makehdr() - Image Processing

HDR = makehdr(files) creates the single-precision,
high dynamic range image from the set of spatially registered low
dynamic range images listed in the files cell array. makehdr uses
the middle exposure between the brightest and darkest images as the
base exposure for the high dynamic range calculations. (This value
does not need to appear in any particular file. For more information
about calculating this middle exposure value, see Algorithm.)Note:  


When you call makehdr with this syntax, the
low dynamic range image files must contain exif exposure
metadata.HDR = makehdr(files, param1, val1,...) creates
a high dynamic range image from the low dynamic range images in files,
specifying parameters and corresponding values that control various
aspects of the image creation. Parameter names can be abbreviated
and case does not matter.Note:  


Only one of the BaseFile, ExposureValues,
and RelativeExposure parameters may be used at
a time.ParameterDescription
'BaseFile'Character array containing the name of the file to use as the
base exposure.
'ExposureValues'Vector of exposure values, with one element for each low dynamic
range image in the cell array files. An increase
in one exposure value (EV) corresponds to a doubling of exposure,
while a decrease in one EV corresponds to a halving of exposure. Any
positive value is allowed. This parameter overrides EXIF exposure
metadata. 
'RelativeExposure'Vector of relative exposure values, with one element for each
low dynamic range image in the cell array files.
An image with a relative exposure (RE) of 0.5 has half as much exposure
as an image with an RE of 1. An RE value of 3 has three times the
exposure of an image with an RE of 1. This parameter overrides EXIF
exposure metadata.
'MinimumLimit'Numeric scalar value in the range [0 255] that
specifies the minimum correctly exposed value. For each low dynamic
range image, pixels with smaller values are considered underexposed
and will not contribute to the final high dynamic range image.
'MaximumLimit'Numeric scalar value in the range [0 255] that
specifies the maximum correctly exposed value. For each low dynamic
range image, pixels with larger values are considered overexposed
and will not contribute to the final high dynamic range image.

Syntax

HDR = makehdr(files)HDR = makehdr(files, param1, val1,...)

Example

files = {'office_1.jpg', 'office_2.jpg', 'office_3.jpg', ...
         'office_4.jpg', 'office_5.jpg', 'office_6.jpg'};
expTimes = [0.0333, 0.1000, 0.3333, 0.6250, 1.3000, 4.0000];
 
hdr = makehdr(files, 'RelativeExposure', expTimes ./ expTimes(1));
rgb = tonemap(hdr);
figure; imshow(rgb)

Output / Return Value

Limitations

Alternatives / See Also

Reference