--- /dev/null
+__author__ = 'tsungyi'
+
+import pycocotools._mask as _mask
+
+# Interface for manipulating masks stored in RLE format.
+#
+# RLE is a simple yet efficient format for storing binary masks. RLE
+# first divides a vector (or vectorized image) into a series of piecewise
+# constant regions and then for each piece simply stores the length of
+# that piece. For example, given M=[0 0 1 1 1 0 1] the RLE counts would
+# be [2 3 1 1], or for M=[1 1 1 1 1 1 0] the counts would be [0 6 1]
+# (note that the odd counts are always the numbers of zeros). Instead of
+# storing the counts directly, additional compression is achieved with a
+# variable bitrate representation based on a common scheme called LEB128.
+#
+# Compression is greatest given large piecewise constant regions.
+# Specifically, the size of the RLE is proportional to the number of
+# *boundaries* in M (or for an image the number of boundaries in the y
+# direction). Assuming fairly simple shapes, the RLE representation is
+# O(sqrt(n)) where n is number of pixels in the object. Hence space usage
+# is substantially lower, especially for large simple objects (large n).
+#
+# Many common operations on masks can be computed directly using the RLE
+# (without need for decoding). This includes computations such as area,
+# union, intersection, etc. All of these operations are linear in the
+# size of the RLE, in other words they are O(sqrt(n)) where n is the area
+# of the object. Computing these operations on the original mask is O(n).
+# Thus, using the RLE can result in substantial computational savings.
+#
+# The following API functions are defined:
+# encode - Encode binary masks using RLE.
+# decode - Decode binary masks encoded via RLE.
+# merge - Compute union or intersection of encoded masks.
+# iou - Compute intersection over union between masks.
+# area - Compute area of encoded masks.
+# toBbox - Get bounding boxes surrounding encoded masks.
+# frPyObjects - Convert polygon, bbox, and uncompressed RLE to encoded RLE mask.
+#
+# Usage:
+# Rs = encode( masks )
+# masks = decode( Rs )
+# R = merge( Rs, intersect=false )
+# o = iou( dt, gt, iscrowd )
+# a = area( Rs )
+# bbs = toBbox( Rs )
+# Rs = frPyObjects( [pyObjects], h, w )
+#
+# In the API the following formats are used:
+# Rs - [dict] Run-length encoding of binary masks
+# R - dict Run-length encoding of binary mask
+# masks - [hxwxn] Binary mask(s) (must have type np.ndarray(dtype=uint8) in column-major order)
+# iscrowd - [nx1] list of np.ndarray. 1 indicates corresponding gt image has crowd region to ignore
+# bbs - [nx4] Bounding box(es) stored as [x y w h]
+# poly - Polygon stored as [[x1 y1 x2 y2...],[x1 y1 ...],...] (2D list)
+# dt,gt - May be either bounding boxes or encoded masks
+# Both poly and bbs are 0-indexed (bbox=[0 0 1 1] encloses first pixel).
+#
+# Finally, a note about the intersection over union (iou) computation.
+# The standard iou of a ground truth (gt) and detected (dt) object is
+# iou(gt,dt) = area(intersect(gt,dt)) / area(union(gt,dt))
+# For "crowd" regions, we use a modified criteria. If a gt object is
+# marked as "iscrowd", we allow a dt to match any subregion of the gt.
+# Choosing gt' in the crowd gt that best matches the dt can be done using
+# gt'=intersect(dt,gt). Since by definition union(gt',dt)=dt, computing
+# iou(gt,dt,iscrowd) = iou(gt',dt) = area(intersect(gt,dt)) / area(dt)
+# For crowd gt regions we use this modified criteria above for the iou.
+#
+# To compile run "python setup.py build_ext --inplace"
+# Please do not contact us for help with compiling.
+#
+# Microsoft COCO Toolbox. version 2.0
+# Data, paper, and tutorials available at: http://mscoco.org/
+# Code written by Piotr Dollar and Tsung-Yi Lin, 2015.
+# Licensed under the Simplified BSD License [see coco/license.txt]
+
+iou = _mask.iou
+merge = _mask.merge
+frPyObjects = _mask.frPyObjects
+
+def encode(bimask):
+ if len(bimask.shape) == 3:
+ return _mask.encode(bimask)
+ elif len(bimask.shape) == 2:
+ h, w = bimask.shape
+ return _mask.encode(bimask.reshape((h, w, 1), order='F'))[0]
+
+def decode(rleObjs):
+ if type(rleObjs) == list:
+ return _mask.decode(rleObjs)
+ else:
+ return _mask.decode([rleObjs])[:,:,0]
+
+def area(rleObjs):
+ if type(rleObjs) == list:
+ return _mask.area(rleObjs)
+ else:
+ return _mask.area([rleObjs])[0]
+
+def toBbox(rleObjs):
+ if type(rleObjs) == list:
+ return _mask.toBbox(rleObjs)
+ else:
+ return _mask.toBbox([rleObjs])[0]
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Code Review / ealt-edge.git / blobdiff