Getting the distance from a QR code with known dimension

 In working towards an app that guide VI to navigate indoors (Blind Navigation System Using QR Code), I am working out the distance of a QR code from the navigator. This will allow the app to works like iBeacon that could tell the distance of navigator from the device.

OpenCV already have methods that could measure object dimension from a known reference. The first step is to convert the known dimension to pixel ratio. This will allow for different camera with different megapixel count. The formula is simple. ratio=pixle/real size of object.

With this constant, I will need to determine the distance from the navigator to the QR code. First I find the QR code then measure the QR Code size. The QR code most likely have to be enclosed within a rectangle so as to allow the measurement of the rectangle. Convert this size (in pixles) by the formula size=pixle*ratio. Viola, we get the distance from the QR code.

Measuring the position of the QR code is an essential metric. This will allow navigator to know the direction towards the QR code. This is easily done by getting the center point of the camera view then get the relative position of the QR code to the center point. We can inform the user whether it is to the right or left. Calculating the distance from the center point is quite meaningless as it is not useful to the navigator.

Unless navigator has a perfect memory of the position of all the QR code, there is a need for a map of the location with precise point of all the QR codes. The app should also allow the plotting of routes from one QR code to another so as to provide a voice guided navigation for the VI.

Deviating from the QR code will be an issue. Unlike iBeacon, once the QR code is not in the camera view, VI is practically lost. A facility to turn VI back to the track has to be made by approximating the last known point.

National Step Challenge Can it be Completed?

I joined and faithfully completed National Step Challenge season 4.  I continue to join Season 5. Season 5 added 2 more tiers to MVPA in Season 5 when I started the season, I was thrown back to Season 4 MVPA tier 5. So my Season 5 cannot start huh? Am I a completer then?

On calculating the time needed to complete 6 tiers of MVPA, I was surprised that it requires 187 days (40 points a day maximum). The challenge period is 189 days. To start MVPA challenge  I am supposed to complete the steps challenge tier 2. Minus the bonus, It takes at least 37.5 days to complete tier 2 of the step challenge. Adding it to 187 days, it is impossible to complete.

Now that I am thrown back to Season 4, I need another 75 days. It is equivalent to I cannot be a completer in season 5. I decided to quit completely. It is a challenge with a set period so it should start and stop within the period. HPB make it so difficult to complete. I wonder why.

By the way, in Season 4, HPB actually recommends 150 minutes per week for MVPA. That is 5 days of 30 minutes MVPA. Which translate to 200 points. Therefore, to complete the 6 tiers (7500 points), you need 37.5 weeks which is 262.5 days. Another puzzling figure. Absolutely mission impossible.

Evaluation of Careeach HR

The Careeach HR is a free tracker provided by Health Promotion Board. The following is a comparison with Garmin Forerunner 935. The comparison is one way. That is to say only compare what Careeach HR has to Forerunner similar functionality only. It is unfair to compare with all the available features of Forerunner 935.

1. Steps - Steps are fundamental feature however it is noted that Careeach HR always track about 10% less compared to Garmin even the steps setting are the same. Garmin seems to show slightly more steps than usual.

2. Heart Rate - Careeach heart rate measurements are very unstable. It can go above 150 while Forerunner shows a modest sub 90. The measurement can simply drops well below 80 while exercising and can drop out of continuous measure mode unexpectedly. Its auto mode is most unreliable. I always turn on continuous mode while exercising. Garmin shows a bit less accurate in auto mode but function well in continuous mode. I can use Garmin to control the heart beat rate but not Careeach. The latter heart beat goes up and down too much and too quickly. Careeach calculates max heart rate according to age. It will buzz user to slow down if the heart rate goes beyond heavy range. Garmin does not buzz user and its range is fixed percentage.

3. Display of the Careeach tracker is always off but can be activated by hand or a twist of the hand but often have to make very large angle swing of arm in order to activate it. Garmin does not have this feature as its display is always on. Both tracker will switch over to clock mode if it not in continuous measure mode. Garmin heart rate display will switch to clock mode after a while but it will stay if it is displayed in sports tracking mode.

4. Upload of data is a hassle. At times the HPB App has to be turned off and on a few times to make it update. Sometimes, the whole hand phone has to be rebooted to get it to work. Garmin update to HPB is via its apps. Although two steps are required but the updates are usually reliable.

5. Charging of Careeach is via USB but the display can some times go straight into full by just plugging in the tracker. The full charge display can stay till it run suddenly out of juice thus lost valuable data. Turning off and on the tracker does not help. Garmin charging can be a bit of problem due to contact issues but never have wrong display issue.

6. Careeach states that its tracker is splash proof. However, one tracker died after going though a light drizzle. Had to replace it. Garmin is water proof up to 50 meters.

7. Battery life of Careeach is way too low to be compared to Garmin. But it can last at least 10 hour of continuous heart beat tracking mode. It could last 2 days or more on normal mode.

8. Careeach will buzz user if they stay static for too long. I am not sure Garmin has it.

For a free device, Careeach HR could be used for tracking steps. Heart rate is at best good for indicator only. Just don't exercise in the rain or use quick charger to charge it.

Victoria Park Hong Kong

Right after Typhoon Manghkut, had a few hours of free time before flight, went to Victoria Park to see the aftermath of the typhoon. It is really a mess. Fallen trees, leaves are all over the place. Still managed to get some good photos. of flora and fauna.

At the entrance, there is a map readable by Visual Impaired people. I wonder how much can they make use of it.

The first tree I see has many branches on the ground. This one is Queen Crape Myrtle, 大花紫薇。

You can see the path is all covered with leaves from trees. At some places, you can't even see the path but that does not deter morning exercise people.

