Single Color Grayscale Blob Tracking Example-while blob in black blob--missing

OpenMV Products
1 
# Single Color Grayscale Blob Tracking Example
#
# This example shows off single color grayscale tracking using the OpenMV Cam.

import sensor, image, time, math

# Color Tracking Thresholds (Grayscale Min, Grayscale Max)
# The below grayscale threshold is set to only find extremely bright white areas.


sensor.reset()
sensor.set_pixformat(sensor.GRAYSCALE)
sensor.set_framesize(sensor.FHD)
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()
thresholds = (170, 255)
# 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):
    clock.tick()
    img = sensor.snapshot()
    for blob in img.find_blobs([thresholds], pixels_threshold=100, area_threshold=100, merge=True):
        # 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=0)
            img.draw_line(blob.major_axis_line(), color=0)
            img.draw_line(blob.minor_axis_line(), color=0)
        # These values are stable all the time.
        img.draw_rectangle(blob.rect(), color=250,thickness=5)
        img.draw_cross(blob.cx(), blob.cy(), color=250,thickness=5)
        # Note - the blob rotation is unique to 0-180 only.
        img.draw_keypoints([(blob.cx(), blob.cy(), int(math.degrees(blob.rotation())))], size=40, color=127)
    print(clock.fps())
    time.sleep(1)

image
image1920×1080 227 KB

the white blob in black blob is missing ,how to find it?

image
image1920×1080 195 KB

2 
# Single Color RGB565 Blob Tracking Example
#
# This example shows off single color RGB565 tracking using the OpenMV Cam.

import sensor, image, time, math

threshold_index = 3 # 0 for red, 1 for green, 2 for blue, 3 for white【<-----------】

# 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
              (29, 99, -47, 115, -47, 127)] # generic_white_thresholds【<-----------】

sensor.reset()
sensor.set_pixformat(sensor.RGB565)
sensor.set_framesize(sensor.FHD)
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()

# 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):
    clock.tick()
    img = sensor.snapshot()
    for blob in img.find_blobs([thresholds[threshold_index]], pixels_threshold=200, area_threshold=200, merge=True):
        # 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(),color=(0,255,0),thickness=5)
        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(clock.fps())

image
image1920×1080 228 KB

i run the code of Single Color RGB565 Blob Tracking Example,and the white in the centre is missing too.
image
image1920×1080 193 KB

3

Hi,

Turn off the merge=True argument which merges blobs.

1 Like
4

thank you! you are right