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Below is a list of Matlab scripts for assembling and / or compressing HDR images. Read the commands in each file. Note the difference between brightness compression and size compression. |
| anisodiff | - Anisotropic Difference - Kovesi (Perona & Malik) |
| bilateral | - Bilateral Filter - Thmoasi & Manducci |
| GradDomComp | - Gradient Domainn Compression - Lishinski et al |
| HDR_matlab_code | - Assemble & Tonemap (Reinhard's) [unknown / untested] |
| LevelSet | - Level Set - Pattanaik-Zhu |
| Linnersund-Assem | - Linnersund-Assembler - Karen Linnersund |
| Meylan-comp | - Retinex based Adaptive Filter compression - Meylan |
| ptf (Print-to-file) | - Print a Matlab figure to a file in one of several formats |
| radread | - read a size-uncompressed HDR |
| read_rle_rgbe | - read HDR with RLE size-compression |
| retinex_mccann99 | - Retinex (Frankle & McCann) |
| Zvi_Devir_Retinex | - Retinex - Zevi Devir, Technion |
| YuanzhenLi-compand | - Compandor compression - Yuanzhen Li |
| Adaptive Logmap | - Drago |
| HDRView | - A viewer by Chris Tchou & Paul Debevec, good for "drag n' drop" or "send-to" |
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There are others, but these are the only ones I've found useful, and that work. Testing all scripts for all possible combinations of values of parameters is impossible. Presume compressed HDR are not designed to be further edited by LDR image editors such as Photoshop. Compression is best considered the final step in processing. The input image format used is usually PPM from the NET PBM distribution (Portable Pixel Map). There are scripts for reading and writing the format available on the web. The HDR has size a compressed version (RLE). Most scripts are designed to read or write the size uncompressed versions. "read_rle_rgbe.m" will read the RLE size compressed versions. The HDR format has been poorly understood and reproduced in software. The biggest problem is the nature of the header. HDR uses a very flexible and generalized header which, in theory, could be bigger than the image. If you have problems reading an HDR try downloading the original HDR processing application designed for non-architects, "HDRShop". The program is (WAS) downloadable at Prof. Paul Debevec's site www.debevec.org. The program is no longer available from the original source, but can be found by searching the internet. ---- about Radiance.htm | |