Next plant on the ground is 異葉南洋杉, Norfolk Island Pine.

Among the fallen branches I found male and female Red-whiskered Bulbul. Their nest probably destroyed.

I just need to look at the ground for plant species. This one is 枫香.

Next one is Eucalyptus robusta.

Black-collared Starling seems to be lost.

A Oriental Magpie-Robin seems to be quite active.

Black Rock Pigeon seems to be lost too.

A burst pipe and a fallen tree trunk.

Another view of the devastation.

Yet another Black-collared Starling foraging.

Did not take photos of fallen trees. It is almost like walking in a jungle trail.

Since it is just in a park, no maps or albums. The trip is just 3 KM.

Mongolia Trip

Went to Mongolia to attend World Blind Union AP Mid-Term General Assembly. In between, went out to have some picture taking session. On the last day, went for a one day tour.

Reached UlaanBaatar Chinggis Khaan International on 9/9/2018.

While waiting for other members of the WBU, Took a few pictures of the plants in the carpark. First one is Heteropappus altaicus. It has another surprising view which I will show later.

Next is Lupine Clover. I cannot confirm its Scientific name.

Next one is not focus properly as I am only using my hand phone to take picture. My camera is still in the luggage. I can't figure out what plant is it.

One other plant is Russian Knapweed. It is also not focus properly but at least it still captures the plant flower in the background.

Took a wide angle photo of the grass patch. The flowers are wild.

Walked further down and took a photo of Scots pine. Still focused wrongly.

Settled down in Holiday Inn Ulaanbaatar. Next morning, went out to have a quick shot of the garden in front of the hotel. It is a long and narrow garden in the middle of the road.

Took a picture of a unknown tree. Unable to identify.

There are no variety of plants in the garden till the end where there is a small patch of flowered plants. Common plants are Petunia.

Managed to get a focused shot of the Scots Pine this time.

Went further down to the junction and saw a mini flower garden. Plenty of Petunias.

One more flower I can't recognize.

At least I recognize this as Silver Ragwort.

Another flower I can't recognize as these are naturalized plants from other countries.

A photo of the tree that  I can't recognize too. Its trunk is painted to prevent frost I think.

Walked across to the further side of the road and saw this Yellow Sweet clover.

Can't recognize this one too.

Unfortunately, I cannot find a lot of plant photos on Mongolia. Many plants are just new to me. This one is a Alfalfa.

This one is Russian Knapweed. The close up is blurred due to wrong focus (auto focus as my eyes are as blur) so it is discarded.

This grass is also not recognized. Focus is out due to wind.

Another unrecognized grass.

Finally one plant that I can recognize. It is a Purple Shamrock. I guess it is not native.

A partially blooming flower. Seems to see it before but can't find in my library.

One more pine tree.

White Campion is one flower that I have searched for its name long ago as the flower pattern is unique.

This single Viola seems to be out of nowhere.

Running out of time so have to head back to hotel for the conference. Took a couple of picture in the conference for fun.

Before the hosted dinner, took a couple of photo on the mongolian tent from the hotel window. Like all cities, traffic jam can be seen below.

A few photos of the dinner entertainment performers. They are performing local music and songs.

Next morning, sneaked out again to venture around. Most of the plants are not recognized except specifically stated. The first one which is a Redroot Pigweed.

Mohilev Mallow is a climber.

This one is a Shrubby Cinquefoil. Notice I wear gloves. The weather is quite cold.

This one is probably a type of Maple.

This one is a Tufted Vetch

That evening went out with the group to Sukhbaatar Square before ending in Modern Nomads restaurant for a second taste of Mongolian food.

The next day is the one day tour. On the way, stopped by to snap some photo of the outskirt of Ulaanbaatar.

Managed to take picture of the Mongolian horse while the vehicle stopped due to traffic.

First stop is the Chinggis Khaan Statue. It is a huge statue with a hall below and a mini museum underground.

Of course I cannot miss those plants there. First one is unknown, the next one is a common dandelion. Last one is the same Heteropappus altaicus at the airport.

Next stop is Gorkhi Telelj National Park. First stop is lunch. Saw a Russian van, a sort of SUV.

After lunch, went to the nearby Mongolian tent hotel to see the inside of it.

Of course cannot miss the flora in the area. Three unidentified plants were there. There is a large fly on one of it.

The next plant is a Edelweiss.

Another one is very hard to identify. Most likely is a Caraway.

Next stop Turtle Rock. We stop a a photo taking spot where there is a souvenir shop with two fox skins outside.

Cannot miss this Greater Plantain plant growing by the road side.

We go further in the park for a horse ride. On the way snap a photo of the rare trees in the mountains.
Can't tell what tree is it. Probably pine trees.

We got a shock when the vehicle we are on goes down a stream and is about to cross a river before the driver decided that it is too deep to cross.

You can see the depth when a horse rider crosses the river.

The tour guide cum driver finally called a SUV to come over to fetch us.

In the ranch, there are two dogs, a Bankhar dog and a Husky. The Husky is extra friendly. It keep trying to play with visitors.

Finally, we get to ride a horse (on tow).

Feel very insecure on the horse thus did not take any picture during the ride. The tour ends after the ride. The driver bring us back to Ulaanbaatar shopping mall for a last minute shopping. Managed to snap photos of plants around the place.

Had a good night sleep before flying back to Hong Kong at 4:30 am.

Wikiloc map is here https://www.wikiloc.com/car-trails/mongolia-tour-28638102

Album is not only Mongolia, it include Hong Kong trips also so skip it.