[libcamera-devel] [PATCH v3 2/8] rkisp1: Control camera lens position from IPA

[Dave Stevenson]

Hi Jacopo and Daniel

On Mon, 6 Feb 2023 at 09:46, Jacopo Mondi via libcamera-devel
<libcamera-devel at lists.libcamera.org> wrote:
>
> Hi Daniel
>
> On Thu, Jan 19, 2023 at 09:41:06AM +0100, Daniel Semkowicz via libcamera-devel wrote:
> > Allow control of lens position from the IPA, by setting corresponding
> > af fields in the IPAFrameContext structure. Controls are then passed to
> > the pipeline handler, which sets the lens position in CameraLens.
> >
>
> As a minor nit: I would move this to the end of the series, after
> having plumbed in the algorithm implementation... Just a nit though
>
> > Signed-off-by: Daniel Semkowicz <dse at thaumatec.com>
> > ---
> >  include/libcamera/ipa/rkisp1.mojom       |  1 +
> >  src/ipa/rkisp1/ipa_context.h             |  5 +++++
> >  src/ipa/rkisp1/rkisp1.cpp                | 12 ++++++++++++
> >  src/libcamera/pipeline/rkisp1/rkisp1.cpp | 16 ++++++++++++++++
> >  4 files changed, 34 insertions(+)
> >
> > diff --git a/include/libcamera/ipa/rkisp1.mojom b/include/libcamera/ipa/rkisp1.mojom
> > index bf6e9141..c3ed87aa 100644
> > --- a/include/libcamera/ipa/rkisp1.mojom
> > +++ b/include/libcamera/ipa/rkisp1.mojom
> > @@ -39,5 +39,6 @@ interface IPARkISP1Interface {
> >  interface IPARkISP1EventInterface {
> >       paramsBufferReady(uint32 frame);
> >       setSensorControls(uint32 frame, libcamera.ControlList sensorControls);
> > +     setLensControls(libcamera.ControlList lensControls);
> >       metadataReady(uint32 frame, libcamera.ControlList metadata);
> >  };
> > diff --git a/src/ipa/rkisp1/ipa_context.h b/src/ipa/rkisp1/ipa_context.h
> > index b9b20653..1fac6af9 100644
> > --- a/src/ipa/rkisp1/ipa_context.h
> > +++ b/src/ipa/rkisp1/ipa_context.h
> > @@ -53,6 +53,11 @@ struct IPASessionConfiguration {
> >  };
> >
> >  struct IPAActiveState {
> > +     struct {
> > +             uint32_t lensPosition;
> > +             bool applyLensCtrls;
>
> Oh gosh lens are -complicated- /o\
>
> For regular sensor controls we defer the decision to apply or not a
> control to DelayedControls on the pipeline handler side, which takes
> care of evaluating if a control has to be updated or not and how many
> frame it takes to take effect.
>
> Lenses (well, VCM to be fair) are a bit more complex than that, in the
> sense that moving the lens might take a number of frames that depends
> on the movement range. Some VCM datasheet I've seen provide a model to
> estimate the delay depending on the movement range and the VCM
> characteristics. The risk is that updating the lens position while the
> lens hasn't reached its final position might trigger some resonation
> effect, especially if the algorithm runs in "continuous auto-focus"
> mode and tries to update the lens position too often.

Please don't limit thinking to VCMs.

>From my days of doing CCTV control systems I have a Computar 7.5-120mm
motorized zoom and focus lens with C-mount [1]. It has motors to drive
the optics, and potentiometers to read back the position. Add a couple
of L298N motor driver chips and an ADC and I can control it fine,
however significant movement takes several seconds.
Likewise there are stepper motor controlled lenses such as [2]. You
need a reset sequence at power on (largely driving into an endstop),
but after that you have calibrated movement.

I have MCU code to drive both of those via I2C, but V4L2 really needs
a control for reporting the current focus (and zoom) position, with
the existing controls taking the requested position. The IPA can then
hold off if it knows the lens hasn't finished moving yet.

Just food for thought.

