Search Similar Images

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The search for similar images is one of the most difficult tasks in digital photography. CodedColor combines a number of different algorithms, in order to detect similar images. However, the word "similar" needs to be defined. It's a wide misunderstanding, that the search for a "cow on a pasture" should only find images with "cows on pastures". In fingerprint recognition this is possible, but not in photos containing a number of overlapped objects from different views, in multiple lighting conditions, and with different sizes and colors. There is basically no way to reliably distinguish a cow from a horse, a pasture from a golf course or a golf cart from a baby carriage. So in our cow example, you may also find images of a "cactus patch in the desert" and a "sailboat on a lake".


CodedColor relies on a number of mathematical comparisons (histogram, color average) and pattern recognitions (grayscale analysis, texture & color map) to find images with similar color compositions, lighting conditions and textures. CodedColor is not capable of object recognition, so try to interpret your results more in the sense of "similar moods". The example below is taken from a folder of vacation photos with different locations and lighting situations. As you can see, candidates 1 & 2 are pretty good matches, whereas candidate 3 can be considered a failure, and it is not clear at first why candidate 4 has a much lower score.



Search subject


1. Score 89.77%


2. Score 88.11%



Grayscale: 88.99%

Histogram: 94.14%

Dimensions: 100.00%

Texture Map: 81.85%

Color Map: 90.34%

Color Average: 93.62%


Grayscale: 81.01%

Histogram: 93.57%

Dimensions: 99.00%

Texture Map: 76.77%

Color Map: 90.71%

Color Average: 88.80%





3. Score 87.06%


4. Score 84.14%


Grayscale: 83.14%

Histogram: 93.33%

Dimensions: 99.37%

Texture Map: 78.90%

Color Map: 89.06%

Color Average: 76.69%



Grayscale: 79.70%

Histogram: 93.52%

Dimensions: 99.32%

Texture Map: 66.49%

Color Map: 86.93%

Color Average: 87.89%



Examining the scores, the result becomes a little more obvious: candidate 3 scored better than candidate 4, because candidate 4 has most of it's dark areas where the seach subject has light areas, and vice versa. The two images are thus pooly matched in their pixel regions, but coincide well in their color average, which - however - has a much lower priority. CodedColor weighs the algorithms quite differently, resulting from elaborate tests on many different images. Here is the optimal distribution we decided on:



Grayscale difference


Histogram difference


Dimension & aspect ratio


Grayscale texture mapping


Pixel color region mapping


Dominant & average color



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CodedColor PhotoStudio by 1STEIN is an award-winning Windows photo viewer and editor to organize, edit, resize, reformat, correct, compare, sort, watermark, annotate and print digital images, and to edit EXIF and IPTC data in digital photos. You can rename multiple images, remove scratches, stich panoramas, convert RAW photos (from Canon, Nikon, Olympus, etc. cameras), burn digital watermarks, correct colors, batch convert and correct images and generate a web album in HTML5. The software is easier to use than Photoshop, but more versatile than ACDSee, Picasa, Irfanview or Gimp. Many magazines consider it to be the Swiss Knife of Image Editing. Have a look at our Before / After tutorials to get an idea of the powerful capabilities. The software comes with a detailed handbook and a fast database to store EXIF/IPTC data and color information. CodedColor PhotoStudio is the ideal image editing tool for every-day and professional digital camera users. The user friendly interface combines features like expert photo editing & printing, layer editing, web album galleries, slide shows, photo management & cataloging, custom sorting, IPTC & EXIF editor, GPS tagging, perspective correction, barrel distortion, effects, thumbnail generation, resize & resample images, batch conversion, database keyword searching, red eye removal, color/sharpness/brightness & contrast correction, artifact removal, clone brush, scanner & TWAIN import, screen capture, lossless JPEG rotation, transparency (alpha channel) and layers, gamma correction, screen shows with many transition effects, watermark text, image annotations, panorama stitch & animation, video capture, PDF album export, photo layouts, collages, frames, shadows, histograms, automatic white balance, photo sharing, etc. Opens and converts all common image formats: BMP, WMF, GIF, JPEG, JPEG2000, TIFF, PCX, PNG, PSP, PSD, PCD, HEIC, HEIF, AVIF and all current RAW formats. The installation includes our the CodedColor Publisher, a versatile photo layout and DTP tool to create individual and rich photo books.