parent
59c59e557a
commit
032cbdc0cf
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#include <stdint.h>
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/*
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The function converts a 16bit GRBG 2x2 CFA coded image into an 8bit
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RGB image by setting the missing RGB values to zero.
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*/
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void debayer_grbg16_simple (uint16_t * src, int src_w, int src_h,
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uint8_t * dst, int dst_w, int dst_h) {
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// GG RR
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// BB GG
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uint16_t t;
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uint8_t r, g, b;
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int ys, yd, xs, xd;
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for (ys = 0, yd = 0; ys < src_h; ys++) {
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for (xs = 0, xd = 0; xs < src_w; xs++) {
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/* read the pixel but only the lower 8bit */
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t = *(src++) & 0x00FF;
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if (xs & 1) {
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if (ys & 1) {
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// lower right green pixel
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b = 0; g = t; r = 0;
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} else {
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// upper right red pixel
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b = 0; g = 0; r = t;
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}
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} else {
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if (ys & 1) {
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// lower left blue pixel
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b = 0; g = t; r = 0;
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} else {
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// upper left green pixel
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b = 0; g = t; r = 0;
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}
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}
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/* only paint the image if the source is within the destination */
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if (xd < dst_w) {
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/* set the pixel */
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*(dst++) = b;
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*(dst++) = g;
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*(dst++) = r;
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xd++;
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}
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}
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/* if the source image is too small ignore the other places */
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if (xd < dst_w)
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dst += 3 * (dst_w - xd);
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yd++;
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}
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}
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// macros to make code better readable
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#define CE (*(src))
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#define UP (*(src-src_w))
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#define DN (*(src+src_w))
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#define LE (*(src-1))
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#define RI (*(src+1))
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#define UPLE (*(src-src_w-1))
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#define UPRI (*(src-src_w+11))
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#define DNLE (*(src+src_w-1))
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#define DNRI (*(src+src_w+11))
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#define STORE *(dst++) = r; *(dst++) = g; *(dst++) = b; src++;
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/*
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The function converts a 16bit GRBG 2x2 CFA coded image into an 8bit
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RGB image by bilinear interpolation.
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*/
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void debayer_grbg16_bilinear (uint16_t * src, int src_w, int src_h,
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uint8_t * dst, int dst_w, int dst_h) {
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// GG RR GG RR
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// BB GG BB GG
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// GG RR GG RR
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// BB GG BB GG
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uint8_t r, g, b;
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int xs, ys;
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// start with upper left pixel (green)
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r = RI;
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g = CE;
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b = DN;
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STORE;
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// upper first line, starts with RR GG RR ...
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for (xs = 1; xs < src_w - 1; xs+=2) {
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// red pixel
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r = CE;
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g = (LE + RI + DN) / 3;
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b = (DNLE + DNRI) / 2;
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STORE;
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// green pixel
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r = (LE + RI) / 2;
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g = CE;
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b = DN;
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STORE;
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}
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// upper right pixel (red)
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r = CE;
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g = (DN + LE) / 2;
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b = DNLE;
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STORE;
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// got through the "body" of the image
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for (ys = 1; ys < src_h - 1; ys+=2) {
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// every second line with BB GG BB GG (start at 2nd line)
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// left hand pixel (blue)
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r = (UPRI + DNRI) / 2;
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g = (UP + DN + RI) / 3;
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b = CE;
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STORE;
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for (xs = 1; xs < src_w - 1; xs+=2) {
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// green pixel
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r = (UP + DN) / 2;
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g = CE;
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b = (LE + RI) / 2;
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STORE;
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// blue pixel
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r = (UPLE + UPRI + DNLE + DNRI) / 4;
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g = (LE + RI + UP + DN) / 4;
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b = CE;
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STORE;
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}
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// last pixel in line (green)
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r = (UP + DN) / 2;
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g = CE;
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b = LE;
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STORE;
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// every second line with GG RR GG RR ... (start at 3rd line)
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// left hand pixel (green)
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r = RI;
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g = CE;
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b = (UP + DN) / 2;
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STORE;
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for (xs = 1; xs < src_w - 1; xs+=2) {
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// red pixel
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r = CE;
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g = (LE + RI + UP + DN) / 4;
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b = (UPLE + UPRI + DNLE + DNRI) / 4;
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STORE;
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// green pixel
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r = (LE + RI) / 2;
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g = CE;
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b = (UP + DN) / 2;
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}
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// last pixel in line (red)
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r = CE;
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g = (UP + DN + LE) / 3;
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b = (UPLE + DNLE) / 2;
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STORE;
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}
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// bottom left pixel
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r = UPRI;
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g = (UP + RI) / 2;
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b = CE;
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STORE;
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// last line starting with GG BB GG ...
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for (xs = 1; xs < src_w - 1; xs+=2) {
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// green pixel
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r = UP;
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g = CE;
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b = (LE + RI) / 2;
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STORE;
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// blue pixel
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r = (UPLE + UPRI) / 2;
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g = (LE + UP + RI) / 2;
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b = CE;
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STORE;
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}
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// bottom right pixel (green)
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r = UP;
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g = CE;
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b = LE;
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STORE;
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}
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@ -0,0 +1,11 @@
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#ifndef _DEBAYER_H_
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#define _DEBAYER_H_
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void debayer_grbg16_simple (uint16_t * src, int src_w, int src_h,
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uint8_t * dst, int dst_w, int dst_h);
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void debayer_grbg16_bilinear (uint16_t * src, int src_w, int src_h,
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uint8_t * dst, int dst_w, int dst_h);
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#endif
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