Before looking into OCV, my wild guess is that it may have to do with the colorspace of the image. What are you setting it to? Profile Name: sRGB IEC61966-2.1?
> On Nov 16, 2017, at 8:31 PM, Rick Mann <rm...@latencyzero.com> wrote: > > I'm trying to write a unit test for some code I wrote that generates one > image from another. In the main app, the source data comes from Open CV as a > buffer of 3 byte-per-pixel elements. My code generates a CGImage. In the unit > test, I load a saved version of one of those images from a PNG file to > UIImage, get at the buffer, pass it to my code, and then compare the result > to a saved version of that same output. > > The saved version is a PNG. I load that, and then get the data buffer using > > let fiData = fi.dataProvider?.data as Data? > > I do a similar thing with the generated CGImage. Then I compare the two > buffers, byte by byte. They are similar, but contain differences (sometimes > more than I would expect). But if I save both as PNG and look at them in > Preview they look identical. > > My guess is something's happening somewhere with color correction. In my > code, I make a CG(bitmap)Context, specifying device RGB color space (should > that be generic?). I don't really know what happens to the PNGs I save and > load. > > Is there a way to ensure the bytes in the buffer are compressed and > decompressed exactly as written? > > -- > Rick Mann > rm...@latencyzero.com > > > _______________________________________________ > > Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) > > Please do not post admin requests or moderator comments to the list. > Contact the moderators at cocoa-dev-admins(at)lists.apple.com > > Help/Unsubscribe/Update your Subscription: > https://lists.apple.com/mailman/options/cocoa-dev/zav%40mac.com > > This email sent to z...@mac.com _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
