141354687501,-0.8899909312499977

2016.616,17.660999999999927,0.03125,0.125,-0.01953125,0.3423375703124882,0.13508880468750098,-0.8912327203124977

2036.8439999999998,20.227999999999913,-0.80078125,0.0703125,0.06640625,0.28402403906248846,0.14020901718750095,-0.8863969640624977

2045.554,8.710000000000218,1.5625,0.1171875,-0.5,0.3330177890624897,0.14388354843750104,-0.9020749640624981

2058.967,13.412999999999897,-1.26953125,0.03125,-0.15625,0.27171618749999016,0.14539251093750102,-0.909619776562498

2065.516,6.549000000000138,-0.640625,0.10546875,0.171875,0.25661255624998985,0.14787908437500108,-0.9055675828124979

2071.93,6.41399999999992,1.67578125,0.14453125,-0.296875,0.2953070156249894,0.15121636875000102,-0.9124225453124978

2087.487,15.556999999999821,-1.6953125,0.15625,-0.01953125,0.20036069999999048,0.15996718125000092,-0.9135163968749979

2101.441,13.954000000000022,1.92578125,0.078125,-0.23828125,0.29710116562499067,0.16389174375000093,-0.925486312499998

2107.1240000000003,5.683000000000327,-0.2578125,0.03125,-0.25,0.2918266312499903,0.16453108125000096,-0.9306010124999983

2116.452,9.328000000000003,-1.875,0.10546875,0.11328125,0.22886263124999032,0.16807280625000098,-0.9267969374999984

2126.406,9.953999999999574,0.90234375,0.13671875,-0.3828125,0.2611975781249889,0.17297204062500074,-0.9405147937499978

2141.299,14.893000000000267,-1.5703125,0.0859375,0.20703125,0.17700558749998738,0.17757956250000081,-0.9294148546874976

2158.757,17.457999999999974,0.40234375,-0.0859375,-0.375,0.20229240937498735,0.17217849375000083,-0.9529831546874976

2171.176,12.418999999999958,-0.765625,0.05859375,0.24609375,0.16806254062498746,0.17479812656250082,-0.9419806968749975

2188.824,17.647999999999886,-0.0546875,0.03125,0.0546875,0.16458809062498747,0.1767835265625008,-0.9385062468749975

2205.342,16.518000000000033,1.4375,0.15625,-0.328125,0.25006874062498763,0.1860749015625008,-0.9580181343749975

2224.0820000000003,18.7400000000002,-0.5546875,0.0625,0.265625,0.21264730312498725,0.19029140156250085,-0.9400980093749973

2238.698,14.61599999999974,1.1015625,0.03125,0.390625,0.2706088781249862,0.19193570156250084,-0.9195442593749976

2256.198,17.50000000000007,0.6328125,0.1171875,-0.05078125,0.31047606562498636,0.19931851406250087,-0.9227434781249977

2263.675,7.477000000000178,1.29296875,0.05859375,0.4765625,0.3452791640624872,0.2008956937500009,-0.9099157499999974

2271.065,7.390000000000008,-1.0078125,-0.046875,-0.203125,0.31846732031248715,0.1996486312500009,-0.9153196874999974

2283.5519999999997,12.486999999999693,0.51953125,0.0703125,0.046875,0.34182191249998656,0.20280940312500084,-0.9132125062499974

2294.441,10.889000000000149,0.06640625,-0.12109375,-0.3203125,0.3444250640624866,0.1980624796875008,-0.9257688843749976

2301.168,6.7270000000001495,-0.98828125,-0.12109375,-0.08984375,0.320491659374986,0.1951299281250007,-0.9279446484374977

2308.8540000000003,7.686000000000082,-0.23828125,0.05859375,0.03515625,0.31389851249998596,0.19675119375000075,-0.9269718890624977

2326.245,17.39099999999949,-1.11328125,-0.0546875,0.07421875,0.24419864531248803,0.19332734062500084,-0.9223252312499978

2338.503,12.258000000000546,0.8515625,-0.0546875,0.640625,0.28177707656248974,0.19091404687500074,-0.8940552187499965

2355.971,17.467999999999595,-0.74609375,-0.02734375,-0.1640625,0.23485912031249082,0.1891945406250008,-0.9043722562499963

2373.526,17.55500000000021,0.94921875,-0.07421875,-0.26171875,0.29484784687499155,0.18450406406250072,-0.9209123578124966

2391.997,18.470999999999904,0.9296875,0.078125,0.54296875,0.3566679749999912,0.1896990328125007,-0.8848073249999967

