[ros-users] Cmvision Blobs Msg Question

Hi All,

I have a question about cmvision package. When I looked at the blobs msg by
"rostopic echo /blobs", I got things like this.

header:
  seq: 466
  stamp:
    secs: 1285021814
    nsecs: 952005043
  frame_id: ''
image_width: 640
image_height: 480
blob_count: 0
blobs:
  -
    red: 0
    green: 255
    blue: 0
    area: 14494
    x: 403
    y: 168
    left: 348
    right: 462
    top: 40
    bottom: 310
  -
    red: 0
    green: 255
    blue: 0
    area: 364
    x: 459
    y: 107
    left: 444
    right: 475
    top: 59
    bottom: 159
  -
    red: 0
    green: 255
    blue: 0
    area: 41
    x: 476
    y: 50
    left: 462

My question is, why the blob_count = 0 but there are blob info in the list?
I am especially curious about the one with area of 14494.

Sorry if it is a noob question.

Thanks.
Li