  Dave

[1] https://computar.com/product/680/H16Z7516PDC (at full zoom it
should be able to view things a couple of miles away with IMX477 or
similar)
[2] https://www.amazon.co.uk/dp/B09V53CMSK

> I've cc-ed Matthias Fend which has recently sent a series for "more
> complex optics"
> https://patchwork.libcamera.org/project/libcamera/list/?series=3735
> (which partially overlaps with the work you've done here) as he
> certainly knows more than me about VCM and optics to know what his
> opinion is
>
>
> > +     } af;
> > +
> >       struct {
> >               struct {
> >                       uint32_t exposure;
> > diff --git a/src/ipa/rkisp1/rkisp1.cpp b/src/ipa/rkisp1/rkisp1.cpp
> > index 9e861fc0..297161b2 100644
> > --- a/src/ipa/rkisp1/rkisp1.cpp
> > +++ b/src/ipa/rkisp1/rkisp1.cpp
> > @@ -270,6 +270,10 @@ int IPARkISP1::configure(const IPAConfigInfo &ipaConfig,
> >                       return format.colourEncoding == PixelFormatInfo::ColourEncodingRAW;
> >               });
> >
> > +     /* Lens position is unknown at the startup, so initilize the variable
>                                                        ^ initialize
> > +      * that holds the current position to something out of the range. */
>
> Multiline comments as
>         /*
>          * first line
>          * next line
>          */
>
> > +     context_.activeState.af.lensPosition = std::numeric_limits<int32_t>::max();
> > +
> >       for (auto const &a : algorithms()) {
> >               Algorithm *algo = static_cast<Algorithm *>(a.get());
> >
> > @@ -452,6 +456,14 @@ void IPARkISP1::setControls(unsigned int frame)
> >       ctrls.set(V4L2_CID_ANALOGUE_GAIN, static_cast<int32_t>(gain));
> >
> >       setSensorControls.emit(frame, ctrls);
> > +
> > +     if (lensControls_ && context_.activeState.af.applyLensCtrls) {
> > +             context_.activeState.af.applyLensCtrls = false;
> > +             ControlList lensCtrls(*lensControls_);
> > +             lensCtrls.set(V4L2_CID_FOCUS_ABSOLUTE,
> > +                           static_cast<int32_t>(context_.activeState.af.lensPosition));
> > +             setLensControls.emit(lensCtrls);
> > +     }
> >  }
> >
> >  } /* namespace ipa::rkisp1 */
> > diff --git a/src/libcamera/pipeline/rkisp1/rkisp1.cpp b/src/libcamera/pipeline/rkisp1/rkisp1.cpp
> > index 0559d261..b2fedc5f 100644
> > --- a/src/libcamera/pipeline/rkisp1/rkisp1.cpp
> > +++ b/src/libcamera/pipeline/rkisp1/rkisp1.cpp
> > @@ -113,6 +113,7 @@ private:
> >       void paramFilled(unsigned int frame);
> >       void setSensorControls(unsigned int frame,
> >                              const ControlList &sensorControls);
> > +     void setLensControls(const ControlList &lensControls);
> >
> >       void metadataReady(unsigned int frame, const ControlList &metadata);
> >  };
> > @@ -337,6 +338,7 @@ int RkISP1CameraData::loadIPA(unsigned int hwRevision)
> >               return -ENOENT;
> >
> >       ipa_->setSensorControls.connect(this, &RkISP1CameraData::setSensorControls);
> > +     ipa_->setLensControls.connect(this, &RkISP1CameraData::setLensControls);
> >       ipa_->paramsBufferReady.connect(this, &RkISP1CameraData::paramFilled);
> >       ipa_->metadataReady.connect(this, &RkISP1CameraData::metadataReady);
> >
> > @@ -400,6 +402,20 @@ void RkISP1CameraData::setSensorControls([[maybe_unused]] unsigned int frame,
> >       delayedCtrls_->push(sensorControls);
> >  }
> >
> > +void RkISP1CameraData::setLensControls(const ControlList &lensControls)
> > +{
> > +     CameraLens *focusLens = sensor_->focusLens();
> > +     if (!focusLens)
> > +             return;
> > +
> > +     if (!lensControls.contains(V4L2_CID_FOCUS_ABSOLUTE))
> > +             return;
> > +
> > +     const ControlValue &focusValue = lensControls.get(V4L2_CID_FOCUS_ABSOLUTE);
> > +
> > +     focusLens->setFocusPosition(focusValue.get<int32_t>());
> > +}
> > +
> >  void RkISP1CameraData::metadataReady(unsigned int frame, const ControlList &metadata)
> >  {
> >       RkISP1FrameInfo *info = frameInfo_.find(frame);
> > --
> > 2.39.0
> >