Code running on camera
# Single Color RGB565 Blob Tracking Example
#
# This example shows off single color RGB565 tracking using the OpenMV Cam.
import sensor, image, time, math, pyb, ustruct
from pyb import USB_VCP
#def blobDetails(blobInput, xMin, xMax, yMin, yMax):
led = pyb.LED(1) # Red LED = 1, Green LED = 2, Blue LED = 3, IR LEDs = 4.
threshold_index = 0 # 0 for red, 1 for green, 2 for blue
# Color Tracking Thresholds (L Min, L Max, A Min, A Max, B Min, B Max)
# The below thresholds track in general red/green/blue things. You may wish to tune them...
thresholds = [(30, 100, 15, 127, 15, 127), # generic_red_thresholds
(30, 100, -64, -8, -32, 32), # generic_green_thresholds
(0, 30, 0, 64, -128, 0)] # generic_blue_thresholds
sensor.reset()
sensor.set_pixformat(sensor.RGB565)
sensor.set_framesize(sensor.QVGA)
sensor.skip_frames(time = 2000)
sensor.set_auto_gain(False) # must be turned off for color tracking
sensor.set_auto_whitebal(False) # must be turned off for color tracking
clock = time.clock()
# Creat usb virtual communication port.
usb = USB_VCP()
# Switch on red led to indicate program is running
led.on()
# Only blobs that with more pixels than "pixel_threshold" and more area than "area_threshold" are
# returned by "find_blobs" below. Change "pixels_threshold" and "area_threshold" if you change the
# camera resolution. "merge=True" merges all overlapping blobs in the image.
while(True):
img = sensor.snapshot()
for blob in img.find_blobs([thresholds[threshold_index]], pixels_threshold=200, area_threshold=200, merge=True):
print(clock.tick())
# These values depend on the blob not being circular - otherwise they will be shaky.
if blob.elongation() > 0.5:
img.draw_edges(blob.min_corners(), color=(255,0,0))
img.draw_line(blob.major_axis_line(), color=(0,255,0))
img.draw_line(blob.minor_axis_line(), color=(0,0,255))
# These values are stable all the time.
img.draw_rectangle(blob.rect())
img.draw_cross(blob.cx(), blob.cy())
# Note - the blob rotation is unique to 0-180 only.
img.draw_keypoints([(blob.cx(), blob.cy(), int(math.degrees(blob.rotation())))], size=20)
print("blob rectangle ", blob.rect())
print("blob center.", blob.cx(), blob.cy())
cmd = usb.recv(4, timeout=5000)
if (cmd == b'snap'):
usb.send(ustruct.pack("<II", blob.cx(), blob.cy()))
Code running on receiving side(raspberry pi 3 b+)
#!/usr/bin/env python2.7
import sys, serial, struct
port = '/dev/ttyACM0'
sp = serial.Serial(port, baudrate=115200, bytesize=serial.EIGHTBITS, parity=serial.PARITY_NONE,
xonxoff=False, rtscts=False, stopbits=serial.STOPBITS_ONE, timeout=None, dsrdtr=True)
sp.setDTR(True) # dsrdtr is ignored on Windows.
while(True):
sp.write("snap")
sp.flush()
sentData = struct.unpack('<II', sp.read(8))
# Raw output.
'''print("X coordinate: {0}, Y coordinate: {1}".format(sentData[0], sentData[1]))'''
# Filter garbage.
if ((sentData[0] > -1) and (sentData[0] < 320)):
if ((sentData[1] > -1) and (sentData[1] < 240)):
print("X coordinate: {0}, Y coordinate: {1}".format(sentData[0], sentData[1]))
sp.close()