12/24/2023 0 Comments Image resolution calculatorSo in order to measure spatial resolution, the pictures below would server the purpose. Remember the factor of zoom does not matter in this condition, the only thing that matters is that these two pictures are not equal. We cannot compare them to see that which one is more clear. Whereas the picture on the right side has the dimensions of 980 X 749 and also it is a zoomed image. The picture on the left is zoomed out picture of Einstein with dimensions of 227 x 222. You cannot compare these two images to see the clarity of the image.Īlthough both images are of the same person, but that is not the condition we are judging on. If we have to compare the two images, to see which one is more clear or which has more spatial resolution, we have to compare two images of the same size. In short what spatial resolution refers to is that we cannot compare two different types of images to see that which one is clear or which one is not. Or in other way we can define spatial resolution as the number of independent pixels values per inch. (Digital Image Processing - Gonzalez, Woods - 2nd Edition) The number of pixels in an image does not matter. Spatial resolution states that the clarity of an image cannot be determined by the pixel resolution. In this tutorial, we are going to define another type of resolution which is spatial resolution. One type of it which is pixel resolution that has been discussed in the tutorial of pixel resolution and aspect ratio. Need support? Please contact us if you find any bug or have any suggestion.Image resolution can be defined in many ways. You can use the PSF calculator option in the form to see the expected size of the PSF of your imaging setup and accordingly, of a distilled Experimental PSF from bead images. as 2D images) and do 2D deconvolution in the Huygens Software planewise. Hint: If you have a data stack that is dramatically undersampled in Z (not fulfilling the Nyquist Criterion by a large factor) it is better to interpret the different planes as independent images (i.e. In case of low Numerical Apertures, like 0.4, we recommend not to undersample in the axial direction. Widefield microscopy data is more sensitive to undersampling, so it is better to stay below a factor of 1.5. When large pinholes are used, up to 2 times larger even. For Confocal Microscope images, sampling distances may be up to 1.7 times the Nyquist ones. In these cases larger sampling distances may be used and a good job can still be done when deconvolving these images. While sampling at the Nyquist rate is a very good idea, it is in many practical situations hard to attain. The correct Nyquist rate is defined in terms of the system Bandwidth (in the frequency domain) which is determined by the Point Spread Function. The pixelation corresponding to the Nyquist rate will be clearly seen.Ī common rule of thumb defines the ideal sampling in terms of spatial resolution ("sample with half of the resolution") but this is not exactly correct, and in some cases will lead to undersampling. The images are shown as Maximum Intensity Projections along Z and Y, and upscaled for a better display. The size of the PSF image will be given in µm. You have also the option to generate an image of the Point Spread Function (PSF) which only takes a few seconds more. The data will be returned in nanometers (nm). (To see what equations are used in this calculator and some theory behind the scenes read the Nyquist rate background article). With the form on this page you can calculate the Ideal Sampling from your optical conditions to acquire a well sampled image. See the examples on anti aliasing and aliasing artifacts, and some consequences in Quality Vs Sampling. Images obtained with sampling distances (voxel dimensions) larger than those established by this rate will suffer from undersampling. It is recommended to sample the image at a rate close to the ideal Nyquist Rate. The ideal Sampling Density (or inversely, Voxel Size) for image acquisition depends on the optics of the microscope. For further details, see below.įor installing our Nyquist app for Android devices, please visit this page. To compute these backprojected values, see the Backprojected Pinhole Calculator. divided by the total magnification of the system. The Pinhole Radius and Pinhole Distances parameters are not physical sizes, but rather BackProjected sizes, i.e. The Huygens Theoretical PSF page contains more information and interactive examples on the impact of RI mismatch on the PSF shape. Note that the pinhole size doesn't alter the bandwidth of the detection system. Additional parameters appear if you check the option to calculate the Theoretical PSF. Please make sure you have the correct values for the Microscopy Parameters necessary for calculating the Nyquist rate. Microscopy Nyquist rate and PSF calculator
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