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Author Topic: estimate image quality  (Read 7803 times)

julio

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estimate image quality
« on: March 26, 2014, 05:38:22 PM »
Hi,

Somebody know what exactly do Photoscan to define the image quality?
I did some tests with different textures and exposure parameters fixed. Results are better for a fine texture (sand than gravel) and always better for S size than L size of the picture. But this coefficient seems to be very variable according to exposure and the type of the object (for example, an aluminium paper will have a better coefficient in under exposure than in over exposure).

More over, I have a photo test with a quality coefficient of 1.06. I thought this coefficient varied between 0 and 1.

Someone can help me? 

Jules.
« Last Edit: March 26, 2014, 05:47:29 PM by julio »

Marcel

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Re: estimate image quality
« Reply #1 on: March 27, 2014, 11:21:24 PM »
In my humble opinion the Estimate Image Quality cannot really be used to detect low quality photos.

The Estimate Image Quality algorithm analyzes contrast between pixels, when there is a lot of contrast then the image is seen as sharp. But camera blur is often directional (like motion blur), so some sharp edges remain even when the camera is moved during the shot. The result is that the estimated quality is not a meaningful value for sharpness.

The only way to make absolutely sure that all your images are sharp is to visually inspect them at 200%. Painfully boring work. XD

Alexey Pasumansky

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Re: estimate image quality
« Reply #2 on: March 29, 2014, 03:00:50 PM »
Estimate Image Quality feature provides only the information about the most sharp border detected on the image and should be used to find only images which are obviously blurred.

Due to image specifics sometime the coefficient could be higher than 1.0.
Best regards,
Alexey Pasumansky,
AgiSoft LLC

Patribus

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Re: estimate image quality
« Reply #3 on: July 22, 2014, 11:26:29 PM »
IS there a possibility to export the Quality table, e.g. to an excel file?
Thanks

3D_Scan_Fan

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Re: estimate image quality
« Reply #4 on: March 16, 2015, 01:49:56 AM »
Sorry for bringing this up again, but in regards to the Estimate Image Quality, isn't there any way to bypass this?? Because I find it unfair that PhotoScan would reject from the photogrammetric processing.

Marcel

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Re: estimate image quality
« Reply #5 on: March 16, 2015, 12:07:17 PM »
The Estimate Image Quality is only a tool for the user to get an idea of the image quality. The values are not used during processing.

Ant

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Estimated image quality
« Reply #6 on: April 03, 2015, 10:49:18 AM »
Hi there,

Does anyone know what is the unit when we ask Photoscan to calculate the estimated image quality?

What is the principle behind this estimation?

Regards,
Ant

nadar

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Re: estimate image quality
« Reply #7 on: April 05, 2015, 11:13:47 AM »
I think you have the perfect answer higher in this discussion  ???

frank.stremke

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Re: estimate image quality
« Reply #8 on: April 08, 2015, 02:52:50 PM »
hi
i can not get it to work where are the results displayed
if i right click on a image or image set in the photos pane and click estimate image quality and it does some work in the console i can see it but no results displayed anywhere ?!
frank

James

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Re: estimate image quality
« Reply #9 on: April 08, 2015, 04:04:33 PM »
Switch the photos pane to 'details' view and you will see a 'quality' column.

Ant

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Estimated image quality unit
« Reply #10 on: April 23, 2015, 12:43:43 PM »
Hi there,

Does anyone know what is the unit of the estimated image quality?

Regards,
Ant

Marcel

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Re: estimate image quality
« Reply #11 on: April 23, 2015, 11:32:37 PM »
It has no unit, it goes from 0 to 1.0 (where 0 is bad and 1 is good).

driftertravel

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Re: estimate image quality
« Reply #12 on: April 27, 2015, 05:04:45 AM »
Image quality can go significantly over 1.0, using an a7r with the sony zeiss 50mm (one of the sharpest lens/body combos on the planet) with the images downsized from 36mp to 12mp shooting at iso 100 f16 I was getting wild quality readings. Of course, it's not really necessary, my canon 100Ds get around .85 and generate similar quality point clouds for 1/6th the price, part of this is the extra depth of field from using a crop lens camera. Still, the sony was nice...