SID Camera video

Started 3 months ago | Discussions thread
OP Turbguy1 Senior Member • Posts: 1,009
Re: SID Camera video

Thank you for your thoughtful response. You have said a lot!

I agree that lenses produce distortion, or warping, of a scene. Photography has always been imperfect. Lenses are imperfect optical computers. When designed, and used, for specific purposes (such as flat-field lenses used for document reproduction over a limited field of capture), the computation can be very successful in output accuracy. With two-view stereophotography, both lenses produce near perfect, or even perfect, identical errors upon each view, and thus induce no significant disparity on there own (within controlled field of capture and field of view angles). For instance, wide field of captures cannot be compressed into narrow fields of view without inducing “un-fusable”, or at least uncomfortable, disparity as your attention moves away from the central portion of the view.

At least lenses are FAST computers!

“Your statement seems more to indicate that your personal capacity for stereopsis is likely somewhere on the left downslope of the Gaussian bell-shaped curve of parametric distribution of stereopsis capacities in the general population.” Actually, I ask you seriously consider the exact opposite to be as likely the truth, else I would not be so involved in the art, and passionate about the effect of stereopsis in stereophotography. My intent was to state my observation that your pairs appeared unrealistic, induced discomfort, and frequently contained serious stereo window violations and frame edge rivalries. Perhaps I am more sensitive to these well-recognized errors than others?

One personal indicator of stereopsis “success” is the ability to comfortably fuse identical views captured with greater and greater disparities. Try these:

Enhanced disparity, easy for me to fuse, comfortable to view:

Extreme disparity, still easy for me to fuse, still comfortable to view:

Your results?

Additionally, I ask you consider why stereophotography continues to be a “niche” in the art. Most of us involved in this niche will possibly first suggest this is due to the requirement of viewing device, or visual trick of some type, as the main hindrance to wider acceptance. Perhaps instead, it is due to that distribution you point out exists in the general population! I believe that some part of the otherwise normally-sighted population observes the world with low attention to stereopsis, and some may even see in pseudo-stereo (with reversed disparity). Some observers have insisted my crosseye views are reversed left-to-right. I cannot explain those observations even after I confirm they are viewing the pairs properly!

Stereopsis indeed falls off at greater distances. There certainly is a distribution of the sensitivity/effectiveness in the population, or the USAF would not test for it, and place the best candidates into the highest performing aircraft. At great distances, our visual cortex continues to use remaining depth clues (which it also uses at close distances) to enhance the fading disparity information. Most of those same visual monocular clues remain in classic stereophotography. So, what is “missing” in ortho stereophotgraphy?

“You also suggest that tactile, aural, stato-kinetic, and even olfactory stimuli contribute, (in some unstated manner) to our cerebral cortical visual center’s presentations of 3D illusions to our consciousness. You then state that “Without these other sensory inputs into our cortical visual centers, it is "less than perfect" to visually perceive the world in front of us, and generate that image into our consciousness” Unfortunately, there be neither neuroanatomical nor neurophysiological evidence supportive of such a fanciful suggestion”. My intent was to suggest…no, INSIST…that ALL body senses contribute to producing the illusion of the world around us, combined into “experience” by the yet-unexplained magic of our cortex. This includes our senses and all body part positioning (much more than feedback from eye muscles). For instance, your head is typically never stationary for long waking periods, so even moving your head produces disparity and other depth information used by our cortex, head movement also is an “input”. Viewing the Grand Canyon from the South Rim is significantly enhanced by strolling one or ten feet along the rim. Even the slight “bobbing” of your head while walking produces time-based disparities our brain makes use of. At least it does for me. Travelling over rough terrain without stumbling over obstacles places demand on our visual system combined with the input of significant body propreoception.

“Additionally, I have to wonder what your attitude might be concerning altering the distance to which parallax extinction can be lengthened or abbreviated in binocular depth cue stereography by altering the “base” of inter-lens axes to accomplish depth warping with “hyper stereography” or with “hypo stereography” ? ...And does this warping of perceptible horizontal parallax have an effect upon image “accuracy”? (The question, obviously, is rhetorical.) " My attitude concerning varying the base capture interaxial is that it is a useful “tool in the toolbox” of the stereophotographer. Certain subjects are well suited to using these tools to achieve a desired effect. Are they “stereopsistically" accurate? IMO, yes they are. In hyperstereo, distant contours and surface textures are correctly and accurately revealed. Are they ortho? Of course not. Are they comfortable to view? Yes. Do they contain stereo window or frame errors? When done well, they do not. When you remove the self-imposed constraint of a rectangular frame, and use a custom frame, they can be very stunning!

I believe that your starting work is a 2D view, which you then transform into a stereo pair (either transforming/warping one or both of the pairs). This is widely recognized as 2D to 3D conversion. Do your conversions result in producing disparity? I have to respond, YES! Can it be effective? I have to respond, YES! Do most of the examples you post seem “correct”? I have to respond, they are not correct, in my opinion. Is it still part of the art? YES! Might it be more effective starting the transformation with a true stereo pair? IT COULD BE! If there were a way of beginning with a hyperstereo for distant elements and blending them into an orthostereoview for closer elements, and perhaps even hypostereo for very close elements, that could be an interesting endeavor. It could produce stunning results. All off the mathematical information is contained in such a beginning to produce some result.

As you are aware, the word “stereo” is from the Greek, meaning “solid”. I can understand the desire for a graphic artist to close one eye when generating a work meant to be produced on a 2D surface. The maker must make use of, and replicate or enhance the monocular clues alone. 2D works can be quite effective in conveying depth within a limited sense. That said, I doubt that sculptors close one eye during their undertaking …their intent is to produce a solid in their work.

Our perception of the stereo world around us is indeed an illusion…but a very useful one. It permits us to glance down at a fresh mug of coffee, close our eyes, and then successfully reach out, pick up that mug and bring it to our waiting lips.

I suggest you join and post your examples to the “Photo3D” group on Yahoo Groups, or on and obtain the opinion of other stereo enthusiasts. My opinions are what they are. We may just have to agree to disagree…

(BTW, I find your vocabulary quite impressive!)

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