FAQ: Automatic Keystone Correction

PicoPix Max Knowledge Base
1

How automatic keystone works

The projector has a tilt sensor. When you tilt the projector up or down, the projector will measure how much it is tilted. Based on this measurement, the projector can apply a correction so that the picture is straight on your wall (or ceiling).

Calibration

The projector has a built-in “zero position” which is set in the factory to be flat (on the floor). When you place the projector on the floor, with no tilt, the picture should be straight. If it is not perfectly straight, it can be due to one of many reasons:

  • you’ve not placed the projector on a perfectly level surface
  • your wall is not exactly 90° from the floor
  • the built-in tilt sensor needs calibration

To correct this, you need to “calibrate” the sensor. This is very easy to do, just follow the steps below:

How to calibrate the tilt sensor?

  • Place the projector on a flat horizontal surface such as the floor or a table top.
  • Go to Projector Settings > Image > Keystone Correction.
  • Select Horizontal Correction and press OK to activate the calibration.

Make sure that the projector is completely still and not moving during this process. It takes a few seconds.

Note: This calibration is also performed every time you turn automatic keystone off and on. So please make sure that the projector is flat and not tilted when you enable the Automatic Keystone Correction feature.

FAQs

Q: After performing calibration, the picture is not straight on the wall!

It means you did not place the projector on a perfectly level surface. Please place the projector on a level surface and calibrate again.

If that doesn’t work, your wall may not be at 90° from the floor. Do this:

  • turn off the Automatic Keystone Correction
  • tilt the projector yourself, such that the picture is straight on your wall
  • turn back on the Automatic Keystone Correction.

The projector will remember this as the “straight” angle.

Q: Will the projector keep the correction, if I turn off automatic correction?

No, the correction is turned off.

Q: Does the picture quality suffer when correction is applied?

Yes there is a small degradation of sharpness when correction is applied, but it will not be very apparent when watching your media content. For the best picture quality it’s always advisable to physically put the projector in the front/center of your wall.

Q: What about projecting on my ceiling? Do I need to do anything special?

No. The projector will figure out when you’re projecting on the ceiling and apply the appropriate correction to make the picture straight on your ceiling above instead of on a wall in front.

Q: Does this work with HDMI or USB-C video input?

Yes!

Only 4-corner correction, digital zoom, and Bluetooth audio don’t work for external video. See INFO: Limitations of features for HDMI and USB-C inputs for more details.

3 Likes
2

So according to this FAQ, I assume if I want to project on the ceiling while leaving the projector on the floor level, auto keystone correction must be disabled every time. Am I right?

3

Hi @Guidone, no, you can keep automatic keystone enabled when projecting on the ceiling.

It will figure this out and apply the appropriate correction so that the picture is straight on your ceiling (parallel to the floor) instead of on the wall. Added to FAQ!

To avoid confusion: this is separate from the image flip option for when you mount the projector on the ceiling.

1 Like
4

Thanks for the clarification. As you mentioned in the FAQ:

This assumes that your wall is at 90° angle (perpendicular) from the floor!

I assumed this wasn’t working for a 180° scenario (projecting from floor to ceiling) :slight_smile:

1 Like
5

Thanks for pointing out, I’ve edited the post to make it clearer.

1 Like
6

Thanks @Philips_Support_P for creating this article! Can you maybe add when you are talking about vertical and when about horizontal corrections?

BTW:

Just wondering why the option „Horizontal Correction“ didn’t fix my horizontal disortion on my PPM with 1.0.25 (After I have moved the PPM from perfectly centered to the wall, to a few degree to the left as shown both in the video)

Video:

I was only able to fix the horizontal disortion manually via 4-corner correction

Video:

Just for reference what is vertical and what is horizontal correction:

2 Likes
7

So is the horizontal keystone correction meant to be automatic via the camera or not?

Thanks.

8

Unfortunately “Horizontal Correction” is a translation error:

9

The other day while adjusting the picture to project a bit ahead of me on the ceiling instead of straight above I found that there’s a cut-off angle at which this happens, when it switches to correcting for wall display to correcting for ceiling display. Is there a way to adjust this (in the future) in a (hidden) setting somewhere (in the planning)?

10

The correction range is ±45° so that’s where it switches. There’s no feature to change this right now.

1 Like
11

Hi PhilipsPrashant,

I cannot find 4 corners corrections in my keystone correction menu, and whenever there is a 5° angle, my projected picture is not a rectangle but a trapezoid.

How does the correction work?

12

Hi @Svphya you must turn off automatic keystone first to access 4-corner (manual) keystone.

It looks like automatic keystone is also not working perfectly. Please follow calibration procedure:

https://support.screeneo.com/hc/en-us/articles/360012985459-How-to-calibrate-the-tilt-sensor

1 Like
13

I like what you did there @Philips_Support_P :sunglasses:

14

So just to be clear, if I did enable keystone correction and done a calibration on a flat shelve which is my intended setup do I leave keystone correction on or off afterwards?

15

If you have it on the flat surface only, you could do either. But then again, why bother turning it off: if it’s not going to be angled up or down, the automatic correction won’t kick in anyways. Leaving it on means that when you eventually do pick it up for use somewhere else it will be ready to use and doing its correction magic.

1 Like
16

Thanks , I’m just trying to work out what the default normal ideal settings should be, so when situations change I have a reference point to gauge on.

1 Like
17

Hi @Philips_Support_P

I got my projector the other day :partying_face:

I did the calibration and the auto correction works perfectly when the projector is straight in front of the wall but not when it’s a bit on the side. Should I use the manual correction in that case?

Thanks :smiley:

1 Like
18

Hi @fedetaglia yes you are right, the left/right correction is not automatic, only the up/down correction is. If you’re using it on the side, please turn off Automatic Keystone, and then use the 4-Corner Correction option that will appear.

1 Like
19

Thanks!
it would be nice to have something that speed up the manual correction, it’s a bit slow when you do big changes, but pretty happy with the quality even from the side :smile:

1 Like
20

Yes we have 3 out of 30 tasks on our list related to improving this feature.

3 Likes