I want to stop Y-Axis autoRange , yAxis.setAutoRange(false).
I have Maximum Values. suppose Minimum = 0,
How can i generate regular value for tickunit by using (max).
To be able to.
Y-axis.setUpperBound(max);
Y-axis.setTickUnit(tickunit);
Related
I am using VTK to build meshes from CT images. I find myself stuck trying to understand the cryptic vtkMarchingCubes::SetValue(). As per the documentation The first parameter is said to be the contour number, the second one is the "contour value", my question here is what exactly is "contour value"? is that an intensity value?
If it is indeed an intensity value, does VTK just look for that exact value or does it look around? is there any way I can specify a range rather than a single number? My last question is, how do I extract multiple contours from the image using vtkMarchingCubes in one pass?
Yes, it is the image intensity, I.e. the level for the level-set.
Image intensities are interpolated, so if you have a voxel with intensity 0 and a neighboring voxel with intensity 1, and set the value to 0.5, the generated surface will be half-way in-between. If you set the value to 0.9, the surface will be closer to the 1 voxel.
To extract multiple contours, you'd specify multiple values, I.e
mc->SetValue(0, 60);
mc->SetValue(1, 600);
I am not sure what you would want to achieve by specifying a range?
I have an image and I am picking colors by RGB (data sampling). I select N points from a specific region in the image which has the "same" color. By "same" I mean, that part of the image belongs to an object, (let's say a yellow object). Each picked point in the RGB case has three values [R,G,B]. For example: [120,150,225]. And the maximum and minimum for each field are 255 and 0 respectively.
Let's assume that I picked N points from the region of the object in the image. The points obviously have different RGB values but from the same family (a gradient of the specific color).
Question:
I want to find a range for each RGB field that when I apply a color filter on the image the pixels related to that specific object remain (to be considered as inliers). Is it correct to find the maximum and minimum from the sampled points and consider them as the filter range? For example if the max and min of the field R are 120 ,170 respectively, can it be used as a the range that should be kept.
In my opinion, the idea is not true. Because when choosing the max and min of a set of sampled data some points will be out of that range and also there will be some point on the object that doesn't fit in this range.
What is a better solution to include more points as inliers?
If anybody needs to see collected data samples, please let me know.
I am not sure I fully grasp what you are asking for, but in my opinion filtering in RGB is not the way to go. You should use a different color space than RGB if you want to compare pixels of similar color. RGB is good for representing colors on a screen, but you actually want to look at the hue, saturation and intensity (lightness, or luminance) for analysing visible similarities in colors.
For example, you should convert your pixels to HSI or HSL color space first, then compare the different parameters you get. At that point, it is more natural to compare the resulting hue in a hue range, saturation in a saturation range, and so on.
Go here for further information on how to convert to and from RGB.
What happens here is that you implicitly try to reinvent either color indexing or histogram back-projection. You call it color filter but it is better to focus on probabilities than on colors and color spaces. Colors of course not super reliable and change with lighting (though hue tends to stay the same given non-colored illumination) that's why some color spaces are better than others. You can handle this separately but it seems that you are more interested in the principles of calculating "filtering operation" that will do segmentation of the foreground object from background. Hopefully.
In short, a histogram back-projection works by first creating a histogram for R, G, B within object area and then back-projecting them into the image in the following way. For each pixel in the image find its bin in the histogram, calculate its relative weight (probability) given overall sum of the bins and put this probability into the image. In such a way each pixel would have probability that it belongs to the object. You can improve it by dividing with probability of background if you want to model background too.
The result will be messy but somewhat resemble an object segment plus some background noise. It has to be cleaned and then reconnected into object using separate methods such as connected components, grab cut, morphological operation, blur, etc.
I have a scatterplot with values that range from 2 to -2. The catch is that 1 is the "zero-point". In other words the minimum positive value is 1.01 and the minimum negative value is -1.01. How can I edit the axis of the graph so that 0 is replaced with 1.
If you have a version of Excel later than 2007 I'd suggest splitting the positives and negatives into separate series and plotting one on a secondary axis (not that I know whether or not that would work!), but with 2007 I have not been able to place one vertical axis above the horizontal and another below. Instead the best I could manage was to use two separate charts:
by again splitting up the series, careful positioning and judicious use of a text box for 0.
At least this way you are not constrained by the outer limits.
Based on some very specific conditions you can print the zero-point as 1 using a custom number format: You have to set the axis options to be fixed at -2 (minimum) and 2 (maximum) with a major unit of 2 as well. This ensure that you only have the three values -2, 0 and 2 on the vertical/y-axis. Why is this important? Well, custom number formats can easily distinguish between positive/negative and zero values which is exactly what you have when you have -2, 0 and 2.
