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February 19, 2025 17:03
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Demo Box Cropping with negative masks
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| import kwimage | |
| import kwplot | |
| import numpy as np | |
| def padded_slice_v1(imdata, sl): | |
| # Shift imdata and slice if negative slice start value | |
| if sl[0].start < 0: | |
| shift = -sl[0].start | |
| imdata = np.roll(imdata, shift, axis=0) | |
| imdata[:shift] = np.zeros((imdata[:shift].shape)) | |
| sl = (slice(0, sl[0].stop - sl[0].start), sl[1]) | |
| if sl[1].start < 0: | |
| shift = -sl[1].start | |
| imdata = np.roll(imdata, shift, axis=1) | |
| imdata[:, :shift] = np.zeros((imdata[:, :shift].shape)) | |
| sl = (sl[0], slice(0, sl[1].stop - sl[1].start)) | |
| relative_submask = imdata[sl] | |
| return relative_submask | |
| def padded_slice_v2(imdata, sl): | |
| import delayed_image | |
| delayed = delayed_image.DelayedIdentity(imdata) | |
| padded_crop = delayed.crop(sl, clip=False, wrap=False) | |
| subdata = padded_crop.finalize() | |
| return subdata | |
| def main(): | |
| imdata = kwimage.grab_test_image('astro') | |
| box1 = kwimage.Box.coerce([-10, -20, 100, 200], format='xywh') | |
| box2 = kwimage.Box.coerce([400, 400, 200, 300], format='xywh') | |
| box3 = kwimage.Box.coerce([-100, -100, 700, 700], format='xywh') | |
| plt = kwplot.autoplt() | |
| pnum_ = kwplot.PlotNums(nRows=3, nCols=4) | |
| kwplot.imshow(imdata, pnum=pnum_(), doclf=1, title='original') | |
| ax = plt.gca() | |
| box1.draw() | |
| box2.draw() | |
| box3.draw() | |
| for c in ax.collections: | |
| c.set_clip_on(False) | |
| sl = box1.to_slice() | |
| import ubelt as ub | |
| with ub.Timer('pad slice v1'): | |
| subdata1 = padded_slice_v1(imdata, sl) | |
| with ub.Timer('pad slice v2'): | |
| subdata2 = padded_slice_v2(imdata, sl) | |
| kwplot.imshow(subdata1, pnum=pnum_(), title='left top submask v1') | |
| kwplot.imshow(subdata2, pnum=pnum_(), title='left top submask v2') | |
| diff = np.abs(kwimage.ensure_float01(subdata2) - kwimage.ensure_float01(subdata1)) | |
| assert diff.sum() == 0 | |
| kwplot.imshow(diff, pnum=pnum_(), title='diff') | |
| # Test bottom right case: | |
| pnum_() # skip first figure | |
| sl = box2.to_slice() | |
| subdata1 = padded_slice_v1(imdata, sl) | |
| subdata2 = padded_slice_v2(imdata, sl) | |
| kwplot.imshow(subdata1, pnum=pnum_(), title='bottom right submask v1') | |
| kwplot.imshow(subdata2, pnum=pnum_(), title='bottom right submask v2') | |
| pnum_() # skip diff figure | |
| # Test bigger than everything case | |
| pnum_() # skip first figure | |
| sl = box3.to_slice() | |
| subdata1 = padded_slice_v1(imdata, sl) | |
| subdata2 = padded_slice_v2(imdata, sl) | |
| kwplot.imshow(subdata1, pnum=pnum_(), title='big submask v1') | |
| kwplot.imshow(subdata2, pnum=pnum_(), title='big submask v2') | |
| pnum_() # skip diff figure | |
| if __name__ == '__main__': | |
| main() |
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