artifacts. If you want to compare gray level, make sure you use weighted
(2) JPG has a nonlinear relation between pixel value and intensity. If
> Michael, I had figured out that I needed to convert to grayscale. Otherwise
> I assumed I would get RGB values. I also dug deeply enough to have found the
> choice of grey conversion. As I'm not doing perceptual analysis, I kept the
> non-weighted conversion.
>
> The answer was to simply File>Save As>Text Image. DUH!
>
> I am comparing two images that are very similar. I have been subtracting
> them w/ Photoshop, but have also found that imagej can do that subtraction.
> :-)
>
> I am wanting to count pixel values and use a custom algorithm to quantify
> the difference. I probably could use imagej, but the learning curve is very
> steep and I am comfortable w/ Excel.
>
> Thanks...
>
> -----Original Message-----
> From: ImageJ Interest Group [mailto:
[hidden email]] On Behalf Of
> Michael Schmid
> Sent: Tuesday, June 14, 2016 1:52 PM
> To:
[hidden email]
> Subject: Re: Help?
>
> Hi Charles,
>
> it seems you need a grayscale image first. Assuming you are starting
> with RGB, use Image>Type>8 bits.
> Make sure you have the correct choice of "Weighted RGB Conversions" in
> Edit>Options>Conversions
>
>
https://imagej.nih.gov/ij/docs/guide/146-27.html#toc-Subsubsection-27.13.11>
> Then save as text image.
>
> Anyhow, what kind of analysis with all pixels do you want to do in Excel?
> I guess that ImageJ could do essentially everything that can be done in
> Excel, but much faster.
>
> Michael
> ________________________________________________________________
> On 2016-06-14 18:10, Charles Davis wrote:
>> I'm a new imagej user and am having a problem. I know that imagej will
>> generate the data that I want, because I [somehow] got it to do it once.
> But
>> I don't remember the sequence of operations that I went through to get
> that
>> result. I have spent 2 weeks, working several hours each day and have not
>> been able to study and find the answer or try everything that seems
>> reasonable. My pride and ego is at ZERO! I can't do this w/o help.
>>
>>
>>
>> Background:
>>
>>
>>
>> I'm using a Nikon D810 camera which produces large files. I need a .csv or
>> .txt file w/ the brightness values. I don't want a Histogram, but the data
>> behind the Histogram.
>>
>>
>>
>> I have been able to produce files w/ all the pixel data [X, Y, R, G, B] in
>> one row. That is too large to load into Excel [36,200,000 is too many
> rows].
>> Yes, I have successfully attempted to break it up into several smaller
>> files, but that takes hours to do one file! Then I have to extract the
>> summary data from each of these 2-dozen+ files and create a global summary
>> file.
>>
>>
>>
>> As I said, I was able to [somehow] create a .txt file that was organized
>> differently. I had all the Y's in the rows and all the X's in the columns.
>> The data in each cell was the gray value [I think]. This had only 4913
> rows
>> x 7359 columns and loaded into Excel [slowly]; it's still big, but
>> manageable.
>>
>>
>>
>> Sorry for the long intro, getting to my question: How do I recreate
> another
>> of those Measurements.txt files, w/ only gray brightness data in cells and
>> in a 2D array?
>>
>>
>>
>> TIA!
>>
>>
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>> ImageJ mailing list:
http://imagej.nih.gov/ij/list.html>>
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