[HDR-photo] Re: Measuring *really* small values.

[Ronald Murray]

When you read this and other values, do you factor in device noise levels? There really should be a convention of stating a luminance value along with some measure of variation (+/-).

Selecting larger or smaller patches of the area of interest will give you a sense of this, and will let you know how much decimal places in the tool readouts matter.

Ron Murray

 
On Friday, June 01, 2007, at 11:54AM, "Dan Reetz" <danreetz at gmail.com> wrote:
>Sorry to reply to my own message.
>
>If I open the file in Photomatix Basic, and open the Histogram, is the
>value under Absolute (2.90E-04) the actual pixel value?
>
>Thanks,
>Dan Reetz
>
>On 6/1/07, Dan Reetz <danreetz at gmail.com> wrote:
>> Hi all,
>>
>> I have a Radiance encoded HDR file, and I want to know the values of
>> the pixels within. The problem is that they seem to exceed the
>> 3-decimal place accuracy of the tools that I usually use. (Meaning, if
>> I use the Info tool in Photoshop or HDRview, they show up as all
>> zeros).
>>
>> Can anyone suggest a tool that can accurately read back the values in
>> the center rectangle of this image?
>>
>> http://danreetz.com/for_HDR-photo/4cdm.hdr (170kb)
>>
>> Thanks,
>> Dan Reetz
>>
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