HTI-H8 vs HT-301 Thermal Imager Comparison and Review

The HT-301 is popular on the internet for its great bang-for-buck: For about $760, you get 384×288 video at 25Hz. Almost nothing else can touch it at that price.

The HTI-H8 is a recent addition to HTI’s portfolio with the same banner specs for not much more money. Is it the same fantastic sensor stuffed into an easier-to-use complete package? I recorded the video below to give you my impressions on that question:

The short answer, unfortunately, is “No”. Here’s a quick comparison between the two with the HT-301 as a baseline. Note that both have most of the baseline must-haves for a many-hundred-dollar device, like adjustable emissivity, a half-decent menu of color maps, image capture, and so on.

HT-301

Pros

  • Excellent resolution and frame rate. Unbeatable at the price point.
  • Almost no latency/lag with either stock or aftermarket software.
  • Good lens, at least for working with PCBs: 13mm is relatively narrow and will cover an entire motherboard from a couple feet, or a single large chip from a couple inches.
  • the lens’ screw mount means it’s adjustable focus, from infinity with an o-ring for reference to about 8cm before the lens falls out of the thread.
  • USB is pretty flexible – can be used on a phone, tablet, or PC as software allows. Also means it’s very easy to mount when using a USB-C extension cable.
  • Third party software at least exists, and ThermViewer for Android provides some nice quality-of-life features not present in the stock software.

Cons

  • The stock software only covers Android
  • Stock software is buggy (Video is broken; HTI seems unwilling to fix it on Android 10)
  • Stock software includes no thermographic data outputs – just color JPEGs of what measurements you see on screen.
  • Integrated measurements are pretty limiting:
    • Crosshairs
    • Full image or single-area (square) high/low
    • Line (horizontal-only) high/low
  • No options for nonuniformity correction in stock app.

So basically, with the HT-301, we’ve got a decent jack-of-all-trades that CAN be supremely useful, but takes a little fiddling and working around software limitations to get there.

HTI-H8

Pros

  • Self-contained form factor
  • Same great frame rate and resolution as HT-301
  • WiFi

Cons

  • Embedded measurements are VERY limited: High/Low/Center only.
  • Embedded UI lags terribly with ~1S latency from image capture to display, and multi-second delay to update measurements.
  • Can’t save video
  • Can’t save radiometric data whatsoever
  • No practical way to mount the device – it MUST be hand-held.
  • WiFi interface doesn’t offer any advantages over local operation and isn’t very reliable.
  • WiFi image latency is 1.5 seconds.

Conclusions

Long story short, the HT-301 isn’t a slam-dunk, but if you’re coming from something like the FLIR One, you’ll be making a few quality-of-life sacrifices for a huge improvement in resolution and comfortable operation. FLIR makes specific PCB inspection cameras that will probably outclass this as much as their price tag suggests, but this thing is a bargain.

On the other hand, the HTI-H8 isn’t a great option. You’d probably be better off with a slightly more expensive mainstream handheld. At least you won’t be stuck tearing your hair out. If your needs are VERY basic and you JUST want to be able to quickly look at something with higher resolution than the $300-$600 pricepoint allows, this MIGHT be ok for you. But I’d save a couple hundred bucks and get a high resolution 9hz device, because the 25hz won’t do you nearly as much good here with such massive UI latency.

2 Comments

  1. Rajesh Mag
    August 8, 2021

    HI Alax, were you able to get any software to run HT-301 in windows PC?

  2. August 9, 2021

    Not exactly. The camera enumerates as a USB UVC device. You can open it and view video with (almost) any webcam app, including VLC. You can CONTROL it (switch video modes, activate the FFC shutter) by writing to one of the UVC control channels. For instance, writing 0x80 to the zoom channel (I think) activates the FFC shutter. I’m guessing that specific info is wrong but can’t check just now. Anyway, I HAVE been working on some python example code that does this, so I can get the camera to switch into a mode where it outputs 16bit temperature data instead of RGB formatted black and white pixels. BUT to go from that to radiometric temperatures is actually quite a bit of math and processing I have not yet done. Some general data like sensor temp, hottest pixel location and value, coldest pixel location and value, etc. is included in a 2px tall strip across the bottom, which is why those rows appear green and corrupted if you view the camera stream with VLC.

    So long story short, you can view the image in the default mode with something like VLC, but anything more useful than that is still not yet available.

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