def HDR(_imgs_nx1, _times_nx1, method=Debevec):
assert _imgs_nx1.dtype == np.uint8 and _times_nx1.dtype == np.float32, "Type Error"
assert len(_imgs_nx1) == len(
_times_nx1) and len(_times_nx1) > 0, "Len Error"
if method == Debevec:
CalibrateDebevec = cv2.createCalibrateDebevec(samples=70, random=True)
crf = CalibrateDebevec.process(src=_imgs_nx1, times=_times_nx1)
merge_debvec = cv2.createMergeDebevec()
hdr_img = merge_debvec.process(src=_imgs_nx1,
times=_times_nx1,
response=crf)
tonemap = cv2.createTonemapDurand(gamma=1.4)
res_img = tonemap.process(hdr_img.copy())
return crf, hdr_img, res_img
if method == Robertson:
CalibrateRobertson = cv2.createCalibrateRobertson()
crf = CalibrateRobertson.process(src=_imgs_nx1, times=_times_nx1)
merge_robertson = cv2.createMergeRobertson()
hdr_img = merge_robertson.process(src=_imgs_nx1,
times=_times_nx1,
response=crf)
#local tonermap
tonemap = cv2.createTonemapDurand(gamma=1.4)
res_img = tonemap.process(hdr_img.copy())
return crf, hdr_img, res_img
if method == Mertens:
merge_mertens = cv2.createMergeMertens()
res_img = merge_mertens.process(_imgs_nx1)
# cv2.imshow("ss", res_img)
# cv2.waitKey(0)
# cv2.destroyAllWindows()
# res_mertens_8bit = np.clip(res_img*255, 0, 255).astype('uint8')
# cv2.imwrite("PyFusion.png", res_mertens_8bit)
return res_img
def process_roberston(images, exposures):
calibrate_robertson = cv2.createCalibrateRobertson()
response_robertson = calibrateRobertson.process(images, times=exposures)
merge_robertson = cv2.createMergeRoberston()
return merge_robertson.process(
images,
times=exposures,
response=response_robertson
)
hdr_robertson = merge_robertson.process(img_list, times=exposure_times.copy())
# Tonemap HDR image
tonemap1 = cv.createTonemap(gamma=2.2)
res_debevec = tonemap1.process(hdr_debevec.copy())
tonemap2 = cv.createTonemap(gamma=1.3)
res_robertson = tonemap2.process(hdr_robertson)
# Exposure fusion using Mertens
merge_mertens = cv.createMergeMertens()
res_mertens = merge_mertens.process(img_list)
# Convert datatype to 8-bit and save
res_debevec_8bit = np.clip(res_debevec * 255, 0, 255).astype('uint8')
res_robertson_8bit = np.clip(res_robertson * 255, 0, 255).astype('uint8')
res_mertens_8bit = np.clip(res_mertens * 255, 0, 255).astype('uint8')
cv.imwrite("hdr_debevec.jpg", res_debevec_8bit)
cv.imwrite("hdr_robertson.jpg", res_robertson_8bit)
cv.imwrite("fusion_mertens.jpg", res_mertens_8bit)
# Estimate camera response function (CRF)
cal_debevec = cv.createCalibrateDebevec()
crf_debevec = cal_debevec.process(img_list, times=exposure_times)
hdr_debevec = merge_debevec.process(img_list,
times=exposure_times.copy(),
response=crf_debevec.copy())
cal_robertson = cv.createCalibrateRobertson()
crf_robertson = cal_robertson.process(img_list, times=exposure_times)
hdr_robertson = merge_robertson.process(img_list,
times=exposure_times.copy(),
response=crf_robertson.copy())
def recover_camera_response(inputFolder = '.',
exposureListFile = None,
outputResponseCurve = "camera_response.spi1d",
outputResponseFormat = "spi1d",
calibrationApproach = "berkeley",
mergeExposures = False,
mergedExposuresOutput = None,
verbose = False,
robertsonMaxIter = 30.0,
robertsonThreshold = 0.01,
berkeleyLambda = 20.0,
berkeleySamples = 1024,
berkeleySamplePlacementRandom = False):
extensions = generalExtensions
if exposureListFile:
with open(exposureListFile, 'r') as f:
exposuresList = f.readlines()
exposuresList = [x.strip() for x in exposuresList if len(x) > 1]
imageUris = [x.split(' ')[0] for x in exposuresList]
exposure_times = [1.0/float(x.split(' ')[1]) for x in exposuresList]
else:
imageUris = sorted( os.listdir( inputFolder ) )
imageUris = [x for x in imageUris if (os.path.splitext(x)[-1].lower()[1:] in extensions) and (x[0] != '.')]
