Talk:Pinhole camera model

From Wikipedia, the free encyclopedia

A fact from Pinhole camera model appeared on Wikipedia's Main Page in the Did you know? column on August 3, 2007.
Wikipedia
The geometry of a pinhole camera
The geometry of a pinhole camera

In this figure we see two similar triangles, both having parts of the projection line (green) as their hypotenuses. The catheti of the left triangle are − y1 and f and the catheti of the right triangle are x1 and x3. Since the two triangles are similar it follows that

\frac{-y_1}{f} = \frac{x_1}{x_3} or y_1 = -\frac{f \, x_1}{x_3}


Is this correct? Since the triangle is similar, the angles are equal. However, the sides are in a proportion to one another, and are not equal but rather in a fixed ratio. damien--198.151.13.15 14:24, 3 August 2007 (UTC)

[edit] Citations needed

I copied this here from my talk page so that others can see my responses (indented) and join in. Dicklyon 14:55, 28 September 2007 (UTC)

Hi, I missed your point about the necessity to provide more specific references in the Pinhole camera model article.

  • The article, as it is, is on a rather introductory level, the geometry is "elementary" and self-explanatory and it is perhaps only the terminology which needs to be verified relative the literature. Any of the textbooks which are included in the reference list provides a similar presentation with some variation (described in the article) in the terminology. As far as I know, there are also no "first references" which can be used for the "citation needed" tags you have inserted, any of the textbook will do.
Then cite one or more of the textbooks there. Having them listed, without saying what they verify, isn't nearly as good.
  • One could possibly stack the citations to all of the current refs, for example, at the end of the lead section or the end of the article, but I don't see the point if there is a reference section which is clearly visible. Also, I have to confess that since the current implementation of the ref makes a mess and clutters the edit text, I don't use it unless it is really necessary.
  • Is there some policy or guideline which can be of any help here? I haven't seen that the ref tags are compulsory.
See WP:V, note 1.
  • I couldn't even figure out the reason for your "citation needed" tags at the places where they are. There must be a few more dozen of statements which are equally "uncited" and we can't have a cite on each and every such statement?

Regards --KYN 12:48, 28 September 2007 (UTC)

Generally speaking, having a cite on almost every statement, or every paragraph, is a good idea. But for ones that follow trivially from what comes before them, it's not really necessary. But the final derived relationship should be cited, so that one can verify that that's the result the experts get, without trying to check every step in the deriviation. Citations are also required to verify assertions about what something is called in the literature. That's why I picked the particular set of things to tag, which are really there just as a first guess of where inline citation would be useful.
Dicklyon 14:55, 28 September 2007 (UTC)