@kidswong999 改成320* 0.5和240 * 0.5，那70和71行是不是也要改啊？

@kidswong999
apritag明显不在中间，输出的x的值约等于0，这偏差这么大
什么原因，我买了几块板子都是这样。

@kidswong999

请在这里粘贴代码![0_1602846716937_微信图片_20201016191141.png](正在上传 100%) 
```就是运行代码，您这偏差这么大，什么情况？我买了几块这样的板子，都是这样的

import sensor, image, time,mjpeg, math,pyb,tv
from struct import pack , unpack
sensor.reset()
sensor.set_pixformat(sensor.RGB565)
sensor.set_framesize(sensor.QVGA)
sensor.skip_frames(time = 2000)
sensor.set_auto_gain(False)
sensor.set_auto_whitebal(False)
tv.init()
tv.channel(8)
clock = time.clock()
uart = pyb.UART(3, 115200, timeout_char = 1000)
packet_sequence = 0
flag = False
n = 0;
def checksum(data, extra):
    output = 0xFFFF
    for i in range(len(data)):
        tmp = data[i] ^ (output & 0xFF)
        tmp = (tmp ^ (tmp << 4)) & 0xFF
        output = ((output >> 8) ^ (tmp << 8) ^ (tmp << 3) ^ (tmp >> 4)) & 0xFFFF
    tmp = extra ^ (output & 0xFF)
    tmp = (tmp ^ (tmp << 4)) & 0xFF
    output = ((output >> 8) ^ (tmp << 8) ^ (tmp << 3) ^ (tmp >> 4)) & 0xFFFF
    return output
def set_position_target_local_ned_send(time_boot_ms, target_system, target_component, coordinate_frame, type_mask, x, y, z, vx, vy, vz, afx, afy, afz, yaw, yaw_rate, force_mavlink1=False):
    seq = 0xb
    global packet_sequence
    tmp=pack("<5BIfffffffffffHBBB",0x35,packet_sequence,target_system, target_component,0x54,time_boot_ms,x,y,z,vx,vy,vz,afx, afy, afz, yaw, yaw_rate,type_mask,0, 0, coordinate_frame)
    crc = checksum(tmp,143)
    tmp= pack("<b58sh",0xfe,tmp,crc)
    packet_sequence += 1
    uart.write(tmp)
def command_long_send( target_system, target_component,  yaw):
    sign = 1
    if yaw<0:
         sign=-1
         yaw=-yaw
    seq = 0xe
    global packet_sequence
    tmp=pack("<5BfffffffHBBB",0x21,seq,target_system, target_component,0x4c,yaw,0,sign,1,0,0,0,0x73,0, 0)
    crc = checksum(tmp,152)
    tmp= pack("<b38sh",0xfe,tmp,crc)
    packet_sequence += 1
    uart.write(tmp)
def data_encode(x,y,z,roll,pitch,yaw):
    global flag
    flag = not flag
    if flag:
        set_position_target_local_ned_send(
                      0,
                      0xff,
                      0,
                      8,
                      0xdf8,
                      x,y,z,
                      roll,pitch,yaw,
                      0, 0, 0,
                      0, 0.9)
    else:
        if yaw>180:
            yaw=yaw-360
        if yaw >5:
            yaw = 5
        elif yaw<-5:
            yaw = -5
        else:
            yaw = 0
        command_long_send( 0xff, 0,  yaw)
f_x = (2.8 / 3.6736) * 160
f_y = (2.8 / 2.7384) * 120
c_x = 160 * 0.5
c_y = 120 * 0.5
Depth = 10000000
tag_families = 0
tag_families |= image.TAG36H11
m = mjpeg.Mjpeg("example.mjpeg")
def family_name(tag):
    if(tag.family() == image.TAG36H11):
        return 112
valid_tag_ids = {
                  0 : 432,
                  1 : 144,
                  2 : 48,
                }
def degrees(radians):
    return (180 * radians) / math.pi
while(True):
    clock.tick()
    img = sensor.snapshot()
    n = n + 1
    apriltagInfor = img.find_apriltags(families=tag_families,fx=f_x, fy=f_y, cx=c_x, cy=c_y)
    x = 0
    y = 0
    z = 0
    xdegrees = 0
    ydegreess = 0
    zdegreess = 0
    num = len(apriltagInfor)
    idMax = 1000
    iSigned = 0
    DepthMin = 100000
    if num > 0:
        for tagMax in apriltagInfor:
            ID = tagMax.id()
            if ID == 0:
                Depth0 = tagMax.z_translation()*(-512.4)
                if DepthMin > Depth0:
                   DepthMin = Depth0
                   idMax = 0
            elif ID == 1:
                Depth1 = tagMax.z_translation() * (-165.5)
                #print("D=%f"%Depth1)
                if DepthMin > Depth1:
                    DepthMin = Depth1
                    idMax = 1
