Hi,
I’ve been having a great time using an OpenMV H7 for an AprilTags application. Unfortunately I’m running into a problem, though, where the camera works perfectly for about 20-30 minutes and then stops sending out data. I saw another thread with a similar problem where the suggestion was to re-flash the firmware, and I’ll give that a try tomorrow, but in the meantime I wondered if there was anything obvious about my code that could be causing problems.
It’s a slightly modified version of one of the AprilTags examples; I drag a set_windowing area around the VGA space so I can look for tags throughout the FOV.
Thanks for any help!
# Code Composer Apriltags
#
# Based on "AprilTags Example" that came with the camera
#
# 0.01: Hello world
# 0.02: Working on moving the subwindow around to scan for tags
# 0.03: It works! Taking out the debug print() commands
# 0.04: New track layout to support both card orientations
#
import sensor, image, time, math
sensor.reset()
sensor.set_pixformat(sensor.GRAYSCALE)
sensor.set_framesize(sensor.VGA) # we run out of memory if the resolution is much bigger...
sensor.set_hmirror(True)
sensor.set_vflip(True)
sensor.set_windowing(0,0,160, 200)
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.
# The apriltag code supports up to 6 tag families which can be processed at the same time.
# Returned tag objects will have their tag family and id within the tag family.
tag_families = 0
#tag_families |= image.TAG16H5 # comment out to disable this family
#tag_families |= image.TAG25H7 # comment out to disable this family
#tag_families |= image.TAG25H9 # comment out to disable this family
#tag_families |= image.TAG36H10 # comment out to disable this family
tag_families |= image.TAG36H11 # comment out to disable this family (default family)
#tag_families |= image.ARTOOLKIT # comment out to disable this family
# 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.
def family_name(tag):
if(tag.family() == image.TAG16H5):
return "TAG16H5"
if(tag.family() == image.TAG25H7):
return "TAG25H7"
if(tag.family() == image.TAG25H9):
return "TAG25H9"
if(tag.family() == image.TAG36H10):
return "TAG36H10"
if(tag.family() == image.TAG36H11):
return "TAG36H11"
if(tag.family() == image.ARTOOLKIT):
return "ARTOOLKIT"
rows = [0, 170, 333]
while(True):
# clock.tick()
print("Z")
track = 0
index = 0
for row in rows:
for step in range(0,5):
sensor.set_windowing(120*step, row, 160, 184)
img = sensor.snapshot()
for tag in img.find_apriltags(families=tag_families): # defaults to TAG36H11 without "families".
# img.draw_rectangle(tag.rect(), color = (255, 0, 0))
# img.draw_cross(tag.cx(), tag.cy(), color = (0, 255, 0))
print_args = (track, index, tag.id(), tag.cx()+120*step, tag.cy()+row, (180 * tag.rotation()) / math.pi)
print("%d,%d,%d,%d,%d,%f," % print_args, end="")
# print_args = (tag.id(), tag.cx()+120*step, tag.cy()+row, (180 * tag.rotation()) / math.pi)
# print("Tag ID %d, x= %d, y= %d, rotation %f (degrees), " % print_args, end="")
index = index + 1
# time.sleep(0.5)
track = (track + 1) % 3
index = 0