Image quality, presets, and frame rate after switching from Cast to Solum

[sxy-sun]

Hi,

We are using a PAL HD3 Multipurpose Scanner and recently switched from the Cast API to the Solum API.

Our team feels that images from our previous Cast integration looked better, and we would like to understand whether differences in presets or output settings could explain this. We are also interested in achieving smoother live imaging at higher frame rates.

Our current setup:

• Solum: PALHD3 with the cardiac and dvt applications.
• Both integrations request 512×512 processed images.
• Our Cast integration encodes received images as JPEG at quality 80. Our Solum integration requests JPEG output and forwards it without re-encoding.
• Solum SDK: v12.2.4
• Clarius App: Version 12.2.11-hotfix-6747+966874bf2a
• Imaging: B-mode, EcoMode disabled, IMU streaming enabled.
• The probe settings:

  settings = ProbeSettings(
      contactDetection=0,
      autoFreeze=0,
      keepAwake=0,
      deepSleep=0,
      stationary=0,
      powerFan=1,
      autoBoot=0,
      wifiOptimization=0,
      htWifi=0,
      keepAwakeCharging=0,
      powerOn=1,
      sounds=1,
      wakeOnShake=1,
      bandwidthOptimization=0,
      forceLogSend=0,
      imageOnUndock=0,
      alarmOnUndock=0,
      up=0,
      down=0,
      handle=0,
      upHold=1,
      downHold=1,
  )

We would appreciate your guidance on the following:

1. Presets: The Clarius App offers Cardiac Basic and Cardiac Advanced, while we currently load cardiac in Solum. Which Solum applications or parameters correspond to these presets? Are there additional imaging optimizations we should enable, or are any exclusive to the Clarius App?
2. Image quality: Our team feels the Cast images look better, although both integrations request 512×512 output. Should image quality be comparable with matching settings? Which output settings should we check, and is Solum’s JPEG quality configurable?
3. Frame rate: Our ROS publisher currently limits image publication to 15 FPS. Before increasing this limit, we would like to understand what higher processed-image frame rates are achievable through Solum for cardiac and dvt on PAL HD3. Which settings affect these rates?

Thanks.

[clariusk]

Hi,

Good detail in the report — that makes this much easier to answer. The short version up front: the
presets are the same data in both paths. The Clarius App and Solum load the identical application
definition, run the identical processing and scan conversion, and encode JPEG with the identical
settings. So a look difference between your Cast and Solum images is not coming from the preset, and
the place to look is the parameter state sitting on top of it.

Everything below is specific to the 12.2 release you are on.

1. Presets

cardiac is Cardiac Advanced — that is the same application the App shows under that name, so
you are already on it. Your dvt is likewise the same DVT preset the App loads, on the scanner's
linear array.

Cardiac Basic is a separate application and it is not offered over Solum. On PALHD3 the two are
closer than the names suggest: identical script, sequence and parameter chain, differing only in the
default starting depth (20 cm for Basic, 15 cm for Advanced) and in image orientation. Advanced is
the superset — it is the one that also carries tissue Doppler — so there is nothing to gain by
chasing Basic.

Nothing in the imaging chain itself is App-exclusive. On 12.2 there is one B-mode adjustment the App
has and Solum does not: sector width, which narrows the phased-array sector. It is an advanced
control in the App and there is no CusParam for it. Aperture offset is likewise App-side, but it is
research-gated and not something to reach for.

For completeness on depth ranges as the presets define them on PALHD3:

• cardiac — 3 to 32 cm, defaulting to 15 cm.
• dvt — 1 to 7 cm, defaulting to 4 cm.

2. Image quality

JPEG is not the cause. Solum encodes at quality 100 and it is not configurable; your Cast path was
re-encoding at 80, so if anything the Solum images are the less lossy of the two. If you want to
control the encode yourself, request Uncompressed8Bit (8-bit grayscale) or Uncompressed (32-bit
ARGB) instead of Jpeg and encode downstream. Png is also available if you want lossless without
the raw bandwidth.

Scan conversion is not the cause either — Cast and Solum share the same processing code at the same
requested 512×512.

What actually differs is where the imaging parameters came from. In your Cast setup the App was
driving the scanner, so the images you received were acquired with whatever the App operator had
dialled in — gain, TGC, depth, sector width — on top of the preset. Solum drives the scanner
directly and starts from the preset defaults every session. That is the most plausible account of
what your team is seeing, and it is worth confirming by having someone note the App's settings during
a side-by-side.

The controls you have in Solum, in rough order of impact on how the image looks:

• setTgc for the top/mid/bottom gain profile, and Gain for overall gain. AutoGain defaults on
  for cardiac; if you have turned it off, your gain profile is whatever you last set rather than what
  the App would have converged to. Leaving auto gain on is the closest match to a default App
  session.
• Contrast and Smooth, both at 50% out of the preset.
• PenetrationMode for deeper cardiac views.
• AutoFocus defaults on; leave it unless you have a reason.

One clarification since the API docs can mislead here: RfStreaming is documented as defaulting on,
but RF is only actually transmitted when an RF, channel or photoacoustic stream is active. In plain
B-mode it costs you nothing, so it is not something you need to turn off.

3. Frame rate

The preset frame-rate ceilings on PALHD3 are 30 Hz for cardiac (at every depth in the range) and
25 Hz for DVT, so your 15 FPS publisher limit is leaving real headroom on the table. Those are
ceilings, not guarantees — the delivered rate falls off with imaging depth and line density, and then
with whatever the Wi-Fi link can carry. Every processed-image callback reports the actual acquisition
rate in CusProcessedImageInfo.fps; log that and you will see where you actually are before you
raise the publisher limit.

What moves the number:

• Reduce depth. Cardiac Advanced defaults to 15 cm; every centimetre you do not need costs you
  line time.
• Keep Eco mode off — you already have. It caps at 60% of the preset rate.
• powerFan=1 is the right call; keep it. It keeps cooling maximised, which is what lets you scan
  for longer before thermal limits force you into Eco mode.
• Colour Doppler and M-mode reduce the B-mode rate as you would expect. B-mode only is your best
  case.
• Narrowing the sector helps on cardiac, but as noted that control is not exposed over Solum today.

Let us know whether a check of the App-side gain and TGC closes the gap. If the images still do not
match after that, please capture a raw data snapshot from each path and we will compare them
directly.