Here's a visual of the input/output:
The custom number format is set to 2;-2;1, thereby formatting all positive numbers to 2, all negative numbers to -2 and zero to 1.
If all you want is to replace the axis label "0" with "1" (as in the answer by Werner), then you can use the following (similar to this):
Add X and Y values for a dummy series, with 3 points. If the minimum value in your X-axis is xm, your points are (xm, -2), (xm, 0), (xm, 2).
Add cells with the 3 labels that you will use for the dummy series: "-2", "1", "2".
Go to the chart, and remove the tick labels of the Y-axis.
Add a series with the 3 dummy data points.
Add the labels to the data points. You can use references to the cells of item 2, or enter explicit labels. Entering each label (either a reference or an explicit label) is tedious when you have many data points. Check this, and in particular Rob Bovey´s add-in. It is excellent.
Format the dummy series so it is visually ok (e.g., small, hairline crosses, no line).
You can use variations on this. For instance, you can add extra points to your dummy series, with corresponding labels. Gridlines would match the dummy series.
But I think this is not appropriate, as the locations of your data points will be inconsistent with the scales.
What is appropriate is having an interrupted axis, where the interval (-1,1) is eliminated.
The answer by pnuts aims at that.
I propose something different, with the advantage of using only one chart:
Create a column where you add 2, only to negative Y-values. Use that column as your new Y-values.
Use the same trick as above, with your dummy series now being (xm, 0), (xm, 1), (xm, 2), and the labels the same as above.
You can use additional points in your dummy series.
You can use this technique to create an arbitrary number of axis interruptions. The formula for the "fake" Y-values would be more complicated, with IFs to detect the interval corresponding to each point, and suitable linear transformations to account for the change in scale for each interval (assuming linear scales; no mixing linear-log). But that is all.
PS: see also the links below. I still think my alternative is better.
http://peltiertech.com/broken-y-axis-in-excel-chart/
http://ksrowell.com/blog-visualizing-data/2013/08/12/how-to-simulate-a-broken-axis-value-axis/
http://www.tushar-mehta.com/excel/newsgroups/broken_y_axis/tutorial/index.html#Rescale%20and%20hide%20the%20y-axis
The xaxis in my flot line charts can take an array of data up to but no more than 16 in length. The problem is when my data is less than 16, the x axis is spreading out to show the maximum value of whatever the length of the data array is.
Even if my data is say 4 in length, i'd still like to show 16 points on the xaxis.
I have tried various configs and nothing seems to be working :(
http://www.discussthemarket.com/ratings/
The graphs lower down have an x axis greater than the graphs nearer the top which have fewer items in the data. I'd like to consistently apply a fixed length of 16 to the x axis but am really struggling.
One possibility is to provide a number for the ticks option:
ticks: 16
However that is treated only as a guideline; Flot always tries to make the ticks fit, and will reduce the number when it detects that they would overlap or run off the side of the plot. If you really want to force it to use 16 (which I wouldn't recommend, since the labels will probably overlap) you'll need to manually provide an array of ticks:
ticks: [0, 5, 10, ...]
I've cracked it byadding another data set which is 16 in length but has lines:{show:false} set :) job done!
You can use minTickSize according to the documentation of flot.
minTickSize : [1, "day"],
I have 3 columns of data, eg:
http://i.stack.imgur.com/XjGmu.jpg
When Excel creates a line graph of this, the blue line is what i get.
This is not correct because the time stamp shows the time when something is switched on (255) or off (0) (could also be the current state eg 16:08). So I'd like a graph like this - see the red line (with a time-based X axis off course):
http://i.stack.imgur.com/vNvPk.jpg
Anyone can help? Thanks
As #Jon49 indicated, you need to plot additional data points--two y values for each x value: one to plot the point at y=255 and one to plot y=0.
If the time-span of the data is at least a few days, you can use a line chart. But in your case since the values are within a day, the scatter chart with straight lines is the only option due to the limitations of the scale units for line charts.
The key is the values need to be in the correct order. Each y=255 value needs to be followed by the next time-stamp's 255 value followed by it's 0 value, followed by the next time-stamp's 0 value:
Excel doesn't support this type of discrete value graph (at least not excel 2k3 that I am using); your best bet is to use a bar graph and then go into the settings and set the gap width down to zero.
Not sure what the best way is but I would automate what I describe below on how to do (unless this is a one time deal, then just brute force it):
Separate the 255s from the 0s. Make sure for every 0 time there is a corresponding 255 time. Take the zero times and put in a scatter plot then add a y-error bar and make the fixed value equal to 255. Format to how you like it.
Now for the 255s. Add those to the chart by pairs. Make the chart type for these pairs scatter plot with a line. Format how you would like them to look.
Let me know if that doesn't make sense to you.