Changes between Version 6 and Version 7 of MOPS_diff_false_positives
- Timestamp:
- Nov 13, 2012, 3:53:12 PM (14 years ago)
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MOPS_diff_false_positives
v6 v7 15 15 == Changes in signal-to-noise == 16 16 17 The improvement in the convolution direction increased the signal-to-noise of detections in the warp-warp diffs. I do not understand the bifurcation in the updated WW inverse data. Objects that match stars also show this split. As suggested by the change in depth above, the signal-to-noise of the warp-stack diffs has decreased, again to below that of the warp-warp data. Further investigation of the photometry process is needed to determine if this lower signal to noise is in fact correct. 18 17 19 || WW || [[Image(WW_SN.png)]] || 18 20 || WWI|| [[Image(WWI_SN.png)]] || … … 21 23 == Accuracy of SINGLE1 convolution == 22 24 25 Mode = 1 corresponds to the SINGLE1 convolution, mode = 2 to SINGLE2, and mode = 5 to DUAL. This figure shows that the original analysis was only doing the warp-warp convolution correctly 41% of the time. 26 23 27 [[Image(updated_submode.png)]] 24 28 25 29 == diff_sn/r p/m == 30 31 This series of plots is somewhat complicated due to the number of values plotted. The goal is to represent the regions in diff_rp/diff_sn_p space occupied by different objects. The red points show all detections in the diff CMF. The green points are objects that have a "star" match, based on a comparison of diff and warp CMF files. Blue points show the region currently accepted by MOPS (if (r < 9) then diff_sn_p > 5 * object_SN). The purple points have flags set that exclude bad and poor measurements, as well as those that have low PSF_QF values. Overplotted in yellow are diff detections that match the locations of known asteroids, as supplied by Larry. 32 33 The first thing to note is that the MOPS cut does a reasonable job of isolating the large "tail" of asteroid detections. In this projection, the majority of asteroids have a positive source close (often less than 1 pixel, with some up to ~3 pixels away), and the S/N of that source is less than 10x the S/N of the difference detection. Therefore, relaxing the MOPS cut to allow these lower significance diffs to be accepted seems reasonable. This tail also has a large number of "star" associations. This is reasonable, as the positive object is likely found in the warp image as well. However, the bulk of the star population falls at larger S/N ratios (as the positive source is far more significant than the source after subtraction) and at larger radii (as the residual is not necessarily going to be symmetric for a star, resulting in a shift between the center between the positive source and the subtracted source). 26 34 27 35 || Positive || Original || Updated || … … 30 38 || WS ||[[Image(original_WS_P.png)]] || [[Image(updated_WS_P.png)]] || 31 39 40 41 These plots are the same, but showing the relations between diff_rm/diff_sn_m for the different diff images (the plot labels are incorrect; these are the M versions). 32 42 33 43 || Minus || Original || Updated ||
