Hi I am (finally) back from summer holidays and cannot help but add my twopence worth - as the supervisor Peony refers to.
Peony seems to have narrowed down the problem to a jpeg format issue that makes the image unreadable, nothing to do with the phone itself. For example, she is able - using the same HDR software on her tablet to generate a camera response curve. The software for the phone that she is using to generate the HDR images allows the turning of off auto white balance and allows the setting up of 3, 5 or 7 images at separate exposure values. She can clearly create the camera response curve for the $2000 Nikon camera with its $2000 fish eye lens With her $300 phone and $50 fish eye lens, and the same software as the tablet she cannot create a curve. The software saves the original jpg images as well as the combined HDR image on each machine. At first we thought it was inadequate EXIF data in the original jpeg images. However, it is not the EXIF data because the Nikon camera images with the phone image EXIF data replacing the Nikon's EXIF data still produce a camera response curve. She has eliminated the jpg image compression from the question because she has opened each jpg original in photoshop and re-saved it in a standard jpg format - the Nikon images still work, the phone not. Personally, I'd like this to work because first year and second year building science student measurement exercises could be so much more interesting if we were measuring a whole space, not a simple grid... Also: We can calibrate the sound level meters on the phones. They can use a simple app on the phones to photograph the horizon line with overlaid sun path diagrams in Augmented Reality mode. The phone as general survey instrument, not just site camera is becoming a reality. Calibration / trust of each phone, and how to test it is the issue At another level, I feel responsible for understanding what the issue might be to try to explain what might be going wrong so a) Peony can understand, and document this process properly in her thesis Appendix and b) some recommendations can be formulated as to what camera-phone characteristics to look for. Thus I return to the question: what might we be unable to control with the phone, but is controlled on the tablet, that would cause this kind of Photosphere error message? And how might we further test what we are doing? Thanks in anticipation of any help. M ------------------------------------ Victoria University of Wellington School of Architecture Michael Donn [email protected] PO Box 600 139 Vivian St Wellington New Zealand tel: +64 4 463 6221 fax: +64 4 463 6204 mobile: +64 21 611 280 Skype ID:the_donn ------------------------------------ Today's Topics: 1. Re: Photosphere "Cannot solve for response function" (Gregory J. Ward) ---------------------------------------------------------------------- Message: 1 Date: Mon, 24 Dec 2012 08:56:34 -0800 From: "Gregory J. Ward" <[email protected]> To: High Dynamic Range Imaging <[email protected]> Subject: Re: [HDRI] Photosphere "Cannot solve for response function" Message-ID: <[email protected]> Content-Type: text/plain; charset=us-ascii Hi Peony, I guess no one ever responded to this... I can really only repeat my response from August, which is that getting calibrated output from phone cameras is not possible at this stage, and may never be. Their application is too different, and repeatability is not one of the design requirements for these modules. They alter sensitivity, color response, and probably tone response without making any record of the original data. I really think it is a waste of your time. Best, -Greg > From: "Peony Au" <[email protected]> > Date: November 27, 2012 11:13:11 PM PST > > Hi everyone, > > After much development on my thesis, I have a few queries I am hoping some of > you will be able to help me out on. > > First of, my supervisor pointed out an application on the iPhone called > iPhotoLux which maps the luminance measurement of an HDR image taken by the > iPhone camera. So I am hoping what I am trying to produce in my thesis does > work. > > Secondly, I have been using a Nikon DSLR camera to create HDR images in the > lighting laboratory using a scale model, so that my skills in creating a > accurate HDR image. I have also used both luminance and illuminance meters to > ensure the photos are accurate. > > Therefore, after experimenting in the lighting laboratory, I got my > Smartphone camera back out and using a HDR Camera application available in > the Android market. I put both cameras side by side and took images of the > same scene on a tripod. However, I am still receiving the same error message > as before, then I found out that the HDR Camera application does not write > the EXIF data required to create a camera response curve. Therefore, just to > try the images produced by the Smartphone out, I coped the EXIF data from the > DSLR camera and inserted into the images produced by the Smartphone camera > ensuring that all the exposure value information are the same. I then try and > fuse these Smartphone camera produced images together, but the same error > message reappears. > > Therefore, I was just wondering if anyone knows why the camera response curve > cannot be created even with the comparison done between the DSLR camera and > the Smartphone camera. > > Thank you for all your help. > > Kind regards, > Peony ------------------------------ _______________________________________________ HDRI mailing list [email protected] http://www.radiance-online.org/mailman/listinfo/hdri End of HDRI Digest, Vol 54, Issue 2 *********************************** _______________________________________________ HDRI mailing list [email protected] http://www.radiance-online.org/mailman/listinfo/hdri
