Some thoughts about Usability

Just from the users perspective, some thoughts and experiences concerning usability…

I have to pay my phone bill every month. It is one for phone, internet, and everything, but it needs to be payed. It is mostly used for the company, so it is paid by my company and I need a proper invoice and the bits of information for how to pay it via e-banking.

Now I get an email every month telling me they want money and I want to pay it. That is not too hard, because the email already contains the information and it is also relatively easy to find on the web site.

But then I need the invoice. When I go to the web site, there are different worlds, like private, small business, big business. It is necessary to log into the right one, and if for historical reasons an account exists for „private“ that is an dead end.

Then it is finally possible to find the money that needs to be paid. But then again, the obvious path leads to the payment information without the link to the PDF of the invoice. It is a dead end.

The web site does have a beautiful design and provides a lot of information and services.

But why don’t they make it really a matter of seconds to pay my bill and printing the invoice? That is the only thing I really want and need to do every month. And it is a bad experience each time. Because I forget how to do it after a month and it is not easy and obvious enough. The invoice could be attached to the email or there could be a link that leads directly to the invoice. Plus another link for whatever else they want to show me, if they like… I can easily ignore that second link most of the time.

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Combining multiple scans

When images are scanned multiple times, maybe there is a way to construct an image that is better than any of the scans from them.

In this case it is assumed, that one scan has a higher resolution, but another scan got the colors better.

It has already been found out, which two scans belong to the same original.

Also one of them has already been rotated to the desired position.

The rotation can easily be found. Since images are roughly rectangular and width is roughly 1.5 times the height, simply two rotations have to be tried. Images are compared pixelwise and the one that has less deviation is probably the right one.

Now the orientation is already the same. And when scaled to the same size, the images should be exactly the same, apart from inaccuracies. But that is not the case. They are scaled slightly differently and they are shifted a bit.

Now the shift and scaling can be expressed by four numbers as x=a*u+b and y=c*v+d, where (x,y) and (u,v) are coordinates of the two images. It could be a matrix, if rotation is also involved and this would work the same way, but professional scans do have shift and scaling problems, but much less rotation problems.

So to estimate a, b, c and d, it is possible to go through all the pixels (u,v) of one image. Now the pixels (x,y) = (u+du, v+dv) are compared for combinations of small du and dv. The result is a sum of squares of differences s in a range between 0 and 3*65536. Now low values are good, that means that the coordiates (u,v,x,y) are a good match and need to be recorded with a high weight. This is achieved by weighting them with (3*65536-s)^2. Now it is just two linear regressions to calculate a,b,c and d. Of course, the points near ues the borders need special care, but it is possible to ommit a bit near the boarder to avoid this issue.

Now the points (u,v) of one image are iterated and the approximate match (x,y) on the other image is found. Now for (r,g,b) there can be a function to transform them. To start, it can be linear again, so this will be three linear regressions for r, g, and b. Or it could involve a matrix multiplied to the input vector. Or some function, then a matrix multiplication then vector addition and then the inverse function. The result has to be constrained to RGB-values between 0 and 255.

Now in the end, for each pixel in one image there is a function that changes the colors more to what the other image has. This can be applied to the full resolution image. Also, a weighted average of the original values and the calculated values, to find the best results. Then this can be applied to the whole series.

A few experiments with the function and a bit research on good functions for this might be done, to improve. In the end of the day there is a solution that is good enough and works. Or maybe a few variants and then some manual work to pick the best.

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Processes

We all encounter once in a while people in the teams who really love processes.

Now processes are a good thing, because they can help us to work, clarify certain things and improve efficiency.

There are even processes that are absolutely mandatory, for security reasons, for example. It should be carefully chosen where to impose such a mandatory process, but then it should never be broken. Other processes are more like a tool, that we use because it helps us. Or because the majority of us or simply the boss think so. Or because they are just there. And have always been there in the last 9 months or so.

A well know example is the work of airplane pilots. When they take over a plane there is a checklist of things what to do. Each item of the checklist has to be followed. Each time.

I have introduced such a checklist for creating a release or of a software into many projects. It proved wrong to shortcut this or just do it somehow, because in the end the wrong or unknown version of the software was installed or something else went wrong. I introduced it also for creating USB-sticks that were used by non-IT-people to install a software on around 1000 devices physically located in different places throughout the country or by hardware people in their workshop. We were not stupid, what could be done via the internet was done via the internet, but machines could get hardware problems or get messed up or simply be set up for the first time. It took a bit more than an hour to do everything by the book and it never became significantly faster. But then again a failure was potentially much much more expensive than a few hours of work. And after this process had been introduced there were no failures at all with any USB-sticks prepared according to this process.

But of course we should always remember that processes are there to help us do our work better. So they should not become so extensive that they use up all the time or that they make work too hard, unless necessary for reasons like the ones mentioned above. So a good understanding is that a lot of things can be done if all who are involved or simply the boss agree to do so after thorough thinking. Do not stop using your brain because of processes.

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