If you don’t want this window to appear during file reads, uncheck the Display this window… checkbox. When these files are detected, Imatest lets you select which image to analyze.īy default, the Multi-image TIFF file selection window opens whenever a multi-image TIFF file is read. These could be for a multispectral camera for different wavelength bands, or they may have different sizes. Some tiff tiles (extension tif or tiff) contain multiple images. Values of “R”, “G” and “B” channels are read as they are stored in the file (no additional colorspace conversions are made). Maximum pixel value is limited by 1.0 and currently is clipped at this level. Any other channels are currently ignored. The latter is internally converted to linear RGB colorspace with Rec.709 primaries. Files with both “R”, “G”, “B” and “Y”, “BY”, “RY” channels are supported. OpenEXR is commonly used to store high dynamic range images encoded in the Academy Color Encoding System (ACES), providing support for 16-bit floating-point, 32-bit floating-point, and 32-bit integer pixels. EXR ( OpenEXR)įiles with EXR extension are read using the OpenEXR library. These files have the Radiance HDR format. HDR (High Dynamic Range) filesįiles with the HDR extension are read with the Matlab hdrread function and can be written by Read Raw, Image Processing and other Imatest modules using Matlab hdrwrite. Special cases of standard files are described below. For full details, see Matlab documentation: imread. JPEG (JPG) - Joint Photographic Experts GroupĬommon file formats are shown in boldface. Standard (interchangeable) still image files All the still image file types supported by the Matlab imread function. If possible, try to fix the problem at the source, which typically involves getting the (EXIF) metadata correct. We don’t have a general recommendation about what to do in such cases, other than be aware that files can get corrupted in strange ways, and should be carefully examined if a program behaves strangely. If you open the file in Irfanview, then save it as a PNG or TIFF, it still opens as a monochrome image, but if you save it as a JPEG, it opens as a color image. Imatest, which uses Matlab libraries, opens it as a monochrome image. This image displays correctly in Windows Explorer (with Icon view), but when you right-click on the image, select Properties, then click on the Details tab, it shows Bit depth = 8, which indicates a monochrome image (it would be 24 or 48 for color). You can download this image (on the right) by clicking or right-clicking on it. Image files are either color or monochrome, but we recently found a file that was color, but appeared to be Monochrome in the Windows Properties display and when opened by Imatest. This usually works well, but the case below is a rare exception. In such cases you can use Irfanview to “launder” the image file by saving it (typically with a slightly different name to indicate that it’s not the original file). “Laundering” defective files Sometimes a file can’t be read by Imatest(which depends on Matlab libraries), but can be read by Irfanview, which evidently has more robust read routines. It will give you a message explaining the issue and suggesting an action (typically renaming the file with the correct extension). If you have trouble reading a file, we recommend opening it in Irfanview (a great free utility strongly recommended). Sometimes a file has an incorrect extension (for example, a PNG file might have a JPG extension). Most file types are recognized by their extensions, which are case-insensitive. Video files – Raw files: Commercial – Generalized Read Raw – DNG – Acquisition devicesĭefective image files Incorrect file extension Standard (interchangeable) image files – HDR – EXR – Special TIFF formats – YUV – TGA – DPX – CSV – HEIC This page lists the file and device types. Imatest can also acquire files from a large number of devices. Imatest can read a great many file types, including many not supported by standard Matlab.
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