Coverage for python/lsst/meas/algorithms/skyObjects.py : 90%

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2__all__ = ["SkyObjectsConfig", "SkyObjectsTask", "generateSkyObjects"]
4from lsst.pex.config import Config, Field, ListField
5from lsst.pipe.base import Task
7import lsst.afw.detection
8import lsst.afw.geom
9import lsst.afw.math
12class SkyObjectsConfig(Config):
13 """Configuration for generating sky objects"""
14 avoidMask = ListField(dtype=str, default=["DETECTED", "DETECTED_NEGATIVE", "BAD", "NO_DATA"],
15 doc="Avoid pixels masked with these mask planes")
16 growMask = Field(dtype=int, default=0,
17 doc="Number of pixels to grow the masked pixels when adding sky objects")
18 sourceRadius = Field(dtype=float, default=8, doc="Radius, in pixels, of sky objects")
19 nSources = Field(dtype=int, default=100, doc="Try to add this many sky objects")
20 nTrialSources = Field(dtype=int, default=None, optional=True,
21 doc="Maximum number of trial sky object positions\n"
22 "(default: nSkySources*nTrialSkySourcesMultiplier)")
23 nTrialSourcesMultiplier = Field(dtype=int, default=5,
24 doc="Set nTrialSkySources to\n"
25 " nSkySources*nTrialSkySourcesMultiplier\n"
26 "if nTrialSkySources is None")
29def generateSkyObjects(mask, seed, config):
30 """Generate a list of Footprints of sky objects
32 Sky objects don't overlap with other objects. This is determined
33 through the provided `mask` (in which objects are typically flagged
34 as `DETECTED`).
36 The algorithm for determining sky objects is random trial and error:
37 we try up to `nTrialSkySources` random positions to find `nSources`
38 sky objects.
40 Parameters
41 ----------
42 mask : `lsst.afw.image.Mask`
43 Input mask plane, which identifies pixels to avoid for the sky
44 objects.
45 seed : `int`
46 Random number generator seed.
47 config : `SkyObjectsConfig`
48 Configuration for finding sky objects.
50 Returns
51 -------
52 skyFootprints : `list` of `lsst.afw.detection.Footprint`
53 Footprints of sky objects. Each will have a peak at the center
54 of the sky object.
55 """
56 if config.nSources <= 0: 56 ↛ 57line 56 didn't jump to line 57, because the condition on line 56 was never true
57 return []
59 skySourceRadius = config.sourceRadius
60 nSkySources = config.nSources
61 nTrialSkySources = config.nTrialSources
62 if nTrialSkySources is None: 62 ↛ 65line 62 didn't jump to line 65, because the condition on line 62 was never false
63 nTrialSkySources = config.nTrialSourcesMultiplier*nSkySources
65 box = mask.getBBox()
66 box.grow(-(int(skySourceRadius) + 1)) # Avoid objects partially off the image
67 xMin, yMin = box.getMin()
68 xMax, yMax = box.getMax()
70 avoid = lsst.afw.geom.SpanSet.fromMask(mask, mask.getPlaneBitMask(config.avoidMask))
71 if config.growMask > 0: 71 ↛ 72line 71 didn't jump to line 72, because the condition on line 71 was never true
72 avoid = avoid.dilated(config.growMask)
74 rng = lsst.afw.math.Random(seed=seed)
76 skyFootprints = []
77 for _ in range(nTrialSkySources): 77 ↛ 91line 77 didn't jump to line 91, because the loop on line 77 didn't complete
78 if len(skyFootprints) == nSkySources:
79 break
81 x = int(rng.flat(xMin, xMax))
82 y = int(rng.flat(yMin, yMax))
83 spans = lsst.afw.geom.SpanSet.fromShape(int(skySourceRadius), offset=(x, y))
84 if spans.overlaps(avoid):
85 continue
87 fp = lsst.afw.detection.Footprint(spans, mask.getBBox())
88 fp.addPeak(x, y, 0)
89 skyFootprints.append(fp)
91 return skyFootprints
94class SkyObjectsTask(Task):
95 ConfigClass = SkyObjectsConfig
97 def run(self, mask, seed):
98 """Generate a list of Footprints of sky objects
100 Sky objects don't overlap with other objects. This is determined
101 through the provided `mask` (in which objects are typically flagged
102 as `DETECTED`).
104 The algorithm for determining sky objects is random trial and error:
105 we try up to `nTrialSkySources` random positions to find `nSources`
106 sky objects.
108 Parameters
109 ----------
110 mask : `lsst.afw.image.Mask`
111 Input mask plane, which identifies pixels to avoid for the sky
112 objects.
113 seed : `int`
114 Random number generator seed.
116 Returns
117 -------
118 skyFootprints : `list` of `lsst.afw.detection.Footprint`
119 Footprints of sky objects. Each will have a peak at the center
120 of the sky object.
121 """
122 skyFootprints = generateSkyObjects(mask, seed, self.config)
123 self.log.info("Added %d of %d requested sky sources (%.0f%%)", len(skyFootprints),
124 self.config.nSources, 100*len(skyFootprints)/self.config.nSources)
125 return skyFootprints