if verbose:
print( imageUris )
cwd = os.getcwd()
os.chdir( inputFolder )
exposure_times = [0]*len(imageUris)
for i in range(len(imageUris)):
exposure_times[i] = getShutterSpeed( imageUris[i], verbose=verbose )
# List has to be sorted from longest shutter speed to shortest for opencv functions to work
exposure_times, imageUris = (list(x) for x in zip(*sorted(zip(exposure_times, imageUris))))
imageUris.reverse()
exposure_times.reverse()
exposure_times = np.array(exposure_times, dtype=np.float32)
if verbose:
for exposure in zip(exposure_times, imageUris):
print( "Image : %s, Shutter speed : %2.6f" % (exposure[1], exposure[0]) )
img_list = [cv2.imread(fn) for fn in imageUris ]
if not exposureListFile:
os.chdir( cwd )
if calibrationApproach == "robertson":
merge = cv2.createMergeRobertson()
calibrate = cv2.createCalibrateRobertson()
calibrate.setMaxIter(robertsonMaxIter)
calibrate.setThreshold(robertsonThreshold)
if verbose:
print( calibrationApproach )
print( "\tmax iter : %d" % robertsonMaxIter )
print( "\tthreshold : %f" % robertsonThreshold )
else:
merge = cv2.createMergeDebevec()
calibrate = cv2.createCalibrateDebevec()
calibrate.setLambda(berkeleyLambda)
calibrate.setSamples(berkeleySamples)
calibrate.setRandom(berkeleySamplePlacementRandom)
if verbose:
print( calibrationApproach )
print( "\tlambda : %3.2f" % berkeleyLambda )
print( "\tsamples : %d" % berkeleySamples )
print( "\trandom : %s" % berkeleySamplePlacementRandom )
if verbose:
print( "recovering camera response" )
curve = calibrate.process(img_list, times=exposure_times)
if verbose:
print( "writing camera response - %s, %s" % (outputResponseFormat, outputResponseCurve) )
if outputResponseFormat == "spi1d":
with open(outputResponseCurve, "w") as f:
f.write( "Version 1\n" )
f.write( "From 0.000000 1.000000\n" )
f.write( "Length 256\n" )
f.write( "Components 3\n" )
f.write( "{\n" )
for i in range(len(curve)):
f.write( "%3.6f %3.6f %3.6f\n" % (curve[i][0][0]*0.18, curve[i][0][1]*0.18, curve[i][0][2]*0.18) )
f.write( "}\n" )
else:
with open(outputResponseCurve, "w") as f:
for i in range(len(curve)):
f.write( "%3.6f %3.6f %3.6f\n" % (curve[i][0][0], curve[i][0][1], curve[i][0][2]) )
if mergedExposuresOutput:
if verbose:
print( "merging exposures" )
hdr = merge.process(img_list, times=exposure_times.copy(), response=curve.copy())
cv2.imwrite(mergedExposuresOutput, hdr)
tonemap1 = cv2.createTonemapDurand(gamma=2.2)
res_debvec = tonemap1.process(hdr_debvec.copy())
tonemap2 = cv2.createTonemapDurand(gamma=1.3)
res_robertson = tonemap2.process(hdr_robertson.copy())
# Exposure fusion using Mertens
# 这里我们展示了一种可以合并曝光图像的替代算法，我们不需要曝光时间。我们也不需要使用任何tonemap算法，因为Mertens算法已经给出了[0..1]范围内的结果。
merge_mertens = cv2.createMergeMertens()
res_mertens = merge_mertens.process(img_list)
# Convert datatype to 8-bit and save
# 为了保存或显示结果，我们需要将数据转换为[0..255]范围内的8位整数。
res_debvec_8bit = np.clip(res_debvec * 255, 0, 255).astype('uint8')
res_robertson_8bit = np.clip(res_robertson * 255, 0, 255).astype('uint8')
res_mertens_8bit = np.clip(res_mertens * 255, 0, 255).astype('uint8')
cv2.imwrite("ldr_debvec.jpg", res_debvec_8bit)
cv2.imwrite("ldr_robertson.jpg", res_robertson_8bit)
cv2.imwrite("fusion_mertens.jpg", res_mertens_8bit)
exit(0)
# Estimate camera response function (CRF)
# 相机响应功能（CRF）给出了场景辐射度与测量强度值之间的连接。如果在一些计算机视觉算法中非常重要，包括HDR算法，CRF。这里我们估计反相机响应函数并将其用于HDR合并。
cal_debvec = cv2.createCalibrateDebevec()
crf_debvec = cal_debvec.process(img_list, times=exposure_times)
hdr_debvec = merge_debvec.process(img_list, times=exposure_times.copy(), response=crf_debvec.copy())
cal_robertson = cv2.createCalibrateRobertson()
crf_robertson = cal_robertson.process(img_list, times=exposure_times)
hdr_robertson = merge_robertson.process(img_list, times=exposure_times.copy(), response=crf_robertson.copy())
