ISO 12233-2014 pdf free download

ISO 12233-2014 pdf free download.Photography Electronic still picture imaging Resolution and spatial frequency responses
Photographie — Imagerie des prises de vues électroniques — Resolution et réponses enfrequence spatiale.
A one-dimensional super-sampled edge spread function shall be formed using the data of the truncated two-dimensional ROl image data. Using the first line as reference points, the data points from all the other lines shall be placed into one of four “bins” between these reference points, according to the distance from the edge for that particular line. This creates a single super-sampled “composite” edge spread function, having four times as many points along the line as the original image data.
From this vector, a corresponding line spread function array shall be derived by computing the length-3 discrete derivative. The derivative vector is computed using a [—1/2, 0, +1/2] finite impulse response (FIR) filter, meaning that the derivative value for pixel “X” is equal to —1/2 times the value of the pixel immediately to the left, plus 1/2 times the value of the pixel to the right. The result is a vector which is the same size as the super-sampled edge spread function.
6.2.5 Computation of the e-SFR
The line spread function array shall be centred by circular rotation, so that the maximum value shall be at location trunk (N/2), where N is the length of the vector (4n). The centred line spread function shall be multiplied by a centred Hamming window. This reduces the effects of noise by reducing the influence of pixels at the extremes of the window, which have response due to noise but little response due to the image edge located at the centre of the window. The discrete Fourier transform (DFT) of the windowed line spread function shall be calculated. The e-SFR is the normalized modulus of the DFT of the centred, windowed line spread function. The final e-SFR is corrected for the bias introduced by the discrete derivative FIR filter. This correction is in the form of a frequency-by-frequency (element-by-element) multiplication by the reciprocal ola sinc function. See References (131, [17], and [2I for supplementary information on the e-SFR method.
7 Sine-based spatial frequency response (s-SFR) measurement
The sine-based spatial frequency response (s-SFR) of an electronic still-picture camera is measured by analysing the camera image taken of a sine wave-modulated starburst pattern. The preferred test chart for measuring the maximum resolution is shown in Figure 7 and will be specified in Annex E.
An executable version of software has been developed to perform measurements using this test chart. The software, which was created using Matlab®1), can he accessed from www.iso.org/12233.
The software can report the results from a single image, or can average the results from numerous images. The star is divided into a user-selected number of segments (typically eight segments) for analysis, The user selects the area of the captured image that contains the chart. The Siemens star is surrounded by 16 grey patches used to linearize the image code values by inverting the opto-electronic conversion function (OECF) of the camera. The opto-electronic conversion function shall be measured as specified in ISO 14524. The posted software requires the lightest patch to be in the upper right corner. The result shows the modulation versus frequency [in line pairs/picture height (LP/PH)1 for each of the segments.ISO 12233-2014 pdf free download.