Slice Tool (no not the one in Photoshop)

B
Posted By
Bernie
Dec 31, 2003
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307
Replies
2
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Closed
greets all,

I’ve been trying to find a "slice tool" that can be used to display an RGB value graph from a "slice" of an image (not to be confused with the ‘Slice Tool’ in Photoshop)

It’s used a lot in compositing: basically it is just a program/application that allows you to "draw" a line of a given length (1 pixel in width) across any image. You click the mouse at the starting point, draw the line across the image, and then release the mouse at the ending point. After this, a graph will appear, showing the luminance and/or RGB values for that one-pixel-wide slice/line that you just drew across the image.

It’s great for seeing if a blue/green screen is evenly lit, or showing the transition values of the FG to the BG blue/green screen, etc.

This tool is talked about in the book ‘Digital Compositing for Film and Video’ by Steve Wright. But haven’t been able to find one.

Does anyone know of an image tool that has this feature or will do this? Thanks.

MJ

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B
Bernie
Dec 31, 2003
To help better clarify, here are some examples of how this application and process works. These are some pictures and their corresponding graphs.

http://68.54.196.116/cimage1.jpg
http://68.54.196.116/cgraph1.jpg

http://68.54.196.116/cimage2.jpg
http://68.54.196.116/cgraph2.jpg

http://68.54.196.116/cimage3.jpg
http://68.54.196.116/cgraph3.jpg
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Bernie
Dec 31, 2003
On 31 Dec 2003 04:56:52 GMT, (MSu1049321) wrote:

in your NLE system of choice, Do a box wipe to black on a still frame you want to analyze, adjust the wipe parametersto get the ‘slice" you want, maybe export to photoshop and look at the histogram, or if on FCP or new Avid, use the scopes there.

The only problem I could foresee is that Photoshop will probably look at the pixels collectively and simply give an average for all the pixels in the slice rather than graphing them in a more linear fashion. To help clarify, have a look at the following page:

http://68.54.196.116/compos.html

Notice how the numerical graph shows the luminance/RGB values of the pixels in a linear way, the same way in which the line or "slice" was drawn. In this case, from left to right. Would this work with a histogram in PS?

MJ

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