How Do I Measure Noise Using Photoshop? And What Is A Significant Change?

Started 2 months ago | Discussions thread
sybersitizen Forum Pro • Posts: 14,814
Re: How Do I Measure Noise Using Photoshop? And What Is A Significant Change?

MrBrightSide wrote:

Question 1: Long ago I remember reading that you could use the statistics tools in Photoshop to measure the noise in a photograph.

I'd be interested in reading such a thing. Because the statistics count the pixel values in the image, I assume you would want an image with no features - one that theoretically should have just one perfect pixel value throughout. Then you could judge noise content by checking how far the actual pixels vary from that norm.

There must be something in the program because it has noise reduction so it must be able to identify noise. How does it work?

I don't think my version of Photoshop (CS3) noise reduction identifies noise. It just identifies local differences in pixel values and makes adjustments to them based on some set rules and according to my input.

Failing that, what other simple methods are there to measure noise in digital photos.

I dunno.

Question 2: Once the noise is measure what constitutes a significant difference in the noise level? Does it fall at 1 percent noisier? 10 percent? 100 percent?

I dunno. Neither 1% nor 10% sounds significant to me, but 100% does.

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