raw2hdr Camera Response Function

All,

Does anyone know if there is a -r option (to write/use a camera response
function) for raw2hdr like there is for hdrgen? Using -r with raw2hdr now
gives me an error message that states that -r is not a supported option.

Thank you,
Mio Stanley
Graduate Student, University of Colorado Boulder

Hi Mio,

not be possible or usefult. The response function maps the pixel value to a sensor signal (sensor illuminance) by comparing the values of pairs of pixel values at different exposure settings. If e.g. the pixel coordinate on the CCD x1y1 has leads to a pixel value of 100 at an exposure time of 100ms, and of 50 at an exposure time of 50ms, the response would be flat. So the idea of reconstructing the response curve is based on the assumption that you have several frames of the same scene to compare, and that the exposure differs between those frames. Even if you got the response time of your camera, it would not be useful - as you are assuming to work with raw sensor data. So what is in the file should be what the sensor gave as a signal.

Cheers, Lars.

···

from my understanding (important disclaimer...), such an option would

All,

Does anyone know if there is a -r option (to write/use a camera response function) for raw2hdr like there is for hdrgen? Using -r with raw2hdr now gives me an error message that states that -r is not a supported option.

Thank you,
Mio Stanley
Graduate Student, University of Colorado Boulder

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Hi Mio,

The -r option is not needed because the camera response for RAW is predefined.

-Greg

···

From: Mio Jane Stanley <[email protected]>
Subject: [HDRI] raw2hdr Camera Response Function
Date: August 6, 2015 12:12:05 PM PDT

All,

Does anyone know if there is a -r option (to write/use a camera response function) for raw2hdr like there is for hdrgen? Using -r with raw2hdr now gives me an error message that states that -r is not a supported option.

Thank you,
Mio Stanley
Graduate Student, University of Colorado Boulder

Lars,

Thank you for the explanation, that makes sense.

-Mio S.

···

On Fri, Aug 7, 2015 at 8:54 AM, Lars O. Grobe <[email protected]> wrote:

Hi Mio,

from my understanding (important disclaimer...), such an option would not
be possible or usefult. The response function maps the pixel value to a
sensor signal (sensor illuminance) by comparing the values of pairs of
pixel values at different exposure settings. If e.g. the pixel coordinate
on the CCD x1y1 has leads to a pixel value of 100 at an exposure time of
100ms, and of 50 at an exposure time of 50ms, the response would be flat.
So the idea of reconstructing the response curve is based on the assumption
that you have several frames of the same scene to compare, and that the
exposure differs between those frames. Even if you got the response time of
your camera, it would not be useful - as you are assuming to work with raw
sensor data. So what is in the file should be what the sensor gave as a
signal.

Cheers, Lars.

All,

Does anyone know if there is a -r option (to write/use a camera response
function) for raw2hdr like there is for hdrgen? Using -r with raw2hdr now
gives me an error message that states that -r is not a supported option.

Thank you,
Mio Stanley
Graduate Student, University of Colorado Boulder

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HDRI mailing [email protected]://www.radiance-online.org/mailman/listinfo/hdri