On a coordinate plane, what is the equation to flip the image upside down?
Could it be as simple as y = -y?
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Im new to using TensorFlows object detection API but understand I need to convert a csv file to a TFRecord. I understand the format of the csv should be 8 columns, as follows:
filename, width, height, class, min, xmax, ymin, ymax
what im confused about is which corner of the image is assumed to be the origin?
Thanks for any help!
The top left corner of the image is assumed to be the origin (0,0), with the width (x coordinates) increasing as you move to the right and the height (y coordinates) increasing as you move downwards.
So basically, the bottom-right corner of the image would be indexed as (width-1,height-1)
The format that you described above is basically the Pascal VOC annotation format in which, for a particular bounding box
xmin denotes the x coordinate of the top left corner
ymin denotes the y coordinate of the top left corner
xmax denotes the x coordinate of the bottom right corner
ymax denotes the y coordinate of the bottom right corner
The y axis instead of going upwards, goes downwards, whilst the x axis has the normal sense from left to right. Why?
It is one of the most annoying obstacles when doing the graphic part of a website because the geometry has to be recalculated, as the usual calculation as in the cartesian plane will be wrong. So, why does this happen? Is there a specific reason? Did they not notice that they were betraying traditional mathematics?
I have a flat object, eventually it will be a circle, but for now I just have a 2d square on the stage. I tip it back 75 degrees, and then rotate it around the y axis.
I have this code which has the object rotating, but it rotates around the global Y axis. But I want it to rotate around it's own Y axis which is tipped 15 degrees from vertical.
box_mc.rotationY=0;
box_mc.rotationX=-75;
addEventListener(Event.ENTER_FRAME, onYRotate);
function onYRotate(e:Event):void{
box_mc.rotationY+=2;
}
Can someone help me change my code so it rotates on its own Y axis?
I am done designing a 3-D cube in pure html.
The cube is rotating fine about its y and z axis, but when I try to rotate it about its axis it behaves a little strange.
Instead of rotating about its new rotated x axis it just rotates about the original X axis.
You can see the code I've provided and suggest necessary amends.
Here is the CODE PEN link for you to tinker:
<a href="http://codepen.io/deviljinkazama/pen/KzoxEL">Link</a>
I have a certain region given by the coordinates of the lefttop corner and bottom right corner. However, the region formed is not square since the radius of the circle decreases as the latitude increases. In my case, there is a difference of 3-4 km when I calculate the distance using top two coordinates and the bottom two coordinates So, how can I get a square region. I can't suppose that the the region bounded by the lefttop corner coordinate and bottomright coordinate is square. I want a region where the top two corners have a distance of x miles and the bottom two corners have a distance of x miles. Suggestions?
If you aren't into super-accuracy (ie the words WGS84 and oblate spheroid mean nothing to you) then it's simply a matter of calculating the km/degree of longitude at the upper latitude and then shifting the longitude of the two corners out a little, one east and one west.
Roughly:
Latitude: 1 deg = 110.54 km
Longitude: 1 deg = 111.320*cos(latitude) km
http://en.wikipedia.org/wiki/Latitude
Being precise, you cannot have square region on sphere surface. If you correct the distance of top 2 coordinates, then the "right" angles will not be 90 degrees and who knows if the vertical sides would be straight lines!
Google maps projection naturally gives you square in [lat, lon] 2D space, which is correct for most purposes - I also use this geographical "rectangle" grid of 11x11km squares on small spatial scales (400x200km) with no problems. If you neglect the small difference, your life will be much much easier. If you don't, I really cannot assure you the problem of exact rectangle on sphere surface even has any solution!