Multiple Instances

In previous examples we’ve focused on images that only contain a single object. This article will focus on the case where a synthetic sample contains more than one object. To get started, we’ll load our test dataset and choose an appropriate sample:

[1]:

from IPython.display import display
import limbo.data

dataset = limbo.data.Dataset("../data")

sample = dataset[2]

if sample.image:
    display(sample.image)

../_images/user-guide_multiple-instances_1_0.png

First, we’ll access a list of labels for every instance visible in the sample:

[2]:

if sample.synthetic and sample.synthetic.cryptomatte:
    print(sample.synthetic.cryptomatte.instances)

['48/0', '48/1', '48/2', '48/3', '48/4', '48/5', '48/6', '48/7', '48/8', '48/9', '48/10', '48/11', '48/12', '48/13', '48/14', '48/15', '48/16', '48/17', '48/18', '48/19', '48/20', '48/21', '48/22', '48/23', '48/24', '48/25', '48/26', '48/27', '48/28', '48/29', '48/30', '48/31', '48/32', '48/33', '48/34', '48/35', '48/36', '48/37', '48/38', '48/39', '48/40', '48/41', '48/42', '48/43', '48/44', '48/45', '48/46', '48/47', '48/48', '48/49', '48/50', '48/51', '48/52', '48/53', '48/54', '48/55', '48/56', '48/57', '48/58', '48/59']

Most operations provided by the sample object default to using every instance, such as extracting a matte:

[3]:

if sample.synthetic and sample.synthetic.cryptomatte:
    display(sample.synthetic.cryptomatte.matte())

../_images/user-guide_multiple-instances_5_0.png

But now, we can use the labels to retrieve a matte for a specific instance:

[4]:

if sample.synthetic and sample.synthetic.cryptomatte:
    display(sample.synthetic.cryptomatte.matte("48/40"))

../_images/user-guide_multiple-instances_7_0.png

Or, we can retrieve a matte that is the union of multiple instances:

[5]:

if sample.synthetic and sample.synthetic.cryptomatte:
    display(sample.synthetic.cryptomatte.matte(["48/40", "48/45"]))

../_images/user-guide_multiple-instances_9_0.png

You can also retrieve a segmentation image where each distinct color represents a specific instance:

[11]:

if sample.synthetic and sample.synthetic.cryptomatte:
    display(sample.synthetic.cryptomatte.segmentation())

../_images/user-guide_multiple-instances_11_0.png

[12]:

if sample.synthetic and sample.synthetic.cryptomatte:
    display(sample.synthetic.cryptomatte.segmentation(["48/40", "48/45"]))

../_images/user-guide_multiple-instances_12_0.png

A similar approach works when previewing bounding boxes and contours: by default, the previews include every instance:

[6]:

if sample.synthetic and sample.synthetic.cryptomatte:
    display(sample.synthetic.cryptomatte.preview(show_bboxes=True).makeImageSnapshot())

../_images/user-guide_multiple-instances_14_0.png

[7]:

if sample.synthetic and sample.synthetic.cryptomatte:
    display(sample.synthetic.cryptomatte.preview(show_contours=True).makeImageSnapshot())

../_images/user-guide_multiple-instances_15_0.png

But now you can target one instance, or several:

[8]:

if sample.synthetic and sample.synthetic.cryptomatte:
    display(sample.synthetic.cryptomatte.preview(show_bboxes=True, instances="48/40").makeImageSnapshot())

../_images/user-guide_multiple-instances_17_0.png

[9]:

if sample.synthetic and sample.synthetic.cryptomatte:
    display(sample.synthetic.cryptomatte.preview(show_contours=True, instances=["48/40", "48/45"]).makeImageSnapshot())

../_images/user-guide_multiple-instances_18_0.png

The same approach can be used when retrieving bounding box and contour data, but be careful: the result is the union of the specified instances:

[10]:

if sample.synthetic and sample.synthetic.cryptomatte:
    print(sample.synthetic.cryptomatte.bbox(["48/40", "48/45"]))

(14.686975432140274, 344.55363432413395, 526.8119756909649, 127.21325612207403)