            elif ID == 2:
                Depth2 = tagMax.z_translation() * (-53.3)
                #Depth3 = tagMax.x_translation() * (1)
                #Depth4 = tagMax.y_translation() * (1)
                #print("x=%f"%Depth3)
                #print("y=%f"%Depth4)
                if DepthMin > Depth2:
                    DepthMin = Depth2
                    idMax = 2
    if (DepthMin - Depth > 200 or Depth > DepthMin):
        Depth = DepthMin
    if num > 0:
        for tag in apriltagInfor:
            ID = tag.id()
            if Depth > 3000:
                if ID == 0:
                    img.draw_rectangle(tag.rect(), color = (255, 0, 0))
                    img.draw_cross(tag.cx(), tag.cy(), color = (0, 255, 0))
                    x = tag.x_translation() * (-104.9)#-180
                    y = tag.y_translation() * (-108.7)#-190.3
                    z = tag.z_translation() * (-512.4)#-259.9
                    xdegrees  = degrees(tag.x_rotation())
                    ydegreess = degrees(tag.y_rotation())
                    zdegreess = degrees(tag.z_rotation())
                    data_encode(x,y,z,xdegrees,ydegreess,zdegreess)
                    print_args = (x, y, z, \
                        degrees(tag.x_rotation()), degrees(tag.y_rotation()), degrees(tag.z_rotation()))
                else:
                    img.draw_rectangle(tag.rect(), color = (0, 255, 0))
                    img.draw_cross(tag.cx(), tag.cy(), color = (0, 0, 255))
            elif(Depth <= 3000) and (Depth > 800):
                if ID == 1:
                    img.draw_rectangle(tag.rect(), color = (255, 0, 0))
                    img.draw_cross(tag.cx(), tag.cy(), color = (0, 255, 0))
                    x = tag.x_translation() * (-33.4)#-180
                    y = tag.y_translation() * (-36.5)#-86.6
                    z = tag.z_translation() * (-165.5)#104
                    xdegrees  = degrees(tag.x_rotation())
                    ydegreess = degrees(tag.y_rotation())
                    zdegreess = degrees(tag.z_rotation())
                    data_encode(x,y,z,xdegrees,ydegreess,zdegreess)
                    print_args = (x, y, z, \
                        degrees(tag.x_rotation()), degrees(tag.y_rotation()), degrees(tag.z_rotation()))
                else:
                    img.draw_rectangle(tag.rect(), color = (0, 255, 0))
                    img.draw_cross(tag.cx(), tag.cy(), color = (0, 0, 255))
            elif(Depth <= 800):
               if ID == 2:
                   img.draw_rectangle(tag.rect(), color = (255, 0, 0))
                   img.draw_cross(tag.cx(), tag.cy(), color = (0, 255, 0))
                   x = tag.x_translation() * (-11.6)#-180
                   y = tag.y_translation() * (-11.8)#-190.3
                   z = tag.z_translation() * (-53.3)#-28.9
                   xdegrees  = degrees(tag.x_rotation())
                   ydegreess = degrees(tag.y_rotation())
                   zdegreess = degrees(tag.z_rotation())
                   data_encode(x,y,z,xdegrees,ydegreess,zdegreess)
                   print_args = (x, y, z, \
                       degrees(tag.x_rotation()), degrees(tag.y_rotation()), degrees(tag.z_rotation()))
               else:
                   img.draw_rectangle(tag.rect(), color = (0, 255, 0))
                   img.draw_cross(tag.cx(), tag.cy(), color = (0, 0, 255))
    tv.display(img)
    if n <=10000:
        m.add_frame(img)
        if n == 10000:
            m.close(clock.fps())
    #print("n = %d"%n)
    #print(clock.fps())

输出的位置信息和实际的位置信息偏差很大

使用OpenMV H4 Plus，QVGA图片，识别Apriltag，帧率很慢，大概只有1秒只有5帧左右，怎样提高识别帧率？

上图红色框分别是识别到的Apritag，及他输出的x，感觉x和实际Apritag在图像中的位置偏差很大啊

@fr5c USB接口的TX和RX,说错了，是usb不是串口

OpenMV上的串口TX和RX和哪些pin是连在一起的啊？我想使用线把TX和RX与其他设备的RX和TX相连

，这是别人的接收器的参数，为啥接收不了啊？