I'm using vtkResliceImageViewer to display image (multi-planar reconstruction). How can I flip\mirror that image vertically and horizontally? Operating with camera is not working as expected, since flip has to take into consideration also camera rotation angle, so it gets very complicated. It would be great if there is a way to change image's texture coordinates. Is this possible?
// Create an image
vtkSmartPointer<vtkImageMandelbrotSource> source =
vtkSmartPointer<vtkImageMandelbrotSource>::New();
source->Update();
// Flip the image
vtkSmartPointer<vtkImageFlip> flipYFilter =
vtkSmartPointer<vtkImageFlip>::New();
flipYFilter->SetFilteredAxis(1); // flip y axis
flipYFilter->SetInputConnection(source->GetOutputPort());
flipYFilter->Update();
// Create the Viewer
vtkSmartPointer<vtkResliceImageViewer> viewer =
vtkSmartPointer<vtkResliceImageViewer>::New();
viewer->SetInputData(flipYFilter->GetOutput())
Related
I have a recorded camera ROS bag file from a Realsense camera. The camera intrinsics for the recorded setting in already know. The initial resolution of the image is 848*480. Because of some visual obstruction in the FOV of the camera I would like to crop out the top of the image so it doesn't gets detected with Visual SLAM Algorithm I am using.
Since SLAM is heavily dependent on the Camera Intrinsics, I would like to know how will the camera parameters f_x, f_y, c_x and c_y change for :
Cropped Image
Resized Image (Image Scaling only)
There is no skew involved in the original camera parameters.
Will the new pricipal point c_x also change as Cropped_image_width?
I am bit confused as to how to calculate the new camera parameters ? Am I correct in assuming the following for the Case 1 - Cropped Case :
Cropping:
cx,cy reduced by the amount of pixels cropped off the left/top. Cropping off of right/bottom edges has no effect.
Scaling:
fx,fy are multiplied by the scaling factor
cx,cy are multiplied by the scaling factor
Remember, the principal point need not be in the center of the image.
Assuming top left image origin. Off-by-one/half (pixel) errors to be checked carefully against the specific scaling algorithm used, or just ignored.
For the case no. 1, cx is the same as the original image, but cy changes as newHeight/2.
For the case no. 2, f changes as fxscale.
I have a dataset of a single class (rectangular object) with a size of 130 images. My goal is to detect the object & draw a circle/dot/mark in the centre of the object.
Because the objects are rectangular, my idea is to get the dimensions of the predicted bounding box and take the circle/dot/mark as (width/2, height/2).
However, if I were to do transfer learning, would YOLO be a good choice to detect a single class of objects in a small dataset?
YOLO should be fine. However it is old now. Try YoloV4 for better results.
People have tried transfer learning from FasterRCNN to detect single objects with 300 images and it worked fine. (Link). However 130 images is a bit smaller. Try augmenting images - flipping, rotating etc if you get inferior results.
Use same augmentation for annotation as well while doing translation, rotation, flip augmentations. For example in pytorch, for segmentation, I use:
if random.random()<0.5: # Horizontal Flip
image = T.functional.hflip(image)
mask = T.functional.hflip(mask)
if random.random()<0.25: # Rotation
rotation_angle = random.randrange(-10,11)
image = T.functional.rotate(image,angle = rotation_angle)
mask = T.functional.rotate(mask ,angle = rotation_angle)
For bounding box you will have to create coordinates, x becomes width-x for horizontal flip.
Augmentations where object position is not changing: do not change annotations e.g.: gamma intensity transformation
I'm looking to use an image for tilling, to fill and area of my page, in my document.
I've seen that there is an IDOMImage and IDOMImageBrush, but I'm not sure how to use them in order to scale and tile my source image.
How can I do this with the Mako SDK?
Mako can tile an image into a given area, and also flip alternate tiles to create a pattern. Use a scaling transform to control its size. This code shows you how.
