That is interesting. I had not heard that. Wonder what happens on the V850.
My stuff for sale is here: https://drive.google.com/drive/folde...-0?usp=sharing
My stuff for sale is here: https://drive.google.com/drive/folde...-0?usp=sharing
The Epson V700-850 may include a sensor similar to the TCD2964BFG
In page 3 of the TCD2964BFG datasheet https://www.glynshop.com/erp/owweb/D...TCD2964BFG.pdf shows the pixel alignment
It looks that the second row has shifted half a pixel, but I guess that the effective separation is close to a full pixel, because the sensitive area of the photosite is smaller than the theoric surface in the arrangement:
In that image we see an area sensor (not linear) including microlenses on the photosites to use a larger effective surface.
Well, it's clear that in that kind of arrangement the information from a row 4um row it is completed after the sensor has advanced 64+64+6 = 134um.
So the a row of the film it is not scanned in one shot, it will take dozens of steps to allow to pass all sensor rows over the film row, so some dozens of film rows are being scanned in course at the same time.
No, it's a true 6400 dpi hardware scanner for a 5.9" wide scan, and true 4800 dpi hardware for a full bed scan. As manufacturer specifies.
There are 6 rows in the sensor: 2 green, 2 red and 2 blue, this is two RGB sets: a half of the rows are shifted to take the (inter-pixel) space that was not scanned by the "first" set of rows. ("first" because in fact both sets are interlaced, as the image shows in previous post)
Because of the opto-mechanical design (mirrors, lenses, vibrations) this delivers 2000 to 2800 dpi optical neat perfomance, depending on the scanning settings and the axis.
All scanners deliver less optical performance that hardware dpi... In the case of the Epson V7/8 there is a lower than usual yield because the targeted manufacturing cost. They distributed the manufacturing budget in the way they could obtain best performance at the intended cost. This is mass production mentality.
A winner mentality, because today they own a market niche.
It in the marketing documentation, they refer to it as ... Epson Double CCD technology
http://content.epson.it/maco/technol...anners/ccd.htm
But there is no information on how it's implemented, when my scanner breaks I will pull it apart and find out for sure. I would also like to understand in more technical details on the scanner. For example what is the spectral sensitivity of the sensor etc.
More or less but with added modest improvement that pixel shifting allows.
This is pixel shift, what not clear is how the algorithm in this particular scanner is working, for example how does it work when the stepper motor is driven at much greater steps. When you scan at say 1200dpi what happens? How is X pixel data merged with Y pixel data?
Ted, I disagree. It is a 200% real improvement. Of course the lens has to match that performance to get the real improvement in the result.
If you review how linear sensors have evolutioned you will find that the pixel in the middle (of the second set) effectively takes just the area that was not covered by the first set.
It can be said that shift is half a pixel... but in fact is a full photosite shift, in terms of sensitive area, and this physically multiplies hardware dpi density by 2.
Look, the modesty of the improvement comes from optical limitations of the rest of the system. In fact a 6 rows arrangement has clear advantages over having the same pixel count in 3 rows, and is the preferred arrangement, single problem is that 6 rows instead 3 is a more expensive part, I think that this is well known.
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