2407.4840000000004,15.48700000000025,-1.16015625,0.0703125,0.2265625,0.2919855515624902,0.19361917968750075,-0.8721757406249965

2420.849,13.36499999999985,0.8515625,0.078125,0.484375,0.3329576296874897,0.19737808593750072,-0.8488705218749968

2435.933,15.083999999999875,-0.765625,0.0390625,0.71484375,0.2913823546874901,0.1994992734375007,-0.8100527906249971

2453.358,17.425000000000246,1.37890625,0.14453125,-0.26171875,0.37788114374999127,0.20856571875000082,-0.8264704078124974

2471.017,17.658999999999647,-0.078125,0.078125,0.46484375,0.37291454999999135,0.2135323125000007,-0.796919174999998

2488.319,17.302000000000373,-0.46875,-0.078125,0.23828125,0.3437174249999907,0.20866612500000062,-0.7820773031249977

2498.355,10.035999999999934,0.0078125,0.0078125,0.49609375,0.3439996874999907,0.2089483875000006,-0.7641536343749977

2504.933,6.577999999999751,1.5703125,0.06640625,0.03515625,0.38118594374998926,0.21052094062500054,-0.7633211062499978

2520.651,15.71800000000012,-0.60546875,0.06640625,0.484375,0.346925615624989,0.21427852500000055,-0.7359128437499975

2540.7039999999997,20.052999999999876,-0.8359375,-0.01171875,0.390625,0.2865786187499894,0.21343253906250054,-0.7077133124999978

2600.744,60.04000000000032,-1.21875,0.078125,0.6015625,0.023153118749987996,0.2303187890625006,-0.5776891874999971

2700.391,99.64700000000005,-1.29296875,0.01171875,0.24609375,-0.4406725265625122,0.2345226468750006,-0.48940817343749704

2708.0009999999997,7.609999999999673,-0.01171875,-0.01953125,0.46875,-0.44099357343751217,0.23398756875000062,-0.4765662984374976

2735.22,27.219000000000104,0.2578125,-0.0859375,0.6328125,-0.4157309390625121,0.2255666906250006,-0.41455801406249737

2750.3669999999997,15.1469999999998,0.640625,-0.09765625,0.046875,-0.3807981703125125,0.2202415734375007,-0.4120019578124974

2757.812,7.445000000000146,-1.51171875,0.02734375,0.671875,-0.42131525625001337,0.22097444062500068,-0.39399436406249705

2768.011,10.19900000000007,1.83984375,0.0859375,0.48046875,-0.3537628171875129,0.22412975625000073,-0.37635328124999695

2775.443,7.432000000000105,0.2890625,-0.25,0.23828125,-0.3460288921875128,0.21744095625000062,-0.36997801874999686

2782.983,7.540000000000102,-1.3984375,-0.01171875,0.5390625,-0.3839880796875133,0.21712286250000062,-0.3553457062499966

2792.8269999999998,9.843999999999742,0.98828125,-0.11328125,0.453125,-0.3489649734375142,0.21310835625000074,-0.33928768124999703

2803.283,10.45600000000002,-0.09375,-0.05859375,0.01171875,-0.3524938734375142,0.21090279375000073,-0.338846568749997

2817.648,14.365000000000183,1.07421875,-0.1328125,0.9140625,-0.29694172500001353,0.2040345281250006,-0.29157674062499644

SDV

As you can see there i negative speed while the camere nevere move backward

I suspect that the camera timestamp is not correct.

SDV

I've made many other try changing the way dt is evaluate, using acceleroValues.getTimestamp()

but values are totally unreliable leading to very high speed or negative speed

SamiUddin

@jakaskerl shouldn't the speed node included in Depthai by the team? Or we can get accurate speed from the same node (IMU). If LUXONIS Team themselves work on this.
Kind Regards!

SDV

I've made others tests and I found something odd.

These are timestamps taken using 15Hz acquisition frequency:

Timestamp (ms) Delta t (ms)
0 0
59,922 59,922
119,826 59,904
179,751 59,925
239,489 59,738
299,436 59,947
359,638 60,202
419,441 59,803

All intervals are around 60 ms but at 15 Hz, it should be 66 ms

if there are 6 ms of error on 66 then there is a 10% of error.

Is it possible that for some reason the interval reported is shorter than the real?

jakaskerl

Hi @SDV
What you have sent seems like standard drift due to integration error. Nothing you can do about it without sensor fusion, but that is part of VIO.
Did you move the device when recording the data you have sent? I can confirm using your script, the accelerometer stays pretty much as 0.0 +/- 0.1 when stationary.

Thanks,
Jaka

SDV

jakaskerl yes. It was recorded with the camera mounted on a car