what format is coco annotations?

zbsean commented 6 years ago

what format is coco annotations?my annotations format is [[x1,y1],[x2,y2],...[xn,yn]]. but coco annotation format is [[312.29, 562.89, 402.25, 232.61, 560.32, 300.72, 571.89]], what different?

dexter1608 commented 6 years ago

https://github.com/cocodataset/cocoapi/issues/111 any suggestions ? thank you

rafaelpadilla commented 6 years ago

According to here it should be "bbox" : [x,y,width,height]

suhyunified commented 5 years ago

Is it right that x means xmin?

rafaelpadilla commented 5 years ago

Is it right that x means xmin?

For object detection annotations, the format is "bbox" : [x,y,width,height] Where: x, y: the upper-left coordinates of the bounding box width, height: the dimensions of your bounding box

nirandiw commented 5 years ago

Wasn't the question on the "segmentations" within "annotations". Did you figure out how to convert the [[x, y]...] to the values in "segmentations"?

I'm having the same problem.

Atul997 commented 3 years ago

@nirandiw use this to generate segmentation from bounding box annotation["segmentation"] = [[x1,y1,x1,(y1 + y2), (x1 + x2), (y1 + y2), (x1 + x2), y1]]

jpatrickpark commented 3 years ago

@zbsean @nirandiw

COCO segmentation format seems to be a list which contains multiple polygons. Each item in the list should be a separate polygon. Each polygon consists of multiple points, which are stored in the following format of [x0, y0, x1, y1, ..., xn, yn].

For example, in the following segmentation [[224.24, 297.18, 228.29, 297.18, 234.91, 298.29, 243.0, 297.55, 249.25, 296.45, 252.19, 294.98, 256.61, 292.4, 254.4, 264.08, 251.83, 262.61, 241.53, 260.04, 235.27, 259.67, 230.49, 259.67, 233.44, 255.25, 237.48, 250.47, 237.85, 243.85, 237.11, 240.54, 234.17, 242.01, 228.65, 249.37, 224.24, 255.62, 220.93, 262.61, 218.36, 267.39, 217.62, 268.5, 218.72, 295.71, 225.34, 297.55]]:

There is one polygon corresponding for the current annotation
This polygon contains 24 points where the first point is (224.24, 297.18) and the last point is (225.34, 297.55)

For another example, I am visualizing an image that has 17 polygons inside a bbox below (using matplotlib.patches.Polygon). Blue lines indicate bbox, and the red lines indicate the polygons. To get segmentation, you should fill inside each of the polygons.

ricber commented 2 years ago

Hi! May I know why the polygon coordinates are float and not integers? I was expecting integer numbers because I thought they were expressed in terms of pixels. Does it mean that I can have polygons' coordinates in the middle of pixels with a centesimal precision?

Abhishek2271 commented 2 years ago

This could be because of resize, based on the discussions here: https://github.com/cocodataset/cocoapi/issues/34

cocodataset / cocoapi

what format is coco annotations? #102