From 92b4bb6fc6e479ca5976d47cc4b566436133e198 Mon Sep 17 00:00:00 2001 From: Chris Hodapp Date: Wed, 12 Oct 2016 16:23:08 -0400 Subject: [PATCH] Edited pi-pan-tilt part 3 a little; added raspistill note --- posts/2016-10-12-pi-pan-tilt-3.md | 29 +++++++++++++++++++---------- 1 file changed, 19 insertions(+), 10 deletions(-) diff --git a/posts/2016-10-12-pi-pan-tilt-3.md b/posts/2016-10-12-pi-pan-tilt-3.md index 6977865..9585e56 100644 --- a/posts/2016-10-12-pi-pan-tilt-3.md +++ b/posts/2016-10-12-pi-pan-tilt-3.md @@ -33,13 +33,10 @@ I may have mentioned in the first post that I'm using [another][arducam_omx219] that uses the 8-megapixel Sony OMX 219, but I haven't gotten my hands on one yet.) -If you are expecting the quality of sensors and exposure control that -even an old entry-level DSLR camera provides, this board will probably -disappoint you. The sensor is tiny, it's noisy, and capturing still -images is quite slow (6-7 seconds, in my tests). - -However, if you are accustomed to basically every other camera that is -within 2-3 times the price and is meant to interface directly with a +If you are expecting the quality of sensor even an old DSLR camera +provides, this board's tiny, noisy sensor will probably disappoint +you. However, if you are accustomed to basically every other camera +that is within double the price and interfaces directly with a computer of some kind (USB webcams and the like), I think you'll find it quite impressive: @@ -52,9 +49,9 @@ it quite impressive: more detail on optics in a later post. - [raspistill][] will provide 10-bit raw images straight off the sensor (see its `--raw` option). Thus, we can bypass all of the - automatic brightness, saturation, contrast, and whitebalance which - are great for snapshots and video, but really annoying for composite - images. + automatic brightness, sharpness, saturation, contrast, and + whitebalance correction which are great for snapshots and video, but + really annoying for composite images. - Likewise via [raspistill][], we may directly set the ISO speed and the shutter time in microseconds, bypassing all automatic exposure control. @@ -71,6 +68,18 @@ to raspistill, and it will produce a JPEG file which contains a normal, lossy image, followed by a binary dump of 10-bit raw Bayer data from the sensor. +Most of my image captures then are with something like: + + raspistill --raw -t 1 -w 640 -h 480 -ss 1000 -ISO 100 -o filename.jpg + +That `-t 1` is to remove the standard 5-second timeout; I'm not sure +if I can take it lower. `-w 640 -h 480 -q 75` applies to the JPEG +image, while the raw data with `--raw` is always full-resolution; I'm +saving only a much-reduced JPEG as a thumbnail of the raw data, rather +than wasting the disk space and I/O on larger JPEG data than I'll use. +`-ss 1000` is for a 1000 microsecond exposure (thus 1 millisecond), +and `-ISO 100` is for ISO 100 speed (the lowest this sensor will do). + # Converting Raw Images People have already put considerable work into converting these rather