def read_image(filename, pointer="IMAGE"): # ^IMAGE
""" Read a PDS IMG formatted file into an array.
TODO: Check for and account for LINE_PREFIX.
TODO: Check for and apply BIT_MASK.
"""
label = parse_label(filename)
if "IMAGE" in label.keys():
BYTES_PER_PIXEL = int(label["IMAGE"]["SAMPLE_BITS"] / 8)
DTYPE = sample_types(label["IMAGE"]["SAMPLE_TYPE"], BYTES_PER_PIXEL)
nrows = label["IMAGE"]["LINES"]
ncols = label["IMAGE"]["LINE_SAMPLES"]
if "LINE_PREFIX_BYTES" in label["IMAGE"].keys():
print("Accounting for a line prefix.")
prefix_cols = int(label["IMAGE"]["LINE_PREFIX_BYTES"] /
BYTES_PER_PIXEL)
else:
prefix_cols = 0
try:
BANDS = label["IMAGE"]["BANDS"]
except KeyError:
BANDS = 1
pixels = nrows * (ncols + prefix_cols) * BANDS
else:
print("*** IMG w/ old format attached label not currently supported.")
print("\t{fn}".format(fn=filename))
return None
fmt = "{endian}{pixels}{fmt}".format(endian=DTYPE[0],
pixels=pixels,
fmt=DTYPE[-1])
try: # a little decision tree to seamlessly deal with compression
if filename.endswith(".gz"):
f = gzip.open(filename, "rb")
elif filename.endswith(".bz2"):
f = bz2.BZ2File(filename, "rb")
elif filename.endswith(".ZIP"):
f = ZipFile(filename, "r").open(
ZipFile(filename, "r").infolist()[0].filename)
else:
f = open(filename, "rb")
f.seek(data_start_byte(label, "^IMAGE"))
image = np.array(struct.unpack(fmt, f.read(pixels * BYTES_PER_PIXEL)))
# Make sure that single-band images are 2-dim arrays.
if BANDS == 1:
image = image.reshape(nrows, (ncols + prefix_cols))
if prefix_cols:
# Ignore the prefix data, if any.
# TODO: Also return the prefix
prefix = image[:, :prefix_cols]
if pointer == "LINE_PREFIX_TABLE":
return prefix
image = image[:, prefix_cols:]
else:
image = image.reshape(BANDS, nrows, ncols)
finally:
f.close()
print("Displaying an image")
plt.figure(figsize=(4, 4))
plt.title(filename.split("/")[-1])
plt.xticks([])
plt.yticks([])
if len(np.shape(image)) == 2:
plt.imshow(image, cmap="gray")
pass
elif len(np.shape(image)) == 3:
if np.shape(image)[0] == 3:
image = np.stack([image[0, :, :], image[1, :, :], image[2, :, :]],
axis=2)
if np.shape(image)[2] == 3:
plt.imshow(image)
pass
return image
def read_image(target, label, pointer="IMAGE"): # ^IMAGE
"""Read a PDS IMG formatted file into an array.
TODO: Check for and account for LINE_PREFIX.
TODO: Check for and apply BIT_MASK.
rasterio will read an ENVI file if the HDR metadata is present...
However, it seems to read M3 L0 images incorrectly because it does
not account for the L0_LINE_PREFIX_TABLE. So I am deprecating
the use of rasterio until I can figure out how to produce consistent
output.
try:
dataset = rasterio.open(filename)
if len(dataset.indexes)==1:
return dataset.read()[0,:,:] # Make 2D images actually 2D
else:
return dataset.read()
except rasterio.errors.RasterioIOError:
#print(' *** Not using rasterio. ***')
pass
"""
# TODO:
# this should maybe always go in map_object_to_function,
# but I'm not sure if read_image might want to get called
# from other places that don't call that first.
# probably best to check /decide this.
# --Michael
special_case = check_special_image_case(label, pointer)
if special_case:
props = special_case
else:
props = generic_image_props(label, pointer)
# commented-out block here should work but it instead produces massive
# quantities of bad spookiness. it specifically doesn't work
# with certain variable names, variables pop in and out of existence,
# somehow we hit undefined behavior:
# read_image_namespace = locals()
# for prop in image_props_list():
# read_image_namespace[prop] = props[prop]
BYTES_PER_PIXEL = props["BYTES_PER_PIXEL"]
start_byte = props["start_byte"]
DTYPE = props["DTYPE"]
nrows = props["nrows"]
ncols = props["ncols"]
prefix_bytes = props["prefix_bytes"]
prefix_cols = props["prefix_cols"]
BANDS = props["BANDS"]
pixels = props["pixels"]
band_storage_type = props["band_storage_type"]
object_name = get_file_area(label, pointer)[1]
# for attached labels, just point to the file
# (which we should have assigned to a special key in the label)
if isinstance(target, int):
filename = label["attached_label_filename"]
# otherwise point to the pointer target
else:
filename = target
# a little decision tree to seamlessly deal with compression
if filename.endswith(".gz"):
f = gzip.open(filename, "rb")
elif filename.endswith(".bz2"):
f = bz2.BZ2File(filename, "rb")
elif filename.endswith(".ZIP"):
f = ZipFile(filename,
"r").open(ZipFile(filename, "r").infolist()[0].filename)
else:
f = open(filename, "rb")
# Make sure that single-band images are 2-dim arrays.
f.seek(start_byte)
# TODO: I don't know what the band-sequential case should look
# like, because I don't have test data rn, but I suspect it should be
# rewritten to look like the line-interleaved case. --Michael
if BANDS == 1:
fmt = "{endian}{pixels}{length}".format(endian=DTYPE[0],
pixels=pixels,
length=DTYPE[-1])
image = np.array(struct.unpack(fmt, f.read(
pixels * BYTES_PER_PIXEL))).reshape(nrows, ncols + prefix_cols)
if prefix_cols:
# Ignore the prefix data, if any.
# TODO: Also return the prefix
prefix = image[:, :prefix_cols]
if object_name == "LINE_PREFIX_TABLE":
return prefix
image = image[:, prefix_cols:]
elif band_storage_type == "BAND_SEQUENTIAL":
raise NotImplemented("BAND_SEQUENTIAL presently not implemented")
# pixels_per_frame = BANDS * nrows
# fmt = "{endian}{pixels}{length}".format(
# endian=DTYPE[0], pixels=pixels_per_frame, length=DTYPE[-1]
# )
# image = np.array(
# struct.unpack(fmt, f.read(pixels * BYTES_PER_PIXEL))
# )
# image = image.reshape(BANDS, nrows)
elif band_storage_type == "LINE_INTERLEAVED":
pixels_per_frame = BANDS * ncols
fmt = "{endian}{pixels}{length}".format(endian=DTYPE[0],
pixels=pixels_per_frame,
length=DTYPE[-1])
image, prefix = [], []
for _ in np.arange(nrows):
prefix.append(f.read(prefix_bytes))
frame = np.array(
struct.unpack(fmt,
f.read(pixels_per_frame *
BYTES_PER_PIXEL))).reshape(BANDS, ncols)
image.append(frame)
del frame
image = np.swapaxes(np.stack([frame for frame in image], axis=2), 1, 2)
else:
raise ValueError(f"Unknown BAND_STORAGE_TYPE={band_storage_type}")
if f:
f.close()
if "PREFIX" in object_name:
return prefix, image
return image
