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# Separate an image into RGB channels. Filenames 1, 2, 3 for red, green and blue respectively | |
convert image.jpg -channel RGB -separate channels_%d.png | |
# Convert an image to grayscale | |
convert image.jpg -set colorspace Gray -separate -average image.png | |
# Threshold an image | |
convert -threshold 75 image.jpg image-thresh.jpg | |
# Combine images using max pixel values of each image | |
convert image1.jpg image2.jpg -evaluate-sequence max image.png | |
# Average a set of fits files | |
convert image*.fits -evaluate-sequence mean -define quantum:format=floating-point -depth 32 result.fits | |
# Subtract a dark image from an image - 2 methods | |
convert dark.png image.png -evaluate-sequence subtract result.png | |
convert dark.png image.png -compose minus -composite result.png | |
# Watermark an image in lower right corner | |
convert -fill grey -transparent white -font "Liberation-Sans" -pointsize 96 label:"Watermark" -shade 120x45 watermark.png | |
composite -watermark 50% -gravity SouthEast -geometry +20+20 watermark.png image.jpg image-watermarked.png | |
######################################## | |
# Large copyright watermark stamp an image | |
# Create a large copyright symbol | |
convert -size 1200x800 -gravity West -fill black -transparent white -font Arial -pointsize 800 label:"©" -shade 240x40 copyright.png | |
# Create the copyright name to fit inside | |
convert -fill black -transparent white -font Arial -pointsize 96 label:"Owner's Name" -shade 240x40 name.png | |
# Compose the 2 images in one watermark stamp | |
composite -gravity Center -geometry -25-20 name.png copyright.png stamp.png | |
# Add the watermark stamp to the main image | |
composite -watermark 15% -gravity South -geometry +20+200 stamp.png image.jpg stamped.jpg | |
######################################## | |
# Overlay one image on another | |
convert input.png trees.png -gravity south -composite result.png | |
# Apply a scale function to an image. This power function improves bright lunar images | |
convert -fx "pow(u,4)" image.jpg image_pow.jpg | |
# Copy EXIF tags from one image to another | |
exiftool -TagsFromFile image1.jpg image2.jpg | |
# Change the EXIF time on an image | |
image_time="2019:10:02 20:06:34.33-05:00" exiftool -m -xmp:dateTimeOriginal=$image_time -xmp:dateTimeDigitized=$image_time -exif:dateTimeOriginal=$image_time -exif:dateTimeDigitized=$image_time image.jpg | |
# Overlay the filename on the image | |
convert input.jpg -gravity Southwest -pointsize 12 -fill white -annotate 0 '%f' output.jpg | |
# Rotate an image by 1 degree | |
convert input.jpg -distort ScaleRotateTranslate 1 +repage output.jpg | |
# Crop a white border around an image | |
convert input.png -flatten -fuzz 25% -trim +repage cropped.png |
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