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Equivalent function for matlab on scilab
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pfshdrcalibrate(1) General Commands Manual pfshdrcalibrate(1) NAME
pfshdrcalibrate - Create an HDR image or calibrate a response curve from a set of differently exposed images supplied in PFS stream. SYNOPSIS
pfshdrcalibrate [--response <type>] [--calibration <type>] [--gauss <val>] [--response-file <filename.m>] [--save-response <filename.m>] [--multiplier <val>] [--bpp <val>] [--luminance] [--samples <val>] [--help] [--verbose] DESCRIPTION
Create an HDR image or calibrate a response curve from a set of differently exposed images supplied in PFS stream. When used with 8bit images, luminance in the output HDR image corresponds to real world values in [cd/m^2] provided that hdrgen script con- tained correct information on exposure time, aperture and iso speed. Note that sometimes ISO speed indicated by camera does not correspond to standard (ISO-100 is in fact ISO-125). The accuracy of absolute calibration has not been thoroughly tested with different camera models, however one can expect the relative mea- surement error below 8%. Use pfsabsolute in case of systematic error. OPTIONS
--response <type>, -r <type> Allows to choose from predefined response curves. This can be used either to apply this response or use it as an initialization for automatic self-calibration. Predefined response curves are: "linear", "gamma", "log". Default is "linear". --calibration <type>, -c <type> Type of automatic self-calibration method used for recovery of the response curve. Accepted types include: "none", "robertson", "mitsunaga". Default is "robertson". In case "none" is chosen, a predefined response will be used, without self-calibration. More infomation on the algorithms can be found in: M.A. Robertson, S. Borman and R.L. Stevenson Dynamic range improvement through multiple exposures In: Proc. of International Conference on Image Processing 1999 (ICIP 99), pp 159-163 vol.3 and T. Mitsunaga and S. K. Nayar Radiometric Self Calibration In: Proc on IEEE Conf. on Computer Vision and Pattern Recognition (CVPR'99). Volume 1, p. 1374 --gauss <val>, -g <val> Sigma value for the Gaussian used as a weighting function. Applies to Robertson02 algorithm. Default value: 16.0f --response-file <filename.m>, -f <filename.m> Use response curve saved in the matlab format file. Turns off automatic self-calibration. Uses Robertson02 model to apply the response curve. --save-response <filename.m>, -s <filename.m> Saves the response curve calculated during automatic self-calibration stage in a matlab format file. Can be later reused for set of images captured with given camera. Also works fine for plotting with gnuplot. --multiplier <val>, -m <val> Input multiplier value. Can be used to manipulate the range of source exposures. Default value is 256 since LDR images are by default scaled to 0..1. --bpp <val>, -b <val> Number of bits per pixel in input data from the camera. Default value is 8. --samples <val>, -p <val> Number of sample pixels used in inverse response computations in Mitsunaga algorithm. Default is 50000. --fix-saturated, -x Use this option if you see black pixels in overexposed / saturated areas. The black pixels are visible if all exposures contain pixel values that are outside reliable range (are under- or over-exposed). This flag gives non-zero weight for the brightest and the darkest pixels, thus avoiding zero-weighted pixels. Note that the calculated luminance values for these pixels are not reliable. --luminance, -Y Recovery of response curve will be performed for luminance channel only. --verbose Print additional information during program execution. --help Print list of commandline options. EXAMPLES
pfsinhdrgen sample.hdrgen | pfshdrcalibrate -v -s response.m Recover the response curve from set of exposures defined in sample.hdrgen and save it to response.m file. To view the response curve, run gnuplot and write 'plot "response.m"'. pfsinhdrgen sample.hdrgen | pfshdrcalibrate -x -f response.m | pfsview Create an HDR image from exposures defined in sample.hdrgen using the response curve "response.m" and view it. Fix the problem with black values given to overexposed pixels. pfsinhdrgen sample.hdrgen | pfshdrcalibrate | pfsview Create an HDR image from exposures defined in sample.hdrgen using the default self-calibration method and view it. pfsinhdrgen sample_dcraw.hdrgen | pfshdrcalibrate -b 16 -r linear -c none | pfsview Given that the script sample_dcraw.hdrgen refers to camera RAW files (see pfsindcraw), this example will generate an HDR image assuming a linear response. pfsinhdrgen sample.hdrgen | pfshdrcalibrate | pfsview Create an HDR image from exposures defined in sample.hdrgen using the default self-calibration method and view it. pfsinhdrgen sample.hdrgen | pfshdrcalibrate -c mitsunaga -samples 100000 | pfsglview Create an HDR image from exposures defined in sample.hdrgen using the mitsunaga self-calibration method with 100000 samples and view it in pfsglview. SEE ALSO
pfsinhdrgen(1) jpeg2hdrgen(1) pfsview(1) pfsindcraw(1) pfsabsolute(1) pfsglview(1) BUGS
Please report bugs and comments on implementation to Grzegorz Krawczyk <gkrawczyk@users.sourceforge.net>. pfshdrcalibrate(1)