// Declare an output pointer
IOutputPtr output;
// Create new assembly, document and page
IDocumentAssemblyPtr assembly = IDocumentAssembly::create(jawsMako);
IDocumentPtr document = IDocument::create(jawsMako);
IPagePtr page = IPage::create(jawsMako);
// Add the page to the document, and the document to the assembly
document->appendPage(page);
assembly->appendDocument(document);
// Create a fixed page to work with
double pageWidth = 10 * 96.0;
double pageHeight = 20 * 96.0;
IDOMFixedPagePtr fixedPage = IDOMFixedPage::create(jawsMako, pageWidth, pageHeight);
// Load the image file into an image
IDOMImagePtr image = IDOMJPEGImage::create(jawsMako, IInputStream::createFromFile(jawsMako, imageFilePath));
// Find its dimensions
IImageFramePtr frame;
image->getFirstImageFrame(jawsMako, frame);
double imageWidth = frame->getWidth();
double imageHeight = frame->getHeight();
// Create a rect to hold the image
FRect printBounds(0.0, 0.0, pageWidth, pageHeight);
// Create a transformation matrix to scale the image, taking into account the page proportions
// Scaling factor is a float ranging from 0.0 to 1.0
double pageWidthHeightRatio = pageWidth / pageHeight;
FMatrix transform;
transform.scale(scalingFactor, scalingFactor * pageWidthHeightRatio);
// Stick the image in a brush
IDOMBrushPtr imageBrush = IDOMImageBrush::create(jawsMako, image, FRect(), printBounds, transform, 1.0, eFlipXY);
// And now create a path using the image brush
IDOMPathNodePtr path = IDOMPathNode::createFilled(jawsMako, IDOMPathGeometry::create(jawsMako, printBounds), imageBrush);
// Add the path to the fixed page
fixedPage->appendChild(path);
// This becomes the page contents
page->setContent(fixedPage);
// Write to the output
output = IPDFOutput::create(jawsMako);
output->writeAssembly(assembly, outputFilePath);
Using this code, with this image:
Produced this tilled image:
The code uses an enum, eTileXY. These are the available tiling options:
eTilingMode
Tiling mode type enumeration.
eNoTile
No tiling. If the area to be painted is larger than the image, just paint the image once (in the location specified by the brush's viewport), and leave the remaining area transparent.
eTile
Tile image without any flipping or rotating of the image. A square image consisting of a single diagonal line between opposite corners would produce diagonal lines when tiled in this mode.
eFlipX
Tile image such that alternate columns of tiles are flipped horizontally. A square image consisting of a single diagonal line between opposite corners would produce chevrons running horizontally across the area when tiled in this mode.
eFlipY
Tile image such that alternate rows of tiles are flipped vertically. A square image consisting of a single diagonal line between opposite corners would produce chevrons running vertically across the area when tiled in this mode.
eFlipXY
Tile image such that alternate columns of tiles are flipped horizontally AND alternate rows of tiles are flipped vertically. A square image consisting of a single diagonal line between opposite corners would produce a grid of squares balanced on their points when tiled in this mode.
I am writing a GUI application that works on Mac and Win and there is one little problem, which i do not know how to solve.
In my application I have a small (250 x 250 px) preview window (let' call it SW) in which placed the image. Image can be much bigger, than SW. Somewhere I have a slider which implements zoom function of image inside SW. My main problem is implement zoom function on this image.
On enter I have:
source image and it's width and height;
view image - it is zoomed copy of source image;
position of zoomed image
size of viewport is 250 x 250 px
It should works like zoom in image processing programs. When we changing our zoom value image becomes smaller or bigger relative to viewport center and position of image inside it. We can move image inside of viewport.
For correct implementation of that problem we need to calculate images size and position inside our view. I'm already wrote some "algo" that implements image size modification.
It is looks like:
float one = (source_original_size - thumbnail_size) / 100;
int bigger_side_size = qRound((100-value) * one) + thumbnail_size;
But I can not imagine how I can calculate position on scene of that zoomed image.
Can anybody help me with ideas?
If it is important I am using Qt framework and QGraphicsView, QGraphicsScene and QGraphicsPixmapItem.
Take a look at the Image Viewer Example, it has some features that you are looking for.
i wrote a face & eye detection code
next step is put an image to the coordinates of the detected eye (for ex: eye
patch, eye glasses)
i couldn't find the function to combine the source frame and the image I want to add
any suggestions
thanks
You can use cvCopy with a mask to do this. If the the images do not have the same height and width set the ROI of the destination image before using cvCopy.
See OpenCV documentation:
cvCopy
cvSetImageROI