4. find_apriltags_3d_pose怎么矫正degrees(tag.y_rotation()输出的角度呢？
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    • find_apriltags_3d_pose怎么矫正degrees(tag.y_rotation()输出的角度呢？

    • G

      我使用find_apriltags_3d_pose进行定位，使用的是自带的例程，degrees(tag.y_rotation()输出的角度误差有点大，怎么矫正呢？

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    • 效果可以看视频https://singtown.com/learn/49590/

      哪里误差大？

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    • G

      Ry测得不太准，角度变化幅度差个10度左右，要用来测偏航角，可以怎么调呢

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    • 完全静止的实验结果。

      Tx: -0.876480, Ty -0.875055, Tz -4.575914, Rx 180.150433, Ry 6.354074, Rz 358.055329
15.73255
Tx: -0.877966, Ty -0.875999, Tz -4.577111, Rx 180.367575, Ry 6.300081, Rz 357.986689
15.75533
Tx: -0.876948, Ty -0.874614, Tz -4.578795, Rx 179.817924, Ry 6.323055, Rz 358.099103
15.76182
Tx: -0.876134, Ty -0.869385, Tz -4.583478, Rx 178.142729, Ry 6.134091, Rz 358.320308
15.75456
Tx: -0.872988, Ty -0.871366, Tz -4.578303, Rx 178.983712, Ry 6.407222, Rz 358.148885
15.74803
Tx: -0.874213, Ty -0.876486, Tz -4.573614, Rx 180.403500, Ry 6.432562, Rz 357.971454
15.76577
Tx: -0.877095, Ty -0.876739, Tz -4.577353, Rx 180.513811, Ry 6.425136, Rz 357.979250
15.77061
Tx: -0.873796, Ty -0.881208, Tz -4.558734, Rx 182.609558, Ry 6.241501, Rz 357.637358
15.95007
Tx: -0.877497, Ty -0.874676, Tz -4.578373, Rx 179.805861, Ry 6.318311, Rz 358.043957
15.96806
Tx: -0.871220, Ty -0.874167, Tz -4.573812, Rx 179.940500, Ry 6.470804, Rz 357.929111
15.94388
Tx: -0.869778, Ty -0.877163, Tz -4.568369, Rx 181.178083, Ry 6.526481, Rz 357.621717
15.91187
Tx: -0.876682, Ty -0.873590, Tz -4.578239, Rx 179.537163, Ry 6.451271, Rz 358.104944
15.8917
Tx: -0.878050, Ty -0.873434, Tz -4.582887, Rx 179.837093, Ry 6.664645, Rz 358.078647
15.87302
Tx: -0.877403, Ty -0.873518, Tz -4.581779, Rx 179.661536, Ry 6.160123, Rz 358.075213
15.85566
Tx: -0.884307, Ty -0.880222, Tz -4.573338, Rx 181.696568, Ry 6.194533, Rz 357.899427
15.85624
Tx: -0.880510, Ty -0.878864, Tz -4.579540, Rx 181.230068, Ry 6.757317, Rz 357.888746
15.87302
Tx: -0.883886, Ty -0.881483, Tz -4.572171, Rx 182.334385, Ry 6.461762, Rz 357.741356
15.88089
Tx: -0.884561, Ty -0.886061, Tz -4.563071, Rx 183.927708, Ry 6.960098, Rz 357.506561
16.12903
Tx: -0.881572, Ty -0.887242, Tz -4.557488, Rx 184.484282, Ry 7.110193, Rz 357.402182
16.80672
Tx: -0.877879, Ty -0.881150, Tz -4.581673, Rx 181.341944, Ry 7.744792, Rz 358.126998
16.94915
Tx: -0.882642, Ty -0.886221, Tz -4.560514, Rx 183.909941, Ry 7.043563, Rz 357.458210
16.59751
Tx: -0.884153, Ty -0.885133, Tz -4.566542, Rx 183.425283, Ry 7.175475, Rz 357.485414
17.60563
Tx: -0.884453, Ty -0.879402, Tz -4.583936, Rx 180.911770, Ry 6.985199, Rz 357.808566
17.54386
Tx: -0.880853, Ty -0.883418, Tz -4.568888, Rx 182.969961, Ry 7.380502, Rz 357.617998
17.41294
Tx: -0.887471, Ty -0.882891, Tz -4.581702, Rx 181.851959, Ry 7.895341, Rz 357.690859
17.13062
Tx: -0.881699, Ty -0.883692, Tz -4.577967, Rx 182.180204, Ry 8.012682, Rz 357.668471
17.01323
Tx: -0.887495, Ty -0.884634, Tz -4.569012, Rx 182.966194, Ry 8.042303, Rz 357.729912
16.89189
Tx: -0.878844, Ty -0.879375, Tz -4.572147, Rx 181.462584, Ry 6.389551, Rz 357.814908
16.71733
Tx: -0.879639, Ty -0.876852, Tz -4.573839, Rx 180.736942, Ry 6.149974, Rz 357.932377
16.64355
Tx: -0.859951, Ty -0.880023, Tz -4.568498, Rx 181.950712, Ry 6.497900, Rz 357.704043
16.51842
Tx: -0.876829, Ty -0.882930, Tz -4.555437, Rx 183.461838, Ry 6.577980, Rz 357.517791
16.47059
Tx: -0.869249, Ty -0.876673, Tz -4.571870, Rx 180.786037, Ry 6.569314, Rz 357.682490
16.51982
Tx: -0.872511, Ty -0.879409, Tz -4.562423, Rx 181.984663, Ry 6.361035, Rz 357.649660
16.46091
Tx: -0.875411, Ty -0.876481, Tz -4.568241, Rx 180.968151, Ry 6.093893, Rz 357.897186
16.42512
Tx: -0.868971, Ty -0.872772, Tz -4.579243, Rx 179.335451, Ry 6.543279, Rz 357.876039
16.33394
Tx: -0.868229, Ty -0.873594, Tz -4.577209, Rx 179.625678, Ry 6.703719, Rz 357.871532
16.29503
Tx: -0.870917, Ty -0.875364, Tz -4.576222, Rx 180.201063, Ry 6.540730, Rz 357.832289
16.27339
Tx: -0.868719, Ty -0.873341, Tz -4.576048, Rx 179.709458, Ry 6.636948, Rz 357.818413
16.2917
      0
    • G

      静止没什么问题，是测变化幅度不准，我把tag水平旋转一定角度，他测得的角度变化幅度(Ry变化度数)不对

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    • 0_1560579924263_65c8b933-2f01-4c99-85ac-4404874a0249-image.png

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    • 0_1560579966336_27a68b1a-a3f7-4459-88cb-3f1ff77690e3-image.png

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    • 0_1560580026555_ae8e945a-99ee-442a-92c9-b5e1ed1f37e9-image.png

      0

    • 我测试数据是正常的。
      请提供你的图片。

      # AprilTags Example
#
# This example shows the power of the OpenMV Cam to detect April Tags
# on the OpenMV Cam M7. The M4 versions cannot detect April Tags.

import sensor, image, time, math

sensor.reset()
sensor.set_pixformat(sensor.GRAYSCALE)
sensor.set_framesize(sensor.QQVGA) # we run out of memory if the resolution is much bigger...
sensor.skip_frames(time = 2000)
sensor.set_auto_gain(False)  # must turn this off to prevent image washout...
sensor.set_auto_whitebal(False)  # must turn this off to prevent image washout...
clock = time.clock()

# Note! Unlike find_qrcodes the find_apriltags method does not need lens correction on the image to work.

# What's the difference between tag families? Well, for example, the TAG16H5 family is effectively
# a 4x4 square tag. So, this means it can be seen at a longer distance than a TAG36H11 tag which
# is a 6x6 square tag. However, the lower H value (H5 versus H11) means that the false positve
# rate for the 4x4 tag is much, much, much, higher than the 6x6 tag. So, unless you have a
# reason to use the other tags families just use TAG36H11 which is the default family.

# The AprilTags library outputs the pose information for tags. This is the x/y/z translation and
# x/y/z rotation. The x/y/z rotation is in radians and can be converted to degrees. As for
# translation the units are dimensionless and you must apply a conversion function.

# f_x is the x focal length of the camera. It should be equal to the lens focal length in mm
# divided by the x sensor size in mm times the number of pixels in the image.
# The below values are for the OV7725 camera with a 2.8 mm lens.

# f_y is the y focal length of the camera. It should be equal to the lens focal length in mm
# divided by the y sensor size in mm times the number of pixels in the image.
# The below values are for the OV7725 camera with a 2.8 mm lens.

# c_x is the image x center position in pixels.
# c_y is the image y center position in pixels.

f_x = (2.8 / 3.984) * 160 # find_apriltags defaults to this if not set
f_y = (2.8 / 2.952) * 120 # find_apriltags defaults to this if not set
c_x = 160 * 0.5 # find_apriltags defaults to this if not set (the image.w * 0.5)
c_y = 120 * 0.5 # find_apriltags defaults to this if not set (the image.h * 0.5)

def degrees(radians):
    return (180 * radians) / math.pi

while(True):
    clock.tick()
    img = sensor.snapshot()
    for tag in img.find_apriltags(fx=f_x, fy=f_y, cx=c_x, cy=c_y): # defaults to TAG36H11
        img.draw_rectangle(tag.rect(), color = (255, 0, 0))
        img.draw_cross(tag.cx(), tag.cy(), color = (0, 255, 0))
        # Translation units are unknown. Rotation units are in degrees.
        img.draw_string(0,0,"Rx %f" % degrees(tag.x_rotation()))
        img.draw_string(0,10,"Ry %f" % degrees(tag.y_rotation()))
        img.draw_string(0,20,"Rz %f" % degrees(tag.z_rotation()))
        img.draw_string(0,90,"Rx %f" % tag.x_translation())
        img.draw_string(0,100,"Ry %f" % tag.y_translation())
        img.draw_string(0,110,"Rz %f" % tag.z_translation())
        #print("Rx %f, Ry %f, Rz %f" % print_args)
    #print(clock.fps())
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      G
       2 条回复
    • G

      @kidswong999 2_1561077384154_3.png 1_1561077384154_2.png 0_1561077384153_1.png

      0
    • G

      @kidswong999
      我在Ry方向间隔10度变化一次，测得的Ry变化角度不对，请教该怎么调呢

      0

    • Ry哪里不对？？

      0
    • G

      三张图片里Ry的实际值分别应该是360.10.20左右，但测得的是360,15,30左右,就是说，第一张图片里Ry应该是20左右,第二张图片里应该是10左右才对

      0

    • 我怎么觉得这属于仪器的精度。

      比如OpenMV的水平精度。apriltag的位置精度，角度你是用的什么仪器摆放的？

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    • G

      仪器精度误差没这么大，openmv固定还算准，Apriltag摆放角度是拿量角器量的，误差都没这么大。
      你测得是准的嘛，你用的程序是上面那个吗，我试了试更离谱，难道我用的镜头不适用这俩程序？0_1561115220246_webwxgetmsgimg